JP7283183B2 - power converter - Google Patents

Description

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

2. Description of the Related Art Conventionally, a power conversion device including a plurality of switching modules (semiconductor switching element units) is known (see Patent Literature 1, for example).

The above Patent Document 1 discloses a power converter provided with a switching module that accommodates two elements inside. This power converter is provided with a plurality of (six) switching modules. Also, this power converter is provided with a plurality of electrolytic capacitors. Further, this power conversion device is provided with a flat bus bar that connects the plurality of switching modules and the plurality of electrolytic capacitors. The busbar has a substantially T-shape when viewed in a direction perpendicular to the surface of the busbar. The substantially T-shaped bus bar includes a first straight portion along the horizontal direction and a second straight portion along the vertical direction branched from the first straight portion. Terminals of the plurality of electrolytic capacitors are connected to the first linear portion. Also, the plurality of switching modules are connected to the second straight portion.

Also, although it is not clearly described in Patent Document 1, it is believed that the electrolytic capacitor has a substantially cylindrical shape. Further, the electrolytic capacitor is connected to the flat-plate-shaped bus bar so as to extend in a direction perpendicular to the surface of the flat-plate-shaped bus bar. Also, the switching module has a substantially rectangular shape (substantially flat plate shape). The plurality of switching modules are arranged such that the substantially flat plate-shaped switching modules are arranged along the surface of the flat plate-shaped bus bar. In other words, the plurality of switching modules are arranged along a direction perpendicular to the side surface of the substantially cylindrical electrolytic capacitor.

JP 2004-135444 A

However, in the power conversion device described in Patent Document 1, the plurality of switching modules are arranged along the direction perpendicular to the side surface of the substantially cylindrical electrolytic capacitor, so that from the direction perpendicular to the surface of the bus bar As you can see, there is a problem that the size of the power converter (the area where the electrolytic capacitor and the plurality of switching modules are arranged) becomes relatively large. Terminals of the plurality of electrolytic capacitors are connected to the first straight portion, and a plurality (six) of switching modules are connected to the second straight portion. For this reason, the switching module arranged on the side of the second straight portion closer to the electrolytic capacitor and the switching module arranged on the side farther from the electrolytic capacitor of the second straight portion have different current flow paths to the electrolytic capacitor. Since the lengths of .alpha.

The present invention has been made to solve the above problems, and one object of the present invention is to reduce unbalance in current flow while suppressing an increase in size. It is to provide a power converter.

In order to achieve the above object, a power converter according to one aspect of the present invention includes a smoothing capacitor connected to an output side of a rectifier circuit that rectifies an alternating voltage, and terminals having terminals of the smoothing capacitor arranged linearly. a power conversion unit that includes a plurality of semiconductor switching element units and converts the DC voltage smoothed by the smoothing capacitor into an AC voltage; and the positive terminal of the semiconductor switching element unit and the positive terminal of the smoothing capacitor and a negative bus bar electrically connected to the negative terminal of the semiconductor switching element section and the negative terminal of the smoothing capacitor, wherein the plurality of semiconductor switching element sections are arranged linearly. The positive side bus bar and the negative side bus bar are arranged in the vicinity of the terminal arrangement surface on the side surface so as to follow the side surface of the smoothing capacitor that intersects the terminal arrangement surface that is line symmetrical with respect to the terminals arranged in the , a substantially U-shape covering the terminal arrangement surface and both side surface regions of the smoothing capacitor, and the plurality of semiconductor switching element portions are arranged on the side surface of the smoothing capacitor, the positive side bus bar and the negative side bus bar, is placed between .

In the power converter according to one aspect of the present invention, as described above, the plurality of semiconductor switching element portions are arranged on the side surface of the smoothing capacitor that intersects the terminal arrangement plane that is line-symmetrical with respect to the linearly arranged terminals. It is arranged in the vicinity of the terminal arrangement surface on the side surface so as to follow. As a result, since the plurality of semiconductor switching element sections are arranged along the side surface of the smoothing capacitor, the area where the smoothing capacitor and the plurality of semiconductor switching element sections are arranged is defined as can be relatively small. As a result, it is possible to suppress an increase in the size of the power converter. In addition, since the semiconductor switching element portion is arranged along the side surface of the smoothing capacitor that is line-symmetrical with respect to the linearly arranged terminals, the semiconductor switching element portion that is arranged on one side of the line-symmetrical side surface The length (distance) of the path through which the current flows between the terminal and the terminal of the smoothing capacitor, and the path through which the current flows between the terminal of the smoothing capacitor and the semiconductor switching element arranged on the other side of the symmetrical side surface can be easily made the same as the length of As a result, it is possible to reduce imbalance in current flow while suppressing an increase in size.

Moreover, since the plurality of semiconductor switching element portions are arranged in the vicinity of the terminal arrangement surface on the side surface of the smoothing capacitor, the distance between the plurality of semiconductor switching element portions and the smoothing capacitor is relatively small. In addition, the terminals of the semiconductor switching element section and the terminals of the smoothing capacitor are connected by bus bars (positive side bus bar and negative side bus bar) having smaller inductance than conducting wires. These can reduce the inductance between the plurality of semiconductor switching element units and the smoothing capacitor. As a result, it is possible to reduce the surge voltage generated during switching. In addition, if the surge voltage is reduced to the extent that it is not necessary to provide a snubber capacitor for reducing the surge voltage, the complication of the configuration of the positive side bus bar and the negative side bus bar due to the provision of the snubber capacitor can be suppressed. be able to. As a result, parts such as the positive side bus bar and the negative side bus bar can be easily replaced.
In addition, since the portion where the approximately U-shaped positive bus bar and the approximately U-shaped negative bus bar face each other becomes relatively large, the inductance can be further reduced.

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

In this case, preferably, the distance on the positive side bus bar between the positive side terminal of the one-side semiconductor switching element portion arranged on one side of the positive side terminal of the smoothing capacitor and the terminal of the smoothing capacitor is equal to The distance on the positive bus bar between the positive terminal of the other semiconductor switching element portion arranged on the other side of the positive terminal and the terminal of the smoothing capacitor is substantially equal to the negative terminal of the one semiconductor switching element portion and the terminal of the smoothing capacitor on the negative bus bar is substantially equal to the distance on the negative bus bar between the negative terminal of the other semiconductor switching element portion and the terminal of the smoothing capacitor. According to this configuration, the impedance between each of the plurality of semiconductor switching element portions and the smoothing capacitor can be easily made approximately equal simply by making the distance approximately equal.

In the power conversion device according to the above aspect, preferably the positive side bus bar and the negative side bus bar are each provided in common to the plurality of semiconductor switching element units .

In the power conversion device according to the above aspect, preferably, with respect to the terminal of the smoothing capacitor, the semiconductor switching element portion arranged on one side surface of the smoothing capacitor is arranged at a height position with respect to the smoothing capacitor, and the other side surface of the semiconductor switching element portion is arranged at a height position with respect to the smoothing capacitor. The height position of the semiconductor switching element portion with respect to the smoothing capacitor is substantially the same. According to this configuration, the distances (distances of paths through which current flows) between each of the plurality of semiconductor switching element portions and the terminals of the smoothing capacitor can be easily made substantially equal.

The power converter according to the above aspect preferably further includes a cooling pipe section provided on a surface of at least one of the positive bus bar and the negative bus bar and through which cooling water flows. With this configuration, the amount of heat generated by at least one of the positive bus bar and the negative bus bar increases due to the large current flowing through at least one of the positive bus bar and the negative bus bar. Even in this case, heat can be effectively radiated from at least one of the positive side bus bar and the negative side bus bar by the cooling pipe portion through which the cooling water flows.
In the power converter according to the above aspect, preferably, a cooling plate is arranged on a side surface of the smoothing capacitor, and the semiconductor switching element section is arranged on the surface of the cooling plate.

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

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

Embodiments embodying the present invention will be described below with reference to the drawings.

[This embodiment]
The configuration of a power converter 100 according to the present embodiment will be described with reference to FIGS. 1 to 5. FIG. Note that 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 alternating current from an alternating current power supply 200 using a semiconductor switching element 31 . Also, a plurality of (for example, two) AC power supplies 200 are provided.

(Circuit configuration of power converter)
A circuit configuration of the power converter 100 will be described with reference to FIG. The power converter 100 includes a plurality of rectifier circuits 10 (rectifier circuits 10a to 10d). The rectifier circuit 10 converts an AC voltage input from the AC power supply 200 into a DC voltage. A plurality of rectifier circuits 10 are provided for one AC power supply 200 .

The power converter 100 also includes a plurality of smoothing capacitors 20 (smoothing capacitors 20a to 20d). The smoothing capacitor 20 is connected to the output side of the 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, smoothing capacitor 20 may be configured by connecting a plurality of capacitors in series or in parallel.

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

A stack (circuit unit) 40 is configured by the smoothing capacitor 20 and the inverter section 30 . A plurality of stacks 40 (stacks 40a to 40d) are provided.

The inverter section 30 also includes a plurality of semiconductor switching elements 31 (semiconductor switching elements 31a to 31d). The semiconductor switching element 31a and the semiconductor switching element 31b are accommodated in one semiconductor module 32 (semiconductor module 32a). The semiconductor switching element 31c and the semiconductor switching element 31d are housed in one semiconductor module 32 (semiconductor module 32b). Although not shown in FIG. 1, each of the semiconductor modules 32a and the semiconductor modules 32b is provided in parallel for six. A full bridge circuit is configured 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 module 32a and the semiconductor module 32b are examples of the "one side semiconductor switching element section" and the "other side semiconductor switching element section", 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. Also, the anode side and the cathode side of the rectifier circuit 10b are electrically connected to the anode side and the cathode side of the rectifier circuit 10d, respectively.

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

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

A connection point between the semiconductor switching element 31c and the semiconductor switching element 31d of the inverter section 30a is electrically connected to a connection point between the semiconductor switching element 31a and the semiconductor switching element 31b of the inverter section 30b. That is, the stacks 40a and 40b are electrically connected in series. A connection point between the semiconductor switching elements 31c and 31d of the inverter section 30c and a connection point between the semiconductor switching elements 31a and 31b of the inverter section 30d are electrically connected. 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 converter 100 .

(Specific structure of stack)
Next, a specific structure of the stack 40 will be described with reference to FIGS. 2 to 5. FIG.

As shown in FIGS. 2 and 3, 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 placement surface 22 on which the terminals 21 of the smoothing capacitor 20 are arranged linearly. The terminal arrangement surface 22 is the surface of the smoothing capacitor 20 on the Z1 direction side. Moreover, the terminal 21 includes a positive terminal 21p and a negative terminal 21n. The positive terminals 21 p and the negative terminals 21 n are alternately arranged along the X direction on the terminal arrangement surface 22 .

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 to the Z2 direction side.

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

Further, as shown in FIG. 3, the semiconductor module 32 is arranged near the terminal arrangement surface 22 in the Z direction. For example, the semiconductor module 32 is arranged 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 arranged on a side surface 23 of the smoothing capacitor 20 . The semiconductor modules 32 are arranged on the surface of the cooling plate 24 . As shown in FIG. 4, a cooling pipe portion 25 through which cooling water flows is provided on the surface of the cooling plate 24 on the smoothing capacitor 20 side. The semiconductor module 32 is cooled via the cooling plate 24 by cooling water flowing through the cooling pipe portion 25 .

Further, in the present embodiment, as shown in FIG. 4, with respect to the terminal 21 of the smoothing capacitor 20, the height position h1 with respect to the smoothing capacitor 20 of the semiconductor module 32a arranged on one side surface 23a, and the height position h1 with respect to the smoothing capacitor 20 on the other side. The height position h2 of the semiconductor module 32b arranged on the side surface 23b with respect to the smoothing capacitor 20 is substantially equal. Specifically, the height position h1 of the end of the semiconductor module 32a in the Z1 direction and the height position h2 of the end of the semiconductor module 32b in the Z1 direction are substantially equal. Also, the height positions h1 of the six semiconductor modules 32a are equal to each other. Also, the height positions h2 of the six semiconductor modules 32b are equal to each other.

Further, as shown in FIG. 3 , the stack 40 is provided with a positive bus bar 50 . Positive bus bar 50 is electrically connected to positive terminal 32 p of semiconductor module 32 and positive terminal 21 p of smoothing capacitor 20 . A negative bus bar 60 is provided in the stack 40 . Negative bus bar 60 is electrically connected to negative terminal 32 n of semiconductor module 32 and negative terminal 21 n of smoothing capacitor 20 . A "bus bar" is a conductor through which a large amount of current flows, and is made of copper or the like.

Here, in the present embodiment, the plurality of semiconductor modules 32 are arranged with respect to the terminal arrangement surface 22 so that the impedances (each impedance) between each of the plurality of semiconductor modules 32 and the smoothing capacitor 20 are substantially equal. are arranged on both the side surface 23a on one side and the side surface 23b on the other side.

Specifically, in this embodiment, as shown in FIG. The distance L1 on the positive side bus bar 50 (the distance indicated by the dashed line in FIG. 4) between the positive side terminal 32p of the semiconductor module 32b arranged on the other side (side surface 23b) of the terminal 21 of the smoothing capacitor 20 is is substantially equal to the distance L2 on the positive bus bar 50 between the terminal 21 of the smoothing capacitor 20 and the terminal 21 of the smoothing capacitor 20 . Further, 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 the distance between the negative terminal 32n of the semiconductor module 32b and the terminal 21 of the smoothing capacitor 20 is approximately equal to the distance L12 on the negative bus bar 60 between. Specifically, 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 It is approximately equal to the distance L2 on the positive bus bar 50 between the positive terminal 21p. Further, 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 It is substantially equal to the distance L12 on the negative bus bar 60 between the terminals 21n. The “distance on the positive bus bar 50 ” means the shortest distance between the positive terminal 32 p of the semiconductor module 32 and the positive terminal 21 p of the smoothing capacitor 20 on the positive bus bar 50 . The meaning of "distance on the negative bus bar 60" is the same.

Moreover, in the present embodiment, as shown in FIG. 3, the positive bus bar 50 and the negative bus bar 60 are provided in common for the plurality of semiconductor modules 32, respectively. Then, as shown in FIG. 4, each of the positive bus bar 50 and the negative bus bar 60 has a substantially U-shape covering the terminal arrangement surface 22 and the areas of both the side surfaces 23a and 23b of the smoothing capacitor 20. . Specifically, a positive side bus bar 50 and a negative side bus bar 60 are laminated in this order on the smoothing capacitor 20 . That is, the substantially U-shaped positive bus bar 50 is arranged inside the substantially U-shaped negative bus bar 60 . Moreover, each of the positive side bus bar 50 and the negative side bus bar 60 is formed by bending one metal plate.

Also, as shown in FIG. 5, an insulating paper 70 is arranged between the positive bus bar 50 and the negative bus bar 60 . A plurality of insulating papers 70 are provided.

4, the positive bus bar 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. including. Negative bus bar 60 also 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. A length L21 along the Y direction of the first portion 51 of the positive bus bar 50 is smaller than a length L22 along the Y direction of the first portion 61 of the negative bus bar 60 . Also, the length L31 along the Z direction of the second portion 52 of the positive bus bar 50 is smaller than the length L32 along the Z direction of the second portion 62 of the negative bus bar 60 .

The positive bus bar 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. Further, the negative bus bar 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 leg portion 53 of the positive bus bar 50 is connected to the positive terminal 32p of the semiconductor module 32 by a screw 80. As shown in FIG. A leg portion 63 of the negative bus bar 60 is connected to the negative terminal 32n of the semiconductor module 32 by a screw 80. As shown in FIG. Further, the leg portions 53 and 63 are provided along the Y direction. In addition, length L41 along the Y direction of leg portion 53 of positive bus bar 50 is smaller than length L42 along the Y direction of leg portion 63 of negative bus bar 60 .

A distance D1 along 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. Also, the distance D2 along the Y direction between the second portion 52 of the positive bus bar 50 and the second portion 62 of the negative bus bar 60 is relatively small. On the other hand, the distance D3 along the Z direction between the leg portion 53 of the positive busbar 50 and the leg portion 63 of the negative busbar 60 is relatively large. However, of the entire region of positive bus bar 50, only leg portion 53 (only a relatively small region) has a relatively large gap from negative bus bar 60. FIG. As a result, the influence of the leg portion 53 (leg portion 63) on the effect of lowering the inductance of the positive bus bar 50 and the negative bus bar 60 by laminating the positive bus bar 50 and the negative bus bar 60 is small.

Further, as shown in FIG. 5 , the positive busbar 50 is provided with a plurality of holes 54 . A plurality of holes 64 are provided in the negative bus bar 60 . Further, the insulating paper 70 is provided with a plurality of holes 71 . A screw 80 is screwed into the positive terminal 21p of the smoothing capacitor 20 from the Z1 direction through the hole 64 of the negative bus bar 60, the hole 71 of the insulating paper 70, and the positive bus bar 50. As shown in FIG. This connects the positive bus bar 50 to the positive terminal 21p of the smoothing capacitor 20 . A screw 80 is screwed to the negative terminal 21n of the smoothing capacitor 20 from the Z1 direction through the negative bus bar 60, the hole 71 of the insulating paper 70, and the hole 54 of the positive bus bar 50. Thereby, the negative bus bar 60 is connected to the negative terminal 21n of the smoothing capacitor 20 .

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

As described above, arranging the semiconductor module 32 in the vicinity of the terminal arrangement surface 22 on the side surface 23 of the smoothing capacitor 20, making the impedance between each of the plurality of semiconductor modules 32 and the smoothing capacitor 20 substantially equal, By laminating the side bus bar 50 and the negative side bus bar 60 or the like, the inductance between each of the plurality of semiconductor modules 32 and the smoothing capacitor 20 is suppressed to about 10 nH or less. This eliminates the need to provide a snubber capacitor for reducing surge voltage.

[Effect of this embodiment]
The following effects can be obtained in this embodiment.

In this embodiment, as described above, the plurality of semiconductor modules 32 are arranged along the side surface 23 of the smoothing capacitor 20 that intersects the terminal arrangement surface 22 that is symmetrical with respect to the linearly arranged terminals 21. It is arranged in the vicinity of the terminal arrangement surface 22 on the side surface 23 . Thus, since the plurality of semiconductor modules 32 are arranged along the side surface 23 of the smoothing capacitor 20, the smoothing capacitor 20 and the plurality of semiconductor modules 32 are arranged when viewed from a direction perpendicular to the terminal arrangement surface 22. The area can be relatively small. As a result, it is possible to suppress the power converter 100 from increasing in size. In addition, since the semiconductor module 32 is arranged along the side surface 23 of the smoothing capacitor 20 which is linearly symmetrical with respect to the terminals 21 which are linearly arranged, the semiconductor module 32 is arranged on one side of the side surface 23 which is linearly symmetrical. The length (distance) of the path through which the current flows between the module 32 and the terminal 21 of the smoothing capacitor 20, and the length (distance) between the semiconductor module 32 and the terminal 21 of the smoothing capacitor 20 arranged on the other side of the side surface 23 that is line-symmetrical. The length of the path through which the current flows can be easily made the same. As a result, it is possible to reduce imbalance in current flow while suppressing an increase in size.

Moreover, since the plurality of semiconductor modules 32 are arranged in the vicinity of the terminal arrangement surface 22 on the side surface 23 of the smoothing capacitor 20, the distance between the plurality of semiconductor modules 32 and the smoothing capacitor 20 is relatively small. The terminals (positive terminal 32p, negative terminal 32n) of the semiconductor module 32 and the terminals 21 of the smoothing capacitor 20 are connected by bus bars (positive bus bar 50 and negative bus bar 60) having smaller inductance than conducting wires. It is connected. These can reduce the inductance between the plurality of semiconductor modules 32 and the smoothing capacitor 20 . As a result, it is possible to reduce the surge voltage generated during switching. Further, if the surge voltage is reduced to the extent that it is not necessary to provide a snubber capacitor for reducing the surge voltage, the complication of the configurations of the positive side bus bar 50 and the negative side bus bar 60 due to the provision of the snubber capacitor can be eliminated. can be suppressed. Thereby, parts such as the positive side bus bar 50 and the negative side bus bar 60 can be easily replaced.

In addition, in the present embodiment, as described above, the plurality of semiconductor modules 32 are arranged with respect to the terminal arrangement surface 22 so that the impedance between each of the plurality of semiconductor modules 32 and the smoothing capacitor 20 is substantially equal. It is arranged on both side surfaces 23 of one side and the other side. As a result, the imbalance in the magnitude of the surge voltage generated in each of the plurality of semiconductor modules 32 can be reduced.

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

Further, in the present embodiment, as described above, the positive bus bar 50 and the negative bus bar 60 are provided in common to the plurality of semiconductor modules 32, respectively, and the terminal arrangement surface 22 and the smoothing capacitor 20 are connected to each other. It has a substantially U-shape covering the area of both side surfaces 23 of the . As a result, the portion where the substantially U-shaped positive bus bar 50 and the substantially U-shaped negative bus bar 60 face each other becomes relatively large, so that the inductance can be further reduced.

Further, in the present embodiment, as described above, the semiconductor module 32a arranged on one side surface 23a of the smoothing capacitor 20 with respect to the terminal 21 of the smoothing capacitor 20 has a height position h1 with respect to the smoothing capacitor 20, and the other side surface 23b The height position h2 of the semiconductor module 32b arranged at 1 is substantially equal to the smoothing capacitor 20 . This makes it possible to easily make the distance between each of the plurality of semiconductor modules 32 and the terminal 21 of the smoothing capacitor 20 (the distance of the current flow path) substantially equal.

Further, in the present embodiment, as described above, the cooling pipe portion 81 through which cooling water flows is provided on the surface of at least one of the positive bus bar 50 and the negative bus bar 60 . As a result, a large amount of current flows through at least one of positive bus bar 50 and negative bus bar 60, resulting in an increase in the amount of heat generated by at least one of positive bus bar 50 and negative bus bar 60. Even in this case, heat can be effectively radiated from at least one of the positive side bus bar 50 and the negative side bus bar 60 by the cooling pipe portion 81 through which cooling water flows.

[Variation]
It should be noted that the embodiments disclosed this time should be considered as examples and not restrictive in all respects. The scope of the present invention is indicated by the scope of claims rather than the description of the above-described embodiments, and includes all modifications (modifications) within the scope and meaning equivalent to the scope of claims.

For example, in the above-described embodiments, the distances between each of the plurality of semiconductor modules and the smoothing capacitor are made approximately equal, thereby making the impedances between each of the plurality of semiconductor modules and the smoothing capacitor approximately equal. However, the present invention is not limited to this. For example, the impedance between each of the plurality of semiconductor modules and the smoothing capacitor may be substantially equalized by adjusting the cross-sectional area of the busbar between each of the plurality of semiconductor modules and the smoothing capacitor.

Moreover, in the above-described embodiment, an example in which the positive bus bar and the negative bus bar are provided in common for a plurality of (12) semiconductor modules has been shown, but the present invention is not limited to this. For example, the positive busbar and the negative busbar may be split.

Also, in the above embodiment, the positive bus bar and the negative bus bar are each formed by bending one 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.

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

Also, in the above embodiments, an example in which two switching elements are housed in one semiconductor module has been shown, but the present invention is not limited to this. For example, a number of switching elements other than two may be accommodated in one semiconductor module.

Further, in the above-described 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 were substantially equal. It 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 substantially equal, each of the plurality of semiconductor modules and the smoothing capacitor If the impedances between are substantially equal, there is no need to align the height positions of a plurality of semiconductor modules.

Further, in the above-described embodiment, an example in which cooling pipe portions are provided on both the positive bus bar and the negative bus bar has been shown, but the present invention is not limited to this. For example, one of the positive bus bar and the negative bus bar may be provided with the cooling pipe portion.

10, 10a to 10d rectifier circuit 20, 20a to 20d smoothing capacitor 21 terminal 21p positive side terminal 21n negative side 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)
32a semiconductor module (semiconductor switching element on one side)
32b semiconductor module (semiconductor switching element on the other side)
32p Positive side terminal 32n Negative side terminal 50 Positive side bus bar 60 Negative side bus bar 81, 81p, 81n Cooling pipe section 100 Power converter h1, h2 Height position

Claims (7)

a smoothing capacitor connected to the output side of a rectifier circuit that rectifies an alternating voltage;
a terminal arrangement surface on which the terminals of the smoothing capacitor are arranged in a straight line;
a power conversion unit that includes a plurality of semiconductor switching element units and converts the DC voltage smoothed by the smoothing capacitor into an AC voltage;
a positive bus bar electrically connected to the positive terminal of the semiconductor switching element portion and the positive terminal of the smoothing capacitor;
a negative bus bar electrically connected to the negative terminal of the semiconductor switching element unit and the negative terminal of the smoothing capacitor;
The plurality of semiconductor switching element portions are arranged in the vicinity of the terminal arrangement surface on the side surface along the side surface of the smoothing capacitor that intersects the terminal arrangement surface that is symmetrical with respect to the linearly arranged terminals. is located in
each of the positive bus bar and the negative bus bar has a substantially U-shape covering the terminal arrangement surface and the side surface regions of both of the smoothing capacitors;
The power conversion device, wherein the plurality of semiconductor switching element units are arranged between the side surface of the smoothing capacitor and the positive side bus bar and the negative side bus bar. The plurality of semiconductor switching element portions are arranged on both one side and the other side of the terminal arrangement surface so that the impedance between each of the plurality of semiconductor switching element portions and the smoothing capacitor is substantially equal. 2. The power conversion device according to claim 1, disposed on said side of a. The distance on the positive bus bar between the positive terminal of the one-side semiconductor switching element portion arranged on one side of the positive terminal of the smoothing capacitor and the terminal of the smoothing capacitor is the positive side of the smoothing capacitor. substantially equal to the distance on the positive bus bar between the positive terminal of the other semiconductor switching element portion arranged on the other side of the terminal and the terminal of the smoothing capacitor;
The distance on the negative bus bar between the negative terminal of the semiconductor switching element on one side and the terminal of the smoothing capacitor is the distance between the negative terminal of the semiconductor switching element on the other side and the terminal of the smoothing capacitor. 3. The power converter according to claim 2, which is approximately equal to the distance on said negative bus bar between. 4. The power converter according to claim 1, wherein said positive side bus bar and said negative side bus bar are respectively provided in common to said plurality of semiconductor switching element units. With respect to the terminal of the smoothing capacitor, the height position of the semiconductor switching element portion arranged on one side surface with respect to the smoothing capacitor and the height position of the semiconductor switching element portion arranged on the other side surface with respect to the terminal of the smoothing capacitor The power converter according to any one of claims 1 to 4, wherein the height positions with respect to the smoothing capacitor are substantially equal. The power converter according to any one of claims 1 to 5, further comprising a cooling pipe portion provided on a surface of at least one of said positive side bus bar and said negative side bus bar and through which cooling water flows. A cooling plate is arranged on the side surface of the smoothing capacitor, and the semiconductor switching element unit is arranged on the surface of the cooling plate. The power conversion according to any one of claims 1 to 6. Device.

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