阅读说明：本技术 电力转换装置 (Power conversion device ) 是由 松永和久 岩丸阳介 于 2020-03-02 设计创作，主要内容包括：ce本发明提供一种电力转换装置,该电力转换装置具备：正侧汇流条,其电连接于半导体开关元件部的正侧端子和平滑电容器的正侧端子；以及负侧汇流条,其电连接于半导体开关元件部的负侧端子和平滑电容器的负侧端子。并且,多个开关元件部以沿着平滑电容器的相对于呈直线状配置的端子成为线对称且与端子配置面交叉的侧面的方式在侧面上配置于端子配置面的附近。(ce the present invention provides a power conversion device, including: a positive bus bar electrically connected to a positive terminal of the semiconductor switching element unit and a positive terminal of the smoothing capacitor; and a negative bus bar electrically connected to the negative terminal of the semiconductor switching element unit and the negative terminal of the smoothing capacitor. The plurality of switching element portions are disposed in the vicinity of the terminal disposition surface on the side surface so as to be line-symmetric along the side surface of the smoothing capacitor, which is arranged with respect to the linearly-disposed terminals and intersects the terminal disposition surface.)

1. A power conversion apparatus, wherein,

the power conversion device is provided with:

a smoothing capacitor connected to an output side of a rectifier circuit that rectifies an alternating-current voltage;

a terminal arrangement surface on which terminals of the smoothing capacitor are linearly arranged;

a power conversion unit including a plurality of semiconductor switching element units for converting the dc voltage smoothed by the smoothing capacitor into an ac voltage;

a positive-side bus bar electrically connected to a positive-side terminal of the semiconductor switching element portion and a positive-side terminal of the smoothing capacitor; and

a negative-side bus bar electrically connected to a negative-side terminal of the semiconductor switching element portion and a negative-side terminal of the smoothing capacitor,

the plurality of semiconductor switching element units are disposed in the vicinity of the terminal disposition surface on the side surface so as to be symmetrical along the terminal line of the smoothing capacitor disposed linearly and intersect the terminal disposition surface.

2. The power conversion apparatus according to claim 1,

the plurality of semiconductor switching element portions are arranged on both the side surfaces on one side and the other side with respect to the terminal arrangement surface so that impedances between the respective semiconductor switching element portions and the smoothing capacitor are equal.

3. The power conversion apparatus according to claim 2,

a distance on the positive side bus bar between the positive side terminal of the one-side semiconductor switching element section disposed on one side of the positive side terminal of the smoothing capacitor and the terminal of the smoothing capacitor is equal to a distance on the positive side bus bar between the positive side terminal of the other-side semiconductor switching element section disposed on the other side of the positive side terminal of the smoothing capacitor and the terminal of the smoothing capacitor,

a distance between the negative side terminal of the one side semiconductor switching element portion and the terminal of the smoothing capacitor on the negative side bus bar is equal to a distance between the negative side terminal of the other side semiconductor switching element portion and the terminal of the smoothing capacitor on the negative side bus bar.

4. The power conversion apparatus according to any one of claims 1 to 3,

the positive-side bus bar and the negative-side bus bar are provided commonly to the plurality of semiconductor switching element portions, respectively, and have U-shapes covering regions of the terminal arrangement surface and the two side surfaces of the smoothing capacitor, respectively.

5. The power conversion apparatus according to claim 1,

The height position of the semiconductor switching element portion arranged on the side surface on one side with respect to the terminal of the smoothing capacitor with respect to the smoothing capacitor is equal to the height position of the semiconductor switching element portion arranged on the side surface on the other side with respect to the terminal of the smoothing capacitor with respect to the smoothing capacitor.

6. The power conversion apparatus according to claim 1,

the power conversion device further includes a cooling pipe portion provided on a surface of at least one of the positive-side bus bar and the negative-side bus bar, and through which cooling water flows.

Technical Field

The present invention relates to a power conversion device, and more particularly, to a power conversion device including a plurality of semiconductor switching element units.

Background

Conventionally, a power conversion device including a plurality of switching elements (semiconductor switching element units) is known. Such a power conversion device is disclosed in, for example, japanese patent laid-open No. 2004-135444.

Japanese patent application laid-open No. 2004-135444 discloses a power conversion device including a switch module that accommodates two elements therein. In this power conversion apparatus, a plurality of (6) switch modules are provided. In addition, the power conversion device is provided with a plurality of electrolytic capacitors. In addition, the power conversion device is provided with a flat plate-shaped bus bar connecting the plurality of switch modules and the plurality of electrolytic capacitors. The bus bar has a substantially T-shape when viewed from a direction perpendicular to a surface of the bus bar. The substantially T-shaped bus bar includes a 1 st straight line portion along the lateral direction and a 2 nd straight line portion along the longitudinal direction branched from the 1 st straight line portion. The terminals of the plurality of electrolytic capacitors are connected to the 1 st straight line portion. In addition, a plurality of switch assemblies are connected with the 2 nd straight line part.

Further, although not explicitly described in japanese patent application laid-open No. 2004-135444, the electrolytic capacitor may be considered to have a substantially cylindrical shape. The electrolytic capacitor is connected to the plate-shaped bus bar so as to extend in a direction perpendicular to the surface of the plate-shaped bus bar. In addition, the switch assembly has a substantially rectangular shape (substantially flat plate shape). The plurality of switch modules are arranged such that the substantially flat switch modules extend along the surface of the flat bus bar. That is, the plurality of switch modules are arranged along a direction orthogonal to the side surface of the substantially cylindrical electrolytic capacitor.

However, in the power conversion device described in japanese patent application laid-open No. 2004-135444, since the plurality of switch modules are arranged along the direction orthogonal to the side surface of the substantially cylindrical electrolytic capacitor, there are problems as follows: the size of the power conversion apparatus (the area where the electrolytic capacitor and the plurality of switching components are arranged) becomes relatively large when viewed from the direction perpendicular to the surface of the bus bar. Further, the terminals of the plurality of electrolytic capacitors are connected to the 1 st straight line portion, and the plurality of (6) switch modules are connected to the 2 nd straight line portion. Therefore, it is considered that the switch modules disposed on the side of the 2 nd straight line portion closer to the electrolytic capacitor and the switch modules disposed on the side of the 2 nd straight line portion farther from the electrolytic capacitor have different lengths of current flow paths from the switch modules to the electrolytic capacitor, and therefore, there is a problem that the flow of current becomes unbalanced among the plurality of switch modules.

Disclosure of Invention

Problems to be solved by the invention

The present invention has been made to solve the above-described problems, and 1 object of the present invention is to provide a power conversion device that can suppress an increase in size and reduce an imbalance in the flow of current.

Means for solving the problems

In order to achieve the above object, one aspect of the present invention provides a power conversion device including: a smoothing capacitor connected to an output side of a rectifier circuit that rectifies an alternating-current voltage; a terminal arrangement surface on which terminals of the smoothing capacitor are linearly arranged; a power conversion unit including a plurality of semiconductor switching element units for converting the dc voltage smoothed by the smoothing capacitor into an ac voltage; a positive bus bar electrically connected to a positive terminal of the semiconductor switching element unit and a positive terminal of the smoothing capacitor; and a negative bus bar electrically connected to the negative terminal of the semiconductor switching element unit and the negative terminal of the smoothing capacitor, wherein the plurality of semiconductor switching element units are arranged in the vicinity of the terminal arrangement surface on the side surface so as to be line-symmetric with respect to the linearly arranged terminals of the smoothing capacitor and to intersect the terminal arrangement surface.

In the power conversion device according to one aspect of the present invention, as described above, the plurality of semiconductor switching element portions are arranged in the vicinity of the terminal arrangement surface on the side surface so as to be line-symmetric with respect to the linearly arranged terminals of the smoothing capacitor and so as to intersect the terminal arrangement surface. Thus, since the plurality of semiconductor switching element portions are arranged along the side surface of the smoothing capacitor, the area in which the smoothing capacitor and the plurality of semiconductor switching element portions are arranged can be made relatively small when viewed in the direction perpendicular to the terminal arrangement surface. As a result, the power conversion device can be prevented from becoming large. Further, since the semiconductor switching element portions are arranged along the side surfaces of the smoothing capacitor which are line-symmetrical with respect to the linearly arranged terminals, the length (distance) of the current flow path between the semiconductor switching element portion arranged on one side of the line-symmetrical side surfaces and the terminals of the smoothing capacitor and the length of the current flow path between the semiconductor switching element portion arranged on the other side of the line-symmetrical side surfaces and the terminals of the smoothing capacitor can be easily made the same. This can reduce imbalance in the flow of current while suppressing an increase in size.

Further, since the plurality of semiconductor switching element portions are disposed in the vicinity of the terminal disposition surface on the side surface of the smoothing capacitor, the distance between the plurality of semiconductor switching element portions and the smoothing capacitor becomes relatively small. The terminals of the semiconductor switching element unit and the terminals of the smoothing capacitor are connected by bus bars (positive-side bus bar and negative-side bus bar) having inductance smaller than that of a lead wire or the like. This reduces the inductance between the plurality of semiconductor switching element units and the smoothing capacitor. This can reduce the surge voltage generated during switching. Further, if the surge voltage is reduced to such a degree that a snubber capacitor for reducing the surge voltage is not necessary, it is possible to suppress complication of the structures of the positive-side bus bar and the negative-side bus bar due to the provision of the snubber capacitor. This makes it possible to easily replace the components such as the positive bus bar and the negative bus bar.

In the power conversion device according to the above-described aspect, the plurality of semiconductor switching element portions are preferably arranged on both the one side surface and the other side surface with respect to the terminal arrangement surface so that impedances between the respective semiconductor switching element portions and the smoothing capacitor in the plurality of semiconductor switching element portions are equal to each other. With this configuration, it is possible to reduce the imbalance in the magnitude of the surge voltage generated in each of the plurality of semiconductor switching element units.

In this case, it is preferable that a distance on the positive-side bus bar between the positive-side terminal of the one semiconductor switching element section disposed on one side of the positive-side terminal of the smoothing capacitor and the terminal of the smoothing capacitor is equal to a distance on the positive-side bus bar between the positive-side terminal of the other semiconductor switching element section disposed on the other side of the positive-side terminal of the smoothing capacitor and the terminal of the smoothing capacitor, and a distance on the negative-side bus bar between the negative-side terminal of the one semiconductor switching element section and the terminal of the smoothing capacitor is equal to a distance on the negative-side bus bar between the negative-side terminal of the other semiconductor switching element section and the terminal of the smoothing capacitor. With this configuration, the impedances between the semiconductor switching element sections and the smoothing capacitor can be easily equalized by only making the distances substantially equal.

In the power conversion device according to the above-described aspect, the positive-side bus bar and the negative-side bus bar are each preferably provided in common to the plurality of semiconductor switching element units and each preferably have a U-shape covering regions of the terminal arrangement surface and both side surfaces of the smoothing capacitor. With this configuration, the portion where the U-shaped positive bus bar and the U-shaped negative bus bar face each other is relatively large, and therefore, the inductance can be further reduced.

In the power converter according to the above-described aspect, it is preferable that a height position of the semiconductor switching element portion arranged on one side surface with respect to the terminal of the smoothing capacitor with respect to the smoothing capacitor is equal to a height position of the semiconductor switching element portion arranged on the other side surface with respect to the terminal of the smoothing capacitor with respect to the smoothing capacitor. With this configuration, the distances between the respective semiconductor switching element portions of the plurality of semiconductor switching element portions and the terminals of the smoothing capacitor (the distances of the paths through which the current flows) can be easily made equal.

In the power conversion device according to the above aspect, it is preferable that the power conversion device further includes a cooling pipe portion that is provided on a surface of at least one of the positive-side bus bar and the negative-side bus bar and through which cooling water flows. With this configuration, even when a large current flows through at least one of the positive-side bus bar and the negative-side bus bar and the amount of heat generated by at least one of the positive-side bus bar and the negative-side bus bar increases, heat can be efficiently dissipated from at least one of the positive-side bus bar and the negative-side bus bar by the cooling pipe portion through which cooling water flows.

Drawings

Fig. 1 is a circuit diagram of a power conversion device according to an embodiment.

Fig. 2 is a perspective view of a stack portion of a power conversion device according to an embodiment.

Fig. 3 is an exploded perspective view (1) of a stack portion of the power conversion device according to the embodiment.

Fig. 4 is a cross-sectional view (side view) of a stacked portion of a power conversion device according to an embodiment.

Fig. 5 is an exploded perspective view (2) of a stack portion of the power conversion device according to the embodiment.

Detailed Description

Hereinafter, embodiments embodying the present invention will be described based on the drawings.

The configuration of the power conversion device 100 according to the present embodiment will be described with reference to fig. 1 to 5. The power converter 100 is, for example, a power converter 100 for an induction heating device of a melting furnace for melting metal by induction heating. The power converter 100 is configured to generate ac from an ac power supply 300 using a semiconductor switching element 31. In addition, a plurality of (for example, two) ac power supplies 200 are provided.

(Circuit configuration of Power conversion device)

A circuit configuration of the power conversion apparatus 100 is explained with reference to fig. 1. The power conversion device 100 includes a plurality of rectifier circuits 10 (rectifier circuits 10a to 10 d). The rectifier circuit 10 converts an ac voltage input from the ac power supply 200 into a dc voltage. The rectifier circuits 10 are provided in plurality for 1 ac power supply 200.

The power conversion device 100 includes a plurality of smoothing capacitors 20 (smoothing capacitors 20a to 20 d). The smoothing capacitor 20 is connected to the output side of the rectifier circuit 10 that rectifies the ac voltage. The smoothing capacitor 20 is provided one for each rectifying circuit 10. The smoothing capacitor 20 may be configured such that a plurality of capacitors are connected in series or in parallel, which is not shown in fig. 1.

The power conversion device 100 includes a plurality of inverter units 30 (inverter units 30a to 30 d). The inverter unit 30 converts the dc voltage smoothed by the rectifier circuit 10 into an ac voltage. Then, the converted ac voltage is output from the inverter unit 30 to the induction heating coil 210. In this example, the inverter unit 30 is provided for each rectifier circuit 10, but a plurality of inverter units 30 may be connected to 1 rectifier circuit 10 and 1 smoothing capacitor 20. The inverter unit 30 (inverter unit 30a to inverter unit 30d) is an example of the "power conversion unit" in the claims.

In addition, the smoothing capacitor 20 and the inverter section 30 constitute a stack section (circuit unit) 40. The stacking unit 40 includes a plurality of stacking units (stacking unit 40a to stacking unit 40 d).

The inverter unit 30 includes a plurality of semiconductor switching elements 31 (semiconductor switching elements 31a to 31 d). Further, the semiconductor switching element 31a and the semiconductor switching element 31b are accommodated in 1 semiconductor package 32 (semiconductor package 32 a). In addition, the semiconductor switching element 31c and the semiconductor switching element 31d are accommodated in 1 semiconductor package 32 (semiconductor package 32 b). The semiconductor modules 32a and 32b are provided in parallel at 6, respectively, and are not shown in fig. 1. The semiconductor switching elements 31a to 31d form a full bridge circuit. The semiconductor element 32 is an example of the "semiconductor switching element portion" in the claims. The semiconductor element 32a and the semiconductor element 32b are examples of "one-side semiconductor switching element portion" and "the other-side semiconductor switching element portion" in the claims.

Further, the anode side and the cathode side of the rectifier circuit 10a are electrically connected to the anode side and the cathode side of the rectifier circuit 10c, respectively. Further, the anode side and the cathode side of the rectifier circuit 10b are electrically connected to the anode side and the cathode side of the rectifier circuit 10d, respectively.

The positive electrode side and the negative electrode side of the smoothing capacitor 20a are electrically connected to the positive electrode side and the negative electrode side of the smoothing capacitor 20c, respectively. The positive electrode side and the negative electrode side of the smoothing capacitor 20b are electrically connected to the positive electrode side and the negative electrode side of the smoothing capacitor 20d, respectively.

Further, a connection point at which the semiconductor switching element 31a and the semiconductor switching element 31b of the inverter unit 30a (inverter unit 30c) are connected is electrically connected to one end side of the induction heating coil 210. Further, a connection point at which the semiconductor switching element 31c and the semiconductor switching element 31d of the inverter unit 30b (inverter unit 30d) are connected is electrically connected to the other end side of the induction heating coil 210.

Further, a connection point between the semiconductor switching element 31c and the semiconductor switching element 31d of the inverter unit 30a is electrically connected to a connection point between the semiconductor switching element 31a and the semiconductor switching element 31b of the inverter unit 30 b. That is, the stack portion 40a and the stack portion 40b are electrically connected in series. Further, a connection point between the semiconductor switching element 31c and the semiconductor switching element 31d of the inverter unit 30c is electrically connected to a connection point between the semiconductor switching element 31a and the semiconductor switching element 31b of the inverter unit 30 d. That is, the stacked portion 40c and the stacked portion 40d are connected in series. This can increase the output voltage of the power conversion device 100.

(concrete construction of Stacking portion)

Next, a specific structure of the stack portion 40 will be described with reference to fig. 2 to 5.

As shown in fig. 2 and 3, the smoothing capacitor 20 is formed of a film capacitor having a substantially rectangular parallelepiped shape. As shown in fig. 3, the smoothing capacitor 20 includes a terminal arrangement surface 22 on which the terminals 21 of the smoothing capacitor 20 are linearly arranged. The terminal disposition surface 22 is a surface on the Z1 direction side of the smoothing capacitor 20. The terminal 21 includes a positive terminal 21p and a negative terminal 21 n. The positive-side terminals 21p and the negative-side terminals 21n are alternately arranged along the X direction on the terminal arrangement surface 22.

The semiconductor element 32 includes a positive side terminal 32p, a negative side terminal 32n, and an output terminal 32 o. The positive terminal 32p, the negative terminal 32n, and the output terminal 32o are arranged in the order of the positive terminal 32p, the negative terminal 32n, and the output terminal 32o from the Z1 direction side toward the Z2 direction side.

Here, in the present embodiment, the semiconductor element 32 is disposed along the side surface 23 of the smoothing capacitor 20 intersecting the terminal disposition surface 22, and the side surface 23 is line-symmetrical with respect to the linearly disposed terminals 21. The semiconductor element 32 is disposed near the terminal disposition surface 22 on the side surface 23. Specifically, for example, 6 parallel (6) semiconductor modules 32a among the plurality of semiconductor modules 32 are arranged along the X direction on the side surface 23a on the Y1 direction side of the smoothing capacitor 20. As shown in fig. 4, the 6 parallel (6) semiconductor modules 32b are arranged along the X direction on the side surface 23b on the Y2 direction side of the smoothing capacitor 20. The semiconductor element 32 is arranged such that the front surface (the surface on which the positive-side terminal 32p, the negative-side terminal 32n, and the output terminal 32o are provided) of the semiconductor element 32 is along the side surface 23.

As shown in fig. 3, the semiconductor element 32 is disposed in the vicinity of the terminal disposition surface 22 in the Z direction. For example, the semiconductor element 32 is disposed on the Z1 direction side with respect to the center C in the Z direction of the side surface 23.

A cooling plate 24 made of a metal plate or the like is disposed on the side surface 23 of the smoothing capacitor 20. The semiconductor module 32 is disposed on the surface of the cooling plate 24. As shown in fig. 4, a cooling pipe portion 25 through which cooling water flows is provided on the surface of the cooling plate 24 on the smoothing capacitor 20 side. The semiconductor modules 32 are cooled by the cooling water flowing through the cooling pipe portion 25 via the cooling plate 24.

In the present embodiment, as shown in fig. 4, the height position h1 of the semiconductor element 32a disposed on the side surface 23a on one side with respect to the terminal 21 of the smoothing capacitor 20 with respect to the smoothing capacitor 20 is substantially equal to the height position h2 of the semiconductor element 32b disposed on the side surface 23b on the other side with respect to the terminal 21 of the smoothing capacitor 20 with respect to the smoothing capacitor 20. Specifically, the height position h1 of the end portion of the semiconductor package 32a on the Z1 direction side is substantially equal to the height position h2 of the end portion of the semiconductor package 32b on the Z1 direction side. In addition, the height positions h1 of the 6 semiconductor elements 32a are equal to each other. In addition, the height positions h2 of the 6 semiconductor elements 32b are equal to each other.

As shown in fig. 3, the positive bus bar 50 is provided in the stack portion 40. The positive-side bus bar 50 is electrically connected to the positive-side terminal 32p of the semiconductor assembly 32 and the positive-side terminal 21p of the smoothing capacitor 20. The negative-side bus bar 60 is provided in the stack portion 40. The negative-side bus bar 60 is electrically connected to the negative-side terminal 32n of the semiconductor assembly 32 and the negative-side terminal 21n of the smoothing capacitor 20. The "bus bar" is a conductor for large capacity current to flow, and is made of copper or the like.

In the present embodiment, the plurality of semiconductor elements 32 are arranged on both the side surface 23a on the one side and the side surface 23b on the other side with respect to the terminal arrangement surface 22 such that the impedance (each impedance) between each semiconductor element 32 of the plurality of semiconductor elements 32 and the smoothing capacitor 20 is substantially equal.

Specifically, in the present embodiment, as shown in fig. 4, a distance L1 (distance indicated by a one-dot chain line in fig. 4) on the positive bus bar 50 between the positive terminal 32p of the semiconductor element 32a disposed on one side (side surface 23a) of the smoothing capacitor 20 and the terminal 21 of the smoothing capacitor 20 is substantially equal to a distance L2 on the positive bus bar 50 between the positive terminal 32p of the semiconductor element 32b disposed on the other side (side surface 23b) of the smoothing capacitor 20 and the terminal 21 of the smoothing capacitor 20. Further, a distance L11 on the negative side bus bar 60 between the negative side terminal 32n of the semiconductor package 32a and the terminal 21 of the smoothing capacitor 20 is substantially equal to a distance L12 on the negative side bus bar 60 between the negative side terminal 32n of the semiconductor package 32b and the terminal 21 of the smoothing capacitor 20. Specifically, the distance L1 on the positive bus bar 50 between the positive terminal 32p of the semiconductor package 32a and the positive terminal 21p of the smoothing capacitor 20 is substantially equal to the distance L2 on the positive bus bar 50 between the positive terminal 32p of the semiconductor package 32b and the positive terminal 21p of the smoothing capacitor 20. Further, a distance L11 on the negative-side bus bar 60 between the negative-side terminal 32n of the semiconductor element 32a and the negative-side terminal 21n of the smoothing capacitor 20 is substantially equal to a distance L12 on the negative-side bus bar 60 between the negative-side terminal 32n of the semiconductor element 32b and the negative-side terminal 21n of the smoothing capacitor 20. Further, "the distance on the positive side bus bar 50" means the shortest distance between the positive side terminal 32p of the semiconductor module 32 and the positive side terminal 21p of the smoothing capacitor 20 on the positive side bus bar 50. The same applies to the meaning of "distance on the negative-side bus bar 60".

In addition, in the present embodiment, as shown in fig. 3, the positive-side bus bar 50 and the negative-side bus bar 60 are provided in common to the plurality of semiconductor modules 32, respectively. As shown in fig. 4, each of the positive-side bus bar 50 and the negative-side bus bar 60 has a substantially U-shape covering the terminal arrangement surface 22 and the areas of both the side surfaces 23a and 23b of the smoothing capacitor 20. Specifically, with respect to the smoothing capacitor 20, the positive-side bus bar 50 and the negative-side bus bar 60 are laminated in the order of the positive-side bus bar 50 and the negative-side bus bar 60. That is, the substantially U-shaped positive bus bar 50 is disposed inside the substantially U-shaped negative bus bar 60. In addition, the positive-side bus bar 50 and the negative-side bus bar 60 are each formed by bending 1 metal plate.

As shown in fig. 5, an insulating paper 70 is disposed between the positive bus bar 50 and the negative bus bar 60. The insulating paper 70 is provided in plural.

As shown in fig. 4, the positive-side bus bar 50 includes a 1 st portion 51 extending in the Y direction and a 2 nd portion 52 extending from both ends of the 1 st portion 51 in the Y direction toward the Z2 direction side. In addition, the negative-side bus bar 60 includes a 1 st portion 61 extending along the Y direction and a 2 nd portion 62 extending toward the Z2 direction side from both ends of the 1 st portion 61 in the Y direction. Also, the length L21 in the Y direction of the 1 st portion 51 of the positive-side bus bar 50 is smaller than the length L22 in the Y direction of the 1 st portion 61 of the negative-side bus bar 60. In addition, the length L31 in the Z direction of the 2 nd portion 52 of the positive-side bus bar 50 is smaller than the length L32 in the Z direction of the 2 nd portion 62 of the negative-side bus bar 60.

The positive-side bus bar 50 has a leg portion 53 connected to the positive-side terminal 32p of the semiconductor package 32a and the positive-side terminal 32p of the semiconductor package 32 b. In addition, the negative-side bus bar 60 has leg portions 63 connected to the negative-side terminal 32n of the semiconductor package 32a and the negative-side terminal 32n of the semiconductor package 32 b. The leg portion 53 of the positive side bus bar 50 is connected to the positive side terminal 32p of the semiconductor package 32 by the screw 80. In addition, the leg portion 63 of the negative side bus bar 60 is connected to the negative side terminal 32n of the semiconductor module 32 by the screw 80. In addition, the leg portion 53 and the leg portion 63 are disposed along the Y direction. In addition, the length L41 in the Y direction of the leg portion 53 of the positive-side bus bar 50 is smaller than the length L42 in the Y direction of the leg portion 63 of the negative-side bus bar 60.

The interval D1 in the Z direction between the 1 st portion 51 of the positive side bus bar 50 and the 1 st portion 61 of the negative side bus bar 60 is relatively small. In addition, the interval D2 in the Y direction between the 2 nd portion 52 of the positive-side bus bar 50 and the 2 nd portion 62 of the negative-side bus bar 60 is relatively small. On the other hand, the interval D3 in the Z direction between the leg portion 53 of the positive-side bus bar 50 and the leg portion 63 of the negative-side bus bar 60 is relatively large. However, the portion of the entire region of the positive-side bus bar 50 that is relatively large in comparison with the interval between the negative-side bus bars 60 is only the leg portion 53 (only a relatively small region). Thus, leg portion 53 (leg portion 63) has a small influence on the effect of reducing inductance of positive-side bus bar 50 and negative-side bus bar 60, which is achieved by stacking positive-side bus bar 50 and negative-side bus bar 60.

As shown in fig. 5, the positive bus bar 50 is provided with a plurality of holes 54. Further, the negative bus bar 60 is provided with a plurality of holes 64. Further, the insulating paper 70 is provided with a plurality of holes 71. The screw 80 is screwed to the positive terminal 21p of the smoothing capacitor 20 from the Z1 direction side via the hole 64 of the negative bus bar 60, the hole 71 of the insulating paper 70, and the positive bus bar 50. Thereby, the positive bus bar 50 is connected to the positive terminal 21p of the smoothing capacitor 20. The screw 80 is screwed to the negative terminal 21n of the smoothing capacitor 20 from the Z1 direction side through the negative bus bar 60, the hole 71 of the insulating paper 70, and the hole 54 of the positive bus bar 50. Thereby, the negative-side bus bar 60 is connected to the negative-side terminal 21n of the smoothing capacitor 20.

In the present embodiment, a cooling pipe portion 81 through which cooling water flows is provided on the surface of at least one (both in the present embodiment) of the positive bus bar 50 and the negative bus bar 60. The positive bus bar 50 is provided with a cooling pipe portion 81p inside the 2 nd portion 52 of the substantially U-shaped positive bus bar 50. In addition, the negative bus bar 60 is provided with the cooling pipe portion 81n outside the 2 nd portion 52 of the negative bus bar 60 having a substantially U-shape. The cooling pipe part 81p (cooling pipe part 81n) is formed in a substantially annular shape with respect to the 2 nd part 52 of the positive bus bar 50 (the 2 nd part 52 of the negative bus bar 60).

As described above, by disposing the semiconductor modules 32 in the vicinity of the terminal disposition surface 22 on the side surface 23 of the smoothing capacitor 20, making the impedances between each of the semiconductor modules 32 and the smoothing capacitor 20 substantially equal, and laminating the positive-side bus bar 50 and the negative-side bus bar 60, etc., the inductance between each of the semiconductor modules 32 and the smoothing capacitor 20 is suppressed to about 10nH or less. This eliminates the need for providing a snubber capacitor for reducing the surge voltage.

[ Effect of the embodiment ]

In the present embodiment, the following effects can be obtained.

In the present embodiment, as described above, the plurality of semiconductor elements 32 are arranged in the vicinity of the terminal arrangement surface 22 on the side surface 23 so as to be symmetrical with respect to the linearly arranged terminals 21 of the smoothing capacitor 20 and so as to be along the side surface 23 intersecting the terminal arrangement surface 22. Thus, since the plurality of semiconductor modules 32 are arranged along the side surface 23 of the smoothing capacitor 20, the area in which the smoothing capacitor 20 and the plurality of semiconductor modules 32 are arranged can be made relatively small when viewed from the direction perpendicular to the terminal arrangement surface 22. As a result, the power converter 100 can be prevented from becoming large. Further, since the semiconductor element 32 is disposed along the side surface 23 of the smoothing capacitor 20 which is line-symmetrical with respect to the linearly-disposed terminal 21, the length (distance) of the current flow path between the semiconductor element 32 disposed on one side of the line-symmetrical side surface 23 and the terminal 21 of the smoothing capacitor 20 and the length of the current flow path between the semiconductor element 32 disposed on the other side of the line-symmetrical side surface 23 and the terminal 21 of the smoothing capacitor 20 can be easily made the same. This can reduce imbalance in the flow of current while suppressing an increase in size.

Further, since the plurality of semiconductor elements 32 are arranged in the vicinity of the terminal arrangement surface 22 on the side surface 23 of the smoothing capacitor 20, the distance between the plurality of semiconductor elements 32 and the smoothing capacitor 20 becomes relatively small. The terminals (the positive-side terminal 32p and the negative-side terminal 32n) of the semiconductor module 32 and the terminal 21 of the smoothing capacitor 20 are connected by bus bars (the positive-side bus bar 50 and the negative-side bus bar 60) having smaller inductance than that of a wire or the like. This reduces the inductance between the plurality of semiconductor elements 32 and the smoothing capacitor 20. This can reduce the surge voltage generated during switching. Further, if the surge voltage is reduced to such a degree that a snubber capacitor for reducing the surge voltage is not necessary, the structure of the positive bus bar 50 and the negative bus bar 60 can be suppressed from being complicated by the provision of the snubber capacitor. This makes it possible to easily replace the components such as the positive bus bar 50 and the negative bus bar 60.

In the present embodiment, as described above, the plurality of semiconductor modules 32 are arranged on both the side surfaces 23 on one side and the other side with respect to the terminal arrangement surface 22 so that the impedances between the respective semiconductor modules 32 of the plurality of semiconductor modules 32 and the smoothing capacitor 20 are substantially equal. This reduces the imbalance in the magnitude of the surge voltage generated in each of the plurality of semiconductor modules 32.

In the present embodiment, as described above, the distance L1 on the positive bus bar 50 between the positive terminal 32p of the semiconductor element 32a disposed on one side of the positive terminal 21p of the smoothing capacitor 20 and the terminal 21 of the smoothing capacitor 20 is substantially equal to the distance L2 on the positive bus bar 50 between the positive terminal 32p of the semiconductor element 32b disposed on the other side of the positive terminal 21p of the smoothing capacitor 20 and the terminal 21 of the smoothing capacitor 20. Further, a distance L11 on the negative side bus bar 60 between the negative side terminal 32n of the semiconductor package 32a and the terminal 21 of the smoothing capacitor 20 is substantially equal to a distance L12 on the negative side bus bar 60 between the negative side terminal 32n of the semiconductor package 32b and the terminal 21 of the smoothing capacitor 20. Thus, by making the distances substantially equal, it is easy to make the impedances between the respective semiconductor elements 32 of the plurality of semiconductor elements 32 and the smoothing capacitor 20 substantially equal.

In the present embodiment, as described above, the positive-side bus bar 50 and the negative-side bus bar 60 are provided in a substantially U-shape that is common to the plurality of semiconductor modules 32 and that covers the regions of the terminal arrangement surface 22 and the two side surfaces 23 of the smoothing capacitor 20. Accordingly, the portion where the substantially U-shaped positive bus bar 50 and the substantially U-shaped negative bus bar 60 face each other is relatively large, and therefore, the inductance can be further reduced.

In the present embodiment, as described above, the height position h1 of the semiconductor element 32a disposed on the side surface 23a on one side with respect to the terminal 21 of the smoothing capacitor 20 with respect to the smoothing capacitor 20 is substantially equal to the height position h2 of the semiconductor element 32b disposed on the side surface 23b on the other side with respect to the terminal 21 of the smoothing capacitor 20 with respect to the smoothing capacitor 20. This makes it easy to make the distances between each of the plurality of semiconductor elements 32 and the terminal 21 of the smoothing capacitor 20 (the distances of the paths through which the current flows) substantially equal.

In the present embodiment, as described above, the cooling pipe portion 81 through which cooling water flows is provided on the surface of at least one of the positive bus bar 50 and the negative bus bar 60. Thus, even when a large current flows through at least one of the positive bus bar 50 and the negative bus bar 60 and the amount of heat generated by at least one of the positive bus bar 50 and the negative bus bar 60 increases, heat can be efficiently dissipated from at least one of the positive bus bar 50 and the negative bus bar 60 by the cooling pipe portion 81 through which cooling water flows.

[ modified examples ]

The embodiments disclosed herein are to be considered in all respects as illustrative and not restrictive. The scope of the present invention is indicated by the claims, rather than by the description of the embodiments described above, and all changes (modifications) that come within the meaning and range of equivalency of the claims are intended to be embraced therein.

For example, in the above-described embodiments, the example in which the impedances between each of the plurality of semiconductor devices and the smoothing capacitor are made substantially equal by making the distances between each of the plurality of semiconductor devices and the smoothing capacitor substantially equal has been described, but the present invention is not limited to this. For example, the impedances between each of the plurality of semiconductor devices and the smoothing capacitor may be made substantially equal by adjusting the cross-sectional area of the bus bar between each of the plurality of semiconductor devices and the smoothing capacitor.

In the above-described embodiment, the positive-side bus bar and the negative-side bus bar are respectively provided in common to the plurality of (12) semiconductor modules, but the present invention is not limited to this. For example, the positive-side bus bar and the negative-side bus bar may be divided.

In the above-described embodiment, the positive-side bus bar and the negative-side bus bar are each formed by bending 1 metal plate, but the present invention is not limited to this. For example, the positive-side bus bar and the negative-side bus bar may be formed by joining metal plates, respectively.

In the above-described embodiment, the example in which the semiconductor modules (the semiconductor module 32a and the semiconductor module 32b) are arranged in parallel at 6 is shown, but the present invention is not limited thereto. For example, the number of semiconductor devices other than the number 6 may be provided in parallel.

In the above-described embodiment, the example in which two switching elements are accommodated in 1 semiconductor module is shown, but the present invention is not limited thereto. For example, a number of switching elements other than two may be accommodated in 1 semiconductor device.

In the above-described embodiments, the height positions of the semiconductor elements arranged on one side surface and the height positions of the semiconductor elements arranged on the other side surface are made substantially equal to each other. For example, even if the height positions of the semiconductor elements arranged on the one side surface and the other side surface are not substantially equal to each other, it is not necessary to align the height positions of the plurality of semiconductor elements as long as the impedances between the respective semiconductor elements and the smoothing capacitor are substantially equal to each other.

In the above-described embodiment, the cooling pipe portions are provided to both the positive-side bus bar and the negative-side bus bar, but the present invention is not limited to this. For example, a cooling pipe portion may be provided in one of the positive-side bus bar and the negative-side bus bar.