阅读说明：本技术 电力转换装置 (Power conversion device ) 是由 纲分智则 松冈大树 石丸大树 佐贺彩子 于 2021-05-27 设计创作，主要内容包括：本发明提供一种在多个由相当于上下桥臂的半导体开关的构成的开关桥臂并联连接的电力转换装置中,能够抑制流过各半导体开关的电流的不平衡的技术。本发明的一个实施方式的电力转换装置包括分别将多个开关模块(410)的正极侧端子(410P)彼此、负极侧端子(410N)彼此、以及交流输出端子(410O)彼此连接的U相正极侧直流母线(41P)、U相负极侧直流母线(41N)、以及U相并联连接用母线(41O1),这些母线构成隔着绝缘层(41I1)层叠的层压构造的U相层压母线(41PNO),U相并联连接用母线与U相输出用母线(41O2)的连接部设于比多个开关模块中的最远离平滑电路的半导体开关远离平滑电路的位置。(The present invention provides a technique capable of suppressing unbalance of currents flowing through respective semiconductor switches in a power conversion device in which a plurality of switching arms each composed of a semiconductor switch corresponding to an upper arm and a lower arm are connected in parallel. A power conversion device according to one embodiment of the present invention includes a U-phase positive-side direct current bus (41P), a U-phase negative-side direct current bus (41N), and a U-phase parallel connection bus (41O1) that connect positive-side terminals (410P) of a plurality of switch modules (410), negative-side terminals (410N), and alternating current output terminals (410O), respectively, to each other, and these buses constitute a U-phase laminated bus (41PNO) having a laminated structure laminated via an insulating layer (41I1), and a connection portion between the U-phase parallel connection bus and the U-phase output bus (41O2) is provided at a position that is farther from a smoothing circuit than a semiconductor switch that is farthest from the smoothing circuit among the plurality of switch modules.)

1. A power conversion device comprising:

a smoothing circuit;

an inverter circuit including a bridge circuit configured by connecting a plurality of phases in parallel to an output circuit in which a plurality of switch arms each including a plurality of semiconductor switches and upper and lower arms connected in series are connected in series and connection points of the upper and lower arms of each of the plurality of switch arms are connected to each other, and outputting a predetermined alternating current based on the direct current input from the smoothing circuit; and

an output terminal for outputting the predetermined alternating current to the outside,

the inverter circuit includes: a positive-side direct-current bus connecting positive-side terminals of the plurality of switching arms to each other; a negative-side direct-current bus connecting negative-side terminals of the plurality of switch arms to each other; and a parallel connection bus bar connecting connection points of the upper and lower arms of each of the plurality of switching arms to each other,

the positive-side DC bus bar, the negative-side DC bus bar, and the parallel connection bus bar have a laminated structure in which the bus bars are laminated with an insulating layer interposed therebetween,

the connection portion between the parallel connection bus and the wiring up to the output terminal is provided at a position farther from the smoothing circuit than the arm farthest from the smoothing circuit among all the arms included in the plurality of switching arms.

2. The power conversion apparatus according to claim 1,

the smoothing circuit and the inverter circuit are arranged in one axial direction,

a plurality of the switching arms are arranged in the one axial direction,

the connection portion is disposed at a position farther from the smoothing circuit than the switching arm farthest from the smoothing circuit among the plurality of switching arms in the one axial direction.

3. The power conversion apparatus according to claim 2,

the plurality of switching arms are arranged such that two groups each arranged in the one axial direction are arranged in two rows in the other axial direction perpendicular to the one axial direction,

the connecting portion is disposed at a position farther from the smoothing circuit than end portions of the two groups farther from the smoothing circuit in the one axial direction, and is disposed at a substantially central position of the two groups in the other axial direction.

4. A power conversion device comprising:

a smoothing circuit;

an inverter circuit including a bridge circuit configured by connecting a plurality of phases in parallel to an output circuit in which a plurality of switch arms each including a plurality of semiconductor switches and upper and lower arms connected in series are connected in series and connection points of the upper and lower arms of each of the plurality of switch arms are connected to each other, and outputting a predetermined alternating current based on the direct current input from the smoothing circuit; and

an output terminal for outputting the predetermined alternating current to the outside,

the inverter circuit includes: a positive-side direct-current bus connecting positive-side terminals of the plurality of switching arms to each other; a negative-side direct-current bus connecting negative-side terminals of the plurality of switch arms to each other; and a parallel connection bus bar connecting connection points of the upper and lower arms of each of the plurality of switching arms to each other,

the positive-side direct-current bus bar and the negative-side direct-current bus bar have a laminated structure in which the positive-side direct-current bus bar and the negative-side direct-current bus bar are laminated with an insulating layer interposed therebetween,

the parallel connection bus is configured such that the lengths of the paths between all of the arms included in the plurality of switching arms and a junction at which all of the paths from the plurality of switching arms join each other are substantially equal to each other.

5. The power conversion apparatus according to claim 4,

the parallel connection bus bar is configured such that current densities of respective paths between all of the arms included in the plurality of switching arms and the merging portion are substantially equal to each other.

6. The power conversion apparatus according to claim 4 or 5,

the parallel connection bus bar causes paths from two switching arms included in the plurality of switching arms and arranged in a row in one axial direction to the output terminal to merge at substantially a center position of the connection points of the two switching arms in the one axial direction.

7. The power conversion apparatus according to claim 6,

a plurality of said switching legs comprises a combination of a plurality of said two switching legs,

the parallel connection bus bar is configured such that the lengths of respective paths between an intermediate junction portion where paths from the two switching arms of each of the plurality of combinations to the output terminal join and the junction portion are substantially equal.

8. The power conversion apparatus according to claim 7,

the plurality of switching arms are arranged such that two sets of the two switching arms align the position in the one axial direction and are arranged in two rows in the other axial direction perpendicular to the one axial direction,

the parallel connection bus is configured as follows: the output terminal is formed to be substantially plane-symmetrical in the one axial direction with reference to a vertical plane at a central position of the two switching arms, and to be substantially plane-symmetrical in the other axial direction with reference to a vertical plane at a central position of the two groups, and a connection portion with a wiring up to the output terminal is formed to be substantially central position between the four switching arms included in the two groups in the one axial direction and the other axial direction.

9. A power conversion device comprising:

a smoothing circuit;

an inverter circuit including a bridge circuit configured by connecting a plurality of phases in parallel to an output circuit in which a plurality of switch arms each including a plurality of semiconductor switches and upper and lower arms connected in series are connected in series and connection points of the upper and lower arms of each of the plurality of switch arms are connected to each other, and outputting a predetermined alternating current based on the direct current input from the smoothing circuit; and

an output terminal for outputting the predetermined alternating current to the outside,

the inverter circuit includes: a positive-side direct-current bus connecting positive-side terminals of the plurality of switching arms to each other; a negative-side direct-current bus connecting negative-side terminals of the plurality of switch arms to each other; and a parallel connection bus bar connecting connection points of the upper and lower arms of each of the plurality of switching arms to each other,

the positive-side direct-current bus bar and the negative-side direct-current bus bar have a laminated structure in which the positive-side direct-current bus bar and the negative-side direct-current bus bar are laminated with an insulating layer interposed therebetween,

the parallel connection bus is configured as follows: the lengths of the paths passing through the junctions between the smoothing circuits and the paths joining the paths of the switching arms are substantially equal for all the switching arms, and the current densities of the paths are substantially equal for each path.

10. The power conversion apparatus according to claim 9,

the parallel connection bus is configured as follows: the current densities of the portions of the paths having a common length are substantially equal to each other, and the current densities of the portions of the paths other than the portions having a common length are substantially equal to the current densities of the positive-side dc bus bar and the negative-side dc bus bar.

11. The power conversion apparatus according to claim 10,

the smoothing circuit and the inverter circuit are arranged in one axial direction,

a plurality of the switching arms are arranged in the one axial direction,

the parallel connection bus bar includes: a plurality of legs that are provided so as to extend in the vertical direction from the connection point of the upper and lower arms of each of the plurality of switch arms, and that have substantially the same length and substantially the same cross-sectional area; and a connecting portion that connects the plurality of leg portions to each other so as to extend in the one axial direction,

the connecting part is configured as follows: the end portion of the flat circuit which is distant from the smoothing circuit in the one axial direction is connected to a wire up to the output terminal, and the current density of each of the paths is made substantially equal to the current density of the positive-side direct-current bus bar and the negative-side direct-current bus bar.

12. The power conversion apparatus according to claim 11,

the plurality of switching arms are arranged such that two groups arranged in the one-axis direction are arranged in two rows in the other-axis direction perpendicular to the one-axis direction,

the connecting portion connects the plurality of leg portions to each other so as to extend in the one axial direction and the other axial direction.

13. A power conversion device comprising:

a smoothing circuit;

an inverter circuit including a bridge circuit configured by connecting a plurality of output circuits in parallel, each of the output circuits including a plurality of switch arms in which upper and lower arms including a plurality of semiconductor switches are connected in series, and connection points of the upper and lower arms of each of the plurality of switch arms are connected to each other, and outputting a predetermined alternating current based on the direct current input from the smoothing circuit; and

an output terminal for outputting the predetermined alternating current to the outside,

the inverter circuit includes: a positive-side direct-current bus connecting positive-side terminals of the plurality of switching arms to each other; a negative-side direct-current bus connecting negative-side terminals of the plurality of switch arms to each other; and a parallel connection bus bar connecting connection points of the upper and lower arms of each of the plurality of switching arms to each other,

the positive-side DC bus bar, the negative-side DC bus bar, and the parallel connection bus bar have a laminated structure in which the bus bars are laminated with an insulating layer interposed therebetween,

the connection portion between the parallel connection bus and the wiring up to the output terminal is provided at a position closer to the smoothing circuit than the arm closest to the smoothing circuit among all the arms included in the plurality of switching arms.

14. The power conversion apparatus according to claim 13,

the smoothing circuit and the inverter circuit are arranged in one axial direction,

a plurality of the switching arms are arranged in the one axial direction,

in the one axial direction, the connection portion is disposed at a position closer to the smoothing circuit than the switching arm closest to the smoothing circuit among the plurality of switching arms.

15. The power conversion apparatus according to claim 14,

the plurality of switching arms are arranged such that two groups each arranged in the one axial direction are arranged in two rows in the other axial direction perpendicular to the one axial direction,

the connecting portion is disposed closer to the smoothing circuit than end portions of the two groups closer to the smoothing circuit in the one axial direction.

Technical Field

The present invention relates to a power conversion device.

Background

Conventionally, in a power conversion device in which a plurality of switching arms each including a semiconductor switch corresponding to an upper arm and a lower arm are connected in parallel, a technique of equalizing currents flowing through the respective semiconductor switches is known (for example, see patent document 1).

In patent document 1, parallel connection buses in which the switching arms are arranged in the width direction and connection points between upper and lower arms of each switching arm are connected in parallel to each other, and output buses connected to the parallel connection buses are provided. The parallel connection bus bars are provided so as to extend in the longitudinal direction from the respective switch arms while occupying the width direction in which the respective switch arms are arranged. The output bus bar is provided so as to be stacked on the parallel connection bus bar via an insulating layer at the other end portion of the parallel connection bus bar on the opposite side to each switching arm in the longitudinal direction thereof and to extend in the width direction, and is connected to the parallel connection bus bar at one end portion in the width direction thereof.

Thus, in patent document 1, the current flowing through the parallel connection bus (i.e., the current merged from each switching arm or the current branched from each switching arm) and the current flowing through the output bus are opposite to each other, and the currents generated by the currents can be cancelled out. Therefore, the inductance of the power path in the width direction of the parallel connection bus when the currents of the respective switching legs merge or branch is reduced, and the imbalance of the currents flowing through the respective switching legs can be suppressed.

< Prior Art document >

< patent document >

Patent document 1: japanese unexamined patent publication No. 2017-055478

Disclosure of Invention

< problems to be solved by the present invention >

However, in patent document 1, the current of the output bus corresponds to the sum of the currents of all the switching arms, whereas the current flowing in the width direction at the other end portion of the parallel connection bus is only the sum of the current passing through one switching arm and the current of a part of the switching arms. Therefore, there is a possibility that the magnetic field generated by the output bus bar is not cancelled by the magnetic field generated by the parallel connection bus bar and remains. This causes the magnetic field to be interlinked with the current flowing through the parallel connection bus bar in the width direction, and inductance is generated in the current path in the width direction of the parallel connection bus bar, which may cause imbalance in the currents flowing through the switching arms.

In view of the above-described problems, it is an object of the present invention to provide a technique that can suppress an imbalance in currents flowing through respective semiconductor switches in a power conversion device in which a plurality of switching arms each including a semiconductor switch corresponding to an upper arm and a lower arm are connected in parallel.

< means for solving the problems >

In order to achieve the above object, according to one embodiment of the present invention, there is provided a power conversion device including:

a smoothing circuit;

an inverter circuit including a bridge circuit configured by connecting a plurality of switching arms in parallel, each of the switching arms including a plurality of semiconductor switches and having upper and lower arms connected in series, and an output circuit in which connection points of the upper and lower arms of each of the plurality of switching arms are connected to each other, the output circuit being connected in parallel to a plurality of phases, and outputting a predetermined alternating current based on the direct current input from the smoothing circuit; and

an output terminal for outputting the predetermined alternating current to the outside,

the inverter circuit includes: a positive-side direct-current bus connecting positive-side terminals of the plurality of switching arms to each other; a negative-side direct-current bus connecting negative-side terminals of the plurality of switch arms to each other; and a parallel connection bus bar connecting connection points of the upper and lower arms of each of the plurality of switching arms to each other,

the positive-side DC bus bar, the negative-side DC bus bar, and the parallel connection bus bar have a laminated structure in which the bus bars are laminated with an insulating layer interposed therebetween,

the connection portion between the parallel connection bus and the wiring to the output terminal is provided at a position farther from the smoothing circuit than the arm farthest from the smoothing circuit among all the arms included in the plurality of switching arms.

In another embodiment of the present invention, there is provided a power conversion device including:

a smoothing circuit;

an inverter circuit including a bridge circuit configured by connecting a plurality of switching arms in parallel, each of the switching arms including a plurality of semiconductor switches and having upper and lower arms connected in series, and an output circuit in which connection points of the upper and lower arms of each of the plurality of switching arms are connected to each other, the output circuit being connected in parallel to a plurality of phases, and outputting a predetermined alternating current based on the direct current input from the smoothing circuit; and

an output terminal for outputting the predetermined alternating current to the outside,

the inverter circuit includes: a positive-side direct-current bus connecting positive-side terminals of the plurality of switching arms to each other; a negative-side direct-current bus connecting negative-side terminals of the plurality of switch arms to each other; and a parallel connection bus bar connecting connection points of the upper and lower arms of each of the plurality of switching arms to each other,

the positive-side direct-current bus bar and the negative-side direct-current bus bar have a laminated structure in which the positive-side direct-current bus bar and the negative-side direct-current bus bar are laminated with an insulating layer interposed therebetween,

the parallel connection bus is configured such that the lengths of the paths between all of the arms included in the plurality of switching arms and the junction at which all of the paths from the plurality of switching arms merge are substantially equal to each other.

In another embodiment of the present invention, there is provided a power conversion apparatus including:

a smoothing circuit;

an inverter circuit including a bridge circuit configured by connecting a plurality of switching arms in parallel, each of the switching arms including a plurality of semiconductor switches and having upper and lower arms connected in series, and an output circuit in which connection points of the upper and lower arms of each of the plurality of switching arms are connected to each other, the output circuit being connected in parallel to a plurality of phases, and outputting a predetermined alternating current based on the direct current input from the smoothing circuit; and

an output terminal for outputting the predetermined alternating current to the outside,

the inverter circuit includes: a positive-side direct-current bus connecting positive-side terminals of the plurality of switching arms to each other; a negative-side direct-current bus connecting negative-side terminals of the plurality of switch arms to each other; and a parallel connection bus bar connecting connection points of the upper and lower arms of each of the plurality of switching arms to each other,

the positive-side direct-current bus bar and the negative-side direct-current bus bar have a laminated structure in which the positive-side direct-current bus bar and the negative-side direct-current bus bar are laminated with an insulating layer interposed therebetween,

the parallel connection bus is configured as follows: the lengths of the paths passing through the junctions between the smoothing circuits and the paths joining the paths of the switching arms are substantially equal, and the current densities of the paths are substantially equal throughout the paths.

In another embodiment of the present invention, there is provided a power conversion apparatus including:

a smoothing circuit;

an inverter circuit including a bridge circuit configured by connecting a plurality of switching arms in parallel, each of the switching arms including a plurality of semiconductor switches and having upper and lower arms connected in series, and an output circuit in which connection points of the upper and lower arms of each of the plurality of switching arms are connected to each other, the output circuit being connected in parallel to a plurality of phases, and outputting a predetermined alternating current based on the direct current input from the smoothing circuit; and

an output terminal for outputting the predetermined alternating current to the outside,

the inverter circuit includes: a positive-side direct-current bus connecting positive-side terminals of the plurality of switching arms to each other; a negative-side direct-current bus connecting negative-side terminals of the plurality of switch arms to each other; and a parallel connection bus bar connecting connection points of the upper and lower arms of each of the plurality of switching arms to each other,

the positive-side DC bus bar, the negative-side DC bus bar, and the parallel connection bus bar have a laminated structure in which the bus bars are laminated with an insulating layer interposed therebetween,

a connection portion between the parallel connection bus and the wiring to the output terminal is provided at a position closer to the smoothing circuit than the arm closest to the smoothing circuit among all the arms included in the plurality of switching arms.

< effects of the invention >

According to the above-described embodiment, it is possible to provide a technique that can suppress an imbalance in currents flowing through respective semiconductor switches in a power conversion device in which a plurality of switching arms each including a semiconductor switch corresponding to an upper arm and a lower arm are connected in parallel.

Drawings

Fig. 1 is a circuit diagram showing an example of a power conversion device of the first embodiment.

Fig. 2 is a configuration diagram showing an example of the power conversion device of the first embodiment.

Fig. 3 is a configuration diagram showing an example of the power conversion device of the first embodiment.

Fig. 4 is a diagram for explaining an example of the arrangement structure of the bus bars.

Fig. 5 is a diagram for explaining an example of the arrangement structure of the bus bars.

Fig. 6 is a diagram for explaining an example of the arrangement structure of the bus bars.

Fig. 7 is a circuit diagram showing an example of the power conversion device according to the second to fourth embodiments.

Fig. 8 is a configuration diagram showing an example of the power conversion device according to the second embodiment.

Fig. 9 is a configuration diagram showing an example of the power conversion device of the second embodiment.

Fig. 10 is a diagram for explaining paths of currents flowing through the respective switch modules.

Fig. 11 is a configuration diagram showing an example of a power conversion device according to a third embodiment.

Fig. 12 is a configuration diagram showing an example of the power conversion device of the third embodiment.

Fig. 13 is a configuration diagram showing an example of a power conversion device according to the fourth embodiment.

Fig. 14 is a configuration diagram showing an example of the power conversion device according to the fourth embodiment.

Detailed Description

Hereinafter, embodiments will be described with reference to the drawings.

[ first embodiment ]

First, a first embodiment will be described with reference to fig. 1 to 6.

< overview of Power conversion device >

Fig. 1 is a circuit diagram showing an example of a power conversion device 1 of the first embodiment.

The power conversion device 1 generates a predetermined three-phase alternating current power using a three-phase alternating current power input from a predetermined external power supply (e.g., a commercial power supply system), and supplies the generated three-phase alternating current power to a predetermined load device (e.g., a motor).

As shown in fig. 1, the power conversion apparatus 1 includes a rectifier circuit 10, a smoothing circuit 20, a fuse 30, and an inverter circuit 40.

The rectifier circuit 10 rectifies three-phase ac power of R phase, S phase, and T phase input from an external power supply via an input terminal 11, and outputs predetermined dc power to the smoothing circuit 20.

The input terminals 11 include an R-phase input terminal 111 to which power of the R-phase is input, an S-phase input terminal 112 to which power of the S-phase is input, and a T-phase input terminal 113 to which power of the T-phase is input.

As shown in fig. 1, the rectifier circuit 10 is a bridge-type full-wave rectifier circuit in which six diodes 12 are connected in a bridge shape, for example.

The smoothing circuit 20 smoothes the dc power output from the rectifier circuit 10 and the dc power regenerated by the inverter circuit 40.

The smoothing circuit 20 includes a positive electrode side bus bar 20P, a negative electrode side bus bar 20N, and a smoothing capacitor 21.

The positive electrode-side bus bar 20P is a flat plate-shaped member made of a material having relatively high conductivity (e.g., copper, aluminum, or the like). Hereinafter, the negative electrode side bus 20N, U phase positive electrode side dc bus 41P, U phase negative electrode side dc bus 41N, V phase positive electrode side dc bus 42P, V phase negative electrode side dc bus 42N, W phase positive electrode side dc bus 43P and the W phase negative electrode side dc bus 43N are also the same.

The positive-side bus bar 20P is connected to a positive-side output terminal of the rectifier circuit 10 and a positive-side input terminal of the inverter circuit 40, respectively.

The negative-side bus 20N is connected to a negative-side output terminal of the rectifier circuit 10 and a negative-side dc input terminal of the inverter circuit 40.

Smoothing capacitor 21 is disposed in parallel with rectifier circuit 10 and inverter circuit 40 in a power path connecting positive-side bus 20P and negative-side bus 20N. The smoothing capacitor 21 smoothes the direct current output from the rectifier circuit 10 and the inverter circuit 40 while repeating charging and discharging as appropriate.

One smoothing capacitor 21 may be provided, or a plurality of smoothing capacitors 21 may be connected in parallel (see fig. 2 and 3).

The smoothing capacitor 21 includes a positive electrode-side terminal 21P connected to the positive electrode-side bus 20P and a negative electrode-side terminal 21N connected to the negative electrode-side bus 20N.

The fuse 30 is disposed on the positive-side power path between the positive-side bus bar 20P and the positive-side dc input terminal of the inverter circuit 40. The fuse 30 is blown when an overcurrent or the like occurs, and protects the power conversion device 1 (the inverter circuit 40) from damage or the like caused by the overcurrent such as an overload or a short circuit.

The inverter circuit 40 generates three-phase ac power of U-phase, V-phase, and W-phase from the dc power supplied from the smoothing circuit 20, and outputs the ac power from the output terminal 40T to an external load device. The output terminal 40T includes a U-phase output terminal 41T for outputting the U-phase alternating current to the outside, a V-phase output terminal 42T for outputting the V-phase alternating current to the outside, and a W-phase output terminal 43T for outputting the W-phase alternating current to the outside.

The inverter circuit 40 includes a bridge circuit including a U-phase circuit 41, a V-phase circuit 42, and a W-phase circuit 43. The U-phase circuit 41, the V-phase circuit 42, and the W-phase circuit 43 (each being an example of an output circuit) are connected in parallel between the positive-side wiring and the negative-side wiring of the power conversion device 1.

The U-phase circuit 41 includes a U-phase positive-side dc bus 41P, U and a U-phase negative-side dc bus 41N, switch modules 411 to 414, and a U-phase ac bus 41O. Hereinafter, in the first embodiment, the switch modules 411 to 414 may be collectively referred to as "switch module 410", or any one of the switch modules 411 to 414 may be individually referred to as "switch module 410".

The U-phase positive-side dc bus 41P is connected to the positive-side bus 20P of the smoothing circuit 20 via the fuse 30.

The U-phase negative-side dc bus 41N is connected to the negative-side bus 20N of the smoothing circuit 20.

The switch modules 411 to 414 (an example of a switch arm) are connected in parallel between the U-phase positive-side dc bus 41P and the U-phase negative-side dc bus 41N.

The switch module 411 includes semiconductor switches 411s1, 411s2 corresponding to upper and lower arms, free wheeling diodes 411d1, 411d2, a positive electrode-side terminal 411P, a negative electrode-side terminal 411N, and an ac output terminal 411O.

The switch module 412 includes semiconductor switches 412s1, 412s2 corresponding to the upper and lower arms, free wheeling diodes 412d1, 412d2, a positive terminal 412P, a negative terminal 412N, and an ac output terminal 412O.

The switch module 413 includes semiconductor switches 413s1, 413s2 corresponding to upper and lower arms, reflux diodes 413d1, 413d2, a positive electrode-side terminal 413P, a negative electrode-side terminal 413N, and an ac output terminal 413O.

The switch module 414 includes semiconductor switches 414s1 and 414s2 corresponding to upper and lower arms, freewheeling diodes 414d1 and 414d2, a positive terminal 414P, a negative terminal 414N, and an ac output terminal 414O.

Hereinafter, in the first embodiment, the semiconductor switches 411s1, 411s2, 412s1, 412s2, 413s1, 413s2, 414s1, and 414s2 may be collectively referred to as "semiconductor switches 410 s" or individually referred to as "semiconductor switches 410 s". In the first embodiment, the constituent elements corresponding to the positive-electrode-side terminals 411P to 414P of the "switch module 410" may be referred to as "positive-electrode-side terminals 410P". In the first embodiment, the constituent elements corresponding to the negative-electrode-side terminals 411N to 414N of the "switch module 410" may be referred to as "negative-electrode-side terminals 410N". In the first embodiment, the components corresponding to the ac output terminals 411O to 414O of the "switch module 410" may be referred to as "ac output terminal 410O".

Since the switch modules 411 to 414 have the same constituent elements and are constituted by the same circuits, the switch module 411 will be described as a representative, and the description of the switch modules 412 to 414 will be omitted.

The semiconductor switches 411s1, 411s2 (an example of upper and lower arms) are arranged on a power path connecting the positive-electrode-side terminal 411P and the negative-electrode-side terminal 411N, and are connected in series with each other. The semiconductor switches 411s1, 411s2 are, for example, igbts (insulated Gate Bipolar transistors).

Semiconductor switch 411s1 corresponds to the upper arm of the switching arm, and is connected to positive electrode-side terminal 411P.

The semiconductor switch 411s2 corresponds to the lower arm of the switch arm, and is connected to the negative electrode-side terminal 411N.

The free wheeling diodes 411d1, 411d2 are connected in parallel with the respective semiconductor switches 411s1, 411s 2.

The positive electrode-side terminal 411P is connected to the U-phase positive electrode-side dc bus 41P.

The negative-electrode-side terminal 411N is connected to the U-phase negative-electrode-side dc bus 41N.

An ac output terminal 411O (an example of a connection point of upper and lower arms) is led out from a connection point (intermediate point) between the semiconductor switches 411s1 and 411s 2.

The U-phase ac bus 41O connects the ac output terminals 411O to 414O of the respective switch modules 411 to 414 to each other at one end thereof, and connects the U-phase output terminal 41T at the other end thereof. Thus, the inverter circuit 40 can output the U-phase ac power output from the switching modules 411 to 414 to the outside from the U-phase output terminal 41T.

The V-phase circuit 42 includes a V-phase positive-side dc bus 42P, V and a negative-side dc bus 42N, switch modules 421 to 424, and a V-phase ac bus 42O. Hereinafter, in the first embodiment, the switch modules 421 to 424 may be collectively referred to as "switch module 420", or any one of the switch modules 421 to 424 may be individually referred to as "switch module 420".

The V-phase positive-side dc bus 42P is connected to the positive-side bus 20P of the smoothing circuit 20 via the fuse 30.

The V-phase negative-side dc bus 42N is connected to the negative-side bus 20N of the smoothing circuit 20.

The switch modules 421 to 424 are connected in parallel between the V-phase positive-side dc bus 42P and the V-phase negative-side dc bus 42N.

The switch module 421 includes semiconductor switches 421s1 and 421s2 corresponding to upper and lower arms, reflux diodes 421d1 and 421d2, a positive terminal 421P, a negative terminal 421N, and an ac output terminal 421O.

The switch module 422 includes semiconductor switches 422s1 and 422s2 corresponding to upper and lower arms, free wheeling diodes 422d1 and 422d2, a positive electrode-side terminal 422P, a negative electrode-side terminal 422N, and an ac output terminal 422O.

The switch module 423 includes semiconductor switches 423s1 and 423s2 corresponding to upper and lower arms, freewheeling diodes 423d1 and 423d2, a positive terminal 423P, a negative terminal 423N, and an ac output terminal 423O.

The switch module 424 includes semiconductor switches 424s1, 424s2 corresponding to upper and lower arms, free wheeling diodes 424d1, 424d2, a positive terminal 424P, a negative terminal 424N, and an ac output terminal 424O.

Hereinafter, in the first embodiment, the semiconductor switches 421s1, 421s2, 422s1, 422s2, 423s1, 423s2, 424s1, and 424s2 may be collectively referred to as "semiconductor switches 420 s", or any one of them may be individually referred to as "semiconductor switches 420 s". In the first embodiment, the constituent elements corresponding to the positive electrode-side terminals 421P to 424P of the "switch module 420" may be referred to as "positive electrode-side terminals 420P". In the first embodiment, the constituent elements corresponding to the negative-electrode-side terminals 421N to 424N of the switch module 420 are sometimes referred to as "negative-electrode-side terminals 420N". In the first embodiment, the components corresponding to the ac output terminals 421O to 424O of the "switch module 420" may be referred to as "ac output terminals 420O".

Since the switch modules 421 to 424 have the same components and the same circuit configuration, the switch module 421 will be described as a representative, and the description of the switch modules 422 to 424 will be omitted.

The semiconductor switches 421s1 and 421s2 (an example of upper and lower arms) are arranged on a power path connecting the positive electrode-side terminal 421P and the negative electrode-side terminal 421N, and are connected in series with each other.

Semiconductor switch 421s1 corresponds to the upper arm of the switch arm, and is connected to positive electrode-side terminal 421P.

The semiconductor switch 421s2 corresponds to the lower arm of the switch arm, and is connected to the negative electrode-side terminal 421N.

The free wheeling diodes 421d1, 421d2 are connected in parallel with the respective semiconductor switches 421s1, 421s 2.

The positive electrode-side terminal 421P is connected to the V-phase positive electrode-side dc bus 42P.

The negative-electrode-side terminal 421N is connected to the V-phase negative-electrode-side dc bus 42N.

An ac output terminal 421O (an example of a connection point of upper and lower arms) is led out from a connection point (intermediate point) between the semiconductor switches 421s1 and 421s 2.

The V-phase ac bus 42O connects the ac output terminals 421O to 424O of the respective switch modules 421 to 424 to each other at one end thereof, and connects the V-phase output terminal 42T at the other end thereof. Thus, the inverter circuit 40 can output the V-phase ac power output from the switching modules 421 to 424 to the outside from the V-phase output terminal 42T.

The W-phase circuit 43 includes a W-phase positive-side dc bus 43P, W and a negative-side dc bus 43N, switching modules 431 to 434, and a W-phase ac bus 43O. Hereinafter, in the first embodiment, the switch modules 431 to 434 may be collectively referred to as "switch module 430", or any one of the switch modules 431 to 434 may be individually referred to as "switch module 430".

The W-phase positive-side dc bus 43P is connected to the positive-side bus 20P of the smoothing circuit 20 via the fuse 30.

The W-phase negative-side dc bus 43N is connected to the negative-side bus 20N of the smoothing circuit 20.

The switch modules 431 to 434 are connected in parallel between the W-phase positive-side dc bus 43P and the W-phase negative-side dc bus 43N.

The switch module 431 includes semiconductor switches 431s1 and 431s2 corresponding to upper and lower arms, reflux diodes 431d1 and 431d2, a positive terminal 431P, a negative terminal 431N, and an ac output terminal 431O.

The switch module 432 includes semiconductor switches 432s1 and 432s2 corresponding to upper and lower arms, free wheeling diodes 432d1 and 432d2, a positive electrode-side terminal 432P, a negative electrode-side terminal 432N, and an ac output terminal 432O.

The switch module 433 includes semiconductor switches 433s1, 433s2 corresponding to upper and lower arms, free wheeling diodes 433d1, 433d2, a positive electrode-side terminal 433P, a negative electrode-side terminal 433N, and an ac output terminal 433O.

The switch module 434 includes semiconductor switches 434s1 and 434s2 corresponding to upper and lower arms, reflux diodes 434d1 and 434d2, a positive electrode side terminal 434P, a negative electrode side terminal 434N, and an ac output terminal 434O.

Hereinafter, in the first embodiment, the semiconductor switches 431s1, 431s2, 432s1, 432s2, 433s1, 433s2, 434s1, and 434s2 may be collectively referred to as "semiconductor switches 430 s", or any one of them may be individually referred to as "semiconductor switches 430 s". In the first embodiment, the constituent elements corresponding to the positive electrode-side terminals 431P to 434P of the "switch module 430" may be referred to as "positive electrode-side terminals 430P". In the first embodiment, the constituent elements corresponding to the negative-electrode-side terminals 431N to 434N of the above-described "switch module 430" may be referred to as "negative-electrode-side terminals 430N". In the first embodiment, the components corresponding to the ac output terminals 431O to 434O of the "switch module 430" may be referred to as "ac output terminal 430O".

Since the switch modules 431 to 434 have the same constituent elements and the same circuit configuration, the switch module 431 will be described as a representative, and the description of the switch modules 432 to 434 will be omitted.

The semiconductor switches 431s1 and 431s2 (an example of upper and lower arms) are arranged on a power path connecting the positive electrode-side terminal 431P and the negative electrode-side terminal 431N, and are connected in series with each other.

Semiconductor switch 431s1 corresponds to the upper arm of the switch arm, and is connected to positive electrode-side terminal 431P.

The semiconductor switch 431s2 corresponds to the lower arm of the switch arm, and is connected to the negative electrode-side terminal 431N.

The free wheeling diodes 431d1, 431d2 are connected in parallel to the respective semiconductor switches 431s1, 431s 2.

The positive electrode-side terminal 431P is connected to the W-phase positive electrode-side dc bus 43P.

The negative electrode-side terminal 431N is connected to the W-phase negative electrode-side dc bus 43N.

An ac output terminal 431O (an example of a connection point of upper and lower arms) is led from a connection point (intermediate point) between the semiconductor switches 431s1 and 431s 2.

The W-phase ac bus 43O connects the ac output terminals 431O to 434O of the respective switch modules 431 to 434 to each other at one end thereof, and connects the W-phase output terminal 43T at the other end thereof. Thus, the inverter circuit 40 can output the W-phase alternating current output from the switching modules 431 to 434 to the outside from the W-phase output terminal 43T.

< Structure of Power conversion device >

Fig. 2 and 3 are configuration diagrams showing an example of the power conversion device 1 according to the first embodiment. Specifically, fig. 2 is a perspective view showing a state in which a part of the case 1H of the power conversion device 1 is removed, and fig. 3 is an exploded perspective view showing a state in which a part of the case 1H of the power conversion device 1 is removed, and the output terminal 40T is removed and moved upward. Fig. 4 to 6 are diagrams for explaining an example of the arrangement structure of the bus bar. Specifically, fig. 4 is an exploded perspective view schematically showing the bus bar with its constituent elements exploded, fig. 5 is a perspective view showing a completed state in which the constituent elements of the bus bar of fig. 4 are assembled, and fig. 6 is a side view schematically showing an example of the arrangement structure of the bus bar.

In fig. 4 and 5, the laminated bus bar 20PN, the U-phase laminated bus bar 41PN, the V-phase laminated bus bar 42PN, and the W-phase laminated bus bar 43PN are depicted as an integral member for convenience. In fig. 4, the positive-side bus 20P of the smoothing circuit 20, and the U-phase positive-side dc bus 41P, V-phase positive-side dc bus 42P and the W-phase positive-side dc bus 43P of the inverter circuit 40 are depicted as an integral component for convenience. Similarly, in fig. 4, the negative-side bus 20N of the smoothing circuit 20, and the U-phase negative-side dc bus 41N, V-phase negative-side dc bus 42N and the W-phase negative-side dc bus 43N of the inverter circuit 40 are depicted as an integral member for convenience. Likewise, in fig. 4, the insulating layers 20I1, 41I1, 42I1, 43I1 are depicted as integral components. Likewise, in fig. 4, the insulating layers 20I2, 41I2, 42I2, 43I2 are depicted as integral components. In fig. 4 and 5, for the sake of simplicity, only a part (4) of all smoothing capacitors 21 of the smoothing circuit 20 is shown as a representative example. Similarly, in fig. 4 and 5, for the sake of simplicity, only a part (1) of all the switch modules 410 of the U-phase circuit 41 is depicted as a representative. Similarly, in fig. 4 and 5, for the sake of simplicity, only a part (1) of the switch modules 420 included in the V-phase circuit 42 is depicted as a representative. Similarly, in fig. 4 and 5, for the sake of simplicity, only a part (1) of the switch modules 430 included in the W-phase circuit 43 is shown as a representative example. In fig. 6, for convenience, the insulating layers 20I1, 20I2, 41I1, 41I2, 42I1, 42I2, 43I1, and 43I2 are not drawn.

As shown in fig. 2 and 3, various components of the power converter 1 are housed in a case 1H having a substantially box shape having a substantially rectangular shape in all of the top view, side view, and front view. "substantially" is intended to allow for manufacturing errors and the like, and is used in the same sense hereinafter.

Hereinafter, the longitudinal direction of the housing 1H in plan view is sometimes referred to as the X-axis direction, the short-side direction of the housing 1H in plan view is sometimes referred to as the Y-axis direction, and the vertical direction is sometimes referred to as the Z-axis direction (see fig. 2 to 6).

As shown in fig. 2 and 3, the smoothing circuit 20, the fuse 30, and the inverter circuit 40 are arranged in this order from one end portion to the other end portion (i.e., in the X-axis direction) in the longitudinal direction of the inside of the housing 1H.

The output terminal 40T is disposed at the center in the longitudinal direction (X-axis direction) of the inside of the housing 1H and at the upper portion of the inside of the housing 1H. Specifically, the output terminal 40T is disposed above the smoothing circuit 20 and the fuse 30 in the case 1H.

As described above, the output terminal 40T includes the U-phase output terminal 41T, V-phase output terminal 42T and the W-phase output terminal 43T. The U-phase output terminal 41T, V and the W-phase output terminal 43T are arranged in this order from one end portion to the center portion in the short side direction (i.e., in the Y-axis direction) in the housing 1H.

In this example, the smoothing circuit 20 includes 24 smoothing capacitors 21.

Smoothing capacitor 21 has a substantially cylindrical shape, and is placed on the bottom surface of case 1H so that the axial direction thereof extends in the vertical direction. Further, a positive electrode-side terminal 21P and a negative electrode-side terminal 21N are provided on an opposite end surface (upper end surface) of the loaded surface of the smoothing capacitor 21.

Specifically, as shown in fig. 2 and 3, the smoothing capacitors 21 are arranged 4 in the X-axis direction and 6 in the Y-axis direction.

On the upper end surface of the smoothing capacitor 21, the laminated bus bar 20PN is arranged substantially parallel to the X-axis direction and the Y-axis direction.

The laminated bus bar 20PN has a substantially rectangular shape in plan view. The laminated bus bar 20PN is disposed over a range covering 24 smoothing capacitors 21 in the X-axis direction and the Y-axis direction.

As shown in fig. 4 and 5, the laminated bus bar 20PN is configured by laminating the positive electrode-side bus bar 20P and the negative electrode-side bus bar 20N with an insulating layer 20I1 interposed therebetween. Specifically, the laminated bus bar 20PN has a 4-layer laminated structure in which the negative electrode side bus bar 20N is disposed in the lowermost layer, the insulating layer 20I1 is disposed on the bus bar 20N, the positive electrode side bus bar 20P is disposed on the insulating layer 20I1, and the insulating layer 20I2 is disposed in the uppermost layer.

As shown in fig. 4 to 6, the negative-electrode-side bus bar 20N at the lowermost layer is provided with a relatively small through hole for bolt-fastening with the negative-electrode-side terminal 21N of the smoothing capacitor 21. Thereby, the negative-electrode-side terminal 21N of the smoothing capacitor 21 can be directly connected to the negative-electrode-side bus bar 20N. The negative-electrode-side bus bar 20N is provided with a relatively large through-hole for exposing the positive-electrode-side terminal 21P in a plan view. This allows the positive-side bus bar 20P located in a layer above the negative-side bus bar 20N to be connected to the positive-side terminal 21P.

As shown in fig. 4 and 5, the insulating layer 20I1 adjacent to the negative-electrode-side bus bar 20N is provided with relatively large through-holes for exposing the positive-electrode-side terminal 21P and the negative-electrode-side terminal 21N (i.e., the through-holes for fastening the negative-electrode-side bus bar 20N) of the smoothing capacitor 21 in a plan view.

As shown in fig. 4 to 6, a relatively small through hole for bolt-fastening with the positive electrode-side terminal 21P of the smoothing capacitor 21 is provided in the positive electrode-side bus bar 20P adjacent to the insulating layer 20I 1. This allows the positive electrode-side terminal 21P of the smoothing capacitor 21 to be directly connected to the positive electrode-side bus bar 20P. The positive-electrode-side bus bar 20P is provided with a relatively large through-hole for exposing the negative-electrode-side terminal 21N of the smoothing capacitor 21 (i.e., the through-hole for fastening the negative-electrode-side bus bar 20N) in a plan view. Thereby, can make contact with the through-hole for fastening the negative electrode bus bar 20N located at a layer lower than the positive electrode bus bar 20P.

As shown in fig. 4 and 5, the uppermost insulating layer 20I2 is provided with relatively large through-holes for exposing the positive-electrode-side terminal 21P (i.e., the through-hole for fastening the positive-electrode-side bus bar 20P) and the negative-electrode-side terminal 21N (i.e., the through-hole for fastening the negative-electrode-side bus bar 20N) of the smoothing capacitor 21 in a plan view.

The positive electrode-side bus bar 20P and the negative electrode-side bus bar 20N of the laminated bus bar 20PN have, for example, substantially the same thickness. Thus, the current densities of the positive-side bus bar 20P and the negative-side bus bar 20N are substantially equal.

The laminated bus bar 20PN may be disposed in the case 1H so that the overlapping area of the positive-side bus bar 20P and the negative-side bus bar 20N is relatively large (preferably maximized). The thickness of the insulating layer 20I1 is set so that the distance between the positive-side bus bar 20P and the negative-side bus bar 20N is relatively small while the insulation properties of the laminated bus bar 20PN are ensured. This allows the current paths flowing in the opposite directions to be spatially close to each other. This can cancel at least a part of the magnetic field generated by the current of the positive-side bus bar 20P and the magnetic field generated by the current of the negative-side bus bar 20N, thereby reducing the inductance of the positive-side bus bar 20P and the negative-side bus bar 20N. As described above, when the current densities are substantially equal, the magnitudes of the magnetic fields generated by both the current of the positive-side bus bar 20P and the current of the negative-side bus bar 20N are substantially equal, and the generated magnetic fields can be substantially cancelled. Therefore, the inductance of the positive-side bus bar 20P and the negative-side bus bar 20N can be further suppressed. This can suppress the surge voltage of the power conversion device 1 with a decrease in the inductance of the positive-side bus bar 20P and the negative-side bus bar 20N.

As described above, the inverter circuit 40 includes a bridge circuit including the U-phase circuit 41, the V-phase circuit 42, and the W-phase circuit 43.

As shown in fig. 2 and 3, the U-phase circuit 41, the V-phase circuit 42, and the W-phase circuit 43 are arranged in the Y-axis direction in this order from the Y-axis negative end toward the Y-axis positive end.

The U-phase circuit 41 includes 4 switch modules 410 (i.e., corresponding to the switch modules 411 to 414).

The 4 switch modules 410 are arranged in two groups of two in the X-axis direction and two in the Y-axis direction. The 4 switch modules 410 are disposed on other components (for example, a control circuit of the power conversion device 1, a drive circuit of the semiconductor switches 410s, 420s, and 430s, a cooling mechanism of the inverter circuit 40, and the like) placed on the bottom surface of the casing 1H. Thereby, the difference from the upper end position of the smoothing capacitor 21 having a relatively large size in the Z-axis direction can be made relatively small. This allows the Z-axis direction positions of the positive-side bus bar 20P and the negative-side bus bar 20N to be relatively close to the Z-axis direction positions of the U-phase positive-side direct-current bus bar 41P and the U-phase negative-side direct-current bus bar 41N.

As shown in fig. 4 and 5, the switch module 410 has a box shape, and a fastening notch and a bolt support surface are provided at a corner portion in a plan view.

The switch module 410 is disposed so that the longitudinal direction in plan view is along the substantially X-axis direction. In the switch module 410, the ac output terminal 410O, the negative electrode-side terminal 410N, and the positive electrode-side terminal 410P are arranged in this order in the vicinity of the smoothing circuit 20 (smoothing capacitor 21) along the longitudinal direction (i.e., the X-axis direction).

In the U-phase circuit 41, a switching arm of a different type from the type in which a series-connected body of two semiconductor switches 410s such as the switching module 410 is housed in a case in advance can be applied. Hereinafter, the switching module 420 of the V-phase circuit 42 and the switching module 430 of the W-phase circuit 43 may be the same, and may be the same as those of the second to fourth embodiments described later.

At the upper end of the switch module 410, the U-phase laminated bus bar 41PN is disposed substantially parallel to the X-axis direction and the Y-axis direction. Specifically, the U-phase lamination bus 41PN is integrally connected to a V-phase lamination bus 42PN and a W-phase lamination bus 43PN, which will be described later. That is, at the upper end portion of the switch module 410, the laminated bus bar 40PN including the U-phase laminated bus bar 41PN, the V-phase laminated bus bar 42PN, and the W-phase laminated bus bar 43PN is arranged substantially parallel to the X-axis direction and the Y-axis direction. Hereinafter, the same applies to the second to fourth embodiments described later.

The U-phase laminated bus bar 41PN is disposed so as to cover the range of 4 switch modules 410 in the X-axis direction and the Y-axis direction.

As shown in fig. 4 and 5, the U-phase laminated bus bar 41PN is configured by laminating a U-phase positive-side dc bus bar 41P and a U-phase negative-side dc bus bar 41N with an insulating layer 41I1 interposed therebetween. Specifically, the U-phase laminated bus bar 41PN has a 4-layer laminated structure in which the U-phase negative-side dc bus bar 41N is disposed on the lowermost layer, the insulating layer 41I1 is disposed on the U-phase negative-side dc bus bar 41N, the U-phase positive-side dc bus bar 41P is disposed on the insulating layer 41I1, and the insulating layer 41I2 is disposed on the uppermost layer.

The U-phase positive-side dc bus 41P is integrally connected to a V-phase positive-side dc bus 42P and a W-phase positive-side dc bus 43P (described later) (for example, as an integral plate-shaped member). That is, as shown in fig. 6, the laminated bus 40PN includes a positive-side dc bus 40P configured to include a U-phase positive-side dc bus 41P, V phase positive-side dc bus 42P and a W-phase positive-side dc bus 43P. Hereinafter, the same applies to the second to fourth embodiments described later.

The U-phase negative-side dc bus 41N is integrally connected to a V-phase negative-side dc bus 42N and a W-phase negative-side dc bus 43N (for example, formed as an integral plate-like member). That is, as shown in fig. 6, the laminated bus bar 40PN includes a negative-side dc bus bar 40N configured to include a U-phase negative-side dc bus bar 41N, V-phase negative-side dc bus bar 42N and a W-phase negative-side dc bus bar 43N. Hereinafter, the same applies to the second to fourth embodiments described later.

The insulating layer 41I1 may be formed so as to be integrally connected to an insulating layer 42I1 and an insulating layer 43I1 (which will be described later) (for example, as an integral plate-like member). Similarly, the insulating layer 42I2 may be formed so as to be integrally connected to the insulating layer 42I2 and the insulating layer 43I2 (for example, as an integral plate-like member). Hereinafter, the same applies to the second to fourth embodiments described later.

As shown in fig. 4 to 6, the U-phase negative-side dc bus bar 41N at the lowermost layer is provided with a relatively small through hole for bolt-fastening with the negative-side terminal 410N of the switch module 410. This allows the negative-electrode-side terminal 410N of the switch module 410 to be directly connected to the U-phase negative-electrode-side dc bus 41N. The U-phase negative-side dc bus bar 41N is provided with a relatively large substantially rectangular through hole for exposing the positive-side terminal 410P in a plan view. This allows the U-phase positive-side dc bus 41P located at a higher level than the U-phase negative-side dc bus 41N to be connected to the positive-side terminal 410P. Further, the U-phase negative electrode-side dc bus bar 41N is provided with a relatively large substantially rectangular through hole for exposing the ac output terminal 410O in a plan view. This allows the U-phase ac bus 41O located above the U-phase negative-side dc bus 41N to be connected to the ac output terminal 410O.

As shown in fig. 4 and 5, a relatively large substantially rectangular through hole corresponding to the switch module 410 is provided in the insulating layer 41I1 adjacent to the U-phase negative-electrode-side dc bus bar 41N. Thus, the positive-electrode-side terminal 410P, the negative-electrode-side terminal 410N (that is, the through-hole for fastening the U-phase negative-electrode-side dc bus bar 41N), and the ac output terminal 410O can be exposed in a plan view.

As shown in fig. 4 to 6, a relatively small through-hole for bolting to the positive electrode-side terminal 410P of the switch module 410 is provided in the U-phase positive electrode-side direct current bus bar 41P adjacent to the insulating layer 41I 1. This allows the positive electrode-side terminal 410P of the switch module 410 to be directly connected to the U-phase positive electrode-side dc bus bar 41P. The U-phase positive-electrode-side dc bus 41P is provided with a relatively large through hole for exposing the negative-electrode-side terminal 410N (i.e., the through hole for fastening the U-phase negative-electrode-side dc bus 41N) and the ac output terminal 410O of the switch module 410 in a plan view. Thereby, can reach the through hole for fastening the U-phase negative-side dc bus bar 41N, which is positioned at a lower level than the U-phase positive-side dc bus bar 41P, and the ac output terminal 410O.

As shown in fig. 4 and 5, the insulating layer 41I2 on the uppermost layer is provided with a relatively large rectangular through hole corresponding to the switch module 410. Thus, the positive-electrode-side terminal 410P (i.e., the through-hole for fastening the U-phase positive-electrode-side direct-current bus bar 41P), the negative-electrode-side terminal 410N (i.e., the through-hole for fastening the U-phase negative-electrode-side direct-current bus bar 41N), and the ac output terminal 410O of the switch module 410 can be exposed in a plan view.

The U-phase positive-side dc bus 41P and the U-phase negative-side dc bus 41N of the U-phase laminated bus 41PN have, for example, substantially the same thickness. Thus, the current densities of the U-phase positive-electrode-side dc bus 41P and the U-phase negative-electrode-side dc bus 41N are substantially equal.

As shown in fig. 2 to 6, the U-phase ac bus 41O connects the ac output terminal 410O of the switch module 410 and the U-phase output terminal 41T. The U-phase ac bus 41O includes a U-phase parallel connection bus 41O1 and a U-phase output bus 41O 2.

The U parallel connection bus 41O1 is a component for connecting the ac output terminals 410O of the 4 switch modules 410 in parallel in the entire configuration of the U ac bus 41O. Specifically, the U-phase parallel connection bus 41O1 is a component for merging power paths from the ac output terminals 410O of the 4 switching modules 410 to the U-phase output terminal 41T in the entire configuration of the U-phase ac bus 41O.

As shown in fig. 2 and 3, the U-parallel connection bus bar 41O1 is configured to be plane-symmetrical with respect to a vertical plane with respect to the X axis at a central position between the two switch modules 410 aligned in the X axis direction. The U-parallel connection bus bar 41O1 is configured to be plane-symmetrical with respect to a Y-axis vertical plane at a central position between the two rows of switch modules 410 arranged in the Y-axis direction. The U-phase parallel connection bus 41O1 is connected to the U-phase output bus 41O2 at a portion corresponding to the center of the ac output terminals 410O of the 4 switch modules 410 in the X-axis direction and the Y-axis direction. This makes it possible to make the path lengths from the ac output terminals 410O to the U-phase output terminal 41T of the 4 switching modules 410 substantially equal to each other up to the point of confluence. Further, the current densities of the respective paths from the ac output terminals 410O of the 4 switching modules 410 to the U-phase output terminal 41T can be made substantially equal. Therefore, the inductances of the power paths between the 4 switch modules 410 and the U-phase output terminal 41T can be made substantially equal.

Specifically, the U-parallel connection bus bar 41O1 includes two leg portions 41O1a and a connection portion 41O1 b.

The two leg portions 41O1a have flat plate shapes that are substantially parallel in the X-axis direction and the Z-axis direction, respectively. The two leg portions 41O1a are connected to the ac output terminals 410O of the two switch modules 410 arranged in two rows in the Y axis direction and arranged in the X axis direction, respectively. The two leg portions 41O1a are configured to be plane-symmetrical with respect to a vertical plane with respect to the X-axis direction at substantially the center position between the ac output terminals 410O of the two switch modules 410 arranged in the X-axis direction. Specifically, the leg portion 41O1a includes two support surface portions, two lower leg portions, a middle leg portion, and an upper leg portion. The two support surface portions have a substantially rectangular shape in plan view, are placed on the ac output terminals 410O of the two switch modules 410 aligned in the X-axis direction, and have fastening holes for bolt fastening with the ac output terminals 410O. Two lower leg portions are provided so as to extend upward from each of the two support surface portions. The middle leg connects the two lower legs to each other in such a manner as to extend in the X-axis direction. The upper leg portion is provided so as to extend from the upper end of the middle leg portion toward the center portion in the X-axis direction. Thus, the leg portion 41O1a can join the paths from the ac output terminals 410O of the two switch modules 410 at substantially the same distance. The leg 41O1a can make the cross-sectional areas of the paths from the ac output terminals 410O of the two switch modules 410 substantially the same, thereby making the current densities substantially the same. The two leg portions 41O1a are configured to be plane-symmetrical with respect to a vertical plane corresponding to the Y-axis direction at a substantially central position between the ac output terminals 410O of the two switch modules 410 arranged in the Y-axis direction. Thus, the two leg portions 41O1a can make the paths from the two switch modules 410 to the point of confluence substantially the same distance.

The connection portion 41O1b has a flat plate shape substantially parallel to the X-axis direction and the Y-axis direction, and is connected to the two leg portions 41O1a arranged in the Y-axis direction. Specifically, the connecting portion 41O1b has a substantially rectangular shape in plan view, and connects the upper legs of the two legs 41O1a to each other so as to extend in the Y-axis direction. The connection unit 41O1b is configured to be plane-symmetrical with respect to a vertical plane with respect to the Y axis at a substantially central position between the two leg portions 41O1a in the Y axis direction, that is, at a substantially central position between the ac output terminals 410O of the two (two) rows of switch modules 410 aligned in the Y axis direction. The connection portion 41O1b is located at a substantially central position between the two leg portions 41O1a in the Y axis direction and the U-phase output bus bar 41O 2. Thus, the U parallel connection bus bar 41O1 can make the lengths of all the paths substantially equal while merging the paths from the four switch modules 410 so that two paths are equal in length, and can make the current densities of the respective paths the same.

The U-phase output bus bar 41O2 is provided so as to extend from the center portion in the Y-axis direction of the connection portion 41O1b of the U-phase parallel connection bus bar 41O1 in the negative X-axis direction in plan view, and is connected to the U-phase output terminal 41T.

The V-phase circuit 42 includes 4 switching modules 420 as well as the U-phase circuit 41.

Since the arrangement configuration of the 4 switch modules 420 is the same as that of the 4 switch modules 410 of the U-phase circuit 41, the description thereof is omitted.

As shown in fig. 4 and 5, the switch module 420 has the same external shape as the switch module 410.

The switch module 420 is disposed such that the longitudinal direction in plan view is along the substantially X-axis direction. In the switch module 420, an ac output terminal 420O, a negative electrode-side terminal 420N, and a positive electrode-side terminal 420P are arranged in this order in the longitudinal direction (i.e., the X-axis direction) in proximity to the smoothing circuit 20 (smoothing capacitor 21).

At the upper end of the switch module 420, the V-phase laminated bus bar 42PN is disposed substantially parallel to the X-axis direction and the Y-axis direction.

The V-phase laminated bus bar 42PN is disposed over a range covering 4 switch modules 420 in the X-axis direction and the Y-axis direction.

As shown in fig. 4 and 5, the V-phase laminated bus 42PN is configured by laminating a V-phase positive-side dc bus 42P and a V-phase negative-side dc bus 42N via an insulating layer 42I 1. Specifically, the V-phase laminated bus bar 42PN has a 4-layer laminated structure in which the V-phase negative-side dc bus bar 42N is disposed in the lowermost layer, the insulating layer 42I1 is disposed on the V-phase negative-side dc bus bar 42N, the V-phase positive-side dc bus bar 42P is disposed on the insulating layer 42I1, and the insulating layer 42I2 is disposed in the uppermost layer.

As described above, the V-phase positive-side dc bus 42P is integrally connected to the U-phase positive-side dc bus 41P and the W-phase positive-side dc bus 43P, which will be described later.

As described above, the V-phase negative-electrode dc bus 42N is integrally connected to the U-phase negative-electrode dc bus 41N and the W-phase negative-electrode dc bus 43N, which will be described later.

As described above, the insulating layer 42I1 can be integrally connected to the insulating layer 41I1 and the insulating layer 43I1 described later. Similarly, as described above, the insulating layer 42I2 may be integrally connected to the insulating layer 41I2 and the insulating layer 43I2 described later.

The detailed configuration of the V-phase laminated bus 42PN is the same as that of the U-phase laminated bus 41PN, and therefore, the description thereof is omitted.

As shown in fig. 2 to 6, the V-phase ac bus 42O connects the ac output terminal 420O of the switch module 420 and the V-phase output terminal 42T. The V-phase ac bus 42O includes a V-phase parallel connection bus 42O1 and a V-phase output bus 42O 2.

Since the arrangement and structure of the V-phase ac bus 42O are the same as those of the U-phase ac bus 41O, the description thereof is omitted.

The W-phase circuit 43 includes 4 switching modules 430, similarly to the U-phase circuit 41.

Since the arrangement configuration of the 4 switch modules 430 is the same as that of the 4 switch modules 410 of the U-phase circuit 41, the description thereof is omitted.

As shown in fig. 4 and 5, the switch module 430 has the same external shape as the switch module 410.

The switch module 430 is disposed such that the longitudinal direction in plan view is along the substantially X-axis direction. In the switch module 430, the ac output terminal 430O, the negative electrode-side terminal 430N, and the positive electrode-side terminal 430P are arranged in this order in the vicinity of the smoothing circuit 20 (smoothing capacitor 21) along the longitudinal direction (i.e., the X-axis direction).

At the upper end of the switch module 430, the W-phase laminated bus bar 43PN is disposed substantially parallel to the X-axis direction and the Y-axis direction.

The W-phase laminated bus bar 43PN is disposed over a range covering 4 switch modules 430 in the X-axis direction and the Y-axis direction.

As shown in fig. 4 and 5, the W-phase laminated bus bar 43PN is configured by laminating a W-phase positive-side dc bus bar 43P and a W-phase negative-side dc bus bar 43N via an insulating layer 43I 1. Specifically, the W-phase laminated busbar 43PN has a 4-layer laminated structure in which the W-phase negative-side dc busbar 43N is disposed on the lowermost layer, the insulating layer 43I1 is disposed on the W-phase negative-side dc busbar 43N, the W-phase positive-side dc busbar 43P is disposed on the insulating layer 43I1, and the insulating layer 43I2 is disposed on the uppermost layer.

As described above, the W-phase positive-side dc bus 43P is integrally connected to the U-phase positive-side dc bus 41P and the V-phase positive-side dc bus 42P.

As described above, the W-phase negative-electrode dc bus 43N is integrally connected to the U-phase negative-electrode dc bus 41N and the V-phase negative-electrode dc bus 42N.

As described above, the insulating layer 43I1 can be formed so as to be integrally connected to the insulating layer 41I1 and the insulating layer 42I 1. Similarly, as described above, the insulating layer 43I2 may be integrally connected to the insulating layer 41I2 and the insulating layer 42I 2.

The detailed configuration of the W-phase laminated bus bar 43PN is the same as that of the U-phase laminated bus bar 41PN, and therefore, the description thereof is omitted.

As shown in fig. 2 to 6, the W-phase ac bus bar 43O connects the ac output terminal 430O of the switching module 430 and the W-phase output terminal 43T. The W-phase ac bus 43O includes a W-phase parallel connection bus 43O1 and a W-phase output bus 43O 2.

The arrangement and structure of the W ac bus 43O are the same as those of the U ac bus 41O, and therefore, the description thereof is omitted.

The laminated bus bar 40PN can be disposed in the case 1H so that the overlapping area of the positive-side dc bus bar 40P and the negative-side dc bus bar 40N is relatively large (preferably maximized). The thickness of the insulating layers 41I1, 42I1, and 43I1 can be set so that the distance between the positive-side dc bus 40P and the negative-side dc bus 40N is relatively small while the insulation properties of the laminated bus 40PN are ensured. This allows current paths flowing in the opposite direction to be spatially close to each other. Therefore, at least a part of the magnetic field generated by the current of the positive-side dc bus 40P and the magnetic field generated by the current of the negative-side dc bus 40N can be cancelled. This is because, for example, when the U-phase current flows through the positive-side dc bus 40P, the V-phase and W-phase currents flow through the negative-side dc bus 40N. This can reduce the inductance of the positive-side dc bus 40P and the negative-side dc bus 40N. As described above, when the current densities are substantially equal, the magnitudes of the magnetic fields generated by both the current of the positive-side dc bus 40P and the current of the negative-side dc bus 40N are substantially equal, and the generated magnetic fields can be substantially cancelled. Therefore, the inductance of the positive-side dc bus 40P and the negative-side dc bus 40N can be further suppressed. This can suppress the surge voltage of the power conversion device 1 with a decrease in the inductance of the positive-side dc bus 40P and the negative-side dc bus 40N.

In this way, in the first embodiment, the positive-side bus bar 20P and the negative-side bus bar 20N of the smoothing circuit 20 have a laminated structure laminated with the insulating layer 20I1 interposed therebetween. Similarly, the positive-side dc bus bar 40P and the negative-side dc bus bar 40N of the inverter circuit 40 have a laminated structure laminated via insulating layers 41I1, 42I1, and 43I 1. This reduces the inductance of the dc portion in the power path of one cycle between the smoothing circuit 20 and the output terminal 40T, and thus the inductance can be made very small. This can suppress the surge voltage caused by turning ON/OFF the semiconductor switches 410s, 420s, and 430s of the power conversion device 1.

In the first embodiment, the U-phase parallel connection bus 41O1 is configured such that the lengths of the power paths from the ac output terminals 410O of the 4 switch modules 410 to the U-phase output terminal 41T until the merged power paths are substantially equal. Specifically, the U-phase parallel connection bus 41O1 is configured such that the lengths of the power paths between (the ac output terminals 410O of) the 4 switch modules 410 and the connection portions of the U-phase output bus 41O2 are substantially equal to each other. This makes it possible to make relatively small the difference in inductance of the power paths between the ac output terminal 410O and the U-phase output terminal 41T of the 4 switching modules 410. This makes it possible to make relatively small the difference in inductance between the power paths in one cycle of 4 switching modules 410 passing between the smoothing circuit 20 and the U-phase output terminal 41T. The U-phase parallel connection bus 41O1 is configured such that the current density of each power path from the ac output terminal 410O of each of the 4 switch modules 410 to the U-phase output terminal 41T until the current merges is substantially equal. This makes it possible to make all the inductances of the power paths between the ac output terminal 410O and the U-phase output terminal 41T of the 4 switching modules 410 substantially equal. This makes it possible to make the inductances of the power paths in one cycle through the 4 switching modules 410 between the smoothing circuit 20 and the U-phase output terminal 41T substantially equal. Similarly, the V-parallel connection bus 42O1 is configured such that the lengths of the power paths from the ac output terminal 420O of each of the 4 switch modules 420 to the V-phase output terminal 42T until the power paths merge are substantially equal. This makes it possible to make relatively small the difference in inductance between the ac output terminal 420O and the V-phase output terminal 42T of the 4 switching modules 420. This makes it possible to make the difference in inductance between the power paths in one cycle of 4 switching modules 420 passing between the smoothing circuit 20 and the V-phase output terminal 42T relatively small. The V-parallel connection bus 42O1 is configured such that the current density of each power path from the ac output terminal 420O of each of the 4 switch modules 420 to the V-phase output terminal 42T until the point of merging is substantially equal. This makes it possible to make all the inductances of the power paths between the ac output terminal 420O and the V-phase output terminal 42T of the 4 switching modules 420 substantially equal. This makes it possible to make the inductances of the power paths passing through the 4 switching modules 420 between the smoothing circuit 20 and the V-phase output terminal 42T in one cycle substantially equal. Similarly, the W parallel connection bus bar 43O1 is configured such that the lengths of the power paths from the ac output terminals 430O of the 4 switch modules 430 to the W phase output terminal 43T until the point of merging are substantially equal. This makes it possible to make relatively small the difference in inductance between the ac output terminal 430O and the W-phase output terminal 43T of the 4 switching modules 430. Therefore, the difference in the inductance of each of the power paths for one cycle passing through the 4 switching modules 430 between the smoothing circuit 20 and the W-phase output terminal 43T can be made relatively small. The W parallel connection bus bar 43O1 is configured such that the current density of the power path from the ac output terminal 430O of each of the 4 switch modules 430 to the W phase output terminal 43T to the point of merging is substantially equal. This makes it possible to make all the inductances of the power paths between the ac output terminal 430O and the W-phase output terminal 43T of the 4 switching modules 430 substantially equal. This makes it possible to make the inductances of the power paths in one cycle through the 4 switching modules 430 between the smoothing circuit 20 and the W-phase output terminal 43T substantially equal. As described above, this is because the inductance of the direct current portion in the power path of one cycle between the smoothing circuit 20 and the output terminal 40T is very small, and the inductance of the alternating current portion is dominant. This can suppress imbalance in the currents of the 4 switch modules 410, the 4 switch modules 420, and the 4 switch modules 430, and can make the currents uniform.

In the first embodiment, the number of the switch modules 410 connected in parallel may be any number as long as the lengths of the power paths from all the paths from the ac output terminal 410O of each switch module 410 to the U-phase output terminal 41T to the merged power path are substantially equal. That is, the number of the switch modules 410 connected in parallel may be 2, 3, or 5 or more. For example, when the number of the switch modules 410 connected in parallel is two, the U-phase parallel connection bus 41O1 may be configured to be composed of only the leg portion 41O1a and to be connected to the U-phase output bus 41O2 at a substantially central position (midpoint) in the X-axis direction of the upper end of the leg portion 41O1 a. The number of the switch modules 420 and 430 may be the same. In the first embodiment, the plurality of switch modules 410 may be arranged arbitrarily as long as the lengths of all paths from the ac output terminal 410O of each switch module 410 to the U-phase output terminal 41T to the merged power path are substantially equal. For example, the plurality of switch modules 410 may be arranged in the X-axis direction by 3 or more. For example, the plurality of switch modules 410 may be arranged in a row in the X-axis direction, or may be arranged in a row number of 3 or more rows in the Y-axis direction. For example, the number of arrays in the X-axis direction and the Y-axis direction is preferably a power of 2. As described above, the lengths of all the paths and the current densities of the respective paths can be made substantially the same while the paths from the ac output terminals 410O of the plurality of switch modules 410 are merged so that the lengths of the paths are equal to each other. The switch modules 420 and 430 may have the same configuration. In the first embodiment, the configuration of the U-phase parallel connection bus 41O1 may be any configuration as long as the lengths of all paths from the ac output terminal 410O of each switch module 410 to the U-phase output terminal 41T to the merged power path are substantially equal. For example, the U-phase parallel connection bus 41O1 may not have the above-described planar symmetry structure as long as the lengths of the power paths from all the paths from the ac output terminals 410O of the four switch modules 410 to the U-phase output terminal 41T to the junction are substantially equal. Specifically, the two leg portions 41O1a of the U-parallel connecting bus bar 41O1 may be formed in substantially the same shape that is separated from each other in the Y-axis direction, instead of being formed in a plane-symmetric shape with respect to a vertical plane with respect to the Y-axis direction. The V parallel connection bus 42O1 and the W parallel connection bus 43O1 may have the same configuration.

[ second embodiment ]

Next, a second embodiment will be described with reference to fig. 7 to 10. Hereinafter, the description will be given mainly on the portions different from the power conversion device 1 of the first embodiment, and the description of the same or corresponding contents as or to the first embodiment may be simplified or omitted.

< overview of Power conversion device >

Fig. 7 is a circuit diagram showing an example of the power conversion device 1 of the second embodiment.

As shown in fig. 7, the power conversion apparatus 1 includes a rectifier circuit 10, a smoothing circuit 20, a fuse 30, and an inverter circuit 40, as in the case of the first embodiment.

The inverter circuit 40 includes a bridge circuit including a U-phase circuit 41, a V-phase circuit 42, and a W-phase circuit 43, as in the case of the first embodiment.

The U-phase circuit 41 includes a U-phase positive-side dc bus 41P, U-phase negative-side dc bus 41N, switch modules 411 to 414, and a U-phase ac bus 41O, as in the first embodiment. In addition, unlike the case of the first embodiment, the U-phase circuit 41 further includes switch modules 415 and 416. Hereinafter, in the second embodiment, and the third and fourth embodiments described below, the switch modules 411 to 416 may be collectively referred to as "switch module 410", or any one of the switch modules 411 to 416 may be individually referred to as "switch module 410". That is, unlike the case of the first embodiment, the U-phase circuit 41 includes 6 switching modules 410.

The switch modules 411 to 416 (an example of a switch arm) are connected in parallel between the U-phase positive-side dc bus 41P and the U-phase negative-side dc bus 41N.

The switch module 415 includes semiconductor switches 415s1, 415s2 corresponding to upper and lower arms, free wheeling diodes 415d1, 415d2, a positive terminal 415P, a negative terminal 415N, and an ac output terminal 415O.

The switch module 416 includes semiconductor switches 416s1, 416s2 corresponding to upper and lower arms, freewheeling diodes 416d1, 416d2, a positive terminal 416P, a negative terminal 416N, and an ac output terminal 416O.

Hereinafter, in the second embodiment and the third and fourth embodiments to be described later, the semiconductor switches 411s1, 411s2, 412s1, 412s2, 413s1, 413s2, 414s1, 414s2, 415s1, 415s2, 416s1, and 416s2 may be collectively referred to as "semiconductor switches 410 s", or any one of them may be individually referred to as "semiconductor switches 410 s". In the second embodiment, and the third and fourth embodiments to be described later, the constituent elements corresponding to the positive-electrode-side terminals 411P to 416P of the "switch module 410" may be referred to as "positive-electrode-side terminals 410P". In the second embodiment, and the third and fourth embodiments to be described later, the constituent elements corresponding to the negative-electrode-side terminals 411N to 416N of the "switch module 410" may be referred to as "negative-electrode-side terminals 410N". In the second embodiment, and the third and fourth embodiments described below, the components corresponding to the ac output terminals 411O to 416O of the "switch module 410" may be referred to as "ac output terminal 410O".

The switch modules 411 to 416 have the same constituent elements and are formed by the same circuit.

The U-phase ac bus 41O is connected at one end thereof to the ac output terminals 411O to 416O of the switch modules 411 to 416, respectively, and is connected at the other end thereof to the U-phase output terminal 41T. Thus, the inverter circuit 40 can output the U-phase ac power output from the switching modules 411 to 416 to the outside from the U-phase output terminal 41T.

The V-phase circuit 42 includes a V-phase positive-side dc bus 42P, V-phase negative-side dc bus 42N, switching modules 421 to 424, and a V-phase ac bus 42O, as in the first embodiment. In addition, unlike the case of the first embodiment, the V-phase circuit 42 further includes switch modules 425 and 426. Hereinafter, in the second embodiment, and the third and fourth embodiments described below, the switch modules 421 to 426 may be collectively referred to as "switch module 420", or any one of the switch modules 421 to 426 may be individually referred to as "switch module 420". That is, unlike the case of the first embodiment, the V-phase circuit 42 includes 6 switching modules 420.

The switch modules 421 to 426 are connected in parallel between the V-phase positive-side dc bus 42P and the V-phase negative-side dc bus 42N.

The switch module 425 includes semiconductor switches 425s1 and 425s2 corresponding to upper and lower arms, free wheeling diodes 425d1 and 425d2, a positive electrode-side terminal 425P, a negative electrode-side terminal 425N, and an ac output terminal 425O.

The switch module 426 includes semiconductor switches 426s1 and 426s2 corresponding to upper and lower arms, freewheeling diodes 426d1 and 426d2, a positive terminal 426P, a negative terminal 426N, and an ac output terminal 426O.

Hereinafter, in the second embodiment and the third and fourth embodiments to be described later, the semiconductor switches 421s1, 421s2, 422s1, 422s2, 423s1, 423s2, 424s1, 424s2, 425s1, 425s2, 426s1, and 426s2 may be collectively referred to as "semiconductor switches 420 s", or any one of them may be individually referred to as "semiconductor switches 420 s". In the second embodiment, and the third and fourth embodiments to be described later, the constituent elements corresponding to the positive electrode-side terminals 421P to 426P of the "switch module 420" may be referred to as "positive electrode-side terminals 420P". In the second embodiment, and the third and fourth embodiments to be described later, the constituent elements corresponding to the negative-electrode-side terminals 421N to 426N of the "switch module 420" may be referred to as "negative-electrode-side terminals 420N". In the second embodiment, and the third and fourth embodiments described below, the constituent elements corresponding to the ac output terminals 421O to 426O of the "switch module 420" may be referred to as "ac output terminals 420O".

The switch modules 421 to 426 have the same constituent elements and are formed of the same circuit.

The V-phase ac bus 42O has ac output terminals 421O to 426O of the switch modules 421 to 426 connected to each other at one end thereof, and is connected to the V-phase output terminal 42T at the other end thereof. Thus, the inverter circuit 40 can output the V-phase ac power output from the switching modules 421 to 426 to the outside from the V-phase output terminal 42T.

The W-phase circuit 43 includes a W-phase positive-side dc bus 43P, W-phase negative-side dc bus 43N, switch modules 431 to 434, and a W-phase ac bus 43O, as in the first embodiment. In addition, unlike the first embodiment, the W-phase circuit 43 further includes switch modules 435 and 436. Hereinafter, in the second embodiment, and the third and fourth embodiments described below, the switch modules 431 to 436 may be collectively referred to as the "switch module 430", or any one of the switch modules 431 to 436 may be individually referred to as the "switch module 430". That is, unlike the case of the first embodiment, the W-phase circuit 43 includes 6 switching modules 430.

The switch modules 431 to 436 are connected in parallel between the W-phase positive-side dc bus 43P and the W-phase negative-side dc bus 43N.

The switch module 435 includes semiconductor switches 435s1, 435s2 corresponding to upper and lower arms, reflux diodes 435d1, 435d2, a positive electrode-side terminal 435P, a negative electrode-side terminal 435N, and an ac output terminal 435O.

The switch module 436 includes semiconductor switches 436s1, 436s2 corresponding to upper and lower arms, free wheeling diodes 436d1, 436d2, a positive electrode side terminal 436P, a negative electrode side terminal 436N, and an ac output terminal 436O.

Hereinafter, in the second embodiment and the third and fourth embodiments to be described later, the semiconductor switches 431s1, 431s2, 432s1, 432s2, 433s1, 433s2, 434s1, 434s2, 435s1, 435s2, 436s1, and 436s2 may be collectively referred to as "semiconductor switches 430 s", or any one of them may be individually referred to as "semiconductor switches 430 s". In the second embodiment, and the third and fourth embodiments to be described later, the constituent elements corresponding to the positive electrode-side terminals 431P to 436P of the "switch module 430" may be referred to as "positive electrode-side terminals 430P". In the second embodiment, and the third and fourth embodiments described below, the constituent elements corresponding to the negative-electrode-side terminals 431N to 436N of the "switch module 430" may be referred to as "negative-electrode-side terminals 430N". In the second embodiment, and the third and fourth embodiments described below, the constituent elements corresponding to the ac output terminals 431O to 436O of the "switch module 430" may be referred to as "ac output terminal 430O".

The switch modules 431 to 436 have the same constituent elements and are formed of the same circuit.

The W-phase ac bus 43O has ac output terminals 431O to 436O of the switching modules 431 to 436 connected to each other at one end thereof, and is connected to a W-phase output terminal 43T at the other end thereof. Thus, the inverter circuit 40 can output the W-phase alternating current output from the switching modules 431 to 436 to the outside from the W-phase output terminal 43T.

< Structure of Power conversion device >

Fig. 8 and 9 are configuration diagrams showing an example of a power conversion device according to a second embodiment. Specifically, fig. 8 is a perspective view showing a state in which a part of the housing 1H of the power conversion device 1 is removed. Fig. 9 is an exploded perspective view showing a state in which a part of the housing 1H of the power conversion device 1 is removed, and the output terminal 40T, the U-phase ac bus 41O, V, the ac bus 42O, and the W-phase ac bus 43O are removed and moved upward. Fig. 10 is a diagram for explaining paths of currents flowing through the switch modules 410 arranged in the X-axis direction. In fig. 10, paths of currents passing through the 3 switch modules 410 arranged in the X-axis direction are indicated by blank arrows, diagonally shaded arrows, and black arrows in order from the switch module 410 closest to the smoothing circuit 20.

As shown in fig. 8 and 9, the smoothing circuit 20, the fuse 30, and the inverter circuit 40 are arranged in this order from one end portion to the other end portion (i.e., in the X-axis direction) in the longitudinal direction of the inside of the housing 1H as in the case of the first embodiment.

The output terminal 40T is disposed in the center portion in the longitudinal direction (X-axis direction) of the inside of the housing 1H and in the upper portion of the inside of the housing 1H, as in the case of the first embodiment. Specifically, the output terminal 40T is disposed above the smoothing circuit 20 and the fuse 30 in the case 1H.

As described above, the output terminal 40T includes the U-phase output terminal 41T, V-phase output terminal 42T and the W-phase output terminal 43T. The U-phase output terminal 41T, V and the W-phase output terminal 43T are arranged in this order from one end portion to the center portion in the short side direction (i.e., in the Y-axis positive direction) in the housing 1H as in the case of the first embodiment.

As described above, the inverter circuit 40 includes a bridge circuit including the U-phase circuit 41, the V-phase circuit 42, and the W-phase circuit 43.

As shown in fig. 8 and 9, the U-phase circuit 41, the V-phase circuit 42, and the W-phase circuit 43 are arranged in the Y-axis direction in this order from the negative Y-axis end toward the positive Y-axis end, as in the case of the first embodiment.

The U-phase circuit 41 includes 6 switch modules 410 (i.e., corresponding to the switch modules 411 to 416).

The 6 switch modules 410 are arranged in two rows in the Y axis direction, two groups of 3 switch modules being arranged at equal intervals in the X axis direction. The 6 switch modules 410 are disposed on other components mounted on the bottom surface of the housing 1H, as in the case of the first embodiment.

The switch module 410 is arranged such that the longitudinal direction in plan view is along the substantially X-axis direction, as in the case of the first embodiment. In the switch module 410, the ac output terminal 410O, the negative electrode-side terminal 410N, and the positive electrode-side terminal 410P are arranged in this order in the vicinity of the smoothing circuit 20 (smoothing capacitor 21) along the longitudinal direction (i.e., the X-axis direction).

As shown in fig. 8 and 9, the U-phase laminated bus bar 41PN is disposed substantially parallel to the X-axis direction and the Y-axis direction at the upper end of the switch module 410, as in the case of the first embodiment.

The U-phase laminated bus bar 41PN is disposed over a range covering 6 switch modules 410 in the X-axis direction and the Y-axis direction.

As shown in fig. 8 and 9, the U-phase ac bus bar 41O connects the ac output terminal 410O of the switch module 410 and the U-phase output terminal 41T. The U-phase ac bus 41O includes a U-phase parallel connection bus 41O1 and a U-phase output bus 41O2, as in the case of the first embodiment.

As shown in fig. 8 and 9, the U-phase parallel connection bus 41O1 is connected to the U-phase output bus 41O2 in the vicinity of the switch module 410 farthest from the smoothing circuit 20 among the 6 switch modules 410 in plan view. Specifically, the U-phase parallel connection bus bar 41O1 is connected to the U-phase output bus bar 41O2 at a position away from the smoothing circuit 20 in the X-axis direction, of the switch modules 410 at the end portion farthest from the smoothing circuit 20 in the group of 3 switch modules 410 arranged in two rows in the Y-axis direction in plan view.

More specifically, the U-parallel connection bus bar 41O1 includes six leg portions 41O1a and a connection portion 41O1 b.

Each of the six leg portions 41O1a has a flat plate shape substantially parallel to the X-axis direction and the Z-axis direction. Each of the six leg portions 41O1a has a support surface portion to be placed on the ac output terminals 410O of the 6 switch modules 410, and a main leg portion extending upward (Z-axis positive direction) from the support surface portion. The dimensions in the Z axis direction of the six leg portions 41O1a are set to be substantially the same. The cross-sectional areas of the six leg portions 41O1a are set to be substantially the same. This makes it possible to make the current densities of the six leg portions 41O1a substantially equal.

The connection portion 41O1b has a flat plate shape substantially parallel to the X-axis direction and the Y-axis direction, and connects the six leg portions 41O1 a. Specifically, the connection portion 41O1b has a substantially rectangular shape in plan view, and extends in the X-axis direction and the Y-axis direction over a range where the six leg portions 41O1a are arranged. The X-axis positive end of the connection unit 41O1b is provided at a position farther from the X-axis positive end than the ac output terminals 410O of the two switch modules 410 located at the X-axis positive end among the 6 switch modules 410, and is connected to the U-phase output bus bar 41O 2.

As shown in fig. 10, all of the paths of the current flowing in the Z-axis direction from the dc input terminal of the U-phase circuit 41 through the 3 switch modules 410 arranged in the X-axis direction to the connection portion between the U-phase parallel connection bus 41O1 and the U-phase output bus 41O2 are substantially equal in length. This is because the dimensions in the Z-axis direction of the six leg portions 41O1a are substantially the same as described above. In addition, of the paths of the current from the dc input terminal of the U-phase circuit 41 through the 3 switch modules 410 arranged in the X-axis direction to the connection part between the U-phase parallel connection bus 41O1 and the U-phase output bus 41O2, the lengths of the paths flowing in the X-axis direction are all substantially the same. This is because the laminated bus bar 20PN, the U-phase laminated bus bar 41PN, and the connection portion 41O1b are arranged substantially parallel to the X-axis direction and the Y-axis direction. Thus, the lengths of the entire paths of the currents passing through the dc input terminals of the U-phase circuit 41 and through the respective 3 switch modules 410 arranged in the X-axis direction to the connection portions between the U-phase parallel connection bus 41O1 and the U-phase output bus 41O2 are all substantially equal. The same applies to the other row of 3 switch modules 410 arranged in the X-axis direction. Accordingly, the entire lengths of the paths from the smoothing circuit 20 to the U-phase output terminal 41T through the 6 switching modules 410 are all substantially equal. Similarly, the lengths of the entire paths of the currents from the U-phase output terminal 41T to the smoothing circuit 20 through the 6 switching modules 410 are all substantially equal.

The cross-sectional area, that is, the width and the thickness of the connection portion 41O1b are set so that the current density is substantially equal to that of the U-phase positive-electrode-side dc bus 41P and the U-phase negative-electrode-side dc bus 41N for each of the six power paths passing through the 6 switch modules 410. Accordingly, the lengths and current densities of the power paths between the smoothing circuits 20 and the U-phase output terminals 41T passing through the 6 switching modules 410 are all substantially equal to each other. Therefore, the inductances of the power paths passing through the smoothing circuits 20 of the 6 switching modules 410 and the U-phase output terminal 41T in one cycle can all be made substantially equal and uniform.

As shown in fig. 8 and 9, the U-phase output bus 41O2 connects the U-phase parallel connection bus 41O1 and the U-phase output terminal 41T. The U-phase output bus bar 41O2 has a folded portion extending upward from the X-axis positive end of the connection portion 41O1b of the U-phase parallel connection bus bar 41O1, and a main portion extending from the upper end of the folded portion toward the U-phase output terminal 41T so as to be substantially parallel to the X-axis direction and the Y-axis direction.

The V-phase circuit 42 includes 6 switching modules 420 (corresponding to the switching modules 421 to 426) in the same manner as the U-phase circuit 41.

Since the arrangement structure of the 6 switch modules 420 is the same as that of the 6 switch modules 410 of the U-phase circuit 41, the description thereof is omitted.

The switch module 420 is arranged such that the longitudinal direction in plan view is along the substantially X-axis direction, similarly to the switch module 410. In the switch module 420, the ac output terminal 420O, the negative electrode-side terminal 420N, and the positive electrode-side terminal 420P are arranged in this order in the vicinity of the smoothing circuit 20 (smoothing capacitor 21) along the longitudinal direction (i.e., the X-axis direction).

At the upper end of the switch module 420, the V-phase laminated bus bar 42PN is disposed substantially parallel to the X-axis direction and the Y-axis direction.

The V-phase laminated bus bar 42PN is disposed over a range covering 6 switch modules 420 in the X-axis direction and the Y-axis direction.

As shown in fig. 8 and 9, the V-phase ac bus 42O connects the ac output terminal 420O of the switch module 420 and the V-phase output terminal 42T. The V-phase ac bus 42O includes a V-phase parallel connection bus 42O1 and a V-phase output bus 42O 2.

Since the arrangement and structure of the V-phase ac bus 42O are the same as those of the U-phase ac bus 41O, the description thereof is omitted.

The W-phase circuit 43 includes 6 switching modules 430 (corresponding to the switching modules 431 to 436) as in the U-phase circuit 41.

Since the arrangement structure of the 6 switch modules 430 is the same as that of the 6 switch modules 410 of the U-phase circuit 41, the description thereof is omitted.

The switch module 430 is disposed such that the longitudinal direction in plan view is along the substantially X-axis direction. In the switch module 430, the ac output terminal 430O, the negative electrode-side terminal 430N, and the positive electrode-side terminal 430P are arranged in this order in the vicinity of the smoothing circuit 20 (smoothing capacitor 21) along the longitudinal direction (i.e., the X-axis direction).

At the upper end of the switch module 430, the W-phase laminated bus bar 43PN is disposed substantially parallel to the X-axis direction and the Y-axis direction.

The W-phase laminated bus bar 43PN is disposed over a range covering 6 switch modules 430 in the X-axis direction and the Y-axis direction.

The detailed configuration of the W-phase laminated bus bar 43PN is the same as that of the U-phase laminated bus bar 41PN, and therefore, the description thereof is omitted.

As shown in fig. 8 and 9, the W-phase ac bus bar 43O connects the ac output terminal 430O of the switching module 430 and the W-phase output terminal 43T. The W-phase ac bus 43O includes a W-phase parallel connection bus 43O1 and a W-phase output bus 43O 2.

The arrangement and structure of the W ac bus 43O are the same as those of the U ac bus 41O, and therefore, the description thereof is omitted.

In this way, in the second embodiment, the U-phase parallel connection bus 41O1 is configured such that the lengths of the power paths passing through the dc input terminals of the U-phase laminated bus 41PN and the connection portions of the U-phase output bus 41O2 of the 6 switch modules 410 are substantially equal to each other. The U-phase parallel connection bus 41O1 is configured such that the current density is substantially equal over the entire path of each power path passing through the dc input terminal of the U-phase laminated bus 41PN and the connection portion of the U-phase output bus 41O2 of each of the 6 switch modules 410. Specifically, the six leg portions 41O1a have substantially the same length and substantially the same cross-sectional area, and all of the current densities thereof are substantially equal. The connection unit 41O1b is configured such that the current density thereof is substantially equal to the current density of the positive-side dc bus 40P and the negative-side dc bus 40N for each of the power paths passing through the 6 switch modules 410. That is, the U-parallel connection bus 41O1 is configured such that the lengths of the six power paths are all substantially equal to the current density of the common portion (i.e., the six legs 41O1 a). The U parallel connection bus 41O1 is configured such that the current density of the other portion, i.e., the portion corresponding to the difference in length between the power paths (connection portion 41O1b) is substantially equal to the current density of the positive side dc bus 40P and the negative side dc bus 40N for each of the six power paths. Accordingly, the length and current density of the power path passing through each of the 6 switching modules 410 in one cycle between the smoothing circuit 20 and the U-phase output terminal 41T are all substantially equal. Therefore, the inductances of the power paths passing through the smoothing circuit 20 and the U-phase output terminal 41T in one cycle of each of the 6 switching modules 410 can be made substantially equal and uniform. Similarly, the V-phase parallel connection bus 42O1 is configured such that the lengths of the power paths passing through the dc input end of the V-phase laminated bus 42PN and the connection portion with the V-phase output bus 42O2 of the 6 switch modules 420 are all substantially equal to each other. The V-phase parallel connection bus 42O1 is configured such that the current density is substantially equal over the entire path passing through the dc input end of the V-phase laminated bus 42PN and the connection portion with the V-phase output bus 42O2 of each of the 6 switch modules 420. This makes it possible to make the inductances of the power paths passing through the smoothing circuits 20 and the V-phase output terminals 42T of the 6 switching modules 420 in one cycle substantially equal and uniform. Similarly, the W-phase parallel connection bus 43O1 is configured such that the lengths of the power paths passing through the dc input terminals of the W-phase laminated bus 43PN and the connection portions with the W-phase output bus 43O2 of the 6 switch modules 430 are all substantially equal to each other. The W-phase parallel connection bus bar 43O1 is configured such that the current density is substantially equal over the entire path passing through the dc input end of the W-phase laminated bus bar 43PN and the connection portion with the W-phase output bus bar 43O2 of each of the 6 switch modules 430. Therefore, the inductances of the power paths passing through the smoothing circuits 20 of the 6 switching modules 430 and the W-phase output terminal 43T in one cycle can all be made substantially equal and uniform. This can suppress imbalance in the currents of the 6 switch modules 410, the 6 switch modules 420, and the 6 switch modules 430, and can make the currents uniform.

In the second embodiment, the number of switch modules 410 connected in parallel may be any number as long as the lengths of the power paths between the dc input terminals of the U-phase laminate bus bar 41PN and the connection portions with the U-phase output bus bar 41O2 of the respective switch modules 410 are substantially equal and the current densities of the respective paths throughout the entire path are equal. That is, the number of the switch modules 410 connected in parallel may be 2 or more and 5 or less, or may be 7 or more. The number of the switch modules 420 and 430 may be the same. In the second embodiment, the plurality of switch modules 410 may be arranged arbitrarily as long as the lengths of the power paths between the dc input end of the U-phase laminated bus bar 41PN and the connection portion with the U-phase output bus bar 41O2 of the switch modules 410 are substantially equal and the current densities of the respective paths are equal throughout the entire path. For example, the plurality of switch modules 410 may be arranged in a row in the X-axis direction, or a group of rows arranged in the X-axis direction may be arranged in 3 rows or more in the Y-axis direction. The switch modules 420 and 430 may have the same configuration. In the second embodiment, the U-phase parallel connection bus bar 41O1 may have any configuration as long as the lengths of the power paths between the dc input end of the U-phase laminated bus bar 41PN and the connection portion with the U-phase output bus bar 41O2 of the respective switch modules 410 are substantially equal and the current densities of the respective paths are equal throughout the entire path. For example, the U-phase parallel connection bus 41O1 may be configured such that only the current density of each power path in the portion between the connection portions of the connection portions 41O1b and the leg portions 41O1a at both ends in the X-axis direction is substantially equal to the U-phase positive electrode side dc bus 41P and the U-phase negative electrode side dc bus 41N. That is, the connection unit 41O1b of the U-phase parallel connection bus 41O1 is configured such that the current density in each path section from at least all the paths of the 6 switch modules 410 to the point of confluence is substantially equal to the U-phase positive electrode side dc bus 41P and the U-phase negative electrode side dc bus 41N. The V parallel connection bus 42O1 and the W parallel connection bus 43O1 may have the same configuration.

[ third embodiment ]

Next, a third embodiment will be described with reference to fig. 11 and 12. The circuit configuration of the power converter 1 of the third embodiment is the same as that of the second embodiment (fig. 7), and therefore, the description thereof is omitted. Hereinafter, the description will be mainly given of the portions different from the power conversion device 1 of the first embodiment and the second embodiment, and the description of the same or corresponding contents as those of the first embodiment and the second embodiment may be simplified or omitted.

< Structure of Power conversion device >

Fig. 11 and 12 are configuration diagrams showing an example of the power conversion device 1 according to the third embodiment. Specifically, fig. 11 is a perspective view showing a state in which a part of the housing 1H of the power conversion device 1 is removed. Fig. 12 is an exploded perspective view showing a state in which a part of the casing 1H of the power conversion device 1 is removed, and the output terminal 40T, the U-phase output bus bar 41O2, the V-phase output bus bar 42O2, and the W-phase output bus bar 43O2 are removed and moved upward.

As shown in fig. 11 and 12, the smoothing circuit 20, the fuse 30, and the inverter circuit 40 are arranged in this order from one end portion to the other end portion (i.e., in the X-axis direction) in the longitudinal direction of the inside of the housing 1H, as in the case of the first embodiment and the like.

As in the case of the first embodiment, the output terminal 40T is disposed at the center in the longitudinal direction (X-axis direction) of the inside of the housing 1H and at the upper portion of the inside of the housing 1H. Specifically, the output terminal 40T is disposed above the smoothing circuit 20 and the fuse 30 in the case 1H.

As described above, the output terminal 40T includes the U-phase output terminal 41T, V-phase output terminal 42T and the W-phase output terminal 43T. As in the case of the first embodiment and the like, the U-phase output terminal 41T, V and the W-phase output terminal 43T are arranged in this order from one end portion to the center portion in the short direction (i.e., in the Y-axis positive direction) in the housing 1H.

As described above, the inverter circuit 40 includes a bridge circuit including the U-phase circuit 41, the V-phase circuit 42, and the W-phase circuit 43.

As shown in fig. 11 and 12, as in the first embodiment, the U-phase circuit 41, the V-phase circuit 42, and the W-phase circuit 43 are arranged in the Y-axis direction in this order from the negative Y-axis end toward the positive Y-axis end.

As in the case of the second embodiment, the U-phase circuit 41 includes 6 switching modules 410 (i.e., corresponding to the switching modules 411 to 416).

As in the case of the second embodiment, the 6 switch modules 410 are arranged in two rows in the Y-axis direction in two groups of 3 in the X-axis direction at equal intervals. As in the case of the first embodiment, the 6 switch modules 410 are disposed on other members placed on the bottom surface of the case 1H.

As in the case of the first embodiment and the like, the switch module 410 is disposed such that the longitudinal direction in a plan view is along the substantially X-axis direction. In the switch module 410, the ac output terminal 410O, the negative electrode-side terminal 410N, and the positive electrode-side terminal 410P are arranged in this order in the vicinity of the smoothing circuit 20 (smoothing capacitor 21) along the longitudinal direction (i.e., the X-axis direction).

As shown in fig. 12, at the upper end portion of the switch module 410, the U-phase laminated bus bar 41PN is disposed substantially parallel to the X-axis direction and the Y-axis direction, as in the case of the first embodiment and the like.

The U-phase laminated bus bar 41PN is disposed so as to cover the range of 6 switch modules 410 in the X-axis direction and the Y-axis direction.

As shown in fig. 12, the U-phase ac bus 41O connects the ac output terminal 410O of the switch module 410 and the U-phase output terminal 41T. As in the case of the first embodiment and the like, the U-phase ac bus 41O includes the U-phase parallel connection bus 41O1 and the U-phase output bus 41O 2.

The U-parallel connection bus bar 41O1 has a flat plate shape substantially parallel to the X-axis direction and the Y-axis direction, and has a substantially rectangular shape covering the range of 6 switch modules 410 in a plan view. The U-phase parallel connection bus bar 41O1 is further stacked on the uppermost insulating layer 41I2 (see fig. 4) of the U-phase laminated bus bar 41 PN. Thus, the U-phase negative-side dc bus 41N, U, the U-phase positive-side dc bus 41P, and the U-phase parallel connection bus 41O1 form a U-phase laminated bus 41PNO having a laminated structure in which the buses are laminated in this order from below through insulating layers 41I1 and 41I 2. Therefore, the current density of the U-phase parallel connection bus 41O1 is substantially equal to that of the U-phase positive electrode-side dc bus 41P and the U-phase negative electrode-side dc bus 41N.

As shown in fig. 11 and 12, in the U parallel connection bus bar 41O1, a relatively large through hole having a substantially rectangular shape in plan view is provided at a position corresponding to the 6 switch modules 410. Thus, the positive-electrode-side terminal 410P (i.e., the through-hole for fastening the U-phase positive-electrode-side direct-current bus bar 41P), the negative-electrode-side terminal 410N (i.e., the through-hole for fastening the U-phase negative-electrode-side direct-current bus bar 41N), and the ac output terminal 410O of the switch module 410 can be exposed in a plan view. Therefore, the worker can touch the positive-electrode-side terminal 410P, the negative-electrode-side terminal 410N, and the ac output terminal 410O of the switch module 410 from above the U-parallel connection bus 41O 1.

As shown in fig. 11 and 12, the U-phase output bus 41O2 connects the U-phase parallel connection bus 41O1 and the U-phase output terminal 41T. The U-phase output bus bar 41O2 is connected at the X-axis positive end of the U-phase parallel connection bus bar 41O1, that is, at the X-axis positive end of the two rows of 3 switch modules 410 arranged in the X-axis direction, and the ac output terminal 410O of the switch module 410 is connected at a position distant from the X-axis positive end. The U-phase output bus bar 41O2 is connected at the X-axis positive end of the U-phase parallel connection bus bar 41O1 at a substantially center position in the Y-axis direction between the ac output terminals 410O of the two rows of the group of 3 switch modules 410 arranged in the X-axis direction. Accordingly, the lengths of the power paths between the dc input terminals of the U-phase circuit 41 and the connection portions of the U-phase parallel connection bus 41O1 and the U-phase output bus 41O2 are all substantially equal in the 6 switch modules 410. Therefore, the length and current density of the power path passing through each of the 6 switching modules 410 in one cycle between the smoothing circuit 20 and the U-phase output terminal 41T are all substantially equal. This makes it possible to make the inductances of the power paths passing through the smoothing circuits 20 of the 6 switching modules 410 and the U-phase output terminal 41T in one cycle substantially equal and uniform

The V-phase circuit 42 includes 6 switching modules 420 (corresponding to the switching modules 421 to 426) similarly to the U-phase circuit 41.

Since the arrangement structure of the 6 switch modules 420 is the same as that of the 6 switch modules 410 of the U-phase circuit 41, the description thereof is omitted.

Like the switch module 410, the switch module 420 is disposed such that the longitudinal direction in a plan view is along the substantially X-axis direction. In the switch module 420, the ac output terminal 420O, the negative electrode-side terminal 420N, and the positive electrode-side terminal 420P are arranged in this order in the longitudinal direction (i.e., the X-axis direction) in the vicinity of the smoothing circuit 20 (smoothing capacitor 21).

As shown in fig. 12, the V-phase laminated bus bar 42PN is disposed substantially parallel to the X-axis direction and the Y-axis direction at the upper end of the switch module 420.

The V-phase laminated bus bar 42PN is disposed so as to cover the range of 6 switch modules 420 in the X-axis direction and the Y-axis direction.

As shown in fig. 12, the V-phase ac bus 42O connects the ac output terminal 420O of the switch module 420 and the V-phase output terminal 42T. The V-phase ac bus 42O includes a V-phase parallel connection bus 42O1 and a V-phase output bus 42O 2.

The V parallel connection bus bar 42O1 has a flat plate shape substantially parallel to the X axis direction and the Y axis direction, and has a substantially rectangular shape covering the range of the 6 switch modules 420 in plan view. The V-phase parallel connection bus bar 42O1 is further stacked on the insulating layer 42I2 (see fig. 4) on the uppermost layer of the V-phase laminated bus bar 42 PN. Thus, the V-phase negative-side dc bus 42N, V, the positive-side dc bus 42P, and the V-phase parallel connection bus 42O1 form a V-phase laminated bus 42PNO having a laminated structure laminated in this order from below via insulating layers 42I1 and 42I 2. Therefore, the current density of the V-phase parallel connection bus 42O1 is substantially equal to that of the V-phase positive electrode-side dc bus 42P and the V-phase negative electrode-side dc bus 42N.

Since the arrangement and structure of the V-phase ac bus 42O (the V-phase parallel connection bus 42O1 and the V-phase output bus 42O2) are the same as those of the U-phase ac bus 41O, the description thereof is omitted.

Similar to the U-phase circuit 41, the W-phase circuit 43 includes 6 switching modules 430 (corresponding to the switching modules 431 to 436).

Since the arrangement structure of the 6 switch modules 430 is the same as that of the 6 switch modules 410 of the U-phase circuit 41, the description thereof is omitted.

Like the switch module 410, the switch module 430 is disposed such that the longitudinal direction in plan view is along the substantially X-axis direction. In the switch module 430, the ac output terminal 430O, the negative electrode-side terminal 430N, and the positive electrode-side terminal 430P are arranged in this order in the vicinity of the smoothing circuit 20 (smoothing capacitor 21) along the longitudinal direction (i.e., the X-axis direction).

As shown in fig. 12, the W-phase laminated bus bar 43PN is disposed substantially parallel to the X-axis direction and the Y-axis direction at the upper end of the switch module 430.

The W-phase laminated bus bar 43PN is disposed so as to cover the range of 6 switch modules 430 in the X-axis direction and the Y-axis direction.

As shown in fig. 12, the W-phase ac bus bar 43O connects the ac output terminal 430O of the switch module 430 and the W-phase output terminal 43T. The W-phase ac bus 43O includes a W-phase parallel connection bus 43O1 and a W-phase output bus 43O 2.

The W parallel connection bus bar 43O1 has a flat plate shape substantially parallel to the X axis direction and the Y axis direction, and has a substantially rectangular shape covering the range of 6 switch modules 430 in plan view. The W-phase parallel connection bus bar 43O1 is further stacked on the insulating layer 43I2 (see fig. 4) in the uppermost layer of the W-phase laminated bus bar 43 PN. Thus, the W-phase negative-side dc bus bar 43N, W, the W-phase positive-side dc bus bar 43P, and the W-phase parallel connection bus bar 43O1 form a W-phase laminated bus bar 43PNO having a laminated structure laminated in this order from below via the insulating layers 43I1 and 43I 2. Therefore, the current density of the W-phase parallel connection bus 43O1 is substantially equal to that of the W-phase positive-electrode dc bus 43P and the W-phase negative-electrode dc bus 43N.

The arrangement and structure of the W-phase ac bus 43O (the W-phase parallel connection bus 43O1 and the W-phase output bus 43O2) are the same as those of the U-phase ac bus 41O, and therefore, the description thereof is omitted.

In this way, the third embodiment has a laminated structure in which the U-phase parallel connection bus bar 41O1 is laminated together with the U-phase positive-side dc bus bar 41P and the U-phase negative-side dc bus bar 41N via the insulating layers 41I1 and 41I 2. Further, the U-phase parallel connection bus bar 41O1 is connected to the U-phase output bus bar 41O2 at a position further away in the X-axis direction than the ac output terminal 410O of the switch module 410 at the end of the 6 switch modules 410 in the X-axis direction. Accordingly, the length and current density of the power path passing through each cycle between the smoothing circuit 20 and the U-phase output terminal 41T are all substantially equal for each of the 6 switching modules 410. Therefore, the inductances of the power paths in one cycle passing through the smoothing circuit 20 and the U-phase output terminal 41T of the 6 switching modules 410 can be made substantially equal and uniform. Similarly, the V-phase parallel connection bus 42O1 has a laminated structure in which the V-phase positive-side dc bus 42P and the V-phase negative-side dc bus 42N are laminated with insulating layers 42I1 and 42I2 interposed therebetween. Further, the V-phase parallel connection bus 42O1 is connected to the V-phase output bus 42O2 at a position further away from the ac output terminal 420O of the switch module 420 than the X-axis positive end portion of the 6 switch modules 420. Thus, the length and current density of the power path passing through each cycle between the smoothing circuit 20 and the V-phase output terminal 42T are all substantially equal for each of the 6 switching modules 420. Therefore, the inductances of the power paths passing through the 6 switching modules 420 in one cycle between the smoothing circuit 20 and the V-phase output terminal 42T can be made substantially equal and uniform. Similarly, the W-phase parallel connection bus bar 43O1 has a laminated structure in which the W-phase positive-side dc bus bar 43P and the W-phase negative-side dc bus bar 43N are laminated with insulating layers 43I1 and 43I2 interposed therebetween. Further, the W-phase parallel connection bus bar 43O1 is connected to the W-phase output bus bar 43O2 at a position further away from the ac output terminal 430O of the switch module 430 than the X-axis positive end portion of the 6 switch modules 430. Thus, the length and current density of the power path for one cycle between the smoothing circuit 20 and the W-phase output terminal 43T are all substantially equal for each of the 6 switching modules 430. Therefore, the inductances of the power paths in one cycle between the smoothing circuit 20 and the W-phase output terminal 43T can be made substantially equal and uniform by the 6 switching modules 430. This can suppress imbalance in the current among the 6 switch modules 410, the 6 switch modules 420, and the 6 switch modules 430, and can make the current uniform.

In the third embodiment, the number of the switch modules 410 connected in parallel may be any number, and may be two or more and 5 or less, or 7 or more. The number of the switch modules 420 and 430 is the same. In the third embodiment, the plurality of switch modules 410 may be arranged arbitrarily, and for example, the plurality of switch modules 410 may be arranged in a row in the X-axis direction, or 3 or more rows may be arranged in the Y-axis direction in a row group arranged in the X-axis direction.

[ fourth embodiment ]

Next, a fourth embodiment will be described with reference to fig. 13 and 14. The circuit configuration of the power converter 1 of the fourth embodiment is the same as that of the second embodiment (fig. 7), and therefore, the description thereof is omitted. Hereinafter, the description will be given mainly on the differences from the power conversion device 1 of the first to third embodiments, and the description of the same or corresponding contents as those of the first to third embodiments may be simplified or omitted.

< Structure of Power conversion device >

Fig. 13 and 14 are configuration diagrams showing an example of the power conversion device 1 according to the fourth embodiment. Specifically, fig. 13 is a perspective view showing a state in which a part of the housing 1H of the power conversion device 1 is removed. Fig. 14 is an exploded perspective view showing a state in which a part of the housing 1H of the power conversion device 1 is removed, and the output terminal 40T is removed and moved upward.

As shown in fig. 13 and 14, the smoothing circuit 20, the fuse 30, and the inverter circuit 40 are arranged in this order from one end portion to the other end portion (i.e., in the X-axis direction) in the longitudinal direction of the inside of the housing 1H, as in the case of the first embodiment and the like.

As in the case of the first embodiment and the like, the output terminal 40T is disposed at the center in the longitudinal direction (X-axis direction) of the inside of the housing 1H and at the upper portion of the inside of the housing 1H. Specifically, the output terminal 40T is disposed above the smoothing circuit 20 and the fuse 30 in the case 1H.

As described above, the output terminal 40T includes the U-phase output terminal 41T, V-phase output terminal 42T and the W-phase output terminal 43T. As in the case of the first embodiment and the like, the U-phase output terminal 41T, V and the W-phase output terminal 43T are arranged in this order from one end portion to the center portion in the short direction (i.e., in the Y-axis positive direction) in the housing 1H.

As described above, the inverter circuit 40 includes a bridge circuit including the U-phase circuit 41, the V-phase circuit 42, and the W-phase circuit 43.

As shown in fig. 13 and 14, as in the first embodiment and the like, the U-phase circuit 41, the V-phase circuit 42, and the W-phase circuit 43 are arranged in the Y-axis direction in this order from the negative Y-axis end toward the positive Y-axis end.

As in the case of the second embodiment and the like, the U-phase circuit 41 includes 6 switching modules 410 (i.e., corresponding to the switching modules 411 to 416).

As in the case of the second embodiment, the 6 switch modules 410 are arranged in two rows in the Y-axis direction, with 3 groups arranged at equal intervals in the X-axis direction. As in the case of the first embodiment, the 6 switch modules 410 are disposed on other members placed on the bottom surface of the case 1H.

As in the case of the first embodiment and the like, the switch module 410 is disposed such that the longitudinal direction in a plan view is along the substantially X-axis direction. In the switch module 410, the ac output terminal 410O, the negative electrode-side terminal 410N, and the positive electrode-side terminal 410P are arranged in this order in the vicinity of the smoothing circuit 20 (smoothing capacitor 21) along the longitudinal direction (i.e., the X-axis direction).

As shown in fig. 13 and 14, at the upper end portion of the switch module 410, the U-phase laminated bus bar 41PN is disposed substantially parallel to the X-axis direction and the Y-axis direction, as in the case of the first embodiment and the like.

The U-phase laminated bus bar 41PN is disposed so as to cover the range of 6 switch modules 410 in the X-axis direction and the Y-axis direction.

As shown in fig. 13 and 14, the U-phase ac bus bar 41O connects the ac output terminal 410O of the switch module 410 and the U-phase output terminal 41T. As in the case of the first embodiment and the like, the U-phase ac bus 41O includes the U-phase parallel connection bus 41O1 and the U-phase output bus 41O 2.

As in the third embodiment, the U parallel connection bus bar 41O1 has a flat plate shape substantially parallel to the X axis direction and the Y axis direction, and has a substantially rectangular shape covering the range of 6 switch modules 410 in a plan view. The U-phase parallel connection bus bar 41O1 is further stacked on the uppermost insulating layer 41I2 (see fig. 4) of the U-phase laminated bus bar 41 PN. Thus, the U-phase negative-side dc bus 41N, U, the U-phase positive-side dc bus 41P, and the U-phase parallel connection bus 41O1 form a U-phase laminated bus 41PNO having a laminated structure in which the buses are laminated in this order from below through insulating layers 41I1 and 41I 2. Therefore, the current density of the U-phase parallel connection bus 41O1 is substantially equal to that of the U-phase positive electrode-side dc bus 41P and the U-phase negative electrode-side dc bus 41N.

As shown in fig. 13 and 14, the U-phase output bus 41O2 connects the U-phase parallel connection bus 41O1 and the U-phase output terminal 41T. The U-phase output bus bar 41O2 is connected in parallel with the U-phase output bus bar 41O1 at the X-axis negative end, that is, at a position distant from the ac output terminals 410 of the switch modules 410 at the X-axis negative end of the two rows of 3 switch modules 410 arranged in the X-axis direction. The U-phase output bus bar 41O2 is connected in parallel to the X-axis negative end of the U-phase output bus bar 41O1, and is connected to the ac output terminals 410O of the group of two rows of 3 switch modules 410 arranged in the X-axis direction at substantially the center in the Y-axis direction. Accordingly, the direction of the current flowing through the U-phase positive-side dc bus 41P toward each of the 6 switch modules 410 is the X-axis positive direction. On the other hand, the direction of the current flowing from each of the 6 switch modules 410 to the U-phase output terminal 41T through the U-phase parallel connection bus 41O1 is the opposite negative X-axis direction. Therefore, when currents of the same current density flow in opposite directions, magnetic fields generated by the currents of the U-phase positive-side dc bus 41P and the U-phase parallel connection bus 41O1 are cancelled out, and the inductance thereof can be greatly reduced. Similarly, the direction of the current flowing from the U-phase output terminal 41T to each of the 6 switch modules 410 and through the U-parallel connection bus 41O1 is the X-axis positive direction. On the other hand, the direction of the current flowing through the U-phase negative-side dc bus 41N from each of the 6 switching modules 410 toward the smoothing circuit 20 is the negative X-axis direction. Therefore, when currents of the same magnitude flow in opposite directions, magnetic fields generated by the currents of the U-phase negative-side dc bus 41N and the U-phase parallel connection bus 41O1 are cancelled out, and the inductance thereof can be greatly reduced. Accordingly, the inductances of the power paths in one cycle between the smoothing circuit 20 and the U-phase output terminal 41T in the 6 switching modules 410 are extremely small, and thus the difference in inductance between the power paths can be suppressed, and the inductances can be made uniform.

The V-phase circuit 42 includes 6 switching modules 420 (corresponding to the switching modules 421 to 426) similarly to the U-phase circuit 41.

Since the arrangement structure of the 6 switch modules 420 is the same as that of the 6 switch modules 410 of the U-phase circuit 41, the description thereof is omitted.

Like the switch module 410, the switch module 420 is disposed such that the longitudinal direction in a plan view is along the substantially X-axis direction. In the switch module 420, the ac output terminal 420O, the negative electrode-side terminal 420N, and the positive electrode-side terminal 420P are arranged in this order in the vicinity of the smoothing circuit 20 (smoothing capacitor 21) along the longitudinal direction (i.e., the X-axis direction).

As shown in fig. 13 and 14, the V-phase laminated bus bar 42PN is disposed substantially parallel to the X-axis direction and the Y-axis direction at the upper end of the switch module 420.

The V-phase laminated bus bar 42PN is disposed so as to cover the range of 6 switch modules 420 in the X-axis direction and the Y-axis direction.

As shown in fig. 13 and 14, the V-phase ac bus 42O connects the ac output terminal 420O of the switch module 420 and the V-phase output terminal 42T. The V-phase ac bus 42O includes a V-phase parallel connection bus 42O1 and a V-phase output bus 42O 2.

As in the case of the third embodiment, the V parallel connection bus 42O1 has a flat plate shape substantially parallel to the X axis direction and the Y axis direction, and has a substantially rectangular shape covering the range of 6 switch modules 420 in plan view. The V-phase parallel connection bus bar 42O1 is further stacked on the insulating layer 42I2 (see fig. 4) on the uppermost layer of the V-phase laminated bus bar 42 PN. Thus, the V-phase negative-side dc bus 42N, V, the positive-side dc bus 42P, and the V-phase parallel connection bus 42O1 form a V-phase laminated bus 42PNO having a laminated structure laminated in this order from below via insulating layers 42I1 and 42I 2. Therefore, the current density of the V-phase parallel connection bus 42O1 is substantially equal to that of the V-phase positive electrode-side dc bus 42P and the V-phase negative electrode-side dc bus 42N.

Since the arrangement and structure of the V-phase ac bus 42O (the V-phase parallel connection bus 42O1 and the V-phase output bus 42O2) are the same as those of the U-phase ac bus 41O, the description thereof is omitted.

Similar to the U-phase circuit 41, the W-phase circuit 43 includes 6 switching modules 430 (corresponding to the switching modules 431 to 436).

Since the arrangement structure of the 6 switch modules 430 is the same as that of the 6 switch modules 410 of the U-phase circuit 41, the description thereof is omitted.

Like the switch module 410, the switch module 430 is disposed such that the longitudinal direction in plan view is along the substantially X-axis direction. In the switch module 430, the ac output terminal 430O, the negative electrode-side terminal 430N, and the positive electrode-side terminal 430P are arranged in this order in the longitudinal direction (i.e., the X-axis direction) in the vicinity of the smoothing circuit 20 (smoothing capacitor 21).

As shown in fig. 13 and 14, the W-phase laminated bus bar 43PN is disposed substantially parallel to the X-axis direction and the Y-axis direction at the upper end of the switch module 430.

The W-phase laminated bus bar 43PN is disposed so as to cover the range of 6 switch modules 430 in the X-axis direction and the Y-axis direction.

As shown in fig. 13 and 14, the W-phase ac bus bar 43O connects the ac output terminal 430O of the switching module 430 and the W-phase output terminal 43T. The W-phase ac bus 43O includes a W-phase parallel connection bus 43O1 and a W-phase output bus 43O 2.

As in the case of the third embodiment, the W parallel connection bus bar 43O1 has a flat plate shape substantially parallel to the X axis direction and the Y axis direction, and has a substantially rectangular shape covering the range of 6 switch modules 430 in plan view. The W-phase parallel connection bus bar 43O1 is further stacked on the insulating layer 43I2 (see fig. 4) in the uppermost layer of the W-phase laminated bus bar 43 PN. Thus, the W-phase negative-side dc bus bar 43N, W, the W-phase positive-side dc bus bar 43P, and the W-phase parallel connection bus bar 43O1 form a W-phase laminated bus bar 43PNO having a laminated structure laminated in this order from below via the insulating layers 43I1 and 43I 2. Therefore, the current density of the W-phase parallel connection bus 43O1 is substantially equal to that of the W-phase positive-electrode dc bus 43P and the W-phase negative-electrode dc bus 43N.

The arrangement and structure of the W-phase ac bus 43O (the W-phase parallel connection bus 43O1 and the W-phase output bus 43O2) are the same as those of the U-phase ac bus 41O, and therefore, the description thereof is omitted.

In this way, the fourth embodiment has a laminated structure in which the U-phase parallel connection bus bar 41O1 is laminated together with the U-phase positive-side dc bus bar 41P and the U-phase negative-side dc bus bar 41N via the insulating layers 41I1 and 41I 2. Further, the U-phase parallel connection bus 41O1 is connected to the U-phase output bus 41O2 at a position further away from the ac output terminal 410O of the switch module 410 in the negative X-axis direction among the 6 switch modules 410. Thus, the current flowing through the U-phase positive-side dc bus 41P and the U-phase parallel connection bus 41O1 and the current flowing through the U-phase parallel connection bus 41O1 and the U-phase negative-side dc bus 41N of each of the 6 switch modules 410 have the same current density and are spatially opposite. Therefore, the magnetic fields generated by the current of the U-phase positive-side dc bus 41P and the U-phase parallel connection bus 41O1 and the current of the U-phase parallel connection bus 41O1 and the U-phase negative-side dc bus 41N cancel each other out, and the inductance of these power paths can be made very small. As a result, it is possible to suppress the difference between the paths of the inductance of the power path in one cycle between the smoothing circuit 20 and the U-phase output terminal 41T in each of the 6 switching modules 410, and oh can achieve uniform inductance. Similarly, the V-phase parallel connection bus 42O1 has a laminated structure in which the V-phase positive-side dc bus 42P and the V-phase negative-side dc bus 42N are laminated with insulating layers 42I1 and 42I2 interposed therebetween. Further, the V-phase parallel connection bus 42O1 is connected to the V-phase output bus 42O2 at a position farther away from the ac output terminal 420O of the switch block 420 in the negative X-axis direction than the end of the 6 switch blocks 420 in the negative X-axis direction. Thus, the current flowing through the front and rear V-phase positive-side dc bus 42P and V-phase parallel connection bus 42O1 and the current flowing through the V-phase parallel connection bus 42O1 and V-phase negative-side dc bus 42N of each of the 6 switch modules 420 have the same current density and are spatially opposite. Therefore, the magnetic fields generated by the current of the V-phase positive-side dc bus 42P and the V-phase parallel connection bus 42O1 and the current of the V-phase parallel connection bus 42O1 and the V-phase negative-side dc bus 42N cancel each other out, and the inductance of these power paths can be made very small. As a result, the difference between the paths of the inductance of the power path in one cycle passing through the smoothing circuit 20 and the V-phase output terminal 42T of each of the 6 switching modules 420 can be suppressed, and the inductance can be made uniform. Similarly, the W-phase parallel connection bus bar 43O1 has a laminated structure in which the W-phase positive-side dc bus bar 43P and the W-phase negative-side dc bus bar 43N are laminated with insulating layers 43I1 and 43I2 interposed therebetween. Further, the W-phase parallel connection bus bar 43O1 is connected to the W-phase output bus bar 43O2 at a position farther away from the ac output terminal 430O of the switch block 430 in the negative X-axis direction among the 6 switch blocks 430. Thus, the current flowing through the W-phase positive-side dc bus 43P and the W-phase parallel connection bus 43O1 and the current flowing through the W-phase parallel connection bus 43O1 and the W-phase negative-side dc bus 43N of each of the 6 switch modules 430 are spatially opposite to each other with the same current density. Therefore, the magnetic fields generated by the current of the W-phase positive-side dc bus 43P and the W-phase parallel connection bus 43O1 and the current of the W-phase parallel connection bus 43O1 and the W-phase negative-side dc bus 43N cancel each other out, and the inductance of these power paths can be made very small. As a result, the difference between the paths of the inductance of the power path in one cycle passing through the smoothing circuit 20 and the W-phase output terminal 43T in each of the 6 switching modules 430 can be suppressed, and the inductance can be made uniform. This can suppress imbalance in the current among the 6 switch modules 410, the 6 switch modules 420, and the 6 switch modules 430, and can make the current uniform.

In the fourth embodiment, the number of the switch modules 410 connected in parallel is arbitrary, and may be two or more and 5 or less, or may be 7 or more. The number of switch modules 420 and 430 is the same. In the fourth embodiment, the plurality of switch modules 410 are arranged in any manner, and for example, the plurality of switch modules 410 may be arranged in a row in the X-axis direction, or may be arranged in 3 rows or more in the Y-axis direction in a group arranged in a row in the X-axis direction.

[ Effect ]

Next, an operation of the power converter 1 of the present embodiment will be described.

In the present embodiment (first embodiment), the power conversion device 1 includes a smoothing circuit 20, an inverter circuit 40, and an output terminal 40T. Specifically, the inverter circuit 40 includes a U-phase circuit 41, and the U-phase circuit 41 is configured by connecting a plurality of switch modules 410 including a plurality of semiconductor switches 410s, in which upper and lower arms are connected in series, in parallel, and connecting points (ac output terminals 410O) of the upper and lower arms of each of the plurality of switch modules 410 to each other. Similarly, the inverter circuit 40 includes a V-phase circuit 42, and the V-phase circuit 42 is configured by connecting a plurality of switch modules 420 including a plurality of semiconductor switches 420s, the upper and lower arms of which are connected in series, in parallel, and connecting the connection points (ac output terminals 420O) of the upper and lower arms of each of the plurality of switch modules 420 to each other. Similarly, the inverter circuit 40 includes a W-phase circuit 43, and the W-phase circuit 43 is configured by connecting a plurality of switching modules 430 including a plurality of semiconductor switches 430s, the upper and lower arms of which are connected in series, in parallel, and connecting the connection points (ac output terminals 430O) of the upper and lower arms of each of the plurality of switching modules 430 to each other. That is, the inverter circuit 40 includes a bridge circuit configured by connecting a plurality of phases in parallel by output circuits (U-phase circuit 41, V-phase circuit 42, and W-phase circuit 43). The inverter circuit 40 outputs a predetermined alternating current based on the direct current input from the smoothing circuit 20. The output terminal 40T outputs a predetermined alternating current from the inverter circuit 40 to the outside. The inverter circuit 40 includes a positive-side dc bus 40P connecting the positive-side terminals 410P, 420P, and 430P of the plurality of switch modules 410, 420, and 430 to each other, and a negative-side dc bus 40N connecting the negative-side terminals 410N, 420N, and 430N of the plurality of switch modules 410, 420, and 430 to each other. The inverter circuit 40 includes a U-parallel connection bus 41O1 that connects the ac output terminals 410O of the plurality of switch modules 410 to each other. Similarly, the inverter circuit 40 includes a V parallel connection bus 42O1 that connects the ac output terminals 420O of the plurality of switch modules 420 to each other. Similarly, the inverter circuit 40 includes a W parallel connection bus bar 43O1 that connects the ac output terminals 430O of the plurality of switch modules 430 to each other. The positive-side dc bus bar 40P and the negative-side dc bus bar 40N have a laminated structure laminated via insulating layers 41I1, 42I1, and 43I 1. The U-parallel connection bus 41O1 is configured such that the lengths of the paths between all the arms (semiconductor switches 410s) included in the switch modules 410 and the junction where all the paths from the switch modules 410 join each other are substantially equal. Similarly, the V parallel connection bus 42O1 is configured such that the lengths of the paths between all the arms (semiconductor switches 420s) included in the plurality of switch modules 420 and the junction where all the paths from the plurality of switch modules 420 join each other are substantially equal. Similarly, the W parallel connection bus bar 43O1 is configured such that the lengths of the paths between all the arms (semiconductor switches 430s) included in the plurality of switch modules 430 and the junction where all the paths from the plurality of switch modules 430 merge are substantially equal.

For example, in the inverter circuit, a plurality of switching legs are connected in parallel, whereby the current capacity of the power conversion device can be increased.

In this case, if the inductance of each of the paths passing through the plurality of switching legs is different, an imbalance occurs in the currents passing through the plurality of switching legs, and there is a possibility that the currents are concentrated in the semiconductor switches included in some of the switching legs. As a result, the element of the semiconductor switch may be damaged due to the temperature increase caused by the loss.

On the other hand, by matching the semiconductor switch in which the current is most concentrated with the allowable current, it is also possible to determine the current capacity of the power conversion device in consideration of the imbalance of the current. However, in this case, only a current relatively smaller than the allowable current flows in the semiconductor switches other than the semiconductor switch in which the current concentrates. As a result, even if the number of switching arms connected in parallel is increased, the allowable current of the entire plurality of switching arms cannot be used effectively, and the current capacity of the power conversion device may not be increased much.

In contrast, in the present embodiment (first embodiment), along with the lamination structure of the positive-side dc bus bar 40P and the negative-side dc bus bar 40N, the inductance of the positive-side and negative-side dc wiring portions of the inverter circuit 40 can be made very small. Therefore, the inductance of the ac wiring portion dominates the inductance of the power path of one cycle between the smoothing circuit 20 and the output terminal 40T. Further, by configuring the plurality of switch modules 410 such that the path lengths from all the arms (semiconductor switches 410s) included in the plurality of switch modules 410 to the junction are substantially equal, the difference in inductance of the power path passing through each semiconductor switch 410s in the U-parallel connection bus 41O1 can be made relatively small. Therefore, in the power conversion device 1, the difference in inductance of the power path in one cycle between the smoothing circuit 20 and the output terminal 40T (U-phase output terminal 41T) can be made relatively small with respect to the power path passing through each of the plurality of switch modules 410. Thus, the power conversion device 1 can suppress the imbalance of the currents of the plurality of semiconductor switches 410s (switch modules 410), and can achieve the equalization of the currents. The same applies to the plurality of switch modules 420. Therefore, in the power conversion device 1, the difference in inductance of the power path in one cycle between the smoothing circuit 20 and the output terminal 40T (V-phase output terminal 42T) can be made relatively small with respect to the power path passing through each of the plurality of switch modules 420. Thus, the power conversion device 1 can suppress the imbalance of the currents of the plurality of semiconductor switches 420s (switch modules 420), and can achieve the equalization of the currents. The same applies to the plurality of switch modules 430. Therefore, in the power conversion device 1, the difference in inductance of the power path in one cycle between the smoothing circuit 20 and the output terminal 40T (W-phase output terminal 43T) can be made relatively small for each power path passing through each of the plurality of switch modules 430. Thus, the power conversion device 1 can suppress the imbalance of the currents of the plurality of semiconductor switches 430s (switch modules 430), and can achieve the equalization of the currents.

In the present embodiment (first embodiment), the U-parallel connection bus 41O1 is configured such that the current densities of the respective paths between all the semiconductor switches 410s included in the plurality of switch modules 410 and the junction where all the paths from the plurality of switch modules 410 join each other are substantially equal. The same applies to the V parallel connection bus 42O1 and the W parallel connection bus 43O 1.

This makes it possible to make the inductances of the power paths of the respective semiconductor switches 410s in the U-parallel connection bus 41O1 substantially equal. Therefore, in the power conversion device 1, the inductance of the power path in one cycle between the smoothing circuit 20 and the output terminal 40T (U-phase output terminal 41T) can be made substantially equal to the inductance of the power path passing through each of the plurality of switch modules 410. Thus, the power conversion device 1 can further suppress the imbalance of the currents of the plurality of semiconductor switches 410s (switch modules 410), and can further achieve the uniformization of the currents. The V parallel connection bus 42O1 and the W parallel connection bus 43O1 also have the same operation and effect.

In the present embodiment (first embodiment), two switch modules 410 included in the plurality of switch modules 410 are arranged in a row in one axial direction (X-axis direction). The plurality of switch modules 420 and 430 may be the same. In the U-phase parallel connection bus bar 41O1, the paths from the two switch modules 410 to the U-phase output terminal 41T are merged at substantially the center (midpoint) of the ac output terminals 410O of the two switch modules 410 in the X-axis direction. The V parallel connection bus 42O1 and the W parallel connection bus 43O1 may be the same.

Thus, in the U parallel connection bus 41O1, the paths from the ac output terminals 410O of the two switch modules 410 can be merged so that the lengths thereof are substantially the same for each combination of the two switch modules 410. The V parallel connection bus 42O1 and the W parallel connection bus 43O1 also have the same operation and effect.

In addition, in the present embodiment (first embodiment), the plurality of switch modules 410 connected in parallel may include a combination of a plurality of two switch modules 410. The same applies to the plurality of switch modules 420 and 430 connected in parallel. The U-parallel connection bus bar 41O1 may be configured such that the lengths of the power paths between the intermediate junction where the paths of the two switch modules 410 combined in each plurality merge and the junction where the paths from all the switch modules 410 merge are substantially equal to each other. The V parallel connection bus 42O1 and the W parallel connection bus 43O1 may be the same.

Thus, the U parallel connection bus 41O1 can make the lengths of all the paths from the plurality of switch modules 410 connected in parallel to the merged path substantially equal. The V parallel connection bus 42O1 and the W parallel connection bus 43O1 also have the same operation and effect.

In the present embodiment (first embodiment), two switch modules 410 of two sets may be aligned in the X-axis direction and arranged in two rows in the other axial direction (Y-axis direction) perpendicular to the X-axis direction with respect to a plurality of (4) switch modules 410 connected in parallel. The same applies to the plurality of (4) switch modules 420 and the plurality of (4) switch modules 430. The U-parallel connection bus bar 41O1 is configured to be substantially plane-symmetrical with respect to a vertical plane at the center position of the two switch modules 410 in the X-axis direction. The U-parallel connection bus bar 41O1 may be configured to be substantially plane-symmetrical with respect to a vertical plane at the center position of the two sets in the Y-axis direction. The U-phase parallel connection bus 41O1 may be configured such that the connection portion with the wiring up to the U-phase output terminal 41T (U-phase output bus 41O2) is located at the center between the four switch modules 410 included in the two sets in the X-axis direction and the Y-axis direction. The same applies to the V parallel connection bus 42O1 and the W parallel connection bus 43O 1.

Thus, in the U parallel connection bus 41O1, specifically, the lengths of the paths from the respective parallel-connected (4) switch modules 410 to the merged path can be made substantially equal. Therefore, in the power conversion device 1, specifically, the inductances of the paths passing through the respective semiconductor switches 410s can be made substantially equal. The same operation and effect are also exerted on the V parallel connection bus 42O1 and the W parallel connection bus 43O 1.

In addition, in the present embodiment (second embodiment), the power conversion device 1 includes the smoothing circuit 20, the inverter circuit 40, and the output terminal 40T. Specifically, the inverter circuit 40 includes a U-phase circuit 41, and the U-phase circuit 41 is configured by connecting a plurality of switch modules 410 including a plurality of semiconductor switches 410s, in which upper and lower arms are connected in series, in parallel, and connecting points (ac output terminals 410O) of the upper and lower arms of each of the plurality of switch modules 410 to each other. Similarly, the inverter circuit 40 includes a V-phase circuit 42, and the V-phase circuit 42 is configured by connecting a plurality of switch modules 420 including a plurality of semiconductor switches 420s, the upper and lower arms of which are connected in series, in parallel, and connecting the connection points (ac output terminals 420O) of the upper and lower arms of each of the plurality of switch modules 420 to each other. Similarly, the inverter circuit 40 includes a W-phase circuit 43, and the W-phase circuit 43 is configured by connecting a plurality of switching modules 430 including a plurality of semiconductor switches 430s, the upper and lower arms of which are connected in series, in parallel, and connecting the connection points (ac output terminals 430O) of the upper and lower arms of each of the plurality of switching modules 430 to each other. That is, the inverter circuit 40 includes a bridge circuit configured by connecting a plurality of phases in parallel by output circuits (U-phase circuit 41, V-phase circuit 42, and W-phase circuit 43). The inverter circuit 40 outputs a predetermined alternating current based on the direct current input from the smoothing circuit 20. The output terminal 40T outputs the predetermined alternating current from the inverter circuit 40 to the outside. The inverter circuit 40 includes a positive-side dc bus 40P connecting the positive-side terminals 410P, 420P, and 430P of the plurality of switch modules 410, 420, and 430 to each other, and a negative-side dc bus 40N connecting the negative-side terminals 410N, 420N, and 430N of the plurality of switch modules 410, 420, and 430 to each other. The inverter circuit 40 includes a U-parallel connection bus 41O1 that connects the ac output terminals 410O of the plurality of switch modules 410 to each other. Similarly, the inverter circuit 40 includes a V parallel connection bus 42O1 that connects the ac output terminals 420O of the plurality of switch modules 420 to each other. Similarly, the inverter circuit 40 includes a W parallel connection bus bar 43O1 that connects the ac output terminals 430O of the plurality of switch modules 430 to each other. The positive-side dc bus bar 40P and the negative-side dc bus bar 40N have a laminated structure laminated via insulating layers 41I1, 42I1, and 43I 1. The U-parallel connection bus 41O1 is configured such that the lengths of the power paths passing through the smoothing circuit 20 of all the arms (semiconductor switches 410s) included in the plurality of switch modules 410 and the junction where the paths from the plurality of switch modules 410 join each other are substantially equal to each other. The U-parallel connection bus 41O1 is configured such that the current density of the entire path extending through each power path between the smoothing circuit 20 and the junction is substantially equal, for each of all the arms included in the plurality of switch modules 410. Similarly, the V parallel connection bus 42O1 is configured such that the lengths of the power paths passing through the smoothing circuit 20 of all the arms (semiconductor switches 420s) included in the plurality of switch modules 420 and the junction where the paths from the plurality of switch modules 420 join each other are substantially equal to each other. The V parallel connection bus 42O1 is configured such that the current density of the entire path extending through each power path between the smoothing circuit 20 and the junction is substantially equal, for each of all the arms included in the plurality of switch modules 420. Similarly, the W parallel connection bus 43O1 is configured such that the lengths of the power paths passing through the smoothing circuit 20 of each arm (semiconductor switch 430s) included in the plurality of switch modules 430 and the junction where the paths from the plurality of switch modules 430 join each other are substantially equal. The W parallel connection bus 43O1 is configured such that the current density of each power path between the smoothing circuit 20 and the junction is substantially equal throughout the entire path, passing through each of the arms included in the plurality of switch modules 430.

Thus, in the inverter circuit 40, the length of all the paths between the junctions of the dc input and the ac output and the current density of each path over the entire path can be made uniform. Therefore, in the power conversion device 1, the inductance of the power path in one cycle between the smoothing circuit 20 and the output terminal 40T (U-phase output terminal 41T) can be made substantially equal to the inductance of the power path passing through each of the plurality of switch modules 410. Thus, the power conversion device 1 can suppress the imbalance of the currents of the plurality of semiconductor switches 410s (switch modules 410), and can achieve the equalization of the currents. The same applies to the plurality of switch modules 420. Therefore, in the power conversion device 1, the inductance of the power path in one cycle between the smoothing circuit 20 and the output terminal 40T (V-phase output terminal 42T) can be made substantially equal to the inductance of the power path passing through each of the plurality of switch modules 420. Thus, the power conversion device 1 can suppress the imbalance of the currents of the plurality of semiconductor switches 420s (switch modules 420), and can achieve the equalization of the currents. The same applies to the plurality of switch modules 430. Therefore, in the power conversion device 1, the inductance of the power path in one cycle between the smoothing circuit 20 and the output terminal 40T (W-phase output terminal 43T) can be made substantially equal to the inductance of the power path passing through each of the plurality of switch modules 430. Thus, the power conversion device 1 can suppress the imbalance of the currents in the plurality of semiconductor switches 430s (switch modules 430), and can make the currents uniform.

In the present embodiment (second embodiment), the U-parallel connection bus 41O1 may be configured such that the current density at the common portion is substantially equal to the length of each of the power paths passing through the plurality of switch modules 410. The U-parallel connection bus 41O1 may be configured such that the current density of the other portion, that is, the portion corresponding to the difference in length between the power paths is substantially equal to the current density of the positive-side dc bus 40P and the negative-side dc bus 40N for each power path. The same applies to the V parallel connection bus 42O1 and the W parallel connection bus 43O 1.

Thus, in the inverter circuit 40, the current density of each path over the entire path between the junctions of the dc input and the ac input can be made substantially equal.

In the present embodiment (second embodiment), the smoothing circuit 20 and the inverter circuit 40 may be arranged in a single axial direction (X-axis direction). In addition, the plurality of switch modules 410 may be arranged in the X-axis direction. The plurality of switch modules 420 and 430 may be the same. The U-parallel connection bus bar 41O1 may include a plurality of legs 41O1a that extend in the vertical direction (Z-axis direction) from the connection point of the upper and lower arms (ac output terminal 410O) of each of the plurality of switch modules 410 and that have substantially the same length and substantially the same cross-sectional area. In addition, the U-parallel connection bus bar 41O1 may include a connection portion 41O1b that connects the plurality of leg portions 41O1a to each other so as to extend in the X-axis direction. The connection unit 41O1b may be connected to a wiring (U-phase output bus bar 41O2) up to the output terminal 40T (U-phase output terminal 41T) at an end portion distant from the smoothing circuit 20 in the X-axis direction. The connection unit 41O1b is configured such that the current density of each power path passing through each of the plurality of switch modules 410 is substantially equal to the current density of the positive-side dc bus 40P and the negative-side dc bus 40N. The V parallel connection bus 42O1 and the W parallel connection bus 43O1 may be the same.

Thus, in the inverter circuit 40, specifically, the length of all the power paths between the merging portions of the dc input and the ac output and the current density of each power path over the entire path can be made substantially equal.

In the present embodiment (second embodiment), two switch modules 410 may be arranged in two rows in two groups arranged in one axial direction (X-axis direction) and in the other axial direction (Y-axis direction) perpendicular to the X-axis direction. Further, the connecting portion 41O1b of the U-parallel connection bus bar 41O1 may connect the plurality of leg portions 41O1a to each other so as to extend in the X-axis direction and the Y-axis direction.

Thus, in the inverter circuit 40, specifically, the length of all the power paths between the merging portions of the dc input and the ac output and the current density of each power path over the entire path can be made substantially equal.

In addition, in the present embodiment (third embodiment), the power conversion device 1 includes the smoothing circuit 20, the inverter circuit 40, and the output terminal 40T. Specifically, the inverter circuit 40 includes a U-phase circuit 41, and the U-phase circuit 41 is configured by connecting a plurality of switch modules 410 including a plurality of semiconductor switches 410s, in which upper and lower arms are connected in series, in parallel, and connecting points (ac output terminals 410O) of the upper and lower arms of each of the plurality of switch modules 410 to each other. Similarly, the inverter circuit 40 includes a V-phase circuit 42, and the V-phase circuit 42 is configured by connecting a plurality of switch modules 420 including a plurality of semiconductor switches 420s, the upper and lower arms of which are connected in series, in parallel, and connecting the connection points (ac output terminals 420O) of the upper and lower arms of each of the plurality of switch modules 420 to each other. Similarly, the inverter circuit 40 includes a W-phase circuit 43, and the W-phase circuit 43 is configured by connecting a plurality of switching modules 430 including a plurality of semiconductor switches 430s, the upper and lower arms of which are connected in series, in parallel, and connecting the connection points (ac output terminals 430O) of the upper and lower arms of each of the plurality of switching modules 430 to each other. That is, the inverter circuit 40 includes a bridge circuit configured by connecting a plurality of phases in parallel by output circuits (U-phase circuit 41, V-phase circuit 42, and W-phase circuit 43). The inverter circuit 40 outputs a predetermined alternating current based on the direct current input from the smoothing circuit 20. The output terminal 40T outputs the predetermined alternating current from the inverter circuit 40 to the outside. The inverter circuit 40 includes a positive-side dc bus 40P connecting the positive-side terminals 410P, 420P, and 430P of the plurality of switch modules 410, 420, and 430 to each other, and a negative-side dc bus 40N connecting the negative-side terminals 410N, 420N, and 430N of the plurality of switch modules 410, 420, and 430 to each other. The inverter circuit 40 includes a U-parallel connection bus 41O1 that connects the ac output terminals 410O of the plurality of switch modules 410 to each other. The positive-side dc bus bar 40P, the negative-side dc bus bar 40N, and the U-side parallel connection bus bar 41O1 have a laminated structure laminated via insulating layers 41I1 and 41I 2. Similarly, the inverter circuit 40 includes a V parallel connection bus 42O1 that connects the ac output terminals 420O of the plurality of switch modules 420 to each other. The positive-side dc bus bar 40P, the negative-side dc bus bar 40N, and the V parallel connection bus bar 42O1 have a laminated structure laminated via insulating layers 42I1 and 42I 2. Similarly, the inverter circuit 40 includes a W parallel connection bus bar 43O1 that connects the ac output terminals 430O of the plurality of switch modules 430 to each other. The positive-side dc bus bar 40P, the negative-side dc bus bar 40N, and the W parallel connection bus bar 43O1 have a laminated structure laminated via insulating layers 43I1 and 43I 2. Further, the connection portion of the U-phase parallel connection bus 41O1 and the wiring (U-phase output bus 41O2) up to the output terminal 40T (U-phase output terminal 41T) is provided at a position farther from the smoothing circuit 20 than the semiconductor switch 410s farthest from the smoothing circuit 20 among all the arms (semiconductor switches 410s) included in the plurality of switch modules 410. Similarly, the connection portion between the V-phase parallel connection bus 42O1 and the wiring up to the output terminal 40T (V-phase output terminal 42T) is provided at a position farther from the smoothing circuit 20 than the semiconductor switch 420s of the first principle smoothing circuit 20 among all the arms (semiconductor switches 420s) included in the plurality of switch modules 420. Similarly, the connection portion of the W-phase parallel connection bus bar 43O1 and the wiring up to the output terminal 40T (W-phase output terminal 43T) is provided at a position distant from the smoothing circuit 20 by the semiconductor switch 430s farthest from the smoothing circuit 20 among all the arms (semiconductor switches 430s) included in the plurality of switch modules 430.

As a result, the current density of all the power paths between the merging portions of the dc input and the ac input of the inverter circuit 40 can be substantially equalized with the lamination structure of the bus bars of the inverter circuit 40. Further, with the arrangement of the connection portion between the U-phase parallel connection bus 41O1 and the U-phase output bus 41O2, the junction where the paths of the plurality of switch modules 410 join together is set so as to be close to the semiconductor switch 410s farthest from the smoothing circuit 20. That is, the lengths of all the power paths passing through the junction of the dc input and the ac output in the inverter circuit 40 of each of the plurality of switching modules 410 can be made substantially equal. Therefore, the power conversion device 1 can make all the inductances of the power paths passing through one cycle between the smoothing circuit 20 and the output terminal 40T (U-phase output terminal 41T) of each of the plurality of switching modules 410 substantially equal. Thus, the power conversion device 1 can suppress the imbalance of the currents of the plurality of semiconductor switches 410s (switch modules 410), and can achieve the equalization of the currents. The same applies to the plurality of switch modules 420. Therefore, the power conversion device 1 can make all the inductances of the power paths passing through one cycle between the smoothing circuit 20 and the output terminal 40T (V-phase output terminal 42T) of each of the plurality of switching modules 420 substantially equal. Thus, the power conversion device 1 can suppress the imbalance of the currents of the plurality of semiconductor switches 420s (switch modules 420), and can achieve the equalization of the currents. The same applies to the plurality of switch modules 430. Therefore, the power conversion device 1 can make all the inductances of the power paths passing through one cycle between the smoothing circuit 20 and the output terminal 40T (W-phase output terminal 43T) of each of the plurality of switching modules 430 substantially equal. Thus, the power conversion device 1 can suppress the imbalance of the currents of the plurality of semiconductor switches 430s (switch modules 430), and can achieve the equalization of the currents.

In the present embodiment (third embodiment), the smoothing circuit 20 and the inverter circuit 40 may be arranged in a single axial direction (X-axis direction). Further, the connection portion between the U-phase parallel connection bus bar 41O1 and the U-phase output bus bar 41O2 may be disposed at a position farther from the smoothing circuit 20 than the switch module 410 that is farthest from the smoothing circuit 20 among the plurality of switch modules 410 in the X-axis direction. The same applies to the connection between the V-phase parallel connection bus 42O1 and the V-phase output bus 42O2 and the connection between the W-phase parallel connection bus 43O1 and the W-phase output bus 43O 2.

For example, the plurality of switch modules 410 may be arranged in two rows in two groups each arranged in the X-axis direction and in the other axis direction (Y-axis direction) perpendicular to the X-axis direction. The same applies to the plurality of switch modules 420 and the plurality of switch modules 430. The connection portion between the U-phase parallel connection bus 41O1 and the U-phase output bus 41O2 may be disposed at a position farther from the ends of the two groups farther from the smoothing circuit 20 in the X-axis direction and at a substantially central position of the two groups in the Y-axis direction. The same applies to the connection between the V-phase parallel connection bus 42O1 and the V-phase output bus 42O2 and the connection between the W-phase parallel connection bus 43O1 and the W-phase output bus 43O 2.

Thus, in the inverter circuit 40, specifically, the lengths of the power paths between the merging portions of the dc input and the ac output can be made substantially equal.

In addition, in the present embodiment (fourth embodiment), the power conversion device 1 includes the smoothing circuit 20, the inverter circuit 40, and the output terminal 40T. Specifically, the inverter circuit 40 includes a U-phase circuit 41, and the U-phase circuit 41 is configured by connecting a plurality of switch modules 410 including a plurality of semiconductor switches 410s, in which upper and lower arms are connected in series, in parallel, and connecting points (ac output terminals 410O) of the upper and lower arms of each of the plurality of switch modules 410 to each other. Similarly, the inverter circuit 40 includes a V-phase circuit 42, and the V-phase circuit 42 is configured by connecting a plurality of switch modules 420 including a plurality of semiconductor switches 420s, the upper and lower arms of which are connected in series, in parallel, and connecting the connection points (ac output terminals 420O) of the upper and lower arms of each of the plurality of switch modules 420 to each other. Similarly, the inverter circuit 40 includes a W-phase circuit 43, and the W-phase circuit 43 is configured by connecting in parallel switching modules 430 including a plurality of semiconductor switches 430s, the upper and lower arms of which are connected in series, and connecting the connection points (ac output terminals 430O) of the upper and lower arms of each of the plurality of switching modules 430 to each other. That is, the inverter circuit 40 includes a bridge circuit configured by connecting a plurality of phases in parallel by output circuits (U-phase circuit 41, V-phase circuit 42, and W-phase circuit 43). The inverter circuit 40 outputs a predetermined alternating current based on the direct current input from the smoothing circuit 20. The output terminal 40T outputs the predetermined alternating current from the inverter circuit 40 to the outside. The inverter circuit 40 includes a positive-side dc bus 40P connecting the positive-side terminals 410P, 420P, and 430P of the plurality of switch modules 410, 420, and 430 to each other, and a negative-side dc bus 40N connecting the negative-side terminals 410N, 420N, and 430N of the plurality of switch modules 410, 420, and 430 to each other. The inverter circuit 40 includes a U-parallel connection bus 41O1 that connects the ac output terminals 410O of the plurality of switch modules 410 to each other. The positive-side dc bus bar 40P, the negative-side dc bus bar 40N, and the U-side parallel connection bus bar 41O1 have a laminated structure laminated via insulating layers 41I1 and 41I 2. Similarly, the inverter circuit 40 includes a V parallel connection bus 42O1 that connects the ac output terminals 420O of the plurality of switch modules 420 to each other. The positive-side dc bus bar 40P, the negative-side dc bus bar 40N, and the V parallel connection bus bar 42O1 have a laminated structure laminated via insulating layers 42I1 and 42I 2. Similarly, the inverter circuit 40 includes a W parallel connection bus bar 43O1 that connects the ac output terminals 430O of the plurality of switch modules 430 to each other. The positive-side dc bus bar 40P, the negative-side dc bus bar 40N, and the W parallel connection bus bar 43O1 have a laminated structure laminated via insulating layers 43I1 and 43I 2. Further, the connection portion between the U-phase connection bus 41O1 and the wiring (U-phase output bus 41O2) up to the output terminal 40T (U-phase output terminal 41T) is provided in parallel at a position closer to the smoothing circuit 20 than the semiconductor switch 410s closest to the smoothing circuit 20 among all the arms (semiconductor switches 410s) included in the plurality of switch modules 410. Similarly, the connection portion between the V-phase connection bus 42O1 and the wiring (V-phase output bus 42O2) up to the output terminal 40T (V-phase output terminal 42T) is provided in parallel at a position closer to the smoothing circuit 20 than the semiconductor switch 420s closest to the smoothing circuit 20 among all the arms (semiconductor switches 420s) included in the plurality of switch modules 420. Similarly, the connection portion of the W-phase parallel connection bus bar 43O1 and the wiring (W-phase output bus bar 43O2) up to the output terminal 40T (W-phase output terminal 43T) is provided at a position close to the smoothing circuit 20 from the semiconductor switch 430s closest to the smoothing circuit 20 among all the arms (semiconductor switches 430s) included in the plurality of switch modules 430.

As a result, the current density of all the power paths between the merging portions of the dc input and the ac input of the inverter circuit 40 can be substantially equalized with the lamination structure of the bus bars of the inverter circuit 40. Further, with the arrangement of the connection portion between the U-phase parallel connection bus 41O1 and the U-phase output bus 41O2, the direction of the current of the U-phase positive-electrode-side direct-current bus 41P and the direction of the current of the U-phase parallel connection bus 41O1 can be reversed in real space. Similarly, the direction of the current of the U-phase parallel connection bus 41O1 and the direction of the current of the U-phase negative electrode-side dc bus 41N can be reversed. Therefore, when currents of substantially the same current density flow in the opposite direction, the generated magnetic fields cancel each other out, and the inductance of the U-phase positive-electrode-side dc bus 41P, U and the U-phase negative-electrode-side dc bus 41O1 can be reduced to be very small. As a result, the difference in inductance of all the power paths passing through the plurality of switching modules 410 between the merging portions of the dc input and the ac input can be reduced, and the inductance between the power paths can be made uniform. Therefore, the power conversion apparatus 1 can suppress the difference in inductance of the power path through one cycle between the smoothing circuit 20 and the output terminal 40T (U-phase output terminal 41T) of each of the plurality of switch modules 410 to be very small. Thus, the power conversion device 1 can suppress the imbalance of the currents of the plurality of semiconductor switches 410s (switch modules 410), and can achieve the equalization of the currents. The same applies to the plurality of switch modules 420. Therefore, the power conversion apparatus 1 can suppress the difference in inductance of the power path through one cycle between the smoothing circuit 20 and the output terminal 40T (V-phase output terminal 42T) of each of the plurality of switch modules 420 to be very small. Thus, the power conversion device 1 can suppress the imbalance of the currents of the plurality of semiconductor switches 420s (switch modules 420), and can achieve the equalization of the currents. The same applies to the plurality of switch modules 430. Therefore, the power conversion apparatus 1 can suppress the difference in inductance of the power path through one cycle between the smoothing circuit 20 and the output terminal 40T (W-phase output terminal 43T) of each of the plurality of switch modules 430 to be very small. Thus, the power conversion device 1 can suppress the imbalance of the currents of the plurality of semiconductor switches 430s (switch modules 430), and can achieve the equalization of the currents.

In the present embodiment (fourth embodiment), the smoothing circuit 20 and the inverter circuit 40 may be arranged in a single axial direction (X-axis direction). The connection portion between the U-phase parallel connection bus bar 41O1 and the U-phase output bus bar 41O2 may be disposed at a position closer to the smoothing circuit 20 than the switch module 410 closest to the smoothing circuit 20 among the plurality of switch modules 410 in the X-axis direction. The same applies to the connection between the V-phase parallel connection bus 42O1 and the V-phase output bus 42O2 and the connection between the W-phase parallel connection bus 43O1 and the W-phase output bus 43O 2.

For example, the plurality of switch modules 410 are arranged in two rows in the other axial direction (Y-axis direction) perpendicular to the X-axis direction, two groups each arranged in the X-axis direction in a plan view. The same applies to the plurality of switch modules 420 and the plurality of switch modules 430. Further, the connection portion of the U-phase parallel connection bus 41O1 and the wiring (U-phase output bus 41O2) up to the U-phase output terminal 41T may be disposed at a position closer to the smoothing circuit 20 than the end portions of the two groups closer to the smoothing circuit 20 in the X-axis direction. The same applies to the connection portion between the V-parallel connection bus 42O1 and the wiring up to the V-phase output terminal 42T (V-phase output bus 42O2), and the connection portion between the W-parallel connection bus 43O1 and the wiring up to the W-phase output terminal 43T (W-phase output bus 43O 2).

Specifically, the directions of the currents of the U-phase positive-side dc bus 41P and the U-phase parallel connection bus 41O1 and the directions of the currents of the U-phase parallel connection bus 41O1 and the U-phase negative-side dc bus 41N can be reversed in real space. Similarly, the directions of the currents of the V-phase positive-side dc bus 42P and the V-phase parallel connection bus 42O1 and the directions of the currents of the V-phase parallel connection bus 42O1 and the V-phase negative-side dc bus 42N can be reversed in real space, respectively. Similarly, the directions of the currents of the W-phase positive-side dc bus 43P and the W-phase parallel connection bus 43O1 and the directions of the currents of the W-phase parallel connection bus 43O1 and the W-phase negative-side dc bus 43N can be reversed in real space, respectively.

Although the embodiments have been described in detail above, the present invention is not limited to the specific embodiments, and various modifications and changes can be made within the scope of the claims.

Description of the reference numerals

1 power conversion device

10 rectifier circuit

20 smoothing circuit

20I1, 20I2 insulating layer

20N negative electrode side bus

20P positive side bus

20PN laminated bus

21 smoothing capacitor

21P positive electrode side terminal

21N negative electrode-side terminal

30 fuse

40 inverter circuit

40N negative pole side direct current bus

40P positive side direct current bus

40PN laminated bus

40T output terminal

41U phase circuit (output circuit)

41I1, 41I2 insulating layer

41N U phase negative pole side DC bus

41O U AC bus

41O 1U bus for parallel connection

41O 2U-phase output bus

41P U phase positive side DC bus

41PN, 41PNO U phase laminated bus

41T U phase output terminal

42V phase circuit (output circuit)

42I1, 42I2 insulating layer

42N V phase negative pole side DC bus

42O V AC bus

42O 1V parallel connection bus

42O 2V phase output bus

42P V phase positive side DC bus

42PN, 42PNO V phase laminated bus

42T V phase output terminal

43W phase circuit (output circuit)

43I1, 43I2 insulating layer

43N W phase negative pole side DC bus

43O W AC bus

43O 1W bus for parallel connection

43O 2W-phase output bus

43P W phase positive side DC bus

43PN, 43PNO W phase laminated bus

43T W phase output terminal

410 ~ 416 switch module (switch arm)

410N-416N negative electrode-side terminal

410O-416O AC output terminal (connection point)

410P-416P Positive electrode-side terminal

410s, 411s 1-416 s1, 411s 2-416 s2 semiconductor switch

411d 1-416 d1, 411d 2-416 d2 reflux diodes

420 ~ 426 switch module (switch bridge arm)

420N-426N negative electrode-side terminal

420O 426O AC output terminal (connection point)

420P-426P positive electrode-side terminal

420s, 421s 1-426 s1, 421s 2-426 s2 semiconductor switch

421d 1-426 d1, 421d 2-426 d2 reflux diodes

430 to 436 switch module (switch arm)

430N-436N negative electrode-side terminal

430O-436O AC output terminal (connection point)

430P-436P positive electrode-side terminal

430s, 431s 1-436 s1, 431s 2-436 s2 semiconductor switch

431d 1-436 d1, 431d 2-436 d2 reflux diodes