POWER CONVERSION DEVICE

A power conversion device includes a power converter including a semiconductor module, to convert input power and output the converted power, and a capacitor electrically connected to the semiconductor module. The capacitor includes a capacitor-side terminal surface on which a capacitor-side terminal is arranged, and the capacitor-side terminal surface faces a module-side terminal surface of the semiconductor module.

CROSS-REFERENCE TO RELATED APPLICATION

The present application claims priority of Japanese Patent Application No. 2022-090896 filed Jun. 3, 2022, the disclosure of which is hereby incorporated by reference.

BACKGROUND OF THE INVENTION

Field of the Invention

The present invention relates to a power conversion device, and more particularly, it relates to a power conversion device including a semiconductor module.

Description of the Background Art

A power conversion device including a semiconductor module is known in general. Such a power conversion device is disclosed in Japanese Patent No. 6858244, for example.

A power conversion device described in Japanese Patent No. 6858244 includes a plurality of semiconductor modules and a plurality of capacitors. In this power conversion device, three semiconductor modules constitute a clamp diode type three-level circuit. The three semiconductor modules are arranged in a row along a cooling surface. Four capacitors face the three semiconductor modules arranged side by side. The four capacitors are arranged two by two along a direction in which the three semiconductor modules are aligned. Each of the four capacitors includes a terminal arranged on an outer side surface in the direction in which the three semiconductor modules are aligned. A U-shaped bus bar is connected to the four capacitors aligned two by two so as to cover the capacitors from the outside.

In the power conversion device described in Japanese Patent No. 6858244, the terminals of the capacitors are arranged on the outer side surface in the direction in which the three semiconductor modules are aligned. Therefore, when a sensor such as a voltage sensor or a temperature sensor, or a device including a substrate such as a gate drive unit is arranged separately from the semiconductor modules and the capacitors, it is necessary to arrange the device while considering insulation distances from the terminals arranged outside the capacitors. Thus, the device arranged separately from the semiconductor modules and the capacitors cannot be arranged close to the side surfaces of the capacitors, and thus the size of the device is disadvantageously increased.

SUMMARY OF THE INVENTION

The present invention has been proposed in order to solve the aforementioned problem, and an object of the present invention is to provide a power conversion device capable of reducing or preventing an increase in its size.

In order to attain the aforementioned object, a power conversion device according to an aspect of the present invention includes a power converter including a semiconductor module having a switching element to convert input power and output the converted power, and a capacitor electrically connected to the semiconductor module of the power converter. The semiconductor module includes a module-side terminal surface on which a module-side terminal of the semiconductor module is arranged, the capacitor includes a capacitor-side terminal surface on which a capacitor-side terminal of the capacitor is arranged, and the capacitor-side terminal surface faces the module-side terminal surface of the semiconductor module.

In the power conversion device according to the aspect of the present invention, as described above, the semiconductor module includes the module-side terminal surface on which the module-side terminal of the semiconductor module is arranged. The capacitor includes the capacitor-side terminal surface on which the capacitor-side terminal of the capacitor is arranged, and the capacitor-side terminal surface faces the module-side terminal surface of the semiconductor module. Accordingly, the capacitor-side terminal surface and the module-side terminal surface face each other, and thus exposure of the capacitor-side terminal on a side surface of the capacitor other than the semiconductor module side can be reduced or prevented. Therefore, a device arranged separately from the capacitor and the semiconductor module can be arranged close to the capacitor without considering an insulation distance. Consequently, an increase in the size of the power conversion device can be reduced or prevented.

The power conversion device according to this aspect preferably further includes a capacitor-side conductor connected to the capacitor-side terminal and arranged along the capacitor-side terminal surface, and a module-side conductor connected to the module-side terminal and arranged along the module-side terminal surface. The capacitor-side conductor and the module-side conductor are preferably connected to each other on an end side of the capacitor-side terminal surface in a direction along the capacitor-side terminal surface while the capacitor-side terminal surface and the module-side terminal surface face each other. Accordingly, the capacitor-side conductor and the module-side conductor are connected to each other on the end side of the capacitor-side terminal surface, and thus the capacitor-side conductor and the module-side conductor can be connected to each other from the outer sides of the capacitor and the semiconductor module on the end side of the capacitor-side terminal surface without inserting a tool or the like between the capacitor and the semiconductor module. Therefore, even when the capacitor-side terminal surface and the module-side terminal surface face each other, it is not necessary to provide a gap to insert a tool or the like between the capacitor and the semiconductor module, and thus the capacitor and the semiconductor module can be arranged close to each other. Consequently, a distance between the capacitor and the semiconductor module can be reduced, and thus an increase in the size of the power conversion device can be further reduced or prevented.

In this case, the power conversion device preferably further includes a relay conductor to connect the capacitor-side conductor and the module-side conductor to each other on the end side of the capacitor-side terminal surface in the direction along the capacitor-side terminal surface. Accordingly, the relay conductor is provided separately from the capacitor-side conductor and the module-side conductor, and thus the capacitor-side conductor and the module-side conductor can be connected to each other by the relay conductor without changing the shapes of the capacitor-side conductor and the module-side conductor facing each other. Therefore, the capacitor-side conductor and the module-side conductor can be connected to each other by the relay conductor while the complexity of the shapes of the capacitor-side conductor and the module-side conductor is reduced or prevented.

In the power conversion device including the relay conductor to connect the capacitor-side conductor and the module-side conductor to each other, the capacitor-side conductor preferably includes a capacitor-side mount bent in a direction along a surface of the capacitor adjacent to the capacitor-side terminal surface from the direction along the capacitor-side terminal surface, the relay conductor preferably has an L-shape extending along the module-side terminal surface and along a direction facing the module-side terminal surface, and includes a relay conductor-side mount connected to the capacitor-side mount in a portion extending along the direction facing the module-side terminal surface, and the relay conductor-side mount preferably includes a notched hole opening in a direction in which the capacitor-side terminal surface and the module-side terminal surface face each other. Accordingly, the relay conductor-side mount of the relay conductor having an L-shape includes the notched hole opening in the direction in which the capacitor-side terminal surface and the module-side terminal surface face each other, and thus even when a manufacturing tolerance occurs in the direction in which the capacitor-side terminal surface and the module-side terminal surface face each other, the capacitor-side conductor and the relay conductor can be easily connected to each other by connecting the notched hole to the capacitor-side mount. Therefore, even when a manufacturing tolerance occurs in the direction in which the capacitor-side terminal surface and the module-side terminal surface face each other, the assembly operation can be easily performed.

In the power conversion device according to this aspect, the power converter preferably includes at least one of a converter to convert input AC power into DC power or an inverter to convert input DC power into AC power and output the AC power. The semiconductor module preferably includes a plurality of aligned semiconductor modules, and the plurality of semiconductor modules preferably includes an input/output module including an AC terminal to which an AC conductor to which or from which AC power is input or output is connected. The input/output module is preferably arranged at an end on one side in a direction in which the plurality of semiconductor modules is aligned, and the AC terminal is preferably arranged on the one side in the input/output module. Accordingly, the AC terminal is arranged on one side in the plurality of aligned semiconductor modules, and thus an increase in the length of the AC conductor connected to the input/output module can be reduced or prevented. Therefore, an increase in the weight of the entire power conversion device can be reduced or prevented.

The power conversion device according to this aspect preferably further includes a module-side conductor connected to the module-side terminal and arranged along the module-side terminal surface. The power converter preferably includes at least one of a three-level inverter to which three levels of potential including an upper potential, an intermediate potential, and a lower potential are input or a three-level converter from which three levels of potential including an upper potential, an intermediate potential, and a lower potential are output, the module-side conductor preferably includes an upper conductor to which an upper potential is applied, an intermediate conductor to which an intermediate potential is applied, and a lower conductor to which a lower potential is applied, and the capacitor-side terminal surface of the capacitor preferably faces the upper conductor, the intermediate conductor, and the lower conductor. Accordingly, even when the power converter includes at least one of the three-level inverter or the three-level converter, the capacitor-side terminal surface faces the upper conductor, the intermediate conductor, and the lower conductor, and thus exposure of the capacitor-side terminal and the upper, intermediate, and lower conductors on the side surface of the capacitor other than the semiconductor module side can be reduced or prevented. Therefore, even when the power converter includes at least one of the three-level inverter or the three-level converter, a device arranged separately from the capacitor and the semiconductor module can be arranged close to the capacitor, and thus an increase in the size of the power conversion device can be reduced or prevented.

In this case, the semiconductor module preferably includes a first module including one switching element and one clamp diode and connected to the upper conductor and the intermediate conductor, a second module including one switching element and one clamp diode and connected to the intermediate conductor and the lower conductor, and a third module including two switching elements and connected to the first module and the second module, and the module-side conductor preferably includes a first connection conductor to connect the first module to the third module, and a second connection conductor to connect the second module to the third module. The upper conductor, the intermediate conductor, and the lower conductor are preferably laminated while being insulated from each other to form a first laminated conductor, and the first connection conductor and the second connection conductor are preferably laminated separately from the first laminated conductor while being insulated from each other to form a second laminated conductor. When each of a plurality of laminated conductors is connected, it is necessary to provide a hole in the other conductor in order to arrange a fastening member such as a screw at a connecting portion of one of the plurality of conductors. In consideration of this point, in the present invention, the upper conductor, the intermediate conductor, and the lower conductor are laminated while being insulated from each other to form the first laminated conductor, and the first connection conductor and the second connection conductor are laminated separately from the first laminated conductor while being insulated from each other to form the second laminated conductor. Accordingly, the first laminated conductor formed by the upper, intermediate, and lower conductors and the second laminated conductor formed by the first and second connection conductors can be separately connected to the semiconductor module. Therefore, as compared with a case in which the upper, intermediate, and lower conductors and the first and second connection conductors are collectively formed as one laminated conductor, the number of holes for avoiding the connecting portion can be reduced, and thus a decrease in the cross-sectional areas of the conductors can be reduced or prevented. Consequently, in the upper, intermediate, and lower conductors and the first and second connection conductors, local heat generation due to current concentration can be reduced or prevented, and an increase in inductance can be reduced or prevented.

The power conversion device according to this aspect preferably further includes a module-side conductor connected to the module-side terminal and arranged along the module-side terminal surface, and the power converter preferably includes at least one of a two-level inverter to which two levels of potential including an upper potential and a lower potential are input or a two-level converter from which two levels of potential including an upper potential and a lower potential are output. The module-side conductor preferably includes an upper conductor to which an upper potential is applied and a lower conductor to which a lower potential is applied, and the capacitor-side terminal surface of the capacitor preferably faces the upper conductor and the lower conductor. Accordingly, even when the power converter includes at least one of the two-level inverter or the two-level converter, the capacitor-side terminal surface faces the upper and lower conductors, and thus exposure of the capacitor-side terminal and the upper and lower conductors on the side surface of the capacitor other than the semiconductor module side can be reduced or prevented. Therefore, even when the power converter includes at least one of the two-level inverter or the two-level converter, a device arranged separately from the capacitor and the semiconductor module can be arranged close to the capacitor, and thus an increase in the size of the power conversion device can be reduced or prevented.

In the power conversion device according to this aspect, the power converter and the capacitor are preferably mounted on a railroad vehicle. Accordingly, even when the power converter and the capacitor are mounted on the railroad vehicle, a device separate from the semiconductor module and the capacitor can be arranged close to the capacitor, and thus an increase in the size of the power conversion device mounted on the railroad vehicle can be effectively reduced or prevented.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

Embodiments of the present invention are hereinafter described with reference to the drawings.

First Embodiment

The configuration of a power conversion device100according to a first embodiment is now described with reference toFIGS.1to10. The power conversion device100is mounted on a railroad vehicle101.

Configuration of Railroad Vehicle

As shown inFIGS.1and2, the railroad vehicle101runs on rails with single-phase AC power supplied from an overhead wire102as an AC power supply. The railroad vehicle101includes a pantograph101a, a transformer101b, motors101c, and the power conversion device100. The pantograph101areceives (collects) power supplied to the overhead wire102. The transformer101btransforms the AC power received by the pantograph101aand outputs the transformed AC power. The motors101cinclude induction motors that rotate drive wheels with the AC power supplied from the power conversion device100. The power conversion device100converts the power from the overhead wire102by the switching operations of switching elements Q1to Q4(seeFIG.3) to control rotation of the motors101cwhen the railroad vehicle101is running.

Overall Configuration of Power Conversion Device

As shown inFIG.2, the power conversion device100includes a power converter10and capacitors31and32. In the power conversion device100, the power converter10and the capacitors31and32mounted on the railroad vehicle101constitute a three-level power conversion circuit for driving the motors101c. The power converter10converts input power and outputs the converted power. The power converter10includes a converter10a, a converter10b, an inverter10c, an inverter10d, and an inverter10e. The two converters10aand10bconvert input single-phase AC power into DC power. The inverters10cto10econvert the DC power input from the converters10aand10binto three-phase AC power and output the three-phase AC power to the motors101c. The converters10aand10bare examples of a “converter” or a “three-level converter” in the claims. The inverter10c, the inverter10d, and the inverter10eare examples of an “inverter” or a “three-level inverter” in the claims.

The converter10areceives U-phase AC power of single-phase AC power having a U-phase and a V-phase. The converter10breceives V-phase AC power of the single-phase AC power. The converters10aand10boutput DC power having three levels of potential including an upper potential, an intermediate potential, and a lower potential. The inverters10cto10ereceive the DC power having three levels of potential including an upper potential, an intermediate potential, and a lower potential, which is output from the converters10aand10b. The inverter10coutputs U-phase AC power of three-phase AC power having a U-phase, a V-phase, and a W-phase. The inverter10doutputs V-phase AC power of three-phase AC power having a U-phase, a V-phase, and a W-phase. The inverter10eoutputs W-phase AC power of three-phase AC power having a U-phase, a V-phase, and a W-phase.

The power converter10includes modules11, modules12, and modules13. Specifically, each of the converters10aand10band the inverters10cto10eincludes a module11, a module12, and a module13. The module11is an example of a “semiconductor module” or a “first module” in the claims. The module12is an example of a “semiconductor module” or a “second module” in the claims. The module13is an example of a “semiconductor module”, a “third module”, or an “input/output module” in the claims.

As shown inFIG.3, the module11includes one switching element Q1and one clamp diode D1. The module12includes one switching element Q4and a clamp diode D2. The module13includes two switching elements Q2and Q3. The switching elements Q1to Q4are metal-oxide semiconductor field-effect transistors (MOSFETs), for example. InFIG.3, diodes connected in parallel to the switching elements Q1to Q4represent parasitic diodes (body diodes) of the MOSFETs. A diode element may be connected in parallel to each of the switching elements Q1to Q4instead of the parasitic diodes.

The module11is provided on the positive electrode side. In the module11, the source side of the switching element Q1is connected to the cathode side of the clamp diode D1. The module11includes terminals11a,11b, and11c. The terminal11ais connected to the drain side of the switching element Q1. The terminal11bis connected to the anode side of the clamp diode D1. The terminal11cis connected between the switching element Q1and the clamp diode D1. That is, the terminal11cis connected to the source side of the switching element Q1and the cathode side of the clamp diode D1. The terminals11a,11b, and11care examples of a “module-side terminal” in the claims.

The module12is provided on the negative electrode side. In the module12, the drain side of the switching element Q4is connected to the anode side of the clamp diode D2. The module12includes terminals12a,12b, and12c. The terminal12ais connected to the cathode side of the clamp diode D2. The terminal12bis connected to the source side of the switching element Q4. The terminal12cis connected between the clamp diode D2and the switching element Q2. That is, the terminal12cis connected to the anode side of the clamp diode D2and the drain side of the switching element Q4. The terminals12a,12b, and12care examples of a “module-side terminal” in the claims.

The module13is connected to the module11and the module12. In the module13, the source side of the switching element Q2is connected to the drain side of the switching element Q3. The module13includes terminals13a,13b, and13c. The terminal13ais connected to the drain side of the switching element Q2. The terminal13bis connected to the source side of the switching element Q3. The terminal13cis connected between the switching element Q2and the switching element Q3. That is, the terminal13cis connected to the source side of the switching element Q2and the drain side of the switching element Q3. The terminals13a,13b, and13care examples of a “module-side terminal” in the claims. The terminal13cis an example of an “AC terminal” in the claims.

In the modules11to13, the switching elements Q1to Q4are connected in series to each other from the upper potential side (positive electrode side) to the lower potential side (negative electrode side). That is, a conductor51, which is an upper potential conductor (upper conductor), is connected to the drain side (terminal11a) of the switching element Q1. A conductor52, which is a lower potential conductor (lower conductor), is connected to the source side (terminal12b) of the switching element Q4. The source side (terminal11c) of the switching element Q1and the drain side (terminal13a) of the switching element Q2are connected to each other via a conductor55. The source side (terminal13b) of the switching element Q3and the drain side (terminal12c) of the switching element Q4are connected to each other via a conductor54. A conductor53, which is an intermediate potential conductor (intermediate conductor), is connected to the anode side of the clamp diode D1and the cathode side of the clamp diode D2. An AC conductor70, which is either an input conductor or an output conductor for AC power, is connected to the terminal13cof the module13. That is, when the modules11to13are included in the converters10aand10b, AC power is input to the terminal13c. When the modules11to13are included in the inverters10cto10e, AC power is output to the terminal13c. The conductors51to55and the AC conductor70are described below in detail.

As shown inFIG.4, the module11has a terminal surface14. The module11has a flat rectangular parallelepiped shape. The terminals11a,11b, and11care aligned in this order along a Y1direction on the terminal surface14. The modules12and13also have terminal surfaces14, similarly to the module11. In the modules12and13, the terminals12a,12b, and12cand the terminals13a,13b, and13care aligned in this order on the terminal surfaces14, respectively, similarly to the module11. AlthoughFIG.4shows the terminal surface14of the module11and the terminals11ato11c, the terminal surface14of the module12and the terminals12ato12cand the terminal surface14of the module13and the terminals13ato13care the same or similar as the terminal surface14of the module11and the terminals11ato11c, and thus illustration thereof is omitted. The terminal surfaces14are examples of a “module-side terminal surface” in the claims.

As shown inFIG.5, the modules11to13are aligned in each of the converters10aand10band the inverters10cto10e. The modules12,11, and13are aligned in this order along a Y2direction. The converter10a, the converter10b, the inverter10c, the inverter10d, and the inverter10eare aligned in this order along an X1direction. In the power converter10, two converters10aand two converters10bare provided. That is, the converters10aand the converters10beach include two modules11, two modules12, and two modules13. The two converters10aare connected in parallel to each other. The two converters10bare connected in parallel to each other. In the power converter10, two inverters10c, two inverters10d, and two inverters10eare similarly provided in parallel. Therefore, the converters10aand10band the inverters10cto10eeach include two modules11, two modules12, and two modules13. In a circuit diagram ofFIG.2, one converter10a, one converter10b, one inverter10c, one inverter10d, and one inverter10eare shown, and portions provided in parallel are omitted.

The power conversion device100includes a cooling body20. The cooling body20cools each of a plurality of modules11to13. The cooling body20has a cooling surface21. The plurality of modules11to13is aligned on the cooling surface21. The cooling body20has the cooling surface21along an X-Y plane on the Z1direction side. Furthermore, the cooling body20includes radiation fins on the side (Z2direction side) opposite to the cooling surface21. The cooling body20cools the modules11to13by exchanging heat with the modules11to13arranged on the cooling surface21on the Z1direction side. Surfaces of the modules11to13on the Z2direction side contact the cooling surface21. The terminal surfaces14of the modules11to13are provided on the Z1direction side opposite to the surfaces contacting the cooling surface21.

As shown inFIGS.2and6, the power conversion device100includes the capacitors31and32. The capacitors31and32are electrically connected to the power converter10. The capacitors31and32smooth DC power output from the converters10aand10band input to the inverters10cto10e, for example. The capacitors31and32are connected in series to each other. The capacitors31each include positive electrode-side terminals31aand negative electrode-side terminals31b. The capacitors32each include positive electrode-side terminals32aand negative electrode-side terminals32b. The terminals31aof the capacitor31are electrically connected to the terminals11aof the modules11. The terminals31bof the capacitor31are connected to the terminals32aof the capacitor32. The terminals32bof the capacitor32are connected to the terminals12bof the modules12. The terminals31aof the capacitor31are connected to a conductor41(seeFIG.7) that is an upper conductor (upper potential conductor). The terminals32bof the capacitor32are connected to a conductor42(seeFIG.7) that is a lower conductor (lower potential conductor). The terminals31bof the capacitor31and the terminals32aof the capacitor32are connected to a conductor43(seeFIG.7) that is an intermediate conductor (intermediate potential conductor). The terminals31a,31b,32a, and32bare examples of a “capacitor-side terminal” in the claims.

As shown inFIG.7, each of the capacitors31and32has a terminal surface33. Each of the capacitors31and32has a substantially rectangular parallelepiped shape. In the capacitors31and32, the terminal surface33is arranged on the Z2direction side. Two terminals31aand two terminals31bare arranged on the terminal surface33of the capacitor31. The terminals31aand the terminals31bare arranged in a staggered manner along an X direction on the terminal surface33. Similarly, on the terminal surface33of the capacitor32, two terminals32aand two terminals32bare arranged in a staggered manner along the X direction. That is, the terminals of the capacitors31and32having the same potential are arranged in a staggered manner. The terminal surface33is an example of a “capacitor-side terminal surface” in the claims.

As shown inFIG.8, a plurality of capacitors31and a plurality of capacitors32are arranged in the power conversion device100. For example, five capacitors31and five capacitors32are arranged. That is, one capacitor31and one capacitor32are provided for each of the converter10a, the converter10b, the inverter10c, the inverter10d, and the inverter10e. That is, one capacitor31and one capacitor32are provided for the two converters10aconnected in parallel, and one capacitor31and one capacitor32are provided for the two converters10bconnected in parallel. Similarly, one capacitor31and one capacitor32are provided for the two inverters10cconnected in parallel, one capacitor31and one capacitor32are provided for the two inverters10dconnected in parallel, and one capacitor31and one capacitor32are provided for the two inverters10econnected in parallel. The plurality of capacitors31is aligned along the X direction on the Y2direction side. The plurality of capacitors32is aligned along the X direction on the Y1direction side.

Connection Between Modules and Capacitors

As shown inFIG.6, in the first embodiment, the terminal surfaces33of the capacitors31and32face the terminal surfaces14of the modules11to13. Specifically, the terminal surface14of each of the modules11to13aligned in a Y direction along the cooling surface21and the terminal surface33of each of the capacitors31and32aligned along the Y direction face each other along a Z direction. That is, the terminal surfaces33of the capacitors31and32face the cooling surface21.

The power conversion device100includes conductors40and50. The conductor40is connected to the terminals31a,31b,32a, and32bof the capacitors31and32. The conductor40is arranged along the terminal surfaces33of the capacitors31and32. Specifically, the conductor40extends along the terminal surfaces33on the Z2direction side and along the Y direction. The conductor50is connected to the terminals11ato11c,12ato12c,13a, and13bof the modules11to13. The conductor50is arranged along the terminal surfaces14of the modules11to13. Specifically, the conductor50extends along the terminal surfaces14on the Z1direction side and along the Y direction. The conductors40and50are flat plate-shaped members. The conductor40is an example of a “capacitor-side conductor” in the claims. The conductor50is an example of a “module-side conductor” in the claims.

As shown inFIG.7, the conductor40connected to the capacitors31and32includes the conductor41, the conductor42, and the conductor43. The conductor41is connected to the terminals31aof the capacitor31. Specifically, the conductor41has a flat plate shape extending along the terminal surface33of the capacitor31. The conductor41is arranged across both the X direction and the Y direction along the X-Y plane so as to be connected to the two terminals31aof the capacitor31. An upper potential is applied to the conductor41. The conductor42is connected to the terminals32bof the capacitor32. Specifically, the conductor42has a flat plate shape extending along the terminal surface33of the capacitor32, similarly to the conductor41. The conductor42is arranged across both the X direction and the Y direction along the X-Y plane so as to be connected to the two terminals32bof the capacitor32. A lower potential is applied to the conductor42. The conductor43is connected to the terminals31bof the capacitor31and the terminals32aof the capacitor32. Specifically, the conductor43has a flat plate shape extending along the terminal surfaces33of the capacitors31and32. The conductor43is arranged in a zig-zag manner along the X-Y plane so as to be connected to the two terminals31bof the capacitor31and the two terminals32aof the capacitor32. An intermediate potential is applied to the conductor43.

The flat plate-shaped conductors41to43are laminated while being insulated from each other. That is, the conductors41to43are formed as laminated conductors. Specifically, the conductors41and42are laminated on the Z1direction side of the conductor43. A plate-shaped insulating member (not shown) is arranged between the conductor43and the conductors41and42.

Each of the conductors41to43includes a mount(s)44connected to relay conductors60(seeFIG.6) described below. The mount(s)44is bent in a direction (Z1direction) along surfaces of the capacitors31and32adjacent to the terminal surfaces33from a direction along the terminal surfaces33. The mount(s)44includes holes into which fastening members65(seeFIG.6) such as screws are screwed for connection with the relay conductors60. Connection by the relay conductors60is described below in detail. The mount(s)44is an example of a “capacitor-side mount” in the claims.

As shown inFIG.9, the conductor50connected to the modules11to13includes a conductor51, a conductor52, a conductor53, a conductor54, and a conductor55. The conductor51is an example of an “upper conductor” in the claims. The conductor52is an example of a “lower conductor” in the claims. The conductor53is an example of an “intermediate conductor” in the claims. The conductor54is an example of a “second connection conductor” in the claims. The conductor55is an example of a “first connection conductor” in the claims.

The conductors51to55each have a flat plate shape extending along the terminal surfaces14of the modules11to13. In other words, the terminal surfaces33of the capacitors31and32and the terminal surfaces14of the modules11to13face the conductors51to55. An upper potential is applied to the conductor51. That is, the conductor51is an upper conductor (upper potential conductor) connected to the terminals11aof the modules11. A lower potential is applied to the conductor52. That is, the conductor52is a lower conductor (lower potential conductor) connected to the terminals12bof the modules12. An intermediate potential is applied to the conductor53. That is, the conductor53is an intermediate conductor (intermediate potential conductor) connected to the terminals11bof the modules11and the terminals12aof the modules12. The conductor54connects the modules12to the modules13. Specifically, the conductor54is connected to the terminals12cof the modules12and the terminals13bof the modules13. The conductor55connects the modules11to the modules13. Specifically, the conductor55is connected to the terminals11cof the modules11and the terminals13aof the modules13. That is, the conductors51,53, and55are connected to the modules11. The conductors52,53, and54are connected to the modules12. The conductors54and55are connected to the modules13. The conductors51to55are electrically connected to the terminals11ato11c,12ato12c,13a, and13bof the modules11to13by being fastened by fastening members such as screws from the Z1direction side.

In the first embodiment, the conductor51, the conductor52, and the conductor53are laminated while being insulated from each other to form a laminated conductor50a. The conductors54and55are laminated separately from the laminated conductor50awhile being insulated from each other to form a laminated conductor50b. The laminated conductor50ais an example of a “first laminated conductor” in the claims. The laminated conductor50bis an example of a “second laminated conductor” in the claims.

Specifically, in the laminated conductor50a, the conductors51and52overlap the conductor53on the Z1direction side of the conductor53. The conductors51and52are arranged along the X-Y plane and arranged adjacent to each other in the Y direction. The conductors51and52and the conductor53are insulated from each other by an insulating member (not shown). In the laminated conductor50b, the conductor54overlaps the conductor55on the Z1direction side of the conductor55. The conductors54and55are insulated from each other by an insulating member (not shown). Two laminated conductors50aare provided to integrally connect the converters10aand10band the inverters10cto10e, respectively. That is, one of the two laminated conductors50aextends along the X direction so as to integrally connect the modules11to13of the converters10aand10b. The other of the two laminated conductors50aextends along the X direction so as to integrally connect the modules11to13of the inverters10cto10e. The two laminated conductors50aare connected to each other between the converters10aand10band the inverters10cto10e. On the other hand, one laminated conductor50bis separately provided for each of the converter10a, the converter10b, the inverter10c, the inverter10d, and the inverter10e.

The conductors53,54, and55are arranged so as to avoid the terminals11aand12bas viewed from the Z1direction side such that the conductors51and52arranged on the Z1direction side are connected to the modules11and12by fastening members. Specifically, the conductors53to55include holes in regions overlapping the terminals11aas viewed from the Z1direction side. The conductors53and54include holes in regions overlapping the terminals12bas viewed from the Z1direction side. Similarly, the conductors54and55are arranged so as to avoid the terminals11band12aas viewed from the Z1direction side such that the conductor53is connected to the modules11and12. Specifically, the conductors54and55include holes in regions overlapping the terminals11bas viewed from the Z1direction side. The conductor54includes holes in regions overlapping the terminals12aas viewed from the Z1direction side. The laminated conductor50aand the laminated conductor50bare separately connected to the modules11to13. That is, after the conductors54and55are fastened and connected to the modules11to13as the laminated conductor50bby fastening members, the conductors51to53are fastened and connected to the modules11to13as the laminated conductor50aby fastening members. Therefore, after the conductors54and55are integrally connected to the modules11to13, the conductors51to53are integrally connected to the modules11to13. Thus, the conductors51to53do not include holes in order to avoid connecting portions to connect the conductors54and55. The conductors51to53are integrally connected as the laminated conductor50a, and thus the conductors51and52are arranged so as to avoid the terminals11band12ato which the conductor53is connected, as viewed from the Z1direction side. The terminals11ato11cof the modules11, the terminals12aand12bof the modules12, and the terminals13aand13bof the modules13are connected to the conductor50(laminated conductors50aand50b) via relay conductors15by fastening members.

As shown inFIG.6, the power conversion device100includes the relay conductors60that connect the conductor40on the capacitors31and32side and the conductor50on the modules11to13side to each other. The conductors40and50are connected to each other by the relay conductors60while the terminal surfaces33of the capacitors31and32and the terminal surfaces14of the modules11to13face each other. Specifically, the conductors40and50are connected to each other on the end sides of the terminal surfaces33in the direction (Y direction) along the terminal surfaces33. That is, the relay conductors60connect the conductor40and the conductor50to each other on the end sides of the terminal surfaces33in the Y direction. Specifically, the relay conductors60connect the conductor40and the conductor50to each other on the Y2direction end side of the terminal surface33of the capacitor31and the Y1direction end side of the terminal surface33of the capacitor32. That is, the conductors40and50are connected to each other at ends of the capacitors31and32in a direction in which the capacitors31and32are aligned. In other words, the conductors40and50are connected to each other on the outer sides in a direction (Y direction) intersecting a direction (Z direction) in which the terminal surfaces33of the capacitors31and32and the terminal surfaces14of the modules11to13face each other.

Specifically, the conductors41and51to which an upper potential is applied are connected to each other by the relay conductor60. That is, an end of the conductor41on the Y2direction side and an end of the conductor51on the Y2direction side are connected to each other via the relay conductor60such that the terminals31aof the capacitor31and the terminals11aof the modules11are electrically connected to each other. The conductors42and52to which a lower potential is applied are connected to each other by the relay conductor60. That is, an end of the conductor42on the Y1direction side and an end of the conductor52on the Y1direction side are connected to each other via the relay conductor60such that the terminals32bof the capacitor32and the terminals12bof the modules12are electrically connected to each other. The conductors43and53to which an intermediate potential is applied are connected to each other by the relay conductor60. That is, ends of the conductors43and53on the Y1direction side are connected to each other via the relay conductor60, and ends of the conductors43and53on the Y2direction side are connected to each other via the relay conductor60such that the terminals31bof the capacitor31, the terminals32aof the capacitor32, the terminals11bof the modules11, and the terminals12aof the modules12are electrically connected to each other.

As shown inFIG.10, each of the relay conductors60has an L-shape extending along the terminal surfaces14of the modules11to13and along a direction (Z direction) facing the terminal surfaces14. Specifically, the relay conductor60includes a portion61extending along the terminal surfaces14of the modules11to13and a portion62extending along the Z direction, which is the direction facing the terminal surfaces14. That is, the portion61is a portion extending along the X-Y plane (seeFIG.6). Therefore, the portion61is arranged parallel to the conductors51to55. The portion62is a portion extending along an X-Z plane (seeFIG.6). The portion62is arranged parallel to the mounts44of the conductors41to43. In the relay conductors60, the portions61are connected to the conductors51to55by fastening members64(seeFIG.6) such as screws, and the portions62are connected to the conductors41to43by the fastening members65(seeFIG.6) such as screws. The relay conductors60are connected to the mounts44of the conductors41to43at the portions62. The portions62are examples of a “relay conductor-side mount” in the claims.

The portion62includes notched holes63. The notched holes63are open in the direction (Z direction) in which the terminal surfaces33of the capacitors31and32and the terminal surfaces14of the modules11to13face each other. Specifically, the fastening members65for connecting the mounts44of the conductors41to43to the portions62of the relay conductors60are screwed into the notched holes63. The notched holes63are open in a direction (Z1direction) in which the capacitors31and32are away from the modules11to13.

In the power conversion device100, the laminated conductor50bis connected to the modules11to13arranged on the cooling surface21, and then the laminated conductor50ais connected. The conductor40is connected to the capacitors31and32separately from the modules11to13. The conductor40connected to the capacitors31and32and the conductor50(laminated conductors50aand50b) connected to the modules11to13are connected to each other by the relay conductors60. The notched holes63provided in the portions62of the relay conductors60can connect the relay conductors60and the conductor40while adjusting their positions in the Z direction with respect to the conductor40.

As shown inFIG.6, the AC conductor70is connected to the terminal13cof the module13. AC power is input to or output from the AC conductor70. That is, AC power is input from the transformer101bto the AC conductors70(input conductors) connected between a secondary winding of the transformer101band the terminals13cof the modules13in the converters10aand10b. AC power is output from the inverters10cto10eto the AC conductors70(output conductors) connected between the terminals13cof the modules13in the inverters10cto10eand windings of the motors101c.

In each of the converter10a, the converter10b, the inverter10c, the inverter10d, and the inverter10e, the modules11to13are arranged in a common arrangement order. Furthermore, in each of the converter10a, the converter10b, the inverter10c, the inverter10d, and the inverter10e, the orientation of the terminals of the modules11to13is also common. That is, the modules12,11, and13are arranged in this order from the Y1direction side to the Y2direction side. In the terminal arrangement, the terminals12c,12b,12a,11c,11b,11a,13a,13b, and13care arranged in this order from the Y1direction side to the Y2direction side. That is, the module13including the terminal13cis arranged at an end on one side (Y2direction side) in a direction in which the three modules11to13are aligned. The terminal13cto which the AC conductor70is connected is arranged at a Y2direction side end of the module13arranged at the end on the Y2direction side. Therefore, the AC conductor70is arranged at an end of the aligned modules11to13on the Y2direction side. Specifically, in the power conversion device100, the AC conductor70to which AC power is input and the AC conductor70from which AC power is output are arranged on the common Y2direction side. In the module11, the terminals11ato11cmay be arranged in the opposite order.

As shown inFIG.8, the power conversion device100includes a gate substrate80. The gate substrate80outputs gate signals for controlling the switching operations of the switching elements Q1to Q4based on control signals from a controller (not shown). The gate signals are signals based on pulse width modulation (PWM) signals, for example. The gate signals output from the gate substrate80are input between a gate terminal (not shown) and a source terminal (not shown) provided on the terminal surface14. The gate substrate80is arranged on the Y1direction side opposite to the Y2direction side on which the AC conductor70is arranged with the capacitors31and32interposed between the gate substrate80and the AC conductor70.

Advantageous Effects of First Embodiment

According to the first embodiment, the following advantageous effects are achieved.

According to the first embodiment, the modules11to13(semiconductor modules) include the terminal surfaces14(module-side terminal surfaces) on which the terminals11ato11c,12ato12c, and13ato13c(module-side terminals) of the modules11to13are arranged. The capacitors31and32include the terminal surfaces33(capacitor-side terminal surfaces) on which the terminals31a,31b,32a, and32b(capacitor-side terminals) of the capacitors31and32are arranged, and the terminal surfaces33(capacitor-side terminal surfaces) face the terminal surfaces14of the modules11to13. Accordingly, the terminal surfaces33and the terminal surfaces14face each other, and thus arrangement with exposure of the terminals31a,31b,32a, and32bon side surfaces of the capacitors31and32other than the modules11to13side can be reduced or prevented. Therefore, a device arranged separately from the capacitors31and32and the modules11to13can be arranged close to the capacitors31and32without considering insulation distances. Consequently, an increase in the size of the power conversion device100can be reduced or prevented.

According to the first embodiment, the power conversion device100includes the conductor40(capacitor-side conductor) connected to the terminals31a,31b,32a, and32b(capacitor-side terminals) and arranged along the terminal surfaces33(capacitor-side terminal surfaces), and the conductor50(module-side conductor) connected to the terminals11ato11c,12ato12c, and13ato13c(module-side terminals) and arranged along the terminal surfaces14(module-side terminal surfaces). The conductor40and the conductor50are connected to each other on the end sides of the terminal surfaces33in the direction along the terminal surfaces33while the terminal surfaces33and the terminal surfaces14face each other. Accordingly, the conductor40and the conductor50are connected to each other on the end sides of the terminal surfaces33, and thus the conductor40and the conductor50can be connected to each other from the outer sides of the capacitors31and32and the modules11to13on the end sides of the terminal surfaces33without inserting a tool or the like between the capacitors31and32and the modules11to13. Therefore, even when the terminal surfaces33and the terminal surfaces14face each other, it is not necessary to provide a gap to insert a tool or the like between the capacitors31and32and the modules11to13, and thus the capacitors31and32and the modules11to13can be arranged close to each other. Consequently, a distance between the capacitors31and32and the modules11to13can be reduced, and thus an increase in the size of the power conversion device100can be further reduced or prevented.

According to the first embodiment, the power conversion device includes the relay conductors60to connect the conductor40(capacitor-side conductor) and the conductor50(module-side conductor) to each other on the end sides of the terminal surfaces33in the direction along the terminal surfaces33(capacitor-side terminal surfaces). Accordingly, the relay conductors60are provided separately from the conductor40and the conductor50, and thus the conductor40and the conductor50can be connected to each other by the relay conductors60without changing the shapes of the conductors40and50facing each other. Therefore, the conductor40and the conductor50can be connected to each other by the relay conductors60while the complexity of the shapes of the conductors40and50is reduced or prevented.

According to the first embodiment, the conductor40(capacitor-side conductor) includes the mounts44(capacitor-side mounts) bent in the direction along the surfaces of the capacitors31and32adjacent to the terminal surfaces33from the direction along the terminal surfaces33(capacitor-side terminal surfaces). The relay conductors60each have an L-shape extending along the terminal surfaces14(module-side terminal surfaces) and along the direction facing the terminal surfaces14, and include the portion62(relay conductor-side mount) connected to the mount44in the portion extending along the direction facing the terminal surfaces14. The portion62includes the notched holes63opening in the direction in which the terminal surfaces33and the terminal surfaces14face each other. Accordingly, the portion62of the relay conductor60having an L-shape includes the notched holes63opening in the direction in which the terminal surfaces33and the terminal surfaces14face each other, and thus even when a manufacturing tolerance occurs in the direction in which the terminal surfaces33and the terminal surfaces14face each other, the conductor40and the relay conductor60can be easily connected to each other by connecting the notched holes63to the mount44. Therefore, even when a manufacturing tolerance occurs in the direction in which the terminal surfaces33and the terminal surfaces14face each other, the assembly operation can be easily performed.

According to the first embodiment, the power converter10includes the converters10aand10bto convert input AC power into DC power, and the inverters10cto10eto convert input DC power into AC power and output the AC power, and the plurality of modules11to13(semiconductor modules) is aligned. The plurality of modules11to13includes the module13(input/output module) including the terminal13c(AC terminal) to which the AC conductor70to which or from which AC power is input or output is connected, and the module13is arranged at the end on one side in the direction in which the plurality of modules11to13is aligned. The terminal13cis arranged on one side in the module13. Accordingly, the terminal13cis arranged on one side in the plurality of aligned modules11to13, and thus an increase in the length of the AC conductor70connected to the module13can be reduced or prevented. Therefore, an increase in the weight of the entire power conversion device100can be reduced or prevented.

According to the first embodiment, the power conversion device100includes the conductor50(module-side conductor) connected to the terminals11ato11c,12ato12c, and13ato13c(module-side terminals) and arranged along the terminal surfaces14(module-side terminal surfaces), and the power converter10includes the inverters10cto10e(three-level inverters) to which three levels of potential including an upper potential, an intermediate potential, and a lower potential are input, and the converters10aand10b(three-level converters) from which three levels of potential including an upper potential, an intermediate potential, and a lower potential are output. The conductor50includes the conductor51(upper conductor) to which an upper potential is applied, the conductor53(intermediate conductor) to which an intermediate potential is applied, and the conductor52(lower conductor) to which a lower potential is applied, and the terminal surfaces33(capacitor-side terminal surfaces) of the capacitors31and32face the conductors51,52, and53. Accordingly, even when the power converter10includes at least one of the three-level inverters or the three-level converters, the terminal surfaces33face the conductors51,52, and53, and thus arrangement with exposure of the terminals31a,31b,32a, and32b(capacitor-side terminals) and the conductors51to53on the side surfaces of the capacitors31and32other than the modules11to13(semiconductor modules) side can be reduced or prevented. Therefore, even when the power converter10includes at least one of the three-level inverters or the three-level converters, a device arranged separately from the capacitors31and32and the modules11to13can be arranged close to the capacitors31and32, and thus an increase in the size of the power conversion device100can be reduced or prevented.

According to the first embodiment, the modules11to13(semiconductor modules) include the module11(first module) including one switching element Q1and one clamp diode D1and connected to the conductor51(upper conductor) and the conductor53(intermediate conductor), the module12(second module) including one switching element Q4and one clamp diode D2and connected to the conductor53and the conductor52(lower conductor), and the module13(third module) including two switching elements Q2and Q3and connected to the modules11and12. The conductor50(module-side conductor) includes the conductor55(first connection conductor) to connect the module11to the module13, and the conductor54(second connection conductor) to connect the module12to the module13, the conductor51, the conductor52, and the conductor53are laminated while being insulated from each other to form the laminated conductor50a(first laminated conductor), and the conductor54and the conductor55are laminated separately from the laminated conductor50awhile being insulated from each other to form the laminated conductor50b(second laminated conductor). When each of the plurality of laminated conductors50is connected, it is necessary to provide holes in the other conductors in order to arrange a fastening member such as a screw at the connecting portion of one of the plurality of conductors50. In consideration of this point, in the first embodiment, the conductor51, the conductor52, and the conductor53are laminated while being insulated from each other to form the laminated conductor50a, and the conductor54and the conductor55are laminated separately from the laminated conductor50awhile being insulated from each other to form the laminated conductor50b. Accordingly, the laminated conductor50aformed by the conductors51,52, and53and the laminated conductor50bformed by the conductors54and55can be separately connected to the modules11to13. Therefore, as compared with a case in which the conductors51,52, and53and the conductors54and55are collectively formed as one laminated conductor, the number of holes for avoiding the connecting portions can be reduced, and thus a decrease in the cross-sectional areas of the conductors can be reduced or prevented. Consequently, in the conductors51,52, and53and the conductors54and55, local heat generation due to current concentration can be reduced or prevented, and an increase in inductance can be reduced or prevented.

According to the first embodiment, the power converter10and the capacitors31and32are mounted on the railroad vehicle101. Accordingly, even when the power converter10and the capacitors31and32are mounted on the railroad vehicle101, a device separate from the modules11to13(semiconductor modules) and the capacitors31and32can be arranged close to the capacitors31and32, and thus an increase in the size of the power conversion device100mounted on the railroad vehicle101can be effectively reduced or prevented.

Second Embodiment

A second embodiment is now described with reference toFIGS.11to13. In the second embodiment, a two-level power converter210is provided, unlike the first embodiment in which the three-level power converter10is provided. In the second embodiment, the same or similar configurations as those of the first embodiment are denoted by the same reference numerals, and description thereof is omitted.

As shown inFIGS.11and12, a power conversion device200according to the second embodiment includes a power converter210, a cooling body220, and a capacitor230. The power converter210includes three modules211,212, and213. The modules211to213are aligned in an X direction on a cooling surface of the cooling body220. Each of the modules211to213includes a terminal210a, a terminal210b, and a terminal210c. The terminals210ato210care arranged on terminal surfaces214provided on the modules211to213. The power converter210is an example of a “power converter”, an “inverter”, or a “two-level inverter” in the claims. The terminals210ato210care examples of a “module-side terminal” in the claims. The modules211to213are examples of a “semiconductor module” in the claims. The terminal surfaces214are examples of a “module-side terminal surface” in the claims.

As shown inFIG.12, the capacitor230includes terminals230aand230b. The terminals230aand230bare arranged on a terminal surface233of the capacitor230. In the second embodiment, the terminal surface233of the capacitor230is arranged so as to correspond to the terminal surfaces214of the modules211to213. The terminal surface233is an example of a “capacitor-side terminal surface” in the claims. The terminals230aand230bare examples of a “capacitor-side terminal” in the claims.

As shown inFIG.13, each of the modules211to213includes a pair of switching elements connected in series to each other. The pair of switching elements is MOSFETs, for example. InFIG.13, diodes connected in parallel to the switching elements represent parasitic diodes of the MOSFETs. The terminal210ais connected to the positive electrode side of the pair of switching elements. The terminal210bis connected to the negative electrode side of the pair of switching elements. The terminal210cis connected between the pair of switching elements. In other words, in the power converter210, a two-level power conversion circuit is formed. For example, a positive electrode-side switching element and a negative electrode-side switching element of the pair of switching elements included in each of the modules211to213constitute the upper arm side and the lower arm side of an inverter circuit, respectively.

As shown inFIGS.12and13, the power conversion device200includes conductors241,242,251, and252. The conductors241and242are examples of a “capacitor-side conductor” in the claims. The conductor251is an example of a “module-side conductor” or an “upper conductor” in the claims. The conductor252is an example of a “module-side conductor” or a “lower conductor” in the claims.

The conductor241is connected to the terminal230aof the capacitor230. The conductor242is connected to the terminal230bof the capacitor230. The conductors241and242are arranged along the terminal surface233of the capacitor230and are bent in a Z2direction on the Y1direction side. The conductor251is connected to the terminals210aof the modules211to213. The conductor252is connected to the terminals210bof the modules211to213. The conductors251and252are arranged along the terminal surfaces214of the modules211to213and are bent in a Z1direction on the Y1direction side. That is, the terminal surface233of the capacitor230faces the conductors251and252.

The conductors241and251are connected to each other from an outer side (Y1direction side) at a Y1direction side end of the terminal surface233of the capacitor230. Similarly, the conductors242and252are connected to each other from the outer side (Y1direction side) at the Y1direction side end of the terminal surface233of the capacitor230.

As described above, the power converter210and the capacitor230of the power conversion device200are connected to each other to form a two-level power conversion circuit. That is, in the second embodiment, an upper potential is applied to the conductors251and241, and a lower potential is applied to the conductors252and242. The power converter210outputs three-phase AC power for operating a motor101cby constituting an inverter circuit to which two levels of potential including an upper potential and a lower potential are input.

Advantageous Effects of Second Embodiment

According to the second embodiment, the following advantageous effects are achieved.

According to the second embodiment, the power conversion device200includes the conductors251and252(module-side conductors) connected to the terminals210ato210c(module-side terminals) and arranged along the terminal surfaces214(module-side terminal surfaces), and the power converter210includes the two-level inverter to which two levels of potential including an upper potential and a lower potential are input. The conductors251and252include the conductor251(upper conductor) to which an upper potential is applied, and the conductor252(lower conductor) to which a lower potential is applied, and the terminal surface233(capacitor-side terminal surface) of the capacitor230faces the conductor251and the conductor252. Accordingly, even when the power converter210includes the two-level inverter that is at least one of the two-level inverter or a two-level converter, the terminal surface233faces the conductors251and252, and thus arrangement with exposure of the terminals230aand230b(capacitor-side terminals) and the conductors251and252on side surfaces of the capacitor230other than the modules211to213(semiconductor modules) side can be reduced or prevented. Therefore, even when the power converter210includes at least one of the two-level inverter or the two-level converter, a device arranged separately from the capacitor230and the modules211to213can be arranged close to the capacitor230, and thus an increase in the size of the power conversion device200can be reduced or prevented.

The remaining advantageous effects of the second embodiment are similar to those of the first embodiment.

Modified Examples

For example, while one module211, one module212, and one module213(semiconductor modules) are provided in the power converter210that outputs three-phase AC power in the aforementioned second embodiment, the present invention is not limited to this. In the present invention, two modules211, two modules212, and two modules213may alternatively be provided as in a power converter310according to a modified example shown inFIGS.14to16. Specifically, on a cooling body320, the modules211to213are arranged in two rows in a Y direction. Also in this case, a terminal surface233of a capacitor230and terminal surfaces214of the aligned modules211to213face each other.

In the power converter310, terminals210aof the two modules211, the two modules212, and the two modules213aligned in the Y direction are connected to each other by a conductor351. Furthermore, terminals210bof the two modules211, the two modules212, and the two modules213aligned in the Y direction are connected to each other by a conductor352. The conductors351and352are similar to the conductors251and252, respectively. That is, the conductors351and352are arranged along the terminal surfaces214of the modules211to213and are bent in a Z1direction. The conductor351is connected to the conductor241, and the conductor352is connected to the conductor242. In the power converter310, the two modules211, the two modules212, and the two modules213are provided to constitute two inverter circuits connected in parallel to each other.

In the power converter310according to the modified example, conductors241and242(capacitor-side conductors) may be connected to the conductors351and352(module-side conductors), respectively, at ends in a direction (X direction) in which the modules211to213are aligned. That is, the capacitor-side conductors and the module-side conductors may be arranged along the X direction, and the capacitor-side conductors may be connected to the module-side conductors on the X1direction side or the X2direction side. In particular, when one set of modules211to213is connected in parallel to the other set of modules211to213and operates, a difference between an inductance on the modules211to213side in a Y1direction and an inductance on the modules211to213side in a Y2direction can be reduced or prevented due to the connection in the X direction.

In the power converter310, the modules211to213may be arranged reversely in the Y direction. That is, terminals210ato210cof the modules211to213may be arranged reversely.

While two inverter circuits connected in parallel to each other are formed by using the two modules211, the two modules212, and the two modules213(semiconductor modules) in the power converter310according to the modified example, the present invention is not limited to this. In the present invention, two-group inverter circuits may alternatively be arranged by changing the connection on the output side of the power converter310. That is, the two inverter circuits may be connected to different loads by changing the connection of the terminals210con the output side of the modules211to213.

While the power converter210includes the two-level inverter in the aforementioned second embodiment, the present invention is not limited to this. For example, the power converter may alternatively include a two-level converter. That is, the power converter may convert input AC power into DC power having two levels of potential including an upper potential and a lower potential and output the DC power. In this case, using semiconductor modules similar to those of the second embodiment, a rectifier circuit including a bridge circuit using switching elements can be made to form a two-level converter circuit. Furthermore, when two inverter circuits are formed using the two modules211, the two modules212, and the two modules213(semiconductor modules) as in the power converter310according to the modified example, one of the two inverter circuits may be used as a converter circuit by changing the connection of the terminals210c(seeFIG.16) on the output side of the modules211to213. That is, one set of modules211to213may be used as a converter circuit that converts input AC power into DC power, and the other set of modules211to213may be used as an inverter circuit that converts the DC power output from one set of modules211to213into AC power and outputs the AC power. Alternatively, a pair of converter circuits connected in parallel to each other may be formed using the two modules211, the two modules212, and the two modules213.

As shown above, the two modules211, the two modules212, and the two modules213arranged on the common cooling body320, the capacitor230, the conductors241and242, and the conductors351and352are common components, and the connection destination of the terminal210cof each of the modules211to213is changed such that a plurality of circuit configurations can be achieved.

While the conductors241and242(capacitor-side conductors) and the conductors251and252(module-side conductors) are connected to each other on the Y1direction side on which the positive electrode-side terminals210aamong the terminals210ato210c(module-side terminals) of the modules211to213(semiconductor modules) are arranged in the aforementioned second embodiment, the present invention is not limited to this. In the present invention, the module-side conductors and the capacitor-side conductors may alternatively be connected to each other at the end in the direction (X direction) in which the semiconductor modules are aligned.

Furthermore, the modules211to213(semiconductor modules) may alternatively be aligned along the direction (Y direction) in which the terminals210ato210care aligned instead of the X direction. In this case, a multi-parallel (two-or-more-parallel) power conversion circuit may be formed by aligning a plurality of modules211, a plurality of modules212, and a plurality of modules213along the Y direction. Also, in this case, the capacitor230may be two capacitors connected in parallel to each other, and the capacitor-side conductors and the module-side conductors may be connected to each other at both ends (Y1-direction and Y2-direction ends) in the Y direction in which the modules211to213are aligned. The capacitors230connected in parallel to each other are aligned along the Y direction, which is the same as the direction in which the modules211to213are aligned, and the capacitor-side conductors and the module-side conductors are connected to each other at both outer sides (the Y1direction side and the Y2direction side) in the Y direction such that an increase in the inductance of the power converter310can be reduced or prevented.

While the switching elements Q1to Q4included in the modules11to13(semiconductor modules) are MOSFETs in the aforementioned first embodiment, the present invention is not limited to this. In the present invention, the switching elements included in the semiconductor modules may alternatively be insulated gate bipolar transistors (IGBTs). In this case, a diode element is connected antiparallel to each of the IGBTs. The switching elements included in the modules211to213of the second embodiment may similarly be IGBTs.

While the conductor40,241, or242(capacitor-side conductor) is connected to the conductor50,251, or252(module-side conductor) on the end side of the terminal surface33or233(capacitor-side terminal surface) of the capacitor31,32, or230in each of the aforementioned first and second embodiments, the present invention is not limited to this. In the present invention, the capacitor-side conductor may alternatively be connected to the module-side conductor on the inner side (central portion) of the capacitor-side terminal surface.

While the conductor40(capacitor-side conductor) and the conductor50(module-side conductor) are connected to each other via the relay conductor60in the aforementioned first embodiment, the present invention is not limited to this. In the present invention, the capacitor-side conductor and the module-side conductor may alternatively be directly connected to each other without using the relay conductor. In addition, while the conductors241and242(capacitor-side conductors) are directly connected to the conductors251and252(module-side conductors) in the aforementioned second embodiment, even in the two-level circuit configuration, the module-side conductor and the capacitor-side conductor may alternatively be connected to each other via a relay conductor as in the first embodiment.

While the relay conductor60includes the notched holes63in the aforementioned first embodiment, the present invention is not limited to this. In the present invention, the relay conductor may alternatively include elongated holes extending in the direction in which the capacitor-side terminal surface and the module-side terminal surface face each other, instead of the notched holes opening in the direction in which the capacitor-side terminal surface and the module-side terminal surface face each other.

While the conductor40(capacitor-side conductor) on the capacitors31and32side includes the bent mounts44(capacitor-side mounts) in the aforementioned first embodiment, the present invention is not limited to this. In the present invention, the conductor50(module-side conductor) on the modules11to13(semiconductor modules) side may alternatively include a module-side bent portion.

While the terminals13c(AC terminals) to which or from which AC power is input or output are arranged at the ends of the aligned modules11to13(semiconductor modules) in the aforementioned first embodiment, the present invention is not restricted to this. In the present invention, the AC terminals may alternatively be arranged in central portions of the aligned semiconductor modules other than the ends.

While the conductor50(module-side conductor) is separated into the laminated conductor50a(first laminated conductor) and the laminated conductor50b(second laminated conductor), and the laminated conductor50aand the laminated conductor50bare laminated in the aforementioned first embodiment, the present invention is not restricted to this. In the present invention, the conductor50may alternatively be integrally formed as one laminated conductor.

While each of the module11(first module) and the module12(second module) includes one switching element Q1or Q4, and the module13(third module) includes two switching elements Q2and Q3in the aforementioned first embodiment, the present invention is not restricted to this. In the present invention, each of the first module and the second module may alternatively include two switching elements connected in series to each other, and the third module may alternatively include two clamp diodes.

While on the terminal surfaces33(capacitor-side terminal surfaces) of the capacitors31and32, the terminals having the same potential are arranged obliquely in a staggered manner in the aforementioned first embodiment, the present invention is not restricted to this. In the present invention, on the capacitors, the terminals having the same potential may alternatively be arranged side by side. Furthermore, the number of terminals of each capacitor may alternatively be plural other than four.

While the power converter10or210and the capacitors31and32or the capacitor230are mounted on the railroad vehicle101in each of the aforementioned first and second embodiments, the present invention is not restricted to this. For example, the power converter and the capacitor(s) may alternatively be mounted on a vehicle such as an electric vehicle instead of a railroad vehicle. Furthermore, the power converter and the capacitor(s) may alternatively supply power to a stationary electric motor (motor) instead of a vehicle, for example.

While each of the converters10aand10bof the power converter10has a two-parallel configuration, and each of the inverters10cto10ehas a two-parallel configuration as well in the aforementioned first embodiment, the present invention is not restricted to this. For example, one power converter (one converter and one inverter) may alternatively be provided instead of being arranged in parallel. Furthermore, each power converter (converter and inverter) may alternatively have a multi-parallel (three-or-more-parallel) configuration. Moreover, the parallel numbers of the converter and the inverter may alternatively be different from each other.