Power Conversion Device

Abstract

To provide a power conversion device in which occurrence of a current imbalance between a plurality of switching modules can be suppressed.SOLUTION: A power conversion device includes a plurality of first switching modules including a first switching element and a second switching element that are connected in series, a plurality of second switching modules including a third switching element a fourth switching element that are connected in series, a first conductor with a plate shape electrically connected to one of a pair of input-output terminals of an AC circuit, a second conductor with a plate shape overlapped over the first conductor with a predetermined space and electrically connected to the one of the input-output terminals, a third conductor with a plate shape overlapped over the second conductor with a predetermined space and electrically connected to the other of the input-output terminals, and a fourth conductor with a plate shape overlapped over the third conductor with a predetermined space and electrically connected to the other of the input-output terminals.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] FIELD An embodiment of the present invention relates to a power conversion device. [Background technology]

[0002] A power conversion device includes a first switching module and a second switching module. The first switching module has a first switching element and a second switching element connected in series. The second switching module has a third switching element and a fourth switching element connected in series. In other words, the first switching module and the second switching module form a half-bridge circuit. The power conversion device configures a full-bridge circuit with the first switching module and the second switching module, and performs at least one of converting DC power to AC power and converting AC power to DC power by switching each switching element.

[0003] In such a power conversion device, a plurality of first switching modules and a plurality of second switching modules are provided, and the plurality of first switching modules are connected in parallel, and the plurality of second switching modules are connected in parallel, which makes it possible to handle large power while suppressing increases in the allowable values ​​of current and voltage required for each switching element.

[0004] However, when multiple first switching modules connected in parallel and multiple second switching modules connected in parallel are provided as described above and the switching modules are arranged side by side, depending on how the switching modules are arranged, an imbalance may occur in the amount of current flowing through each switching module.

[0005] For example, if a current imbalance occurs and current is concentrated in a specific switching module, the temperature burden of the switching module where the current is concentrated increases. This requires measures such as increasing the cooling capacity of the switching module or increasing the number of parallel connections of each switching module, which may result in an increase in the size and cost of the device.

[0006] Therefore, in a power conversion device in which a plurality of switching modules are connected in parallel, it is desirable to be able to suppress the occurrence of current imbalances among the plurality of switching modules. [Prior art documents] [Patent documents]

[0007] [Patent Document 1] Japanese Patent Application Publication No. 2019-134543 Summary of the Invention [Problem to be solved by the invention]

[0008] The embodiments provide a power conversion device that can suppress the occurrence of current imbalance among a plurality of switching modules. [Means for solving the problem]

[0009] According to this embodiment, a power conversion device is connected to a DC circuit and an AC circuit and performs at least one of converting DC power to AC power and converting AC power to DC power, the power conversion device comprising: a plurality of first switching modules having first switching elements and second switching elements connected in series; a plurality of second switching modules having third switching elements and fourth switching elements connected in series; a plate-shaped first conductor electrically connected to one of a pair of input / output terminals of the AC circuit; a plate-shaped second conductor provided overlapping the first conductor at a predetermined interval and electrically connected to the one of the pair of input / output terminals of the AC circuit; a plate-shaped third conductor provided overlapping the second conductor at a predetermined interval and electrically connected to the other of the pair of input / output terminals of the AC circuit; and a plate-shaped fourth conductor provided overlapping the third conductor at a predetermined interval and electrically connected to the other of the pair of input / output terminals of the AC circuit, a switching module is provided in a row beside the laminated body separately from the plurality of first switching modules, and each of the plurality of first switching modules is electrically connected to the DC circuit via both ends of the first switching element and the second switching element, and is electrically connected to one of the pair of input / output terminals of the AC circuit via a connection point between the first switching element and the second switching element, thereby being connected in parallel with each other; and each of the plurality of second switching modules is electrically connected to the DC circuit via both ends of the third switching element and the fourth switching element, and is electrically connected to the other of the pair of input / output terminals of the AC circuit via a connection point between the third switching element and the fourth switching element, thereby being connected in parallel with each other; and the plurality of first switching modules and the plurality of second switching modules form a full bridge circuit by the first switching element, the second switching element, the third switching element, and the fourth switching element,a power conversion device configured to perform at least one of conversion from DC power to AC power and conversion from AC power to DC power by switching the second switching element, the third switching element, and the fourth switching element; two first switching modules located at both ends of a row of the plurality of first switching modules are connected to the first conductor and are electrically connected to one of the pair of input / output terminals of the AC circuit via the first conductor; at least one first switching module located between the two first switching modules of the plurality of first switching modules is connected to the second conductor and is electrically connected to the one of the pair of input / output terminals of the AC circuit via the second conductor; two second switching modules located at both ends of the row of the plurality of second switching modules are connected to the fourth conductor and are electrically connected to the other of the pair of input / output terminals of the AC circuit via the fourth conductor; and at least one second switching module located between the two second switching modules of the plurality of second switching modules is connected to the third conductor and is electrically connected to the other of the pair of input / output terminals of the AC circuit via the third conductor. [Effects of the Invention]

[0010] In this embodiment, a power conversion device capable of suppressing the occurrence of current imbalance among a plurality of switching modules is provided. [Brief explanation of the drawings]

[0011] [Figure 1] 1 is a block diagram schematically illustrating a power conversion device according to an embodiment. [Figure 2] 1 is an explanatory diagram schematically illustrating a power conversion device according to an embodiment; [Figure 3] 1 is an explanatory diagram schematically illustrating a power conversion device according to an embodiment; [Figure 4] FIG. 1 is an explanatory diagram schematically illustrating a reference power conversion device. [Figure 5]FIG. 10 is an explanatory diagram schematically illustrating a modified example of the power conversion device according to the embodiment. DETAILED DESCRIPTION OF THE INVENTION

[0012] Hereinafter, an embodiment of the present invention will be described with reference to the drawings. The drawings are schematic or conceptual, and the relationship between the thickness and width of each part, the size ratio between parts, etc. are not necessarily the same as those in reality. Furthermore, even when the same part is shown, the dimensions and ratios may be different depending on the drawing. In the present specification and the drawings, elements similar to those described above with reference to the previous drawings are given the same reference numerals, and detailed descriptions thereof will be omitted as appropriate.

[0013] FIG. 1 is a block diagram schematically illustrating a power conversion device according to an embodiment. As shown in FIG. 1, the power conversion device 10 includes a plurality of first switching modules 11 and a plurality of second switching modules 12.

[0014] In this example, the power conversion device 10 includes four first switching modules 11 and four second switching modules 12. However, the number of first switching modules 11 and second switching modules 12 provided in the power conversion device 10 is not limited to the above. The number of first switching modules 11 and the number of second switching modules 12 may be any number equal to or greater than three.

[0015] The power conversion device 10 is connected to the DC circuit 2 and the AC circuit 4. The power conversion device 10 performs at least one of converting DC power to AC power and converting AC power to DC power. In other words, the power conversion device 10 performs at least one of an operation of converting DC power supplied from the DC circuit 2 into AC power and supplying the converted AC power to the AC circuit 4, and an operation of converting AC power supplied from the AC circuit 4 into DC power and supplying the converted DC power to the DC circuit 2.

[0016] The DC circuit 2 is, for example, a DC power supply or a DC load. The AC circuit 4 is, for example, an AC power supply, an AC load, or a power system. The DC circuit 2 and the AC circuit 4 may be, for example, other converters. The DC circuit 2 and the AC circuit 4 are not limited to the above and may be any circuits.

[0017] Each of the multiple first switching modules 11 has a first switching element 21 and a second switching element 22 connected in series. Each of the multiple second switching modules 12 has a third switching element 23 and a fourth switching element 24 connected in series. In other words, the first switching module 11 and the second switching module 12 form a half-bridge circuit.

[0018] Each of the first switching element 21, the second switching element 22, the third switching element 23, and the fourth switching element 24 has a pair of main terminals and a control terminal. Each of the first switching element 21, the second switching element 22, the third switching element 23, and the fourth switching element 24 has an on state and an off state.

[0019] The on state is a state in which a current flows between a pair of main terminals. The off state is a state in which the flow of current between the pair of main terminals is blocked. Each of the first switching element 21, the second switching element 22, the third switching element 23, and the fourth switching element 24 switches between the on state and the off state depending on the voltage between the pair of main terminals and the voltage of the control terminal. Note that the off state is not limited to a state in which no current flows between the pair of main terminals, but may also be a state in which a weak current flows between the pair of main terminals within a range that does not affect the operation of the power conversion device 10.

[0020] The first switching element 21, the second switching element 22, the third switching element 23, and the fourth switching element 24 are, for example, IGBTs. In other words, the plurality of first switching modules 11 and the plurality of second switching modules 12 are IGBT modules. However, the first switching element 21, the second switching element 22, the third switching element 23, and the fourth switching element 24 are not limited to IGBTs and may be other self-excited semiconductor elements such as MOSFETs. The first switching element 21, the second switching element 22, the third switching element 23, and the fourth switching element 24 are not limited to the above and may be any elements that can be arbitrarily switched between an on state and an off state.

[0021] Each of the multiple first switching modules 11 has a first DC terminal 11a, a second DC terminal 11b, and a first AC terminal 11c. Each of the multiple first switching modules 11 also has a first housing 11d. The first switching element 21 and the second switching element 22 are provided inside the first housing 11d. In other words, the first housing 11d accommodates the first switching element 21 and the second switching element 22 inside. The first housing 11d is, for example, an insulating package.

[0022] The first DC terminal 11a, the second DC terminal 11b, and the first AC terminal 11c are provided on the outer surface of the first housing 11d and are used for electrical connection with external devices. The first AC terminal 11c is provided, for example, at one end of the first housing 11d. The first DC terminal 11a and the second DC terminal 11b are provided, for example, at the other end of the first housing 11d. In other words, the first DC terminal 11a and the second DC terminal 11b are provided at the end of the first housing 11d opposite the first AC terminal 11c. The first housing 11d has, for example, a substantially rectangular parallelepiped shape. The first housing 11d has a substantially rectangular shape when viewed from above. The first AC terminal 11c is provided, for example, at one longitudinal end of the substantially rectangular parallelepiped first housing 11d. The first DC terminal 11a and the second DC terminal 11b are provided, for example, on the other end side in the longitudinal direction of the first housing 11d which has a substantially rectangular parallelepiped shape.

[0023] However, the shape of the first housing 11d is not limited to the above and may be any shape. The arrangement of the first DC terminal 11a, the second DC terminal 11b, and the first AC terminal 11c is not limited to the above and may be any arrangement.

[0024] The first DC terminal 11a is electrically connected to one main terminal of the first switching element 21 in the first housing 11d. The other main terminal of the first switching element 21 is electrically connected to one main terminal of the second switching element 22. The other main terminal of the second switching element 22 is electrically connected to the second DC terminal 11b. In other words, the second DC terminal 11b is electrically connected to the other main terminal of the second switching element 22 in the first housing 11d. The first AC terminal 11c is electrically connected to a connection point between the other main terminal of the first switching element 21 and one main terminal of the second switching element 22 in the first housing 11d.

[0025] In this way, in the first switching module 11, both ends of the first switching element 21 and the second switching element 22 connected in series become a pair of DC connection points, and the connection point between the first switching element 21 and the second switching element 22 becomes an AC connection point.

[0026] Although not shown, each of the multiple first switching modules 11 further includes a terminal for inputting a control signal to the control terminal of the first switching element 21 and a terminal for inputting a control signal to the control terminal of the second switching element 22. The terminals are provided on the outer surface of the first housing 11d. The on and off states of the first switching element 21 and the second switching element 22 are switched by inputting a control signal to the control terminal via the terminals provided on the first housing 11d.

[0027] Each of the multiple second switching modules 12 has a third DC terminal 12a, a fourth DC terminal 12b, and a second AC terminal 12c. Each of the multiple second switching modules 12 also has a second housing 12d. The second housing 12d accommodates a third switching element 23 and a fourth switching element 24. The second AC terminal 12c is provided, for example, on one end of the second housing 12d. The third DC terminal 12a and the fourth DC terminal 12b are provided, for example, on the other end of the second housing 12d. The configuration of the second switching module 12 is substantially the same as the configuration of the first switching module 11, so a detailed description thereof will be omitted.

[0028] The first DC terminal 11a of each of the multiple first switching modules 11 is electrically connected to the high potential side terminal 2a of the DC circuit 2. The second DC terminal 11b of each of the multiple first switching modules 11 is electrically connected to the low potential side terminal 2b of the DC circuit 2. The first AC terminal 11c of each of the multiple first switching modules 11 is electrically connected to one of a pair of input / output terminals 4a, 4b of the AC circuit 4. The first AC terminal 11c of each of the multiple first switching modules 11 is electrically connected to, for example, the input / output terminal 4a of the AC circuit 4.

[0029] In other words, each of the multiple first switching modules 11 is electrically connected to the DC circuit 2 via both ends of the first switching element 21 and the second switching element 22, and is also electrically connected to one of a pair of input / output terminals 4a, 4b of the AC circuit 4 via the connection point between the first switching element 21 and the second switching element 22. As a result, each of the multiple first switching modules 11 is connected in parallel with one another.

[0030] The third DC terminal 12a of each of the multiple second switching modules 12 is electrically connected to the high potential side terminal 2a of the DC circuit 2. The fourth DC terminal 12b of each of the multiple second switching modules 12 is electrically connected to the low potential side terminal 2b of the DC circuit 2. The second AC terminal 12c of each of the multiple second switching modules 12 is electrically connected to the other of the pair of input / output terminals 4a, 4b of the AC circuit 4. The second AC terminal 12c of each of the multiple second switching modules 12 is electrically connected to, for example, the input / output terminal 4b of the AC circuit 4.

[0031] In other words, each of the multiple second switching modules 12 is electrically connected to the DC circuit 2 via both ends of the third switching element 23 and the fourth switching element 24, and is also electrically connected to the other of the pair of input / output terminals 4a, 4b of the AC circuit 4 via the connection point of the third switching element 23 and the fourth switching element 24. As a result, each of the multiple second switching modules 12 is connected in parallel with one another.

[0032] The plurality of first switching modules 11 and the plurality of second switching modules 12 form a full bridge circuit with a first switching element 21, a second switching element 22, a third switching element 23, and a fourth switching element 24, and perform at least one of conversion from DC power to AC power and conversion from AC power to DC power by switching the first switching element 21, the second switching element 22, the third switching element 23, and the fourth switching element 24.

[0033] The first switching module 11 constitutes, for example, one of a pair of legs of a single-phase full-bridge circuit, and the second switching module 12 constitutes, for example, the other of the pair of legs of the single-phase full-bridge circuit. In other words, the first switching module 11 is a switching module electrically connected to one input / output terminal 4a of the AC circuit 4 among multiple switching modules constituting the full-bridge circuit. In other words, the second switching module 12 is a switching module electrically connected to the other input / output terminal 4b of the AC circuit 4 among multiple switching modules constituting the full-bridge circuit.

[0034] In this way, the power conversion device 10 has a plurality of first switching modules 11 and a plurality of second switching modules 12 connected in parallel. This allows the power conversion device 10 to handle large amounts of power while suppressing increases in the allowable values ​​of current and voltage required for each of the switching elements 21 to 24. The numbers of the plurality of first switching modules 11 and the plurality of second switching modules 12 may be set appropriately depending on the amount of power to be handled.

[0035] The AC power of the AC circuit 4 is, for example, single-phase AC power. The power conversion device 10, for example, performs at least one of conversion from DC power to single-phase AC power and conversion from single-phase AC power to DC power. However, the AC power of the AC circuit 4 may be, for example, three-phase AC power. The power conversion device 10 may be configured, for example, to perform at least one of conversion from DC power to three-phase AC power and conversion from three-phase AC power to DC power using three single-phase full-bridge circuits. The multiple first switching modules 11 and the multiple second switching modules 12 may be, for example, parts corresponding to one phase of the three-phase AC power.

[0036] 2 and 3 are explanatory diagrams that schematically show the power conversion device according to the embodiment. As shown in FIGS. 2 and 3, the power conversion device 10 further includes a first conductor 31, a second conductor 32, a third conductor 33, and a fourth conductor .

[0037] The first conductor 31 is a plate-like conductor electrically connected to one 4a of the pair of input / output terminals 4a, 4b of the AC circuit 4. The second conductor 32 is a plate-like conductor provided on top of the first conductor 31 with a predetermined gap therebetween and electrically connected to one 4a of the pair of input / output terminals 4a, 4b of the AC circuit 4. The third conductor 33 is a plate-like conductor provided on top of the second conductor 32 with a predetermined gap therebetween and electrically connected to the other 4b of the pair of input / output terminals 4a, 4b of the AC circuit 4. The fourth conductor 34 is a plate-like conductor provided on top of the third conductor 33 with a predetermined gap therebetween and electrically connected to the other 4b of the pair of input / output terminals 4a, 4b of the AC circuit 4. The first conductor 31 to the fourth conductor 34 may be called, for example, bus bars.

[0038] The first conductors 31 to the fourth conductors 34 are stacked at predetermined intervals in the thickness direction of each plate-like conductor, which is orthogonal to the upper and lower surfaces of each plate-like conductor 31 to 34.

[0039] For example, an insulating sheet or the like may be provided between each of the conductors 31 to 34. For example, an air layer or the like may be provided between each of the conductors 31 to 34. The material between each of the conductors 31 to 34 may be any material that can properly ensure electrical insulation between each of the conductors 31 to 34. The distance (spacing) between each of the conductors 31 to 34 may be any distance that can properly ensure electrical insulation between each of the conductors 31 to 34.

[0040] In Fig. 3, for ease of illustration, the conductors 31 to 34 are shown slightly offset from one another. The outer shapes of the conductors 31 to 34 may be substantially the same. However, the shapes of the conductors 31 to 34 do not necessarily have to be the same. It is sufficient that the conductors 31 to 34 are arranged so that at least a portion of them overlap in the thickness direction.

[0041] The multiple first switching modules 11 are arranged in a row on the side of a stack 35 of a first conductor 31, a second conductor 32, a third conductor 33, and a fourth conductor 34. The multiple second switching modules 12 are arranged in a row on the side of the stack 35 separately from the multiple first switching modules 11. The side is a direction perpendicular to the vertical direction in which the conductors 31 to 34 are arranged. In other words, the side is a direction perpendicular to the stacking direction of the conductors 31 to 34.

[0042] In other words, the multiple first switching modules 11 are provided adjacent to the laminate 35 in a direction perpendicular to the thickness direction of the conductors 31 to 34. The multiple second switching modules 12 are provided adjacent to the laminate 35 separately from the multiple first switching modules 11 in a direction perpendicular to the thickness direction of the conductors 31 to 34.

[0043] The direction in which the multiple second switching modules 12 are lined up is, for example, the same as the direction in which the multiple first switching modules 11 are lined up. The multiple second switching modules 12 are arranged, for example, on the side of the stack 35 opposite to the multiple first switching modules 11. In other words, the stack 35 is arranged between the multiple first switching modules 11 lined up in a predetermined direction and the multiple second switching modules 12 lined up approximately parallel to the multiple first switching modules 11.

[0044] The shape of each of the conductors 31 to 34 when viewed from above is, for example, substantially rectangular. The multiple first switching modules 11 are lined up, for example, along one longitudinal side of each of the rectangular conductors 31 to 34. The multiple second switching modules 12 are lined up, for example, along the other longitudinal side of each of the rectangular conductors 31 to 34.

[0045] However, the arrangement of the plurality of first switching modules 11, the plurality of second switching modules 12, and the laminate 35 is not limited to the above. The direction in which the plurality of second switching modules 12 are arranged does not necessarily have to be the same as the direction in which the plurality of first switching modules 11 are arranged. The shape of each of the conductors 31 to 34 is not limited to the above and may be any shape.

[0046] Of the multiple first switching modules 11, two first switching modules 11 located at both ends of the row are connected to the first conductor 31. The two first switching modules 11 located at both ends are connected to the first conductor 31 via the first AC terminal 11c. The two first switching modules 11 located at both ends are mechanically and electrically connected to the first conductor 31 via the first AC terminal 11c, for example, by screwing the first conductor 31 to the first AC terminal 11c. As a result, the two first switching modules 11 located at both ends are electrically connected to one input / output terminal 4a of the pair of input / output terminals 4a, 4b of the AC circuit 4 via the first conductor 31.

[0047] At least one first switching module 11 located between two first switching modules 11 of the plurality of first switching modules is connected to the second conductor 32. The at least one first switching module 11 located between the first switching modules is connected to the second conductor 32 via the first AC terminal 11c. The at least one first switching module 11 located between the first switching modules is mechanically and electrically connected to the second conductor 32 via the first AC terminal 11c, for example, by screwing the second conductor 32 to the first AC terminal 11c. As a result, the at least one first switching module 11 located between the first switching modules is electrically connected to one input / output terminal 4a of the pair of input / output terminals 4a, 4b of the AC circuit 4 via the second conductor 32.

[0048] Of the multiple second switching modules 12, two second switching modules 12 located at both ends of the row are connected to the fourth conductor 34. The two second switching modules 12 located at both ends are connected to the fourth conductor 34 via the second AC terminal 12c. The two second switching modules 12 located at both ends are mechanically and electrically connected to the fourth conductor 34 via the second AC terminal 12c, for example, by screwing the fourth conductor 34 to the second AC terminal 12c. As a result, the two second switching modules 12 located at both ends are electrically connected to the other input / output terminal 4b of the pair of input / output terminals 4a, 4b of the AC circuit 4 via the fourth conductor 34.

[0049] At least one second switching module 12 located between two second switching modules 12 of the plurality of second switching modules 12 is connected to the third conductor 33. The at least one second switching module 12 located between the two second switching modules 12 is connected to the third conductor 33 via the second AC terminal 12c. The at least one second switching module 12 located between the two second switching modules 12 is mechanically and electrically connected to the third conductor 33 via the second AC terminal 12c, for example, by screwing the third conductor 33 to the second AC terminal 12c. As a result, the at least one second switching module 12 located between the two second switching modules 12 is electrically connected to the other input / output terminal 4b of the pair of input / output terminals 4a, 4b of the AC circuit 4 via the third conductor 33.

[0050] In this example, of the four first switching modules 11, the two first switching modules 11 located at both ends are connected to a first conductor 31, and the two first switching modules 11 between the two first switching modules 11 located at both ends are connected to a second conductor 32. In this example, of the four second switching modules 12, the two second switching modules 12 located at both ends are connected to a fourth conductor 34, and the two second switching modules 12 between the two second switching modules 12 located at both ends are connected to a third conductor 33.

[0051] However, the number of first switching modules 11 connected to the first conductor 31 and the second conductor 32, and the number of second switching modules 12 connected to the third conductor 33 and the fourth conductor 34 are not limited to the above.

[0052] The number of first switching modules 11 connected to the first conductor 31 may be any number including at least two first switching modules 11 located at both ends. The number of first switching modules 11 connected to the second conductor 32 may be any number. For example, the number of first switching modules 11 may be three, and only one first switching module 11 between the two first switching modules 11 located at both ends may be connected to the second conductor 32. For example, the number of first switching modules 11 may be six, with four first switching modules 11 at both ends connected to the first conductor 31 and two first switching modules 11 in the center connected to the second conductor 32. The number of first switching modules 11 connected to the second conductor 32 may be the same as or different from the number of first switching modules 11 connected to the first conductor 31.

[0053] Similarly, the number of second switching modules 12 connected to the fourth conductor 34 may be any number, including at least two second switching modules 12 located at both ends. The number of second switching modules 12 connected to the third conductor 33 may be any number.

[0054] 2 and 3, each of the multiple first switching modules 11 is arranged, for example, with one end of the first housing 11d where the first AC terminal 11c is provided facing the stack body 35. Each of the multiple second switching modules 12 is arranged, for example, with one end of the second housing 12d where the second AC terminal 12c is provided facing the stack body 35.

[0055] The second conductor 32 is electrically connected to the first conductor 31, for example, at a position outside the row of the first switching modules 11 in the direction in which the first switching modules 11 are lined up. The second conductor 32 is electrically connected to the first conductor 31, for example, at a position outside the row of the first switching modules 11 in the longitudinal direction. The first conductor 31 and the second conductor 32 function as two approximately parallel conductor plates, for example, in the portion between the two first switching modules 11 located at both ends (the portion where the first switching modules 11 are lined up).

[0056] The fourth conductor 34 is electrically connected to the third conductor 33, for example, at a position outside the row of the second switching modules 12 in the direction in which the second switching modules 12 are lined up. The fourth conductor 34 is electrically connected to the third conductor 33, for example, at a position outside the row of the second switching modules 12 in the longitudinal direction. The third conductor 33 and the fourth conductor 34 function as two approximately parallel conductor plates, for example, in the portion between the two second switching modules 12 located at both ends (the portion where the second switching modules 12 are lined up).

[0057] FIG. 4 is an explanatory diagram that schematically shows a reference power conversion device. As shown in FIG. 4, the reference power conversion device 40 includes only two conductors 41 and 42. The first switching modules 11 are arranged side by side on one side of each of the conductors 41 and 42. The second switching modules 12 are arranged side by side on the other side of each of the conductors 41 and 42. The first switching modules 11 are connected to the conductor 41 via the first AC terminal 11c and electrically connected to one input / output terminal 4a of the AC circuit 4 via the conductor 41. The second switching modules 12 are connected to the conductor 42 via the second AC terminal 12c and electrically connected to the other input / output terminal 4b of the AC circuit 4 via the conductor 42.

[0058] In FIG. 4, the flow of current when the first switching element 21 and the fourth switching element 24 are in the ON state and the second switching element 22 and the third switching element 23 are in the OFF state is schematically represented by the dashed double-dashed arrows.

[0059] When switching is performed as described above, the current output from the high-potential side terminal 2a of the DC circuit 2 flows to the AC circuit 4 via the first DC terminal 11a of the first switching module 11, the first switching element 21, the first AC terminal 11c of the first switching module 11, and the conductor 41, and the current flowing through the AC circuit 4 flows to the low-potential side terminal 2b of the DC circuit 2 via the conductor 42, the second AC terminal 12c of the second switching module 12, the fourth switching element 24, and the fourth DC terminal 12b of the second switching module 12.

[0060] As a result of extensive investigation, the inventors of the present application have found that, in the configuration of the reference power conversion device 40, when switching is performed as described above, an imbalance may occur in the currents flowing through the switching modules. More specifically, the inventors have found that, among the four lined up first switching modules 11, it may be difficult for current to flow through the two innermost first switching modules 11, resulting in current concentration in the two outermost first switching modules 11. Similarly, among the four lined up second switching modules 12, it may be difficult for current to flow through the two innermost second switching modules 12, resulting in current concentration in the two outermost second switching modules 12.

[0061] 4, in the configuration of the reference power conversion device 40, when switching is performed as described above, current flows in the same direction in four adjacent first switching modules 11, and current flows in the same direction in four adjacent second switching modules 12. The current imbalance described above is thought to be due to the influence of mutual induction between the adjacent first switching modules 11 and the adjacent second switching modules 12, for example.

[0062] In contrast, the power conversion device 10 of this embodiment has four conductors, namely, a first conductor 31 to a fourth conductor 34, and two of the multiple first switching modules 11 located at both ends of the row are connected to the first conductor 31, at least one of the multiple first switching modules 11 located between two of the multiple first switching modules 11 is connected to the second conductor 32, two of the multiple second switching modules 12 located at both ends of the row are connected to the fourth conductor 34, and at least one of the multiple second switching modules 12 located between two of the multiple second switching modules 12 is connected to the third conductor 33.

[0063] As a result, in the power conversion device 10 of this embodiment, as shown in Figure 2, when switching is performed as described above, current can be passed in the same direction through the first conductor 31 and the second conductor 32, current can be passed in the same direction through the third conductor 33 and the fourth conductor 34, and the directions of the currents flowing through the second conductor 32 and the third conductor 33 can be reversed.

[0064] Therefore, in each of the conductors 31 to 34, the influence of mutual induction is suppressed and current can flow easily in the inner second conductor 32 and third conductor 33, where current flows in opposite directions between two adjacent conductors. Conversely, the influence of mutual induction is increased in the outer first conductor 31 and fourth conductor 34, where current flows in the same direction between two adjacent conductors, making it difficult for current to flow.

[0065] As described above, current flows less easily through the two innermost first switching modules 11 of the four lined up first switching modules 11 than through the two outermost first switching modules 11. On the other hand, current flows more easily through the second conductor 32 to which the two innermost first switching modules 11 are connected than through the first conductor 31 to which the two outermost first switching modules 11 are connected. Similarly, current flows less easily through the two innermost second switching modules 12 of the four lined up second switching modules 12 than through the two outermost second switching modules 12. On the other hand, current flows more easily through the third conductor 33 to which the two innermost second switching modules 12 are connected than through the fourth conductor 34 to which the two outermost second switching modules 12 are connected.

[0066] In the power conversion device 10 according to this embodiment, the conductors 31 to 34 can provide a current imbalance that is opposite to the current imbalance that occurs in the plurality of first switching modules 11 and the plurality of second switching modules 12. As a result, in the power conversion device 10 according to this embodiment, the conductors 31 to 34 can suppress the current imbalance that occurs in the plurality of first switching modules 11 and the plurality of second switching modules 12. In other words, the magnitude of the current flowing through each of the plurality of first switching modules 11 and the plurality of second switching modules 12 can be adjusted by each of the conductors 31 to 34, thereby suppressing the imbalance in the current flowing through each of the plurality of first switching modules 11 and the plurality of second switching modules 12.

[0067] In this way, the power conversion device 10 according to this embodiment can suppress the occurrence of current imbalances between the multiple first switching modules 11 and the multiple second switching modules 12. This also suppresses an increase in the temperature burden of each switching module, thereby reducing the need for measures such as increasing the cooling capacity of each switching module or increasing the number of switching modules connected in parallel. This also suppresses increases in the size and cost of the device.

[0068] Furthermore, in the power conversion device 10 according to this embodiment, each of the multiple first switching modules 11 is arranged with one end side of the first housing 11d on which the first AC terminal 11c is provided facing the first conductor 31 and the second conductor 32, and each of the pair of second switching modules 12 is arranged with one end side of the second housing 12d on which the second AC terminal 12c is provided facing the first conductor 31 and the second conductor 32.

[0069] This makes it possible, for example, to align the direction of current flowing through each of the multiple first switching modules 11 and appropriately set the influence of mutual induction between the multiple first switching modules 11, and to align the direction of current flowing through each of the multiple second switching modules 12 and appropriately set the influence of mutual induction between the multiple second switching modules 12.

[0070] This makes it easier to adjust, for example, imbalances in the currents flowing through the plurality of first switching modules 11 and the plurality of second switching modules 12 using the conductors 31 to 34. For example, it is possible to more appropriately suppress imbalances in the currents flowing through the plurality of first switching modules 11 and the plurality of second switching modules 12.

[0071] FIG. 5 is an explanatory diagram that schematically shows a modified example of the power conversion device according to the embodiment. 5, in the power conversion device 10a, the multiple second switching modules 12 are arranged on the same side of the stack 35 as the multiple first switching modules 11. In other words, in the power conversion device 10a, the multiple first switching modules 11 and the multiple second switching modules 12 are arranged along one side of each of the conductors 31 to 34. The multiple second switching modules 12 are arranged, for example, in a line with the multiple first switching modules 11.

[0072] In this way, the second switching modules 12 may be arranged on the same side of the stack 35 as the first switching modules 11. In this case, the conductors 31 to 34 can also prevent current imbalances from occurring between the first switching modules 11 and the second switching modules 12.

[0073] 1 to 3, it is more preferable to arrange the second switching modules 12 on the side of the stack 35 opposite to the first switching modules 11. This makes it possible to prevent, for example, a change in the condition of mutual induction between one end of the row of the second switching modules 12 adjacent to the first switching module 11 and the other end of the row of the second switching modules 12 not adjacent to the first switching module 11.

[0074] Therefore, when the second switching modules 12 are arranged on the side of the stack 35 opposite to the first switching modules 11, the current imbalance can be more easily adjusted by the conductors 31 to 34 than when the second switching modules 12 are arranged on the same side, for example. This makes it possible to more appropriately suppress the occurrence of current imbalance.

[0075] The present embodiment includes the following aspects. (Appendix 1) A power conversion device connected to a DC circuit and an AC circuit and performing at least one of conversion from DC power to AC power and conversion from AC power to DC power, a plurality of first switching modules each having a first switching element and a second switching element connected in series; a plurality of second switching modules each having a third switching element and a fourth switching element connected in series; a plate-shaped first conductor electrically connected to one of a pair of input / output terminals of the AC circuit; a plate-shaped second conductor that is provided on top of the first conductor with a predetermined gap therebetween and is electrically connected to one of the pair of input / output terminals of the AC circuit; a plate-shaped third conductor that is provided on top of the second conductor with a predetermined gap therebetween and is electrically connected to the other of the pair of input / output terminals of the AC circuit; a plate-shaped fourth conductor that is provided on top of the third conductor with a predetermined gap therebetween and is electrically connected to the other of the pair of input / output terminals of the AC circuit; Equipped with the plurality of first switching modules are arranged in a row on the sides of a stack of the first conductor, the second conductor, the third conductor, and the fourth conductor; the plurality of second switching modules are arranged in a line on a side of the stack, separately from the plurality of first switching modules; each of the plurality of first switching modules is electrically connected to the DC circuit via both ends of the first switching element and the second switching element, and is electrically connected to one of the pair of input / output terminals of the AC circuit via a connection point between the first switching element and the second switching element, thereby being connected in parallel with each other; each of the plurality of second switching modules is electrically connected to the DC circuit via both ends of the third switching element and the fourth switching element, and is electrically connected to the other of the pair of input / output terminals of the AC circuit via a connection point between the third switching element and the fourth switching element, thereby being connected in parallel with each other; the plurality of first switching modules and the plurality of second switching modules form a full bridge circuit with the first switching element, the second switching element, the third switching element, and the fourth switching element, and perform at least one of conversion from DC power to AC power and conversion from AC power to DC power by switching the first switching element, the second switching element, the third switching element, and the fourth switching element; two first switching modules located at both ends of a row among the plurality of first switching modules are connected to the first conductor and electrically connected to one of the pair of input / output terminals of the AC circuit via the first conductor; at least one first switching module located between the two first switching modules among the plurality of first switching modules is connected to the second conductor and is electrically connected to one of the pair of input / output terminals of the AC circuit via the second conductor; two second switching modules located at both ends of a row among the plurality of second switching modules are connected to the fourth conductor and electrically connected to the other of the pair of input / output terminals of the AC circuit via the fourth conductor; At least one second switching module located between two second switching modules among the plurality of second switching modules is connected to the third conductor and is electrically connected to the other of the pair of input / output terminals of the AC circuit via the third conductor.

[0076] (Appendix 2) 2. The power conversion device according to claim 1, wherein the second switching modules are arranged on a side of the stack opposite to the side on which the first switching modules are arranged.

[0077] (Appendix 3) each of the plurality of first switching modules includes a first housing that accommodates the first switching element and the second switching element; a first DC terminal electrically connected to a high potential side terminal of the DC circuit; a second DC terminal electrically connected to a low potential side terminal of the DC circuit; and a first AC terminal electrically connected to one of the pair of input / output terminals of the AC circuit; the first AC terminal is provided on one end side of the first housing, the first DC terminal and the second DC terminal are provided on the other end side of the first housing, each of the plurality of first switching modules is arranged such that the one end side of the first housing provided with the first AC terminal faces the stacked body; each of the plurality of second switching modules includes a second housing that accommodates the third switching element and the fourth switching element; a third DC terminal electrically connected to a high potential side terminal of the DC circuit; a fourth DC terminal electrically connected to a low potential side terminal of the DC circuit; and a second AC terminal electrically connected to the other of the pair of input / output terminals of the AC circuit; the second AC terminal is provided on one end side of the second housing, the third DC terminal and the fourth DC terminal are provided on the other end side of the second housing, 3. The power conversion device according to claim 1, wherein each of the second switching modules is arranged such that the one end of the second housing provided with the second AC terminal faces the stack.

[0078] (Appendix 4) the second conductor is electrically connected to the first conductor at a position outside the row of the first switching modules in the direction in which the first switching modules are arranged, The power conversion device according to any one of claims 1 to 3, wherein the fourth conductor is electrically connected to the third conductor at a position outside the row of the second switching modules in the direction in which the second switching modules are arranged.

[0079] Although several embodiments of the present invention have been described above, these embodiments are presented as examples and are not intended to limit the scope of the invention. These novel embodiments can be embodied in various other forms, and various omissions, substitutions, and modifications can be made without departing from the spirit of the invention. These embodiments and their modifications are included within the scope and spirit of the invention, as well as within the scope of the invention and its equivalents as set forth in the claims. Furthermore, the above-described embodiments can be implemented in combination with each other. [Explanation of symbols]

[0080] 2...DC circuit, 4...AC circuit, 10, 10a, 40...power conversion device, 11...first switching module, 12...second switching module, 21...first switching element, 22...second switching element, 23...third switching element, 24...fourth switching element, 31...first conductor, 32...second conductor, 33...third conductor, 34...fourth conductor, 35...laminated body, 41, 42...conductor

Claims

1. A power conversion device connected to a DC circuit and an AC circuit and performing at least one of conversion from DC power to AC power and conversion from AC power to DC power, a plurality of first switching modules each having a first switching element and a second switching element connected in series; a plurality of second switching modules each having a third switching element and a fourth switching element connected in series; a plate-shaped first conductor electrically connected to one of a pair of input / output terminals of the AC circuit; a plate-shaped second conductor that is provided on top of the first conductor with a predetermined gap therebetween and is electrically connected to one of the pair of input / output terminals of the AC circuit; a plate-shaped third conductor that is provided on top of the second conductor with a predetermined gap therebetween and is electrically connected to the other of the pair of input / output terminals of the AC circuit; a plate-shaped fourth conductor that is provided on top of the third conductor with a predetermined gap therebetween and is electrically connected to the other of the pair of input / output terminals of the AC circuit; Equipped with the plurality of first switching modules are arranged in a row laterally of the stack of the first conductor, the second conductor, the third conductor, and the fourth conductor; the second switching modules are arranged in a line on a side of the stack, separately from the first switching modules; each of the plurality of first switching modules is electrically connected to the DC circuit via both ends of the first switching element and the second switching element, and is electrically connected to one of the pair of input / output terminals of the AC circuit via a connection point between the first switching element and the second switching element, thereby being connected in parallel with each other; each of the plurality of second switching modules is electrically connected to the DC circuit via both ends of the third switching element and the fourth switching element, and is electrically connected to the other of the pair of input / output terminals of the AC circuit via a connection point between the third switching element and the fourth switching element, thereby being connected in parallel with each other; the plurality of first switching modules and the plurality of second switching modules form a full bridge circuit using the first switching element, the second switching element, the third switching element, and the fourth switching element, and perform at least one of conversion from DC power to AC power and conversion from AC power to DC power by switching the first switching element, the second switching element, the third switching element, and the fourth switching element; two first switching modules located at both ends of a row of the plurality of first switching modules are connected to the first conductor and electrically connected to one of the pair of input / output terminals of the AC circuit via the first conductor; at least one first switching module located between the two first switching modules among the plurality of first switching modules is connected to the second conductor and is electrically connected to one of the pair of input / output terminals of the AC circuit via the second conductor; two second switching modules located at both ends of a row among the plurality of second switching modules are connected to the fourth conductor and electrically connected to the other of the pair of input / output terminals of the AC circuit via the fourth conductor; At least one second switching module located between two of the plurality of second switching modules is connected to the third conductor and electrically connected to the other of the pair of input / output terminals of the AC circuit via the third conductor.

2. The power conversion device according to claim 1 , wherein the second switching modules are arranged on a side of the stack opposite to the side on which the first switching modules are arranged.

3. each of the plurality of first switching modules includes a first housing that accommodates the first switching element and the second switching element; a first DC terminal electrically connected to a high potential side terminal of the DC circuit; a second DC terminal electrically connected to a low potential side terminal of the DC circuit; and a first AC terminal electrically connected to one of the pair of input / output terminals of the AC circuit; the first AC terminal is provided on one end side of the first housing, the first DC terminal and the second DC terminal are provided on the other end side of the first housing, each of the plurality of first switching modules is arranged such that the one end side of the first housing provided with the first AC terminal faces the stack body; each of the plurality of second switching modules includes a second housing that accommodates the third switching element and the fourth switching element; a third DC terminal electrically connected to a high potential side terminal of the DC circuit; a fourth DC terminal electrically connected to a low potential side terminal of the DC circuit; and a second AC terminal electrically connected to the other of the pair of input / output terminals of the AC circuit; the second AC terminal is provided on one end side of the second housing, the third DC terminal and the fourth DC terminal are provided on the other end side of the second housing, The power conversion device according to claim 1 , wherein each of the plurality of second switching modules is arranged such that the end of the second housing provided with the second AC terminal faces the stack.

4. The first conductor and the second conductor are electrically connected at a second side surface that communicates with a first side surface on the side where the plurality of first switching modules are arranged side by side, among four side surfaces parallel to the stacking direction of the laminate; 2. The power conversion device according to claim 1, wherein the third conductor and the fourth conductor are electrically connected at a fourth side surface that is connected to a third side surface that faces the opposite side to the first side surface and on which the plurality of second switching modules are arranged side by side, among four side surfaces parallel to the stacking direction.

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