JP7501732B2 - Power Conversion Equipment - Google Patents

Description

This invention relates to a power conversion device, and in particular to a power conversion device equipped with multiple semiconductor switching element units.

Conventionally, power conversion devices equipped with multiple switching modules (semiconductor switching element units) are known (see, for example, Patent Document 1).

The above-mentioned Patent Document 1 discloses a power conversion device including a switching module that houses two elements inside. In this power conversion device, multiple (six) switching modules are provided. In addition, this power conversion device is provided with multiple electrolytic capacitors. In addition, this power conversion device is provided with a flat bus bar that connects the multiple switching modules and the multiple electrolytic capacitors. When viewed from a direction perpendicular to the surface of the bus bar, the bus bar has an approximately T-shape. The approximately T-shaped bus bar includes a first straight portion along the horizontal direction and a second straight portion along the vertical direction that branches off from the first straight portion. The terminals of the multiple electrolytic capacitors are connected to the first straight portion. In addition, the multiple switching modules are connected to the second straight portion.

Although not clearly stated in the above Patent Document 1, the electrolytic capacitor is considered to have a substantially cylindrical shape. The electrolytic capacitor is connected to the flat busbar so as to extend in a direction perpendicular to the surface of the flat busbar. The switching module has a substantially rectangular shape (substantially flat shape). The multiple switching modules are arranged so that the substantially flat switching modules are aligned along the direction along the surface of the flat busbar. In other words, the multiple switching modules are arranged along a direction perpendicular to the side of the substantially cylindrical electrolytic capacitor.

JP 2004-135444 A

However, in the power conversion device described in Patent Document 1, the multiple switching modules are arranged in a direction perpendicular to the side of the approximately cylindrical electrolytic capacitor, which causes a problem that the size of the power conversion device (the area in which the electrolytic capacitor and multiple switching modules are arranged) is relatively large when viewed from a direction perpendicular to the surface of the busbar. In addition, the terminals of the multiple electrolytic capacitors are connected to the first straight section, and multiple (six) switching modules are connected to the second straight section. For this reason, the length of the path through which current flows to the electrolytic capacitor differs between the switching module arranged on the side of the second straight section closer to the electrolytic capacitor and the switching module arranged on the side of the second straight section farther from the electrolytic capacitor, which is thought to cause a problem of unbalanced current flow between the multiple switching modules.

This invention was made to solve the above problems, and one objective of the invention is to provide a power conversion device that can reduce the imbalance of current flow while preventing the device from becoming too large.

In order to achieve the above-mentioned object, a power conversion device according to a first aspect of the present invention comprises a capacitor , a terminal arrangement surface on which terminals of the capacitor are arranged , a power conversion section including a plurality of semiconductor switching element sections and converting a voltage of the capacitor , and a bus bar electrically connecting the semiconductor switching element sections to the capacitor , wherein the plurality of semiconductor switching element sections are arranged on a side surface near the terminal arrangement surface so as to follow a side surface of the capacitor that intersects with the terminal arrangement surface which is linearly symmetrical with respect to the terminal , the bus bar has a generally U-shaped configuration covering the terminal arrangement surface and areas of both side surfaces of the capacitor , and the plurality of semiconductor switching element sections are arranged between the side surface of the capacitor and the bus bar .

In the power converter according to the first aspect of the present invention, as described above, the semiconductor switching element units are arranged in the vicinity of the terminal arrangement surface on the side surface so as to be along the side surface of the capacitor that intersects with the terminal arrangement surface that is line-symmetrical with respect to the terminals arranged in a straight line. As a result, since the semiconductor switching element units are arranged along the side surface of the capacitor , the area in which the capacitor and the semiconductor switching element units are arranged can be made relatively small when viewed from a direction perpendicular to the terminal arrangement surface. As a result, the power converter can be prevented from becoming large. Furthermore , since the semiconductor switching element units are arranged along the side surface of the capacitor that is line-symmetrical with respect to the terminal, the length (distance) of the path through which current flows between the semiconductor switching element units arranged on one side of the line-symmetrical side surface and the terminal of the capacitor can be easily made the same as the length of the path through which current flows between the semiconductor switching element units arranged on the other side of the line-symmetrical side surface and the terminal of the capacitor. As a result, the imbalance of the current flow can be reduced while preventing the device from becoming large.

In addition, since the semiconductor switching element units are arranged near the terminal arrangement surface on the side surface of the capacitor , the distance between the semiconductor switching element units and the capacitor is relatively small. Furthermore, the terminals of the semiconductor switching element units and the terminals of the capacitor are connected by a bus bar having a smaller inductance than a conductor wire or the like. As a result, the inductance between the semiconductor switching element units and the capacitor can be reduced. This reduces the surge voltage generated during switching. Furthermore, if the surge voltage is reduced to a level where it is not necessary to provide a snubber capacitor for reducing the surge voltage, the complication of the bus bar configuration caused by providing a snubber capacitor can be suppressed. This makes it easy to replace parts such as the bus bar . Furthermore , since the portion where the approximately U-shaped bus bar faces each other becomes relatively large, the inductance can be further reduced.

In the power conversion device according to the first aspect, the semiconductor switching element units are preferably arranged on both sides of the terminal arrangement surface such that impedances between the capacitor and each of the semiconductor switching element units are substantially equal. With this configuration, it is possible to reduce imbalance in the magnitude of surge voltages generated in each of the semiconductor switching element units.

In this case, preferably, the distance on the busbar between the positive terminal of the one-side semiconductor switching element unit arranged on one side of the positive terminal of the capacitor and the terminal of the capacitor is approximately equal to the distance on the busbar between the positive terminal of the other-side semiconductor switching element unit arranged on the other side of the positive terminal of the capacitor and the terminal of the capacitor, and the distance on the busbar between the negative terminal of the one-side semiconductor switching element unit and the terminal of the capacitor is approximately equal to the distance on the busbar between the negative terminal of the other-side semiconductor switching element unit and the terminal of the capacitor . With this configuration, it is possible to easily make the impedance between each of the multiple semiconductor switching element units and the capacitor approximately equal by simply making the above distances approximately equal.

In the aforementioned power conversion device according to the first aspect, the bus bar is preferably provided in common to the plurality of semiconductor switching element portions.

In the power conversion device according to the first aspect, the height position of the semiconductor switching element unit arranged on one side relative to the capacitor and the height position of the semiconductor switching element unit arranged on the other side relative to the capacitor are preferably substantially equal. With this configuration, the distances between each of the plurality of semiconductor switching element units and the capacitor terminals (the distances of the paths through which current flows) can be easily made substantially equal.

The power conversion device according to the first aspect preferably further includes a cooling pipe section provided on a surface of the bus bar and through which cooling water flows. With this configuration, even if the amount of heat generated by the bus bar increases due to a large current flowing through the bus bar, the cooling pipe section through which the cooling water flows can effectively dissipate heat from the bus bar.
In the aforementioned power conversion device according to the first aspect, a cooling plate is preferably arranged on a side surface of the capacitor, and the semiconductor switching element portion is arranged on a surface of the cooling plate.
A power conversion device according to a second aspect of the present invention includes a capacitor, a terminal arrangement surface on which terminals of the capacitor are arranged, a power conversion section including a plurality of semiconductor switching element sections and converting a voltage of the capacitor, and a bus bar electrically connecting the terminal and the semiconductor switching element sections, wherein the plurality of semiconductor switching element sections are arranged on a side surface near the terminal arrangement surface so as to follow a side surface of the capacitor that intersects with the terminal arrangement surface which is linearly symmetrical with respect to the terminal, a cooling plate for cooling the semiconductor switching element sections is arranged between the plurality of semiconductor switching element sections and the side surface of the capacitor , and the bus bar is provided in common to the plurality of semiconductor switching element sections .
In the power conversion device according to the second aspect described above, the bus bar preferably has a generally U-shape covering the terminal arrangement surface and both side surface areas of the capacitor, and the plurality of semiconductor switching element portions are arranged between the side surface of the capacitor and the bus bar.

According to the present invention, as described above, it is possible to reduce the imbalance in the current flow while suppressing the increase in size.

1 is a circuit diagram of a power conversion device according to an embodiment. FIG. 2 is a perspective view of a stack of power converters according to one embodiment. FIG. 1 is an exploded perspective view (1) of a stack of a power converter according to one embodiment. 1 is a cross-sectional view (side view) of a stack of a power converter according to one embodiment. FIG. 2 is an exploded perspective view (2) of a stack of a power converter according to one embodiment.

The following describes an embodiment of the present invention with reference to the drawings.

[Present embodiment]
The configuration of a power conversion device 100 according to this embodiment will be described with reference to Figures 1 to 5. The power conversion device 100 is, for example, a power conversion device 100 for an induction heating device used in a melting furnace that melts metal by induction heating. The power conversion device 100 is configured to generate an AC current from an AC power source 200 using a semiconductor switching element 31. A plurality of AC power sources 200 (for example, two) are provided.

(Circuit configuration of power conversion device)
The circuit configuration of the power conversion device 100 will be described with reference to Fig. 1. The power conversion device 100 includes a plurality of rectifier circuits 10 (rectifier circuits 10a to 10d). The rectifier circuits 10 convert an AC voltage input from an AC power source 200 into a DC voltage. A plurality of rectifier circuits 10 are provided for one AC power source 200.

The power conversion device 100 also includes a plurality of smoothing capacitors 20 (smoothing capacitors 20a to 20d). The smoothing capacitors 20 are connected to the output side of a rectifier circuit 10 that rectifies the AC voltage. A smoothing capacitor 20 is provided for each rectifier circuit 10. Although not shown in FIG. 1, the smoothing capacitor 20 may be configured by connecting a plurality of capacitors in series or in parallel.

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

The smoothing capacitor 20 and the inverter section 30 form a stack (circuit unit) 40. Multiple stacks 40 (stacks 40a to 40d) are provided.

The inverter section 30 includes a plurality of semiconductor switching elements 31 (semiconductor switching elements 31a to 31d). The semiconductor switching elements 31a and 31b are housed in one semiconductor module 32 (semiconductor module 32a). The semiconductor switching elements 31c and 31d are housed in one semiconductor module 32 (semiconductor module 32b). Although not shown in FIG. 1, six semiconductor modules 32a and 32b are each provided in parallel. A full bridge circuit is formed by the semiconductor switching elements 31a to 31d. The semiconductor module 32 is an example of the "semiconductor switching element section" in the claims. The semiconductor modules 32a and 32b are examples of the "one-side semiconductor switching element section" and "other-side semiconductor switching element section" in the claims, respectively.

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

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

The connection point between the semiconductor switching element 31a and the semiconductor switching element 31b of the inverter unit 30a (inverter unit 30c) is electrically connected to one end of the induction heating coil 210. The connection point between the semiconductor switching element 31c and the semiconductor switching element 31d of the inverter unit 30b (inverter unit 30d) is electrically connected to the other end of the induction heating coil 210.

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

(Specific structure of stack)
Next, a specific structure of the stack 40 will be described with reference to FIGS.

As shown in Figs. 2 and 3, the smoothing capacitor 20 is 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 arranged in a straight line. The terminal arrangement surface 22 is the surface of the smoothing capacitor 20 on the Z1 direction side. The terminals 21 include a positive terminal 21p and a negative terminal 21n. The positive terminal 21p and the negative terminal 21n are arranged alternately on the terminal arrangement surface 22 along the X direction.

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

Here, in this embodiment, the semiconductor modules 32 are arranged along the side surface 23 of the smoothing capacitor 20 that intersects with the terminal arrangement surface 22 that is linearly symmetrical with respect to the terminals 21 arranged in a straight line. The semiconductor modules 32 are arranged near the terminal arrangement surface 22 on the side surface 23. Specifically, of the multiple semiconductor modules 32, for example, six parallel (six) semiconductor modules 32a are arranged along the X direction on the side surface 23a on the Y1 direction side of the smoothing capacitor 20. Also, as shown in FIG. 4, six parallel (six) semiconductor modules 32b are arranged along the X direction on the side surface 23b on the Y2 direction side of the smoothing capacitor 20. Also, the semiconductor modules 32 are arranged so that the surface of the semiconductor modules 32 (the surface on which the positive terminal 32p, the negative terminal 32n, and the output terminal 32o are provided) is arranged along the side surface 23.

As shown in FIG. 3, the semiconductor module 32 is disposed near the terminal arrangement surface 22 in the Z direction. For example, the semiconductor module 32 is disposed on the Z1 direction side of the center C of the semiconductor module 32 in the Z direction.

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 section 25 through which cooling water flows is provided on the surface of the cooling plate 24 facing the smoothing capacitor 20. The semiconductor module 32 is cooled via the cooling plate 24 by the cooling water flowing through the cooling pipe section 25.

In addition, in this embodiment, as shown in FIG. 4, the height position h1 of the semiconductor module 32a arranged on one side 23a relative to the smoothing capacitor 20 and the height position h2 of the semiconductor module 32b arranged on the other side 23b relative to the smoothing capacitor 20 are approximately equal to each other with respect to the terminal 21 of the smoothing capacitor 20. Specifically, the height position h1 of the end of the semiconductor module 32a on the Z1 direction side and the height position h2 of the end of the semiconductor module 32b on the Z1 direction side are approximately equal to each other. Furthermore, the height positions h1 of the six semiconductor modules 32a are equal to each other. Furthermore, the height positions h2 of the six semiconductor modules 32b are equal to each other.

As shown in FIG. 3, the stack 40 is provided with a positive bus bar 50. The positive bus bar 50 is electrically connected to the positive terminal 32p of the semiconductor module 32 and the positive terminal 21p of the smoothing capacitor 20. The stack 40 is provided with a negative bus bar 60. The negative bus bar 60 is electrically connected to the negative terminal 32n of the semiconductor module 32 and the negative terminal 21n of the smoothing capacitor 20. Note that a "bus bar" is a conductor that carries a large amount of current and is made of copper or the like.

In this embodiment, the multiple semiconductor modules 32 are arranged on both the side surface 23a on one side and the side surface 23b on the other side of the terminal arrangement surface 22 so that the impedance (each impedance) between each of the multiple semiconductor modules 32 and the smoothing capacitor 20 is approximately equal.

Specifically, in this embodiment, as shown in FIG. 4, the distance L1 (distance shown by the dashed line in FIG. 4) on the positive bus bar 50 between the positive terminal 32p of the semiconductor module 32a arranged on one side (side surface 23a) of the terminal 21 of the smoothing capacitor 20 and the terminal 21 of the smoothing capacitor 20 is approximately equal to the distance L2 on the positive bus bar 50 between the positive terminal 32p of the semiconductor module 32b arranged on the other side (side surface 23b) of the terminal 21 of the smoothing capacitor 20 and the terminal 21 of the smoothing capacitor 20. Also, the distance L11 on the negative bus bar 60 between the negative terminal 32n of the semiconductor module 32a and the terminal 21 of the smoothing capacitor 20 is approximately equal to the distance L12 on the negative bus bar 60 between the negative terminal 32n of the semiconductor module 32b and the terminal 21 of the smoothing capacitor 20. In detail, the distance L1 on the positive bus bar 50 between the positive terminal 32p of the semiconductor module 32a and the positive terminal 21p of the smoothing capacitor 20 is approximately equal to the distance L2 on the positive bus bar 50 between the positive terminal 32p of the semiconductor module 32b and the positive terminal 21p of the smoothing capacitor 20. Also, the distance L11 on the negative bus bar 60 between the negative terminal 32n of the semiconductor module 32a and the negative terminal 21n of the smoothing capacitor 20 is approximately equal to the distance L12 on the negative bus bar 60 between the negative terminal 32n of the semiconductor module 32b and the negative terminal 21n of the smoothing capacitor 20. Note that the "distance on the positive bus bar 50" means the shortest distance on the positive bus bar 50 between the positive terminal 32p of the semiconductor module 32 and the positive terminal 21p of the smoothing capacitor 20. The meaning of "distance on the negative bus bar 60" is the same.

In the present embodiment, as shown in FIG. 3, the positive bus bar 50 and the negative bus bar 60 are each provided in common to a plurality of semiconductor modules 32. As shown in FIG. 4, the positive bus bar 50 and the negative bus bar 60 each have a substantially U-shape that covers the terminal arrangement surface 22 and both side surfaces 23a and 23b of the smoothing capacitor 20. Specifically, the positive bus bar 50 and the negative bus bar 60 are stacked in this order on the smoothing capacitor 20. That is, the substantially U-shaped positive bus bar 50 is disposed inside the substantially U-shaped negative bus bar 60. Also, the positive bus bar 50 and the negative bus bar 60 are each formed by bending a single metal plate.

As shown in FIG. 5, insulating paper 70 is disposed between the positive bus bar 50 and the negative bus bar 60. Multiple pieces of insulating paper 70 are provided.

As shown in FIG. 4, the positive busbar 50 includes a first portion 51 extending along the Y direction and a second portion 52 extending from both ends of the first portion 51 in the Y direction toward the Z2 direction. The negative busbar 60 includes a first portion 61 extending along the Y direction and a second portion 62 extending from both ends of the first portion 61 in the Y direction toward the Z2 direction. The length L21 of the first portion 51 of the positive busbar 50 along the Y direction is smaller than the length L22 of the first portion 61 of the negative busbar 60 along the Y direction. The length L31 of the second portion 52 of the positive busbar 50 along the Z direction is smaller than the length L32 of the second portion 62 of the negative busbar 60 along the Z direction.

The positive busbar 50 has legs 53 connected to the positive terminal 32p of the semiconductor module 32a and the positive terminal 32p of the semiconductor module 32b. The negative busbar 60 has legs 63 connected to the negative terminal 32n of the semiconductor module 32a and the negative terminal 32n of the semiconductor module 32b. The legs 53 of the positive busbar 50 are connected to the positive terminal 32p of the semiconductor module 32 by screws 80. The legs 63 of the negative busbar 60 are connected to the negative terminal 32n of the semiconductor module 32 by screws 80. The legs 53 and 63 are arranged along the Y direction. The length L41 of the legs 53 of the positive busbar 50 along the Y direction is smaller than the length L42 of the legs 63 of the negative busbar 60 along the Y direction.

The distance D1 in the Z direction between the first portion 51 of the positive busbar 50 and the first portion 61 of the negative busbar 60 is relatively small. The distance D2 in the Y direction between the second portion 52 of the positive busbar 50 and the second portion 62 of the negative busbar 60 is relatively small. On the other hand, the distance D3 in the Z direction between the leg 53 of the positive busbar 50 and the leg 63 of the negative busbar 60 is relatively large. However, of the entire area of the positive busbar 50, only the leg 53 (only a relatively small area) has a relatively large distance from the negative busbar 60. As a result, the effect of the leg 53 (leg 63) on the effect of reducing the inductance of the positive busbar 50 and the negative busbar 60 due to the stacking of the positive busbar 50 and the negative busbar 60 is small.

As shown in FIG. 5, the positive bus bar 50 has a plurality of holes 54. The negative bus bar 60 has a plurality of holes 64. The insulating paper 70 has a plurality of holes 71. The screw 80 is screwed into the positive terminal 21p of the smoothing capacitor 20 from the Z1 direction side through the hole 64 of the negative bus bar 60, the hole 71 of the insulating paper 70, and the positive bus bar 50. This connects the positive bus bar 50 to the positive terminal 21p of the smoothing capacitor 20. The screw 80 is screwed into 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. This connects the negative bus bar 60 to the negative terminal 21n of the smoothing capacitor 20.

In addition, in this embodiment, a cooling pipe section 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 (in this embodiment, both). The positive bus bar 50 is provided with a cooling pipe section 81p on the inside of the second part 52 of the substantially U-shaped positive bus bar 50. The negative bus bar 60 is provided with a cooling pipe section 81n on the outside of the second part 52 of the substantially U-shaped negative bus bar 60. The cooling pipe section 81p (cooling pipe section 81n) is provided in a substantially annular shape with respect to the second part 52 of the positive bus bar 50 (second part 52 of the negative bus bar 60).

As described above, by arranging the semiconductor modules 32 on the side surface 23 of the smoothing capacitor 20 near the terminal arrangement surface 22, by making the impedance between each of the multiple semiconductor modules 32 and the smoothing capacitor 20 approximately equal, and by stacking the positive bus bar 50 and the negative bus bar 60, the inductance between each of the multiple semiconductor modules 32 and the smoothing capacitor 20 is suppressed to approximately 10 nH or less. This eliminates the need to provide a snubber capacitor to reduce surge voltage.

[Effects of this embodiment]
In this embodiment, the following effects can be obtained.

In this embodiment, as described above, the multiple semiconductor modules 32 are arranged near the terminal arrangement surface 22 on the side surface 23 so as to be along the side surface 23 of the smoothing capacitor 20 that intersects with the terminal arrangement surface 22 that is line-symmetrical with respect to the terminals 21 arranged in a straight line. As a result, since the multiple 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 multiple semiconductor modules 32 are arranged can be relatively small when viewed from a direction perpendicular to the terminal arrangement surface 22. As a result, it is possible to prevent the power conversion device 100 from becoming large. In addition, since the semiconductor modules 32 are arranged along the side surface 23 of the smoothing capacitor 20 that is line-symmetrical with respect to the terminals 21 arranged in a straight line, the length (distance) of the path through which current flows between the semiconductor modules 32 arranged on one side of the line-symmetrical side surface 23 and the terminals 21 of the smoothing capacitor 20 can be easily made the same as the length of the path through which current flows between the semiconductor modules 32 arranged on the other side of the line-symmetrical side surface 23 and the terminals 21 of the smoothing capacitor 20. As a result, it is possible to reduce the imbalance of the current flow while preventing the device from becoming large.

In addition, since the multiple semiconductor modules 32 are arranged near the terminal arrangement surface 22 on the side surface 23 of the smoothing capacitor 20, the distance between the multiple semiconductor modules 32 and the smoothing capacitor 20 is relatively small. In addition, the terminals (positive terminal 32p, negative terminal 32n) of the semiconductor modules 32 and the terminal 21 of the smoothing capacitor 20 are connected by bus bars (positive bus bar 50 and negative bus bar 60) that have a smaller inductance than conductors. This makes it possible to reduce the inductance between the multiple semiconductor modules 32 and the smoothing capacitor 20. This makes it possible to reduce the surge voltage generated during switching. In addition, if the surge voltage is reduced to a level where it is not necessary to provide a snubber capacitor to reduce the surge voltage, it is possible to suppress the complication of the configuration of the positive bus bar 50 and the negative bus bar 60 caused by providing a snubber capacitor. This makes it easy to replace parts such as the positive bus bar 50 and the negative bus bar 60.

In addition, in this embodiment, as described above, the multiple semiconductor modules 32 are arranged on both side surfaces 23 on one side and the other side of the terminal arrangement surface 22 so that the impedance between each of the multiple semiconductor modules 32 and the smoothing capacitor 20 is approximately equal. This makes it possible to reduce the imbalance in the magnitude of the surge voltage generated in each of the multiple semiconductor modules 32.

In addition, in this embodiment, as described above, the distance L1 on the positive bus bar 50 between the positive terminal 32p of the semiconductor module 32a arranged on one side of the positive terminal 21p of the smoothing capacitor 20 and the terminal 21 of the smoothing capacitor 20 is approximately equal to the distance L2 on the positive bus bar 50 between the positive terminal 32p of the semiconductor module 32b arranged on the other side of the positive terminal 21p of the smoothing capacitor 20 and the terminal 21 of the smoothing capacitor 20. In addition, the distance L11 on the negative bus bar 60 between the negative terminal 32n of the semiconductor module 32a and the terminal 21 of the smoothing capacitor 20 is approximately equal to the distance L12 on the negative bus bar 60 between the negative terminal 32n of the semiconductor module 32b and the terminal 21 of the smoothing capacitor 20. As a result, the impedance between each of the multiple semiconductor modules 32 and the smoothing capacitor 20 can be easily made approximately equal by simply making the above distances approximately equal.

In addition, in this embodiment, as described above, the positive bus bar 50 and the negative bus bar 60 are each provided in common to multiple semiconductor modules 32, and have a generally U-shape that covers the terminal arrangement surface 22 and both side surfaces 23 of the smoothing capacitor 20. This makes the area where the generally U-shaped positive bus bar 50 and the generally U-shaped negative bus bar 60 face each other relatively large, thereby further reducing inductance.

In addition, in this embodiment, as described above, the height position h1 of the semiconductor module 32a arranged on one side 23a relative to the smoothing capacitor 20 and the height position h2 of the semiconductor module 32b arranged on the other side 23b relative to the smoothing capacitor 20 are approximately equal to each other with respect to the terminal 21 of the smoothing capacitor 20. This makes it easy to make the distances between each of the multiple semiconductor modules 32 and the terminal 21 of the smoothing capacitor 20 (the distance of the path through which the current flows) approximately equal.

In addition, in this embodiment, as described above, a cooling pipe section 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. As a result, even if the amount of heat generated by at least one of the positive bus bar 50 and the negative bus bar 60 increases due to a large current flowing through at least one of the positive bus bar 50 and the negative bus bar 60, the cooling pipe section 81 through which cooling water flows can effectively dissipate heat from at least one of the positive bus bar 50 and the negative bus bar 60.

[Variations]
It should be noted that the embodiments disclosed herein are illustrative and not restrictive in all respects. The scope of the present invention is indicated by the claims, not by the description of the embodiments above, and further includes all modifications (variations) within the meaning and scope of the claims.

For example, in the above embodiment, an example was shown in which the impedance between each of the multiple semiconductor modules and the smoothing capacitor is approximately equalized by making the distance between each of the multiple semiconductor modules and the smoothing capacitor approximately equal, but the present invention is not limited to this. For example, the impedance between each of the multiple semiconductor modules and the smoothing capacitor may be approximately equalized by adjusting the cross-sectional area of the bus bar between each of the multiple semiconductor modules and the smoothing capacitor.

In addition, in the above embodiment, an example was shown in which the positive bus bar and the negative bus bar are each provided in common for multiple (12) semiconductor modules, but the present invention is not limited to this. For example, the positive bus bar and the negative bus bar may be divided.

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

In addition, in the above embodiment, an example was shown in which six semiconductor modules (semiconductor module 32a and semiconductor module 32b) were provided in parallel, but the present invention is not limited to this. For example, the semiconductor modules may be provided in a number other than six parallel.

In addition, in the above embodiment, an example was shown in which two switching elements were housed in one semiconductor module, but the present invention is not limited to this. For example, a number of switching elements other than two may be housed in one semiconductor module.

In addition, in the above embodiment, an example was shown in which the height position of the semiconductor module arranged on one side surface and the height position of the semiconductor module arranged on the other side surface are approximately equal, but the present invention is not limited to this. For example, even if the height position of the semiconductor module arranged on one side surface and the height position of the semiconductor module arranged on the other side surface are not approximately equal, as long as the impedance between each of the multiple semiconductor modules and the smoothing capacitor is approximately equal, there is no need to align the height positions of the multiple semiconductor modules.

In addition, in the above embodiment, an example was shown in which the cooling pipe section is provided on both the positive bus bar and the negative bus bar, but the present invention is not limited to this. For example, the cooling pipe section may be provided on one of the positive bus bar and the negative bus bar.

10, 10a to 10d Rectifier circuit 20, 20a to 20d Smoothing capacitor 21 Terminal 21p Positive terminal 21n Negative terminal 22 Terminal arrangement surface 23, 23a, 23b Side surface 30, 30a to 30d Inverter section (power conversion section)
32 Semiconductor module (semiconductor switching element section)
32a Semiconductor module (one-side semiconductor switching element portion)
32b Semiconductor module (other-side semiconductor switching element portion)
32p Positive terminal 32n Negative terminal 50 Positive bus bar 60 Negative bus bar 81, 81p, 81n Cooling pipe section 100 Power conversion device h1, h2 Height position

Claims (9)

A capacitor;
a terminal arrangement surface on which terminals of the capacitor are arranged;
a power conversion unit including a plurality of semiconductor switching element units and converting a voltage of the capacitor;
a bus bar electrically connecting the semiconductor switching element unit and the capacitor,
the plurality of semiconductor switching element portions are arranged on a side surface of the capacitor in the vicinity of the terminal arrangement surface so as to be aligned along the side surface intersecting the terminal arrangement surface and being symmetrical with respect to the terminal;
the bus bar has a generally U-shape that covers the terminal arrangement surface and both side surface areas of the capacitor,
The power conversion device, wherein the plurality of semiconductor switching element units are disposed between the side surface of the capacitor and the bus bar. The power conversion device according to claim 1, wherein the plurality of semiconductor switching element units are arranged on both the side surfaces on one side and the other side of the terminal arrangement surface so that the impedance between each of the plurality of semiconductor switching element units and the capacitor is approximately equal. a distance on the bus bar between a positive terminal of one side semiconductor switching element part arranged on one side of the positive terminal of the capacitor and the terminal of the capacitor is substantially equal to a distance on the bus bar between a positive terminal of the other side semiconductor switching element part arranged on the other side of the positive terminal of the capacitor and the terminal of the capacitor,
3. The power conversion device according to claim 2, wherein a distance on the bus bar between a negative terminal of the one side semiconductor switching element unit and a terminal of the capacitor is approximately equal to a distance on the bus bar between a negative terminal of the other side semiconductor switching element unit and a terminal of the capacitor. The power conversion device according to any one of claims 1 to 3, wherein the bus bar is provided in common to the plurality of semiconductor switching element units. The power conversion device according to any one of claims 1 to 4, wherein the height position of the semiconductor switching element part arranged on one side of the terminal of the capacitor relative to the capacitor is approximately equal to the height position of the semiconductor switching element part arranged on the other side of the terminal of the capacitor relative to the capacitor. The power conversion device according to any one of claims 1 to 5, further comprising a cooling pipe section provided on the surface of the busbar and through which cooling water flows. The power conversion device according to any one of claims 1 to 6, wherein a cooling plate is arranged on the side of the capacitor, and the semiconductor switching element unit is arranged on the surface of the cooling plate. A capacitor;
a terminal arrangement surface on which terminals of the capacitor are arranged;
a power conversion unit including a plurality of semiconductor switching element units and converting a voltage of the capacitor;
a bus bar electrically connecting the terminal and the semiconductor switching element unit,
the plurality of semiconductor switching element units are arranged along a side surface of the capacitor intersecting the terminal arrangement surface and being line-symmetrical with respect to the terminal, in the vicinity of the terminal arrangement surface;
a cooling plate for cooling the semiconductor switching element units is disposed between the plurality of semiconductor switching element units and the side surface of the capacitor ;
The bus bar is provided in common to the plurality of semiconductor switching element units . the bus bar has a generally U-shape that covers the terminal arrangement surface and both side surface areas of the capacitor,
The power conversion device according to claim 8 , wherein the plurality of semiconductor switching element units are disposed between the side surface of the capacitor and the bus bar.

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