阅读说明：本技术 电力变换装置 (Power conversion device ) 是由 和田敏裕 石原浩毅 于 2017-05-19 设计创作，主要内容包括：电力变换装置(101)具备：第一平滑电路(105),连接于第一电气装置(102)；第二平滑电路(109),连接于第二电气装置(106)；第一桥电路(110),连接于第一平滑电路(105)；变压器(112),初级侧连接有第三电气装置(111),次级侧连接有第一桥电路(110)和第二平滑电路(109)；以及控制器(113),控制器(113)使第一桥电路(110)的占空比以高于第一和第二平滑电路(105、109)的截止频率的频率变动,控制占空比的不变分量而控制第一和第二电气装置(102、106)之间的电力授受的同时控制占空比的变动分量的相位,控制与第三电气装置(111)之间的电力授受。(A power conversion device (101) is provided with: a first smoothing circuit (105) connected to the first electrical device (102); a second smoothing circuit (109) connected to the second electrical device (106); a first bridge circuit (110) connected to the first smoothing circuit (105); a transformer (112) having a primary side connected to a third electrical device (111) and a secondary side connected to a first bridge circuit (110) and a second smoothing circuit (109); and a controller (113), wherein the controller (113) controls the phase of the variable component of the duty ratio while controlling the transmission and reception of electric power between the first and second electric devices (102, 106) by varying the duty ratio of the first bridge circuit (110) at a frequency higher than the cutoff frequencies of the first and second smoothing circuits (105, 109) and controlling the invariant component of the duty ratio, and controls the transmission and reception of electric power to and from the third electric device (111).)

1. A power conversion device is provided with: a first smoothing circuit connected to the first electrical device; a second smoothing circuit connected to a second electrical device; a first bridge circuit connected to the first smoothing circuit; a transformer having a primary side connected to a third electrical device and a secondary side connected to the first bridge circuit and the second smoothing circuit; and a controller that performs switching control of the first bridge circuit,

the controller varies a duty ratio of the first bridge circuit at a frequency higher than a cutoff frequency of the first smoothing circuit and a cutoff frequency of the second smoothing circuit, controls a constant component of the duty ratio, controls power transmission and reception between the first electrical device and the second electrical device, controls a phase of a varying component of the duty ratio, and controls power transmission and reception between the first electrical device and the third electrical device.

2. The power conversion device according to claim 1,

the first smoothing circuit includes a first inductor and a first capacitor,

the secondary side self-inductance of the transformer and the capacitance of the first capacitor are selected such that an amplitude of a variation in a voltage applied to the secondary side of the transformer due to a resonance effect of the first capacitor and the secondary side self-inductance of the transformer is larger than a voltage of the first electrical device.

3. The power conversion device according to claim 1,

the second smoothing circuit includes a second inductor and a second capacitor,

the secondary side self-inductance of the transformer and the capacitance of the second capacitor are selected such that an amplitude of a variation in a voltage applied to the secondary side of the transformer due to a resonance effect of the second capacitor and the secondary side self-inductance of the transformer is larger than a voltage of the first electrical device.

4. The power conversion device according to claim 1,

the first smoothing circuit includes a first inductor and a first capacitor, and the second smoothing circuit includes a second inductor and a second capacitor,

the secondary side self-inductance of the transformer and the capacitances of the first and second capacitors are selected such that an amplitude of a variation in voltage applied to the secondary side of the transformer due to a resonance effect of the first and second capacitors and the secondary side self-inductance of the transformer is larger than a voltage of the first electrical device.

5. The power conversion device according to any one of claims 1 to 4, wherein the second smoothing circuit is connected to a secondary side of the transformer via a second bridge circuit, and the controller complementarily varies the duty ratio of the first bridge circuit and the duty ratio of the second bridge circuit.

6. The power conversion device according to any one of claims 1 to 4, comprising: a third smoothing circuit connected to the third electrical device; a third bridge circuit connected to the third smoothing circuit; and a fourth bridge circuit also connected to the third smoothing circuit,

the primary side of the transformer is connected to the third and fourth bridge circuits,

the controller controls the first bridge circuit, the third bridge circuit, and the fourth bridge circuit.

7. The power conversion device according to claim 5, comprising: a third smoothing circuit connected to the third electrical device; a third bridge circuit connected to the third smoothing circuit; and a fourth bridge circuit also connected to the third smoothing circuit,

the primary side of the transformer is connected to the third and fourth bridge circuits,

the controller controls the first bridge circuit to the fourth bridge circuit.

8. The power conversion device according to any one of claims 1 to 4, comprising: a third smoothing circuit connected to the third electrical device; a fourth smoothing circuit connected to the fourth electrical device; and a third bridge circuit connected to the third smoothing circuit,

the primary side of the transformer is connected to the third bridge circuit and the fourth smoothing circuit,

the controller controls the first bridge circuit and the third bridge circuit.

9. The power conversion device according to claim 5, comprising: a third smoothing circuit connected to the third electrical device; a fourth smoothing circuit connected to the fourth electrical device; and a third bridge circuit connected to the third smoothing circuit,

the primary side of the transformer is connected to the third bridge circuit and the fourth smoothing circuit,

the controller controls the first bridge circuit, the second bridge circuit, and the third bridge circuit.

10. The power conversion device according to claim 9,

a fourth bridge circuit connected to the fourth smoothing circuit,

the primary side of the transformer is connected to the third bridge circuit and the fourth bridge circuit,

the controller controls the first bridge circuit to the fourth bridge circuit.

11. The power conversion device according to any one of claims 1 to 5, wherein at least one of the first electric device or the second electric device is an electric storage device that doubles as the first smoothing circuit or the second smoothing circuit.

12. The power conversion device according to claim 11, wherein a frequency of the duty fluctuation component is set to a value that dominates an electric double layer capacitance at a battery electrode interface of a battery as the power storage device.

13. The power conversion device according to any one of claims 1 to 12, wherein the controller includes: a triangular wave generating unit that generates a triangular wave that oscillates at a switching frequency of each of the bridge circuits; and a comparator that compares a signal proportional to the duty ratio, the power conversion device controlling the switching element of the bridge circuit by an output of the comparator.

Technical Field

The present invention relates to a power conversion device that converts power among three or more power sources, loads, or power storage devices to control the transfer of power without using a plurality of power conversion circuits.

Background

Conventionally, in order to control power transmission between three or more electrical devices using a power conversion device, it is necessary to provide each electrical device with a power conversion device separately. There is a need for a low-cost, small-sized, and lightweight power conversion device having a function of controlling power transmission between three or more electrical devices.

In order to solve this problem, the following power conversion device is disclosed: a transformer including three or more coils that are magnetically coupled is used, and an ac voltage applied to each coil is controlled using a full-bridge circuit provided for each coil (for example, patent document 1). Disclosed is a power conversion device: power transmission between the first and second electrical devices is controlled by a bidirectional chopper including a half-bridge circuit using a switching element and an inductor, and the inductor is used as a secondary side coil of a transformer, so that power can be supplied to a third electrical device (for example, patent documents 2 and 3). Further, a power converter using a step-up/step-down bidirectional chopper instead of the bidirectional chopper is disclosed (for example, patent document 4). Further, the following power conversion device is disclosed: power transmission between the first and second electrical devices and power transmission between the first or second electrical device and the third electrical device are temporally separated, and the self-inductance of the transformer is switched according to the situation (for example, patent document 5).

Disclosure of Invention

Technical problem to be solved by the invention

However, the invention disclosed in patent document 1 requires a full bridge circuit and a coil corresponding to the number of electric devices, and has problems in terms of cost reduction and size and weight reduction of the device. In the inventions disclosed in patent documents 2 to 4, there are conflicting requirements as follows: in order to obtain a direct current between the first and second electrical devices, the transformer secondary side coil needs to cut off the ripple current, but in order to supply power to the third electrical device, the transformer secondary side coil needs to pass the ripple current, resulting in a decrease in power transmission efficiency. Although the invention disclosed in patent document 5 solves this problem, there is a problem that the power transmission between the first and second electrical devices and the power transmission between the first or second electrical device and the third electrical device cannot be performed simultaneously.

The present invention has been made to solve the above-described problems, and an object thereof is to provide a power conversion device capable of simultaneously and efficiently transmitting power between three electrical devices.

Means for solving the problems

The power conversion device of the present invention includes: a first smoothing circuit connected to the first electrical device; a second smoothing circuit connected to a second electrical device; a first bridge circuit connected to the first smoothing circuit; the primary side of the transformer is connected with a third electric device, and the secondary side of the transformer is connected with a first bridge circuit and a second smoothing circuit; and a controller that controls switching of the first bridge circuit, wherein the controller varies a duty ratio of the first bridge circuit at a frequency higher than a cutoff frequency of the first smoothing circuit and a cutoff frequency of the second smoothing circuit, controls a constant component (constant component) of the duty ratio, controls power transmission to and from the first electrical device and the second electrical device, and controls a phase of a varying component (varying component) of the duty ratio, thereby controlling power transmission to and from the third electrical device.

Effects of the invention

In the power converter of the present invention, the controller varies the duty ratio of the first bridge circuit at a frequency higher than the cutoff frequency of the first smoothing circuit and the cutoff frequency of the second smoothing circuit, controls the invariant component of the duty ratio, controls the phase of the fluctuating component of the duty ratio while controlling the transfer of power between the first electrical device and the second electrical device, and controls the transfer of power to and from the third electrical device. Therefore, in a small and lightweight configuration, it is possible to control power transmission between three or more electrical devices, and to realize efficient power transmission.

Drawings

Fig. 1 is a configuration diagram of a power converter according to embodiment 1 of the present invention.

Fig. 2 is an explanatory diagram of a method of controlling the duty ratio of the power conversion device according to embodiment 1 of the present invention.

Fig. 3 is an explanatory diagram of a relationship between a control amount and power transmission of the power conversion device according to embodiment 1 of the present invention.

Fig. 4 is a block diagram of a controller of a power converter according to embodiment 1 of the present invention.

Fig. 5 is another configuration diagram of the power converter according to embodiment 1 of the present invention.

Fig. 6 is a configuration diagram of a power converter according to embodiment 3 of the present invention.

Fig. 7 is a configuration diagram of a power converter according to embodiment 4 of the present invention.

Fig. 8 is a configuration diagram of a power converter according to embodiment 5 of the present invention.

Fig. 9 is a configuration diagram of a power converter according to embodiment 6 of the present invention.

Fig. 10 is a configuration diagram of a power converter according to embodiment 7 of the present invention.

Fig. 11 is a configuration diagram of a power converter according to embodiment 8 of the present invention.

Detailed Description