Power conversion module

Abstract

A power conversion module (20) comprises: semiconductor elements (51H, 51L) constituting a first inverter connected to one end of a winding of a rotary electric machine; semiconductor elements (52H, 52L) constituting a second inverter connected to the other end of the winding; a snubber circuit (62) connected in parallel with the second inverter; and a changeover switch (70). The changeover switch (70) is provided in a path connecting the first inverter and the second inverter, connects a DC power source and the second inverter in a closed state, and cuts off the connection between the DC power source and the second inverter in an open state. The changeover switch (70) is disposed at a position closer to the semiconductor elements (52H, 52L) than to the semiconductor elements (51H, 51L).

Description

Power Conversion Module CROSS-REFERENCE TO RELATED APPLICATIONS

[0001] This application is based on Patent Application No. 2024-8238 filed in Japan on January 23, 2024, and the contents of the original application are incorporated by reference in their entirety.

[0002] The disclosure herein relates to power conversion modules.

[0003] Patent Document 1 discloses a power conversion module including a first inverter connected to one end of a winding of a rotating electric machine, a second inverter connected to the other end of the winding, and a changeover switch. The changeover switch is disposed in a path connecting the first inverter and the second inverter, and connects the DC power source and the second inverter in a closed state and disconnects the DC power source and the second inverter in an open state. The contents of the prior art document are incorporated by reference as explanations of technical elements in this specification.

[0004] Japanese Patent Application Laid-Open No. 2022-179964

[0005] To reduce inductance, a configuration in which a snubber circuit is connected in parallel to the inverter can be considered. However, when the changeover switch is open, there is a risk that the capacitor of the snubber circuit connected in parallel to the second inverter may be charged or discharged. In other words, there is a problem of low power conversion efficiency. In terms of the above and other aspects not mentioned, further improvements are required in power conversion modules.

[0006] One disclosed object is to provide a power conversion module that can improve power conversion efficiency.

[0007] One aspect of the disclosure is a power conversion module comprising: a first semiconductor element constituting a first inverter connected to one end of a winding of a rotating electric machine; a second semiconductor element constituting a second inverter connected to the other end of the winding; a changeover switch provided in a path connecting the first inverter and the second inverter, connecting the DC power supply and the second inverter in a closed state and cutting off the connection between the DC power supply and the second inverter in an open state; and a snubber circuit connected in parallel to the second inverter, wherein the changeover switch is positioned closer to the second semiconductor element than to the first semiconductor element.

[0008] According to the disclosed power conversion module, the changeover switch is located close to the second semiconductor element (second inverter), which increases the degree of freedom in wiring and suppresses charging and discharging of the capacitor in the snubber circuit when the changeover switch is in the open state, thereby improving power conversion efficiency.

[0009] The various aspects disclosed in this specification employ different technical means to achieve their respective objectives. The reference numerals in parentheses in the claims and in this section are intended to exemplify correspondences with the following embodiments and are not intended to limit the technical scope. The objectives, features, and advantages disclosed in this specification will become more apparent by reference to the following detailed description and the accompanying drawings.

[0010] 5 is a diagram illustrating a power conversion circuit and a drive system. FIG. 6 is a diagram illustrating an example of an operating point map of a rotating electric machine. FIG. 7 is a diagram illustrating star connection drive. FIG. 8 is a diagram illustrating open connection drive. FIG. 9 is a plan view illustrating a power conversion module according to a first embodiment. FIG. 10 is a cross-sectional view taken along line VI-VI in FIG. 5. FIG. 11 is a cross-sectional view taken along line VII-VII in FIG. 5. FIG. 12 is a diagram illustrating a reference example. FIG. 13 is a diagram illustrating a reference example. FIG. 14 is a schematic view illustrating an arrangement of semiconductor elements, snubber circuits, and changeover switches. FIG. 15 is an enlarged view of region XI in FIG. 12. FIG. 16 is a plan view illustrating a modified example. FIG. 17 is a plan view illustrating a modified example. FIG. 18 is a diagram illustrating a modified example of a power conversion circuit. FIG. 19 is a diagram illustrating a modified example of a power conversion module. FIG. 19 is a diagram illustrating a modified example of a power conversion circuit. FIG. 19 is a diagram illustrating a power conversion module according to a second embodiment. FIG. 20 is a diagram illustrating a power conversion module according to a third embodiment. FIG. 21 is a diagram illustrating a power conversion module according to a fourth embodiment.

[0011] Hereinafter, several embodiments will be described with reference to the drawings. Note that in each embodiment, corresponding components are designated by the same reference numerals, and redundant description may be omitted. When only a portion of the configuration is described in each embodiment, the configuration of another embodiment previously described may be applied to the remaining portion of the configuration. Furthermore, in addition to the combinations of configurations explicitly stated in the description of each embodiment, configurations of several embodiments may be partially combined together even if not explicitly stated, provided that there is no particular problem with the combination.

[0012] The power conversion module of this embodiment is applied to, for example, a mobile object powered by a rotating electric machine, such as an electric vehicle (BEV), a hybrid electric vehicle (HEV), a plug-in hybrid electric vehicle (PHEV), an aircraft such as an electric vertical take-off and landing aircraft or a drone, a ship, a construction machine, or an agricultural machine.

[0013] First Embodiment First, a schematic configuration of a drive system for a moving body will be described with reference to FIG.

[0014] <Drive System for a Moving Body> As shown in FIG. 1 , a drive system 1 for a moving body includes a DC power supply 2 , a rotating electric machine 3 , and a power conversion circuit 4 .

[0015] The DC power supply 2 may be, for example, a rechargeable secondary battery such as a lithium ion battery, a nickel-metal hydride battery, etc. The DC power supply 2 may also be one that converts AC power into DC power and outputs it.

[0016] The rotating electric machine 3 is a three-phase open-winding type rotating electric machine with an open neutral point. The rotating electric machine 3 has a U-phase winding 3U, a V-phase winding 3V, and a W-phase winding 3W. Hereinafter, the U-phase winding 3U, the V-phase winding 3V, and the W-phase winding 3W may be simply referred to as windings 3U, 3V, and 3W.

[0017] The rotating electric machine 3 functions, for example, as a drive source for a moving body, that is, as an electric motor. If the moving body is a vehicle, the rotating electric machine 3 generates torque for driving drive wheels (not shown). The rotating electric machine 3 is not limited to an electric motor. The rotating electric machine 3 may be a motor generator that functions as both an electric motor and a generator, or may be a generator.

[0018] The power conversion circuit 4 converts power between the DC power supply 2 and the rotating electric machine 3. The drive system 1 is a common power supply system in which power is supplied from a common DC power supply 2 to two inverters 8 and 9, which will be described later. The drive system 1 may include only one common DC power supply 2, as illustrated in FIG. 1 , or may include multiple common DC power supplies 2. The drive system 1 may include a power supply switch (not shown), such as an SMR, between the DC power supply 2 and the power conversion circuit 4. SMR is an abbreviation for System Main Relay. Turning the power supply switch on enables power supply from the DC power supply 2 to the rotating electric machine 3, and turning the power supply switch off cuts off the power supply from the DC power supply 2 to the rotating electric machine 3.

[0019] <Power Conversion Circuit> Next, the power conversion circuit 4 will be described with reference to Fig. 1. Fig. 1 shows an example of the power conversion circuit 4. The power conversion circuit 4 illustrated in Fig. 1 includes power supply lines 5 and 6, a smoothing capacitor 7, inverters 8 and 9, a changeover switch 10, and snubber circuits 11 and 12.

[0020] The power supply line 5 is a high-potential power line. The power supply line 5 is connected to the positive electrode of the DC power supply 2. The power supply line 5 may be referred to as a positive power supply line, a P line, etc. The power supply line 6 is a low-potential power line. The power supply line 6 is connected to the negative electrode of the DC power supply 2. The power supply line 6 may be referred to as a negative power supply line, an N line, etc. The power supply lines 5 and 6 are configured to include bus bars that are, for example, metal plates.

[0021] The power supply line 5 has wiring 5A and 5B. The wiring 5A and 5B are part of the wiring that constitutes the power supply line 5. The wiring 5A and 5B are wirings that connect the inverter 8 and the inverter 9 in the power supply line 5. The wiring 5A is wiring that connects the inverter 8 and the changeover switch 10 in the power supply line 5. The wiring 5B is wiring that connects the changeover switch 10 and the inverter 9 in the power supply line 5.

[0022] The smoothing capacitor 7 mainly smoothes the DC voltage supplied from the DC power supply 2. The smoothing capacitor 7 is provided between the power supply lines 5 and 6. The positive electrode of the smoothing capacitor 7 is connected to the power supply line 5 between the DC power supply 2 and the inverters 8 and 9. The negative electrode of the smoothing capacitor 7 is connected to the power supply line 6 between the DC power supply 2 and the inverters 8 and 9. The smoothing capacitor 7 is connected in parallel to the inverters 8 and 9.

[0023] The inverters 8 and 9 are DC-AC conversion circuits. The inverter 8 corresponds to a first inverter, and the inverter 9 corresponds to a second inverter. The inverter 8 is configured with upper and lower arm circuits 8HL for three phases. The upper and lower arm circuits 8HL are sometimes referred to as legs. The upper and lower arm circuit 8HL has an upper arm 8H and a lower arm 8L. The upper arm 8H and the lower arm 8L are connected in series between the power supply lines 5 and 6, with the upper arm 8H on the power supply line 5 side.

[0024] The connection point between the upper arm 8H and the lower arm 8L is connected to the winding of the corresponding phase in the rotating electric machine 3 via an output line 13. The inverter 8 has six arms. Each arm is configured with a switching element. The number of switching elements constituting each arm is not particularly limited. There may be one or more. When there are more than one switching elements, the multiple switching elements connected in parallel to each other are turned on and off at the same timing by a common gate drive signal (drive voltage).

[0025] In the example shown in Fig. 1, an n-channel MOSFET 8S is used as the switching element constituting each arm. MOSFET is an abbreviation for Metal Oxide Semiconductor Field Effect Transistor. In the upper arm 8H, the drain terminal of the MOSFET 8S is connected to the power supply line 5. In the lower arm 8L, the source terminal of the MOSFET 8S is connected to the power supply line 6. The source terminal of the MOSFET 8S in the upper arm 8H and the drain terminal of the MOSFET 8S in the lower arm 8L are connected to each other.

[0026] A freewheeling diode 8D is connected in antiparallel to each MOSFET 8S. The diode 8D may be a parasitic diode (body diode) of the MOSFET 8S or may be provided separately from the parasitic diode. The anode terminal of the diode 8D is connected to the source terminal of the corresponding MOSFET 8S, and the cathode terminal is connected to the drain terminal.

[0027] The inverter 9 has the same configuration as the inverter 8. The inverter 9 is configured with upper and lower arm circuits 9HL for three phases. The upper and lower arm circuits 9HL have an upper arm 9H and a lower arm 9L. The upper arm 9H and the lower arm 9L are connected in series between the power supply lines 5 and 6, with the upper arm 9H on the power supply line 5 side.

[0028] The connection point between the upper arm 9H and the lower arm 9L is connected to the winding of the corresponding phase in the rotating electric machine 3 via an output line 14. The inverter 9 also has six arms. Each arm is configured with a switching element. The number of switching elements constituting each arm is not particularly limited. It may be one or more.

[0029] 1, an n-channel MOSFET 9S is used as the switching element constituting each arm. In the upper arm 9H, the drain terminal of the MOSFET 9S is connected to the power supply line 5. In the lower arm 9L, the source terminal of the MOSFET 9S is connected to the power supply line 6. The source terminal of the MOSFET 9S in the upper arm 9H and the drain terminal of the MOSFET 9S in the lower arm 9L are connected to each other. A freewheeling diode 9D is connected in antiparallel to each MOSFET 9S.

[0030] As described above, the high-potential terminals (drain terminals) of the upper arms 8H, 9H of the inverters 8, 9 are connected to the power supply line 5. The low-potential terminals (source terminals) of the lower arms 8L, 9L are connected to the power supply line 6. A node connecting the upper arm 8H and the lower arm 8L is connected to one end of the corresponding phase winding via an output line 13, and a node connecting the upper arm 9H and the lower arm 9L is connected to the other end of the corresponding phase winding via an output line 14. Specifically, one end of the U-phase winding 3U is connected to a node U1 of the U-phase upper and lower arm circuit 8HL, and the other end of the U-phase winding 3U is connected to a node U2 of the U-phase upper and lower arm circuit 9HL. One end of the V-phase winding 3V is connected to a node V1 of the V-phase upper and lower arm circuit 8HL, and the other end of the V-phase winding 3V is connected to a node V2 of the V-phase upper and lower arm circuit 9HL. One end of the W-phase winding 3W is connected to a node W1 of the W-phase upper and lower arm circuit 8HL, and the other end of the W-phase winding 3W is connected to a node W2 of the W-phase upper and lower arm circuit 9HL.

[0031] The switching elements constituting the inverters 8 and 9 are not limited to the above-described MOSFETs. For example, IGBTs may be used. IGBT is an abbreviation for Insulated Gate Bipolar Transistor. In the case of an IGBT, a freewheeling diode is connected in antiparallel. The types of switching elements constituting the inverters 8 and 9 may be the same or different. For example, one of the inverters 8 and 9 may be composed of a MOSFET and the other of an IGBT. The types (materials) of the semiconductor substrates may be different.

[0032] The changeover switch 10 is a semiconductor switch. The semiconductor switch has a switching element formed on a semiconductor chip. The switching element is not particularly limited. It may have the same configuration as the switching element constituting at least one of the inverters 8, 9, or may have a different configuration. The changeover switch 10 is provided between the inverters 8 and 9 on at least one of the power supply lines 5, 6. The changeover switch 10 is provided on the power supply line. When the changeover switch 10 is closed, it connects the high-potential side terminal of the upper arm 9H of the inverter 9 to the smoothing capacitor 7 (DC power supply 2). When the changeover switch 10 is open, it disconnects the high-potential side terminal of the upper arm 9H from the smoothing capacitor 7 (DC power supply 2). The changeover switch 10 may also be referred to as a switch, an open / close switch, etc.

[0033] The switching element of the changeover switch 10 illustrated in Fig. 1 is a MOSFET. A diode is connected in anti-parallel to the MOSFET. The diode is, for example, a parasitic diode. The drain terminal of the changeover switch 10 (MOSFET) is connected to the wiring 5A, and the source terminal is connected to the wiring 5B. When the MOSFET is turned on and the changeover switch 10 is closed, the high-potential side terminal of the upper arm 9H is electrically connected to the smoothing capacitor 7. When the MOSFET is turned off and the changeover switch 10 is opened, the electrical connection between the high-potential side terminal of the upper arm 9H and the smoothing capacitor 7 is interrupted.

[0034] Furthermore, in the power conversion circuit 4, a changeover switch 10 is provided for each phase of the upper and lower arm circuits 9HL. The power conversion circuit 4 includes three changeover switches 10. The drain terminal of each changeover switch 10 is connected to a wiring 5A, and the source terminal is connected to a wiring 5B. One of the changeover switches 10 is connected in series to the upper and lower arm circuit 9HL of the U phase. The other changeover switch 10 is connected in series to the upper and lower arm circuit 9HL of the V phase. The other changeover switch 10 is connected in series to the upper and lower arm circuit 9HL of the W phase. The source terminals of the three changeover switches 10 are electrically connected to each other by a wiring 5B. The source terminals of the three changeover switches 10 are commonly connected.

[0035] The snubber circuit 11 is connected in parallel to the inverter 9, i.e., the upper and lower arm circuits 9HL. The snubber circuit 11 reduces the inductance of the upper and lower arm circuits 9HL. In other words, the snubber circuit 11 absorbs transient high voltages, so-called switching surges, that occur when the switching elements (MOSFETs 9S) that make up the upper and lower arm circuits 9HL are switched. This enables the inverter 9 to perform high-speed switching.

[0036] The snubber circuit 11 includes at least a capacitor 11C. The snubber circuit 11 may be, for example, a C snubber circuit including a capacitor, or an RC snubber circuit including a capacitor and a resistor. It may also be an RCD snubber circuit including a capacitor, a resistor, and a diode. The snubber circuit 11 shown in FIG. 1 is an RC snubber circuit in which a capacitor 11C and a resistor 11R are connected in series. One end of the snubber circuit 11 is connected to the power supply line 5. One end of the snubber circuit 11 is connected to the wiring 5A of the power supply line 5. The other end of the snubber circuit 11 is connected to the power supply line 6. The snubber circuit 11 is electrically connected to the smoothing capacitor 7 and the DC power supply 2 without passing through the selector switch 10.

[0037] In the power conversion circuit 4 illustrated in FIG. 1 , a snubber circuit 11 is provided for each phase of the upper and lower arm circuits 9HL. The power conversion circuit 4 includes three snubber circuits 11 in addition to the three changeover switches 10 described above. One end of each snubber circuit 11 is connected to the wiring 5A, and the other end is connected to the power line 6. Each snubber circuit 11 includes a capacitor 11C and a resistor 11R. One of the snubber circuits 11 is connected in parallel to the U-phase upper and lower arm circuit 9HL. The other snubber circuit 11 is connected in parallel to the V-phase upper and lower arm circuit 9HL. The other snubber circuit 11 is connected in parallel to the W-phase upper and lower arm circuit 9HL.

[0038] The snubber circuit 12 is connected in parallel to the inverter 8, i.e., the upper and lower arm circuits 8HL. The snubber circuit 12 reduces the inductance of the upper and lower arm circuits 8HL, thereby enabling high-speed switching of the inverter 8. The snubber circuit 12 includes at least a capacitor 12C. The snubber circuit 12 may be, for example, a C snubber circuit, an RC snubber circuit, or an RCD snubber circuit. The snubber circuit 12 shown in FIG. 1 is an RC snubber circuit in which a capacitor 12C and a resistor 12R are connected in series. One end of the snubber circuit 12 is connected to the power supply line 5. The other end of the snubber circuit 12 is connected to the power supply line 6.

[0039] In the power conversion circuit 4 illustrated in FIG. 1 , a snubber circuit 12 is provided for each phase of the upper and lower arm circuits 8HL. The power conversion circuit 4 includes three snubber circuits 12. One end of each snubber circuit 12 is connected to the power supply line 5, and the other end is connected to the power supply line 6. Each snubber circuit 12 includes a capacitor 12C and a resistor 12R. One of the snubber circuits 12 is connected in parallel to the U-phase upper and lower arm circuit 8HL. The other snubber circuit 12 is connected in parallel to the V-phase upper and lower arm circuit 8HL. The other snubber circuit 12 is connected in parallel to the W-phase upper and lower arm circuit 8HL.

[0040] As illustrated in FIG. 1 , the power conversion circuit 4 may further include a control unit (CTR) 15. The control unit 15 may be configured to include, for example, a processor, a memory, a storage, and the like. The processor executes various processes by accessing the memory. The memory is a rewritable volatile storage medium. The memory is, for example, RAM. RAM is an abbreviation for Random Access Memory. The storage is, for example, a rewritable non-volatile storage medium. The storage stores a program executed by the processor. The program constructs multiple functional units by causing the processor to execute multiple instructions. The processes executed by the control unit 15 may be realized by software processing in which the processor executes the above-mentioned program, or may be realized by hardware processing using a dedicated electronic circuit. They may also be realized by a combination of software processing and hardware processing.

[0041] The control unit 15 may include, for example, a drive command generation unit and a drive circuit unit (not shown). The drive command generation unit controls the inverters 8 and 9. The drive command generation unit generates drive commands (command signals) for controlling the on / off of the MOSFETs 8S and 9S and outputs them to the drive circuit unit. The drive command generation unit generates drive commands based on drive requests for the rotating electric machine 3, such as torque command values ​​input from a higher-level ECU (not shown), and signals detected by various sensors. The various sensors may include current sensors, rotation angle sensors, voltage sensors, and the like (not shown). The current sensors detect phase currents flowing through the windings 3U, 3V, and 3W of each phase. The rotation angle sensors detect the rotation angle of the rotor of the rotating electric machine 3. The voltage sensor detects the voltage across the smoothing capacitor 7.

[0042] The drive command generation unit controls the changeover switch 10. The drive command generation unit generates drive commands for controlling the on / off of the changeover switch 10 and outputs the drive commands to the drive circuit unit. The drive circuit unit is sometimes referred to as a driver. The drive circuit unit can independently control the on / off of the MOSFET 8S, the MOSFET 9S, and the changeover switch 10 based on the drive commands. For convenience, signal lines for transmitting drive signals from the control unit 15 to each switching element are omitted from FIG. 1 .

[0043] <Star Connection Drive and Open Connection Drive> Next, star connection drive and open connection drive will be described with reference to Figures 2, 3, and 4. Figure 2 shows an example of an operating point map of a rotating electric machine, with the horizontal axis representing rotation speed and the vertical axis representing torque. Figure 3 is a diagram showing star connection drive. Figure 4 is a diagram showing open connection drive. For convenience, the control unit 15 is omitted from Figures 3 and 4.

[0044] As shown in Figure 2, the driving range of the rotating electric machine 3 is divided into two ranges depending on the rotation speed and torque. One of the driving ranges is the star connection driving range. The star connection driving range is a normal use range. The other driving range is the open connection driving range. The open connection driving range is a range of higher rotation speeds or higher torques than the star connection driving range.

[0045] When the operating point is in the star connection drive region, the control unit 15 executes star connection drive control. Star connection drive is sometimes referred to as Y drive. The control unit 15 controls the MOSFETs 8S, 9S and the changeover switch 10 so that the windings 3U, 3V, and 3W are in a star connection state. Specifically, as shown in FIG. 3 , the MOSFETs of all the changeover switches 10 are turned off and opened. The inverter 9 is also neutralized. As shown in FIG. 3 , for example, the MOSFETs 9S of the upper arms 9H of all phases may be turned on and the MOSFETs 9S of the lower arms 9L of all phases may be turned off. The MOSFETs 9S of the upper arms 9H of all phases may be turned off and the MOSFETs 9S of the lower arms 9L of all phases may be turned on. The MOSFETs 8S of the inverter 8 are then controlled according to drive requirements, etc.

[0046] FIG. 3 shows one current conduction pattern in star-connection drive. The dashed-dotted arrows in FIG. 3 indicate an example of a current path. FIG. 3 shows the current path when the MOSFET 8S in the U-phase upper arm 8H and the MOSFET 8S in the W-phase lower arm 8L are turned on. In the example shown in FIG. 3, the upper arm 9H of the inverter 9 is turned on and the lower arm 9L is turned off. The current flows in the following order: U-phase upper arm 8H → node U1 → U-phase winding 3U → node U2 → U-phase upper arm 9H → W-phase upper arm 9H → node W2 → W-phase winding 3W → node W1 → W-phase lower arm 8L. In this way, in star-connection drive, current flows without passing through the selector switch 10.

[0047] When the operating point is in the open connection drive region, the control unit 15 executes open connection drive control. Open connection drive is sometimes referred to as H drive. For example, the control unit 15 turns on the MOSFETs of all the changeover switches 10, closing the changeover switches 10. The control unit 15 may also close the changeover switches 10 of the corresponding phases when it turns on the MOSFET 9S of the upper arm 9H. The control unit 15 also opens the neutral point of the inverter 9. Opening the neutral point forms an open connection circuit of the U-phase upper and lower arm circuits 8HL, 9HL via the U-phase winding 3U. Similarly, an open connection circuit of the V-phase upper and lower arm circuits 8HL, 9HL via the V-phase winding 3V is formed. An open connection circuit of the W-phase upper and lower arm circuits 8HL, 9HL via the W-phase winding 3W is formed. The control unit 15 regards each phase as an independent open connection circuit and controls the applied voltage for each phase.

[0048] Figure 4 shows one current conduction pattern in open connection drive. The two-dot chain arrow in Figure 4 indicates one example of a current path. Figure 4 shows the current path when MOSFET 8S in W-phase lower arm 8L and MOSFET 9S in W-phase upper arm 9H are turned on. Current flows in the following order: changeover switch 10 → W-phase upper arm 9H → node W2 → W-phase winding 3W → node W1 → W-phase lower arm 8L. In this way, in open connection drive, current flows via changeover switch 10.

[0049] As described above, the inverters 8 and 9 can switch between star connection drive and open connection drive. By performing open connection drive instead of star connection drive, it is possible to output a higher rotation speed range or a higher torque range.

[0050] <Power Conversion Module> Next, a power conversion module will be described with reference to Fig. 5, Fig. 6, and Fig. 7. Fig. 5 is a plan view showing an example of a power conversion module. Fig. 6 is a cross-sectional view taken along line VI-VI in Fig. 5. Fig. 7 is a cross-sectional view taken along line VII-VII in Fig. 5.

[0051] In the following, the thickness direction of the substrate is referred to as the Z direction, and one direction perpendicular to the Z direction is referred to as the X direction. The direction perpendicular to both the Z direction and the X direction is referred to as the Y direction. Unless otherwise specified, the shape viewed from the Z direction, in other words, the shape along the XY plane defined by the X and Y directions, is referred to as the planar shape. Furthermore, the planar view from the Z direction may be simply referred to as the planar view.

[0052] The power conversion module 20 provides at least a part of the above-described power conversion circuit 4. The power conversion module 20 includes a cooler 30, a substrate 40, a semiconductor element 50, a snubber circuit 60, a changeover switch 70, a clip 80, and a main terminal 90. The power conversion module 20 may further include a capacitor device that provides a smoothing capacitor 7. The power conversion module 20 may further include a circuit board that provides a control unit 15. The power conversion module 20 may further include a seal that seals the semiconductor element 50, the snubber circuit 60, the changeover switch 70, etc. The power conversion module 20 may also be referred to as a semiconductor module, an inverter module, a power conversion device, etc.

[0053] The cooler 30 supports other elements constituting the power conversion module 20. The cooler 30 cools circuit elements of the power conversion module 20, such as the semiconductor device 50 and the snubber circuit 60. The cooler 30 is formed using a metal material such as Al or Cu. The cooler 30 illustrated in FIG. 6 includes a case 31 and a lid 32. The case 31 and the lid 32 form a flow path 33 when the lid 32 is attached to the case 31. The case 31 is, for example, box-shaped with one side open. The lid 32 is fixed to the case 31 so as to close the opening of the case 31. Fins 34, for example, a plurality of pin fins, are provided on the inner surface of the lid 32. The fins 34 are arranged in the flow path 33. The flow path 33 extends, for example, in the X direction.

[0054] The cooler 30 has an inlet pipe 35 and an outlet pipe 36 provided on the side wall of the case 31. In the example shown in FIG. 6 , the inlet pipe 35 is attached to the side wall on the substrate 42 side in the X direction, and the outlet pipe 36 is attached to the side wall on the substrate 41 side. A refrigerant 37 is supplied to the flow path 33 via the inlet pipe 35. The refrigerant 37 that has flowed through the flow path 33 is discharged to the outside of the cooler 30 via the outlet pipe 36. The refrigerant 37 may be a phase-change refrigerant such as water or ammonia, or a phase-non-change refrigerant such as an ethylene glycol-based refrigerant. For example, LLC may be used as the refrigerant 37. LLC is an abbreviation for long life coolant.

[0055] The cooler 30 has one surface 301 and a back surface 302. The back surface 302 is the surface opposite to the one surface 301 in the Z direction. A substrate 40 is disposed on the one surface 301. The flow path 33 is provided so as to overlap the semiconductor element 50 and the snubber circuit 60 in a plan view so as to effectively cool the semiconductor element 50, the snubber circuit 60, etc. The flow path 33 is provided so as to overlap most of the substrate 40 in a plan view.

[0056] The cooler 30 is not limited to the above-described configuration having the flow path 33. A heat dissipation member such as a heat sink may be used as the cooler 30. A heat sink may also be referred to as a heat sink or cooling plate. The heat dissipation member may include heat dissipation fins. If insulation of the substrate 40 from the cooler 30 is not required, a bonding material such as solder or sintered Ag may be interposed between the substrate 40 and the cooler 30. In other words, the substrate 40 may be bonded to one surface 301 of the cooler 30. If insulation is required, an electrically insulating member may be disposed between the substrate 40 and the cooler 30. For example, a ceramic plate or a resin sheet may be used as the insulating member. A TIM such as silicone gel may be used to improve thermal conductivity. TIM stands for Thermal Interface Material. A support member that does not provide cooling function may be used instead of the cooler 30.

[0057] The substrate 40 provides a wiring function. The substrate 40 may also be referred to as a wiring substrate, a printed circuit board, or the like. A semiconductor element 50, a snubber circuit 60, and a changeover switch 70 are mounted on the substrate 40. The substrate 40 has, for example, a substantially rectangular shape in plan view. The power conversion module 20 may include a single substrate 40 or multiple substrates 40. The substrate 40 includes a substrate 41 and a substrate 42. The substrate 41 corresponds to the first substrate, and the substrate 42 corresponds to the second substrate. The substrates 41 and 42 are arranged side by side in the X direction on one surface 301 of the cooler 30.

[0058] The substrate 41, together with the electronic components mounted on the substrate 41, constitutes a circuit on the inverter 8 side. The substrate 42, together with the electronic components mounted on the substrate 42, constitutes a circuit on the inverter 9 side. The substrate 41 has an insulating substrate 411 and a conductor disposed on the insulating substrate 411. The substrate 42 has an insulating substrate 421 and a conductor disposed on the insulating substrate 421. The insulating substrates 411 and 421 are formed using an electrically insulating material such as ceramic or resin.

[0059] The conductors are formed from metals with good electrical and thermal conductivity, such as Cu or Al. The conductors may have a plating film of Ni-based metals, Au, or the like on their surfaces. The conductors may be disposed on only one surface of the insulating substrates 411 and 421, or on both one surface and the back surface. The back surfaces of the insulating substrates 411 and 421 are the surfaces facing the cooler 30 in the Z direction. The conductors may be disposed inside the insulating substrates 411 and 421. In other words, the substrates 41 and 421 may be single-sided substrates, double-sided substrates, or multilayer substrates with three or more layers including inner layer wiring. The conductors may include via conductors. The via conductors are formed by disposing a conductor, such as a plating, in through holes (vias) formed in the insulating layers that make up the insulating substrates 411 and 421. The via conductors electrically connect conductors disposed on different layers.

[0060] The illustrated substrate 41 has a conductor 412 arranged on one surface and a conductor 413 arranged on the back surface. The substrate 42 has a conductor 422 arranged on one surface and a conductor 423 arranged on the back surface. The conductors 413 and 423 are electrically isolated from the corresponding conductors 412 and 422 by insulating substrates 411 and 421. The conductors 413 and 423 provide, for example, a heat dissipation function. The substrates 41 and 42 are arranged in the cooler 30 with the conductors 413 and 423 facing the cooler 30.

[0061] The conductors 412 and 422 are patterned. The patterned conductors 412 and 422 provide wiring functions. That is, they form a circuit together with the mounted electronic components. The conductor 412 includes a P wiring 414, an N wiring 415, an O wiring 416, and a signal wiring 417. The wirings are electrically separated by a predetermined gap. The conductor 422 includes a P wiring 424, an N wiring 425, an O wiring 426, and signal wirings 427 and 428. The wirings are electrically separated by a predetermined gap. The P wirings 414 and 424 may be referred to as positive wiring or high-potential power supply wiring. The N wirings 415 and 425 may be referred to as negative wiring or low-potential power supply wiring. The O wirings 416 and 426 may be referred to as output wiring.

[0062] The P wiring 414 is connected to the drain electrode (drain terminal) of the semiconductor element 51H. The P terminal 91 is joined to the P wiring 414. The P wiring 414 electrically connects the P terminal 91 and the semiconductor element 51H. A P wiring 414 is provided for each phase of the upper and lower arm circuits 8HL that constitute the inverter 8. The P wiring 414 extends generally in the Y direction. Three P wirings 414 are aligned in the X direction at a predetermined interval. One end of the P wiring 414 is located near an end of the substrate 41 in the Y direction. The P terminal 91 is joined to one end of the P wiring 414. The other end of the P wiring 414 is located in the middle of the substrate 41 in the Y direction. The corresponding semiconductor element 51H (drain terminal) is joined to the other end of the P wiring 414.

[0063] The P wiring 424 is connected to the drain electrode (drain terminal) of the semiconductor element 52H. The P wiring 424 is electrically connected to the P terminal 91 via the P wiring 414. The P wiring 424 includes wirings 424A, 424B, and 424C. The wirings 424A and 424B are provided for each phase of the upper and lower arm circuits 9HL that constitute the inverter 9. The wiring 424A extends generally in the Y direction. One end of the wiring 424A is located near an end of the substrate 42 in the Y direction. The other end of the wiring 424A is located in the middle of the substrate 41 in the Y direction. The drain electrode (drain terminal) of the corresponding changeover switch 70 is joined to the other end of the wiring 424A.

[0064] The wiring 424B extends in the Y direction with a predetermined gap between it and the lower end of the corresponding wiring 424A. The wiring 424B is aligned with the wiring 424A of the corresponding phase in the Y direction. The drain electrode (drain terminal) of the corresponding semiconductor element 52H is joined to the wiring 424B. The source electrode (source terminal) of the semiconductor element 52H is electrically connected to the wiring 424B via a clip 823. The three pairs of wiring 424A, 424B are aligned in the X direction with a predetermined gap between them. The wiring 424C is connected to the end of the wiring 424A opposite the end connected to the selector switch 70. The wiring 424C is located near the end of the substrate 42 in the Y direction. The wiring 424C is located near the end on the side where the P terminal 91 and the N terminal 92 are located in the Y direction. The wiring 424C extends generally in the X direction. The wiring 424C commonly connects the wiring 424A provided for each phase. The wiring 424C is connected to one end of the wiring 424A.

[0065] The N wiring 415 is electrically connected to the source electrode (source terminal) of the semiconductor element 51L via the clip 812. An N terminal 921 (92) is joined to the N wiring 415. The N wiring 415 electrically connects the N terminal 921 and the semiconductor element 51L. The N wiring 415 has wirings 415A and 415B. The wiring 415A extends generally in the Y direction. The wiring 415A has a length in the Y direction that is approximately equal to that of the P wiring 414. The wiring 415A is arranged alternately with the P wiring 414 in the X direction and between the P wirings 414. In other words, the N wiring 415 has two wirings 415A. In the X direction, the wirings are arranged in the following order: P wiring 414, wiring 415A, P wiring 414, wiring 415A, P wiring 414.

[0066] One end of the wiring 415A is disposed near an end of the substrate 41 in the Y direction. An N terminal 921 (92) is joined to one end of the wiring 415A. A wiring 415B is connected to the other end of the wiring 415A. The wiring 415B is disposed in the middle of the substrate 41 in the Y direction. The wiring 415B is disposed between the P wiring 414 and the O wiring 416. The wiring 415B extends generally in the X direction. The wiring 415B extends from near one end of the substrate 41 to near the other end in the X direction. The wiring 415B commonly connects the wirings 415A. The clip 812 is connected to the wiring 415B.

[0067] The N wiring 425 is electrically connected to the source electrode (source terminal) of the semiconductor element 52L via a clip 822. An N terminal 922 (92) is joined to the N wiring 425. The N wiring 425 electrically connects the N terminal 922 to the semiconductor element 52L. An N wiring 425 is provided for each phase of the upper and lower arm circuits 9HL that constitute the inverter 9. The N wiring 425 extends generally in the Y direction. Three N wirings 425 are lined up in the X direction at a predetermined interval. One end of the N wiring 425 is located near the end of the substrate 42 in the Y direction. An N terminal 922 is joined to one end of the N wiring 425. The other end of the N wiring 425 is located in the middle of the substrate 42 in the Y direction. A clip 822 is connected to the other end of the N wiring 425.

[0068] The N wiring 425 is arranged alternately with the P wiring 424 (wiring 424A, 424B) in the X direction. The N wiring 425 runs parallel to the wiring 424A, 424B (P wiring 424). Running parallel means that they extend side by side. The P wiring 424 is arranged at the end on the substrate 41 side in the X direction. The N wiring 425 is arranged parallel to the O wiring 426 of the corresponding phase in the Y direction.

[0069] The O wiring 416 is connected to the drain electrode (drain terminal) of the semiconductor element 51L. An O terminal 931 (93) is joined to the O wiring 416. The source terminal of the semiconductor element 51H is electrically connected to the O wiring 416 via a clip 811. The O wiring 416 electrically connects the source terminal of the semiconductor element 51H, the drain terminal of the semiconductor element 51L, and the O terminal 931. An O wiring 416 is provided for each phase. The O wiring 416 is aligned in the Y direction with the P wiring 414 of the corresponding phase via wiring 415B.

[0070] The O wiring 426 is connected to the drain electrode (drain terminal) of the semiconductor element 51L. An O terminal 932 (93) is joined to the O wiring 426. The source terminal of the semiconductor element 52H is electrically connected to the O wiring 426 via a clip 821. The O wiring 426 electrically connects the source terminal of the semiconductor element 52H, the drain terminal of the semiconductor element 52L, and the O terminal 932. An O wiring 426 is provided for each phase. The O wiring 426 is aligned in the Y direction with the P wiring 424 (wirings 424A and 424B) and N wiring 425 of the corresponding phase.

[0071] The signal wiring 417 electrically connects the pads of the semiconductor elements 51H and 51L to signal terminals (not shown). The signal wiring 427 electrically connects the pads of the semiconductor elements 52H and 52L to signal terminals (not shown). The signal wiring 417 and 427 are electrically connected to the pads via bonding wires, for example. The signal wiring 417 and 427 are signal islands formed on the corresponding substrates 41 and 42, for example. For convenience, FIG. 5 shows one signal wiring 417 and 427 for one semiconductor element 50.

[0072] On the substrate 41, the signal wiring 417 is aligned with the corresponding semiconductor elements 51H and 51L in the Y direction. In the Y direction, the signal wiring 417 corresponding to the semiconductor element 51H is disposed closer to the end of the substrate 41 on the P terminal 91 side than the semiconductor element 51H. The signal wiring 417 corresponding to the semiconductor element 51L is disposed closer to the end of the substrate 41 on the O terminal 931 side than the semiconductor element 51L. On the substrate 42, the signal wiring 427 is aligned with the corresponding semiconductor elements 52H and 52L in the X direction. In the X direction, the signal wiring 427 is disposed closer to the substrate 41 than the corresponding semiconductor elements 52H and 52L.

[0073] The signal wiring 428 electrically connects the pad of the changeover switch 70 to a signal terminal (not shown). The signal wiring 428 is electrically connected to the pad via, for example, a bonding wire. The signal wiring 428 is, for example, a signal island formed on the substrate 42. For convenience, FIG. 5 shows one signal wiring 427 for each semiconductor element 52H, 52L. The signal wiring 428 is arranged in the same manner as the signal wiring 427. On the substrate 42, the signal wiring 428 is aligned with the corresponding changeover switch 70 in the X direction. In the X direction, the signal wiring 428 is arranged closer to the substrate 41 than the corresponding changeover switch 70.

[0074] The semiconductor element 50 is an electronic component that provides the inverters 8 and 9. The semiconductor element 50 is formed by forming a vertical element on a semiconductor substrate made of silicon (Si), a wide bandgap semiconductor with a wider bandgap than silicon, or the like. Examples of wide bandgap semiconductors include silicon carbide (SiC), gallium nitride (GaN), gallium oxide (Ga2O3), and diamond. The semiconductor element 50 may also be called a power element, a semiconductor chip, or the like.

[0075] The vertical element is configured to pass a main current in the thickness direction of the semiconductor element 50 (semiconductor substrate). The semiconductor element 50 is arranged so that its thickness direction is approximately parallel to the Z direction. The semiconductor element 50 has main electrodes (main terminals) on both sides in the thickness direction. In the illustrated power conversion module 20, the semiconductor element 50 is formed by forming an n-channel MOSFET as a vertical element on a semiconductor substrate made of SiC. The semiconductor element 50 has a drain electrode (drain terminal) on its bottom surface facing the substrate 40 and a source electrode (source terminal) on its top surface opposite the bottom surface.

[0076] When a MOSFET is turned on, a current (main current) flows between the main terminals, that is, between the drain terminal and the source terminal. If the diode is a parasitic diode, the source terminal also serves as the anode terminal, and the drain terminal also serves as the cathode terminal. The diode may be formed on a chip separate from the MOSFET. The drain terminal is the main electrode on the high potential side, and the source terminal is the main terminal on the low potential side. The drain terminal is formed over almost the entire bottom surface. The source terminal is formed on a part of the top surface.

[0077] The semiconductor element 50 has a generally rectangular shape in plan view. The semiconductor element 50 has pads, which are signal terminals, on its upper surface. The pads are formed at positions on the upper surface that are different from the source terminals. The pads include at least a gate pad.

[0078] The multiple semiconductor elements 50 include a semiconductor element 51H constituting the upper arm 8H, a semiconductor element 51L constituting the lower arm 8L, a semiconductor element 52H constituting the upper arm 9H, and a semiconductor element 52L constituting the lower arm 9L. The semiconductor elements 50 include three semiconductor elements each, 51H, 51L, 52H, and 52L. The semiconductor elements 51H, 51L, 52H, and 52L are provided for each phase. One semiconductor element 50 provides one arm. The semiconductor elements 51H and 51L correspond to first semiconductor elements, and the semiconductor elements 52H and 52L correspond to second semiconductor elements. The semiconductor elements 51H and 52H are sometimes referred to as upper arm elements. The semiconductor elements 51L and 52L are sometimes referred to as lower arm elements.

[0079] The semiconductor elements 51H and 51L are mounted on the substrate 41. The semiconductor element 51H is disposed so as to overlap the end of the P wiring 414 on the O wiring 416 side in a plan view. The drain terminal of the semiconductor element 51H is joined to the P wiring 414 via a bonding material such as solder (not shown). The semiconductor element 51L is disposed so as to overlap the O wiring 416 in a plan view. The drain terminal of the semiconductor element 51L is joined to the O wiring 416 via a bonding material (not shown).

[0080] The semiconductor elements 51H of each phase are aligned in the X direction. The semiconductor elements 51L of each phase are aligned in the X direction. The semiconductor elements 51H, 51L of corresponding phases are aligned roughly in the Y direction. The semiconductor elements 51H, 51L of corresponding phases are offset in the X direction so that only a portion of them face each other in the Y direction. The semiconductor elements 51H, 51L are aligned 180 degrees around the Z axis, that is, they are inverted relative to each other. The pads of the semiconductor elements 51H, 51L are aligned on the outside in the Y direction, rather than on the inside, that is, on the opposing sides. The Z axis is an axis parallel to the Z direction.

[0081] The semiconductor elements 52H and 52L are mounted on the substrate 42. The semiconductor element 52H is disposed so as to overlap with the wiring 424B (P wiring 424) in a plan view. The drain terminal of the semiconductor element 52H is bonded to the wiring 424B via a bonding material (not shown). The semiconductor element 52L is disposed so as to overlap with the O wiring 426 in a plan view. The drain terminal of the semiconductor element 52L is bonded to the O wiring 426 via a bonding material (not shown).

[0082] The semiconductor elements 52H of each phase are aligned in the X direction. The semiconductor elements 52L of each phase are aligned in the X direction. The semiconductor elements 52H, 52L of corresponding phases are aligned roughly in the Y direction. The semiconductor elements 52H, 52L of corresponding phases are arranged offset in the X direction so that only portions of them face each other in the Y direction. The arrangement of the semiconductor elements 52H, 52L is the same around the Z axis. The pads of the semiconductor elements 52H, 52L are provided on the substrate 41 side in the X direction.

[0083] The snubber circuit 60 is an electronic component that provides a snubber circuit. The snubber circuit 60 includes a snubber circuit 61 that provides the snubber circuit 12 and a snubber circuit 62 that provides the snubber circuit 11. For convenience, the snubber circuits 61 and 62 are illustrated in a simplified manner in FIGS. 5 and 6 . The snubber circuits 61 and 62 are sometimes referred to as snubber components. The snubber circuit 61 includes at least a capacitor to provide the snubber circuit 12. The snubber circuit 61 is mounted on the substrate 41. As described above, the snubber circuit 61 is connected in parallel with the upper and lower arm circuits 8HL. The snubber circuit 61 electrically bridges the P wiring 414 and the N wiring 415. In the illustrated power conversion module 20, a snubber circuit 61 is provided for each phase. The snubber circuit 61 electrically bridges the P wiring 414 and the wiring 415A. The snubber circuit 61 electrically bridges the P wiring 414 and the N wiring 415 at a position closer to the P terminal 91 and the N terminal 921 than the semiconductor element 51H. Two adjacent snubber circuits 61 are connected to a common wiring 415A. The snubber circuits 61 for each phase are aligned in the X direction.

[0084] The snubber circuit 62 has at least a capacitor to provide the snubber circuit 11. The snubber circuit 62 is mounted on the substrate 42. As described above, the snubber circuit 62 is connected in parallel to the upper and lower arm circuits 9HL. The snubber circuit 62 electrically bridges the P wiring 424 and the N wiring 425. In the illustrated power conversion module 20, a snubber circuit 62 is provided for each phase. The snubber circuit 62 electrically bridges the wiring 424A and the N wiring 425. The snubber circuit 62 electrically bridges the P wiring 424 and the N wiring 425 at a position closer to the wiring 424C than the selector switch 70. The snubber circuits 62 for each phase are aligned in the X direction.

[0085] The changeover switch 70 functions as the changeover switch 10 in the power conversion circuit 4. The changeover switch 70 is formed by forming a switching element on a semiconductor substrate. In the illustrated power conversion module 20, the changeover switch 70 has a configuration similar to that of the semiconductor element 50. The changeover switch 70 is formed by forming a MOSFET on the semiconductor substrate. A parasitic diode is connected in antiparallel to the MOSFET.

[0086] The changeover switch 70 is disposed closer to the inverter 9 (semiconductor elements 52H, 52L) than to the inverter 8 (semiconductor elements 51H, 51L) in plan view. In the illustrated power conversion module 20, the changeover switch 70 is mounted on the substrate 42. Like the snubber circuit 62, the changeover switch 70 is provided for each phase. The changeover switch 70 is disposed so as to overlap with the end of the wiring 424A on the wiring 424B side in plan view. The drain terminal of the changeover switch 70 is joined to the wiring 424A (P wiring 424) via a bonding material (not shown). The changeover switches 70 corresponding to each phase are lined up in the X direction. The pads of the changeover switches 70 are provided on the substrate 41 side in the X direction.

[0087] The clip 80 may also be referred to as a bridging member, relay member, metal bridge, etc. The clip 80 is a metal plate material whose base material is a metal with good conductivity, such as Cu or a Cu alloy. The clip 80 may be formed by punching and pressing a metal plate of a predetermined thickness. The clip 80 may also be formed using a profiled material with a different thickness in parts. The clip 80 may have a film applied to the surface of the base material by surface treatment. The clip 80 may have a plated film of Ni, Au, or the like on its surface. The clip 80 may have a Ni plated film containing P formed on the base material. The NiP film is formed, for example, by electroless plating. Instead of Cu, Ag, Au, Al, Mg, etc. may be used as the base material. Instead of Ni or Au, Sn, Ag, etc. may be used as the film applied to the base material.

[0088] The clip 80 includes clips 811 and 812, clips 821, 822, 823, and 824, and a clip 83. The clip 811 is connected to the semiconductor element 51H. The clip 811 is provided individually for the semiconductor element 51H. The clip 811 extends generally in the Y direction and electrically connects the source terminal of the semiconductor element 51H to the O wiring 416. The clip 812 is connected to the semiconductor element 51L. The clip 812 is provided individually for the semiconductor element 51L. The clip 812 extends generally in the Y direction and electrically connects the source terminal of the semiconductor element 51L to the wiring 415B of the N wiring 415. The clips 811 and 812, together with the semiconductor elements 51H and 51L, the P wiring 414, the N wiring 415, and the O wiring 416, constitute an inverter 8. The clips 811 and 812 are mounted on the substrate 41.

[0089] The clip 821 is connected to the semiconductor element 52H. The clip 821 is provided individually for each semiconductor element 52H. The clip 821 extends generally in the Y direction and electrically connects the source terminal of the semiconductor element 52H to the O wiring 426. The clip 822 is connected to the semiconductor element 52L. The clip 822 is provided individually for each semiconductor element 52L. The clip 822 extends generally in the Y direction and electrically connects the source terminal of the semiconductor element 52L to the N wiring 425. The clips 821 and 822, together with the semiconductor elements 52H and 52L, the P wiring 424, the N wiring 425, and the O wiring 426, constitute the inverter 9. The clips 821 and 822 are mounted on the substrate 42.

[0090] The clip 823 is connected to the changeover switch 70. The clip 823 is provided individually for each changeover switch 70. The clip 823 extends generally in the Y direction and electrically connects the source terminal of the changeover switch 70 to the wiring 424B of the P wiring 424. The clip 823 functions as part of the P wiring 424. The clip 824 extends generally in the X direction. The clip 824 electrically connects adjacent wirings 424B. The clip 80 includes two clips 824. As shown in FIGS. 5 and 7 , the clip 824 crosses the N wiring 425 in a three-dimensional manner. The clip 824 electrically connects adjacent wirings 424B across the N wiring 425. The clip 824 commonly connects the low-potential side terminals of the changeover switch 70. The clips 823 and 824 are mounted on the substrate 42. The clip 823 and the wiring 424B provide wiring 5B. The clip 823 and the wiring 424B correspond to the second wiring.

[0091] The clip 83 electrically connects the P wiring 414 and the P wiring 424. The clip 83 electrically connects the inverter 8 and the inverter 9. The clip 83 extends generally in the X direction. The clip 83 bridges the substrate 41 and the substrate 42. The clip 83 and the wiring 424A, 424C provide the wiring 5A. The clip 83 and the wiring 424A, 424C correspond to the first wiring. Note that the bridging member may be an inner layer wiring of the substrate or a bonding wire.

[0092] The main terminals 90 are formed using a metal material with good conductivity, such as Cu. The main terminals 90 are, for example, plate materials. The main terminals 90 are external connection terminals that are electrically connected to the main terminals (main electrodes) of the semiconductor element 50. The main terminals 90 include a P terminal 91 and an N terminal 92 that are power supply terminals, and an O terminal 93.

[0093] The P terminal 91, together with the P wirings 414, 424 and the clips 823, 83, provides the power line 5 described above. The P terminal 91 is an external connection terminal connected to a capacitor device (not shown) that provides the smoothing capacitor 7. The P terminal 91 is electrically connected to the positive terminal of the smoothing capacitor 7. The P terminal 91 may also be referred to as a positive terminal, a high-potential power supply terminal, or the like. The P terminal 91 is joined to the P wiring 414. The P terminal 91 is mounted on the substrate 41. In the illustrated power conversion module 20, one end of the P terminal 91 branches into three, each of which is joined to the P wiring 414 of a corresponding phase. The P terminal 91 extends generally in the Y direction from the junction with the P wiring 414. The P terminal 91 extends outward from the substrate 41 to a position where it does not overlap with the cooler 30 in a plan view.

[0094] The N terminal 92, together with the N wirings 415, 425 and the clips 812, 822, provides the power supply line 6 described above. The N terminal 92 is an external connection terminal connected to a capacitor device that provides the smoothing capacitor 7. The N terminal 92 is electrically connected to the negative terminal of the smoothing capacitor 7. The N terminal 92 may also be referred to as a negative terminal, a low-potential power supply terminal, or the like. The N terminal 92 includes an N terminal 921 joined to the N wiring 415 and an N terminal 922 joined to the N wiring 425. The N terminal 921 is mounted on the substrate 41. The N terminal 922 is mounted on the substrate 42.

[0095] The illustrated power conversion module 20 includes one N terminal 921 and three N terminals 922. One end of the N terminal 921 branches into two, each of which is joined to the corresponding wiring 415A (N wiring 415). The N terminal 921 extends generally in the Y direction from the junction with the wiring 415A. The N terminal 921 extends outward from the substrate 41 to a position where it does not overlap with the cooler 30 in a plan view. An N terminal 922 is provided for each phase. The N terminal 922 is joined to the N wiring 425 of the corresponding phase. The N terminal 922 extends generally in the Y direction from the junction with the corresponding wiring 425. The N terminal 922 extends outward from the substrate 42 to a position where it does not overlap with the cooler 30 in a plan view. The N terminal 922 may have one end branched into three, each of which is joined to the corresponding N wiring 425.

[0096] The O terminals 93 are electrically connected to the windings 3U, 3V, and 3W of the corresponding phases of the rotating electric machine 3. The O terminals 93 may also be referred to as output terminals, AC terminals, etc. The O terminals 93 include an O terminal 931 joined to the O wire 416 and an O terminal 932 joined to the O wire 426. An O terminal 931 is provided for each phase of the upper and lower arm circuits 8HL. The O terminals 931, together with the O wire 416, provide the output line 13. The O terminals 931 extend from the joint with the O wire 416 generally in the Y direction, on the opposite side to the P terminal 91 and the N terminal 92. The O terminals 931 extend outward from the substrate 41 to a position where they do not overlap with the cooler 30 in a plan view.

[0097] The O terminal 932 is provided for each phase of the upper and lower arm circuits 9HL. The O terminal 932, together with the O wire 426, provides the output line 14. The O terminal 932 extends from the junction with the O wire 426 generally in the Y direction, on the opposite side to the P terminal 91 and the N terminal 92. The O terminal 932 extends outward from the substrate 42 to a position where it does not overlap with the cooler 30 in a plan view.

[0098] Summary of First Embodiment Figures 8 and 9 show a reference example of a power conversion device. Figure 8 shows an example of a current conduction pattern when star-connected driving is performed in the reference example. Figure 9 shows a current conduction pattern with timing different from that in Figure 5 when star-connected driving is performed. In the reference example, the symbols of related elements shown in this embodiment are indicated by adding r to the end.

[0099] The control unit performs star connection drive while switching between multiple current conduction patterns. The control unit performs star connection drive using, for example, a PWM control method. PWM is an abbreviation for Pulse Width Modulation. The multiple current conduction patterns include the zero vector current conduction patterns shown in FIGS. 8 and 9. The current conduction pattern shown in FIG. 8 is a zero vector pattern in which all upper arms 8Hr of the inverter 8r are turned on and all lower arms 8Lr are turned off. The current conduction pattern shown in FIG. 9 is a zero vector pattern in which all lower arms 8Lr of the inverter 8r are turned on and all upper arms 8Hr are turned off.

[0100] As shown in Figures 8 and 9, in the power conversion circuit 4r of the reference example, a snubber circuit 11r connected in parallel to an inverter 9r is connected to a wiring 5Br of a power line 5r that connects a changeover switch 10r and the inverter 9r. One end of the snubber circuit 11r is connected to the wiring 5Br of the power line 5r, and the other end is connected to a power line 6r. For convenience, Figures 8 and 9 omit the smoothing capacitor and the snubber circuit connected in parallel to the inverter 8r. Furthermore, the snubber circuit 11r is common to each phase of the inverter 9r.

[0101] In the examples shown in Figures 8 and 9, all three-phase upper arms 9Hr of inverter 9r are turned on to neutralize inverter 9r. In this state, when all three-phase upper arms 8Hr of inverter 8r are turned on as shown in Figure 8, the voltage across capacitor 11Cr becomes approximately equal to the supply voltage of DC power supply 2r, i.e., power supply voltage Vdc. Furthermore, when all three-phase lower arms 8Lr of inverter 8r are turned on as shown in Figure 9, the voltage across capacitor 11Cr becomes approximately 0 V (zero volts).

[0102] As described above, star connection driving is performed while switching between multiple current patterns, so the voltage across the capacitor 11Cr of the snubber circuit 11r fluctuates during star connection driving. The voltage across the capacitor 11Cr fluctuates within a range from 0 V to Vdc. As such, the capacitor 11Cr is charged and discharged during star connection driving, resulting in a low power conversion efficiency. The resistor 11Rr of the snubber circuit 11r consumes the energy stored in the capacitor 11Cr and generates heat. This heat affects the capacitor 11Cr.

[0103] FIG. 10 schematically illustrates the arrangement of the semiconductor elements 52H and 52L, the snubber circuit 62, and the selector switch 70 in the power conversion module 20 according to this embodiment. As shown in FIGS. 5 and 10 , in the power conversion module 20, the selector switch 70 is positioned closer to the semiconductor elements 52H and 52L (inverter 9) than to the semiconductor elements 51H and 51L (inverter 8). This facilitates connection of the snubber circuit 62 to the wiring 424A (first wiring). In other words, it facilitates connection of the snubber circuit 11 to the wiring 5A. By connecting the snubber circuit 11 to the wiring 5A, the voltage across the capacitor 11C is clamped to the power supply voltage of the DC power supply 2 (the voltage across the smoothing capacitor 7). Therefore, when the selector switch 10 is off (open state), i.e., when the power supply is in star connection mode, charging and discharging of the capacitor 11C can be suppressed. This improves power conversion efficiency.

[0104] As illustrated, the power conversion module 20 may include two substrates 41 and 42. The semiconductor elements 51H and 51L (first semiconductor elements) may be mounted on the substrate 41 (first substrate), and the semiconductor elements 52H and 52L (second semiconductor elements), snubber circuit 62, and selector switch 70 may be mounted on the substrate 42 (second substrate). Mounting the semiconductor elements 52H and 52L, snubber circuit 62, and selector switch 70 that constitute the inverter 9 on the common substrate 42 allows the selector switch 70 to be closer to the inverter 9. This makes it easier to connect the snubber circuit 62 via the wiring 424A. This facilitates the realization of a circuit configuration that improves power conversion efficiency. Furthermore, dividing the substrate into multiple parts can suppress warping.

[0105] As illustrated, the changeover switch 70 may be disposed between the semiconductor elements 52H and 52L (second semiconductor elements) and the snubber circuit 62. This allows the size in the X direction to be reduced.

[0106] Furthermore, as shown in FIG. 11 , the second power supply line may include a second upper power supply line connecting one end of the snubber circuit 62 to the semiconductor element 52H (second upper arm element) and a second lower power supply line connecting the semiconductor element 52L (second lower arm element) to the other end of the snubber circuit 62, with the second upper power supply line and the second lower power supply line running parallel to each other. One of the second upper power supply line and the second lower power supply line includes a changeover switch 70. FIG. 11 is an enlarged view of the area XI indicated by the two-dot chain line in FIG. 5 on the substrate 42. The dashed line indicates a current loop including the snubber circuit 62. In the example shown in FIG. 11 (FIG. 5), the second upper power supply line includes wirings 424A and 424B, a clip 823, and a changeover switch 70. The second lower power supply line includes a clip 822 and an N wiring 425. By disposing the changeover switch 70 between the snubber circuit 62 and the semiconductor elements 52H, 52L and by running the power supply lines in parallel as described above, the area of ​​the current loop can be reduced, and thus the wiring inductance can be reduced.

[0107] As illustrated, the semiconductor elements 52H, 52L may be provided for each phase, and the changeover switch 70 and snubber circuit 62 may be provided for each phase. This allows the area of ​​the current loop formed by the semiconductor elements 52H, 52L, snubber circuit 62, and changeover switch 70 to be smaller than in a configuration in which a single changeover switch and snubber circuit are provided common to all three phases. This further reduces the wiring inductance of the upper and lower arm circuits 9HL, thereby improving power conversion efficiency.

[0108] The total chip area of ​​the three changeover switches 70 can be made smaller than the chip area of ​​a single changeover switch common to the three phases. Also, the total capacitance of the capacitors of the three snubber circuits 62 can be made smaller than the capacitance of a single capacitor common to the three phases. Therefore, the size of the power conversion module 20 can be reduced.

[0109] As shown in the example, the source terminals of the changeover switches 70 provided for each phase may be commonly connected. In other words, the source terminals may be electrically connected to each other by a common wiring. This allows, for example, if one of the changeover switches 70 fails, another changeover switch 70 to be used instead. Note that a configuration without a common connection is also possible.

[0110] As illustrated, the common wiring and the second power line not including the changeover switch 70 may intersect in a three-dimensional manner. For example, a clip 824 may be used as the common wiring, and the clip 824 may straddle the N wiring 425, which is the second power line. This three-dimensional arrangement that also utilizes the Z direction improves the degree of freedom in wiring and allows the size of the power conversion module 20 to be reduced. Note that the common wiring may be an inner layer wiring of the substrate 42 (40), a bonding wire, or the like.

[0111] As illustrated, in a configuration in which the semiconductor elements 52H, 52L and the changeover switch 70 are aligned in a predetermined direction, the signal wirings 427, 428 may be aligned on the opposite side of the second power supply line (N wiring 425) that does not include the changeover switch 70 relative to the corresponding semiconductor elements 52H, 52L and changeover switch 70 in a direction perpendicular to the predetermined direction. As shown in FIG. 5 , the semiconductor elements 52H, 52L and the changeover switch 70 are aligned in the Y direction. The semiconductor elements 52H, 52L and the corresponding signal wiring 427 are aligned in the X direction. The changeover switch 70 and the signal wiring 428 are aligned in the X direction. This allows the board 42, and therefore the power conversion module 20, to be smaller in size in the Y direction.

[0112] Furthermore, the signal wiring 417 and the corresponding semiconductor elements 51H, 51L may be arranged side by side in a predetermined direction. The changeover switch 70 is not arranged on the inverter 8 side. Therefore, the degree of freedom in arrangement in the Y direction is higher than on the inverter 9 side. By arranging the signal wiring 417 differently from the signal wiring 427, 428 (second signal wiring), specifically by arranging the signal wiring 417 (first signal wiring) and the semiconductor elements 51H, 51L side by side in the Y direction, the physical size in the X direction can be reduced.

[0113] As illustrated, the second upper power line and the second lower power line may be alternately arranged in one direction. The first power line may include a first upper power line electrically connected to a high-potential terminal of semiconductor element 51H (first upper arm element) and a first lower power line electrically connected to a low-potential terminal of semiconductor element 51L (first lower arm element), and the first upper power line and the first lower power line may be alternately arranged in one direction. Furthermore, the second power line of the second upper power line and the second lower power line, on which a selector switch is arranged, may be arranged opposite the first power line of the first upper power line and the first lower power line, which is electrically connected to the second power line on which a selector switch is arranged, in one direction. The first upper power line includes P wiring 414. The first lower power line includes wiring 415A (N wiring 415).

[0114] 5, the P wiring 414 and the P wiring 424 (wirings 424A and 424B) face each other and are adjacent to each other in the X direction. This simplifies the wiring (power supply line) electrically connecting the inverter 8 and the inverter 9. This allows the size in the X direction to be reduced.

[0115] <Modifications> In the present embodiment, the power conversion circuit 4 includes the snubber circuit 12, and the power conversion module 20 includes the snubber circuit 61. However, the present invention is not limited to this. A configuration without the snubber circuit 61 may also be used.

[0116] The number of substrates 40 is not limited to two. For example, as shown in FIG. 12, a configuration may be adopted in which all semiconductor elements 50, all snubber circuits 60, and all changeover switches 70 are mounted on a common (single) substrate 40. In this configuration, wiring 424C (P wiring 424) is connected to P wiring 414. This allows for further miniaturization in the X direction. The other configurations are the same as those shown in FIG. 5.

[0117] The number of substrates 40 may be three or more. For example, as shown in FIG. 13 , the power conversion module 20 may include three substrates 41, 42, and 43. In FIG. 13 , the configuration of the substrate 42 shown in FIG. 5 is divided into substrates 42 and 43. The substrate 42, together with the mounted electronic components, provides the configuration for two phases. The substrate 43, together with the mounted electronic components, provides the configuration for the remaining one phase. The power conversion module 20 further includes clips 825 and 826. The clips 825 and 826 bridge the substrates 42 and 43. The clip 825 extends generally in the X direction and electrically connects the wiring 424B of the substrate 42 to the wiring 424B of the substrate 43. The clip 826 extends generally in the X direction and electrically connects the wiring 424C of the substrate 42 to the wiring 424C of the substrate 43. The other configurations are the same as those shown in FIG. 5 .

[0118] Although an example in which a changeover switch 10 and a snubber circuit 11 are provided for each phase has been described, this is not limiting. Although an example in which a snubber circuit 12 is provided for each phase has been described, this is not limiting. For example, as shown in FIG. 14 , in the power conversion circuit 4, one changeover switch 10 and one snubber circuit 11 may be provided for each of the three-phase upper and lower arm circuits 9HL that constitute the inverter 9. The snubber circuit 11 is connected to the wiring 5A. One snubber circuit 12 may be provided for each of the three-phase upper and lower arm circuits 8HL that constitute the inverter 8.

[0119] FIG. 15 shows a schematic configuration of a power conversion module 20 that provides the power conversion circuit 4 shown in FIG. 14 . FIG. 15 corresponds to FIG. 10 . As shown in FIG. 15 , a snubber circuit 61 is commonly arranged for the three phases of the inverter 8. A snubber circuit 62 is commonly arranged for the three phases of the inverter 9. A changeover switch 70 is also commonly arranged for the inverter 9. The changeover switch 70 is also located closer to the inverter 9 than the inverter 8. The changeover switch 70 is located between the snubber circuit 62 and the semiconductor elements 52H, 52L. The snubber circuit 62 and the changeover switch 70 are provided on a common substrate with the semiconductor elements 52H, 52L, but on a substrate separate from the semiconductor elements 51H, 51L. The same effects as those of the configurations shown in FIGS. 5 and 10 can be achieved.

[0120] In the power conversion circuit 4, an example in which the changeover switch 10 is provided on the power line 5 has been shown, but this is not limiting. For example, as shown in FIG. 16 , the changeover switch 10 may be provided on the power line 6. The power line 6 has a wiring 6A connecting the inverter 8 and the changeover switch 10 and a wiring 6B connecting the changeover switch 10 and the inverter 9. The wiring 6A corresponds to the first wiring, and the wiring 6B corresponds to the second wiring. The source terminal of the changeover switch 10 is connected to the wiring 6A, and the drain terminal is connected to the wiring 6B. The lower arm 9L (source terminal) of each phase is connected to the wiring 6B. One end of the snubber circuit 11 is connected to the power line 5, and the other end is connected to the wiring 6A. Although not shown, the power conversion circuit 4 can be provided by a power conversion module 20 having a configuration similar to that of FIG. 15 .

[0121] Second Embodiment This embodiment is a modification of the preceding embodiment, and the description of the preceding embodiment can be used. In the preceding embodiment, the changeover switch 70 is disposed between the snubber circuit 62 and the semiconductor elements 52H and 52L. Alternatively, the snubber circuit 62 and the changeover switch 70 may be disposed side-by-side.

[0122] Fig. 17 shows a power conversion module according to this embodiment. Fig. 17 corresponds to Fig. 10 . Fig. 17 schematically shows a power conversion module 20. As in the previous embodiment, the changeover switch 70 is disposed closer to the semiconductor elements 52H and 52L than to the semiconductor elements 51H and 51L. As in the previous embodiment, a snubber circuit 62 and a changeover switch 70 are provided for each phase of the inverter 9.

[0123] The snubber circuits 62 and the changeover switches 70 are aligned in the X direction for each phase. The snubber circuits 62 and the changeover switches 70 are arranged along the direction in which the inverters 8 and 9 are aligned. The snubber circuits 62 and the changeover switches 70 are aligned in the Y direction relative to the semiconductor elements 52H and 52L of the corresponding phase. The power conversion module 20 illustrated in FIG. 17 includes two substrates 41 and 42. The substrates 41 and 42 are aligned in the X direction. The semiconductor elements 51H and 51L and the snubber circuit 61 are mounted on the substrate 41. The semiconductor elements 52H and 52L, the snubber circuit 62, and the changeover switch 70 are mounted on the substrate 42. The other configurations are similar to those of the power conversion module shown in the preceding embodiment (see FIG. 10 ).

[0124] Summary of the Second Embodiment As illustrated, the changeover switch 70 and the snubber circuit 62 may be arranged side by side in the X direction (a predetermined direction). The changeover switch 70 and the snubber circuit 62, which are arranged side by side with the semiconductor elements 52H and 52L in the X direction, may be arranged side by side in the Y direction (a direction perpendicular to the X direction). The changeover switch 70 and the snubber circuit 62 may be arranged side by side along the direction in which the inverters 8 and 9 are arranged. This arrangement allows the changeover switch 70 to be closer to the semiconductor elements 52H and 52L (inverter 9) than to the semiconductor elements 51H and 51L (inverter 8). This provides the same effects as the configurations described in the preceding embodiments. In other words, it is possible to improve power conversion efficiency.

[0125] In the example shown, the changeover switch 70 is disposed on the inverter 8 side, and the changeover switch 70 and the snubber circuit 62 are disposed side by side. Alternatively, the snubber circuit 62 may be disposed on the inverter 8 side, and the changeover switch 70 and the snubber circuit 62 may be disposed side by side.

[0126] Although an example including the substrates 41 and 42 has been shown, this is not limiting. As shown in Figures 12 and 13, a single substrate 40 may be provided, or three or more substrates 40 may be provided. The power conversion module 20 may be configured without including the snubber circuit 61.

[0127] Third Embodiment This embodiment is a modification based on the preceding embodiment, and the description of the preceding embodiment can be used. In the preceding embodiment, the snubber circuit 62 and the changeover switch 70 are arranged side by side along the X direction. Alternatively, the snubber circuit 62 and the changeover switch 70 may be arranged side by side along the Y direction.

[0128] Fig. 18 shows a power conversion module according to this embodiment. Fig. 18 corresponds to Fig. 17 . Fig. 18 schematically shows a power conversion module 20. As in the previous embodiment, the changeover switch 70 is disposed closer to the semiconductor elements 52H and 52L than to the semiconductor elements 51H and 51L. As in the previous embodiment, a snubber circuit 62 and a changeover switch 70 are provided for each phase of the inverter 9.

[0129] The snubber circuits 62 and the changeover switches 70 are arranged in the Y direction for each phase. The snubber circuits 62 and the changeover switches 70 are arranged in a direction perpendicular to the arrangement direction of the inverters 8, 9. The snubber circuits 62 and the changeover switches 70 are arranged in the X direction relative to the semiconductor elements 52H, 52L of the corresponding phase. The snubber circuits 62 and the changeover switches 70 and the semiconductor elements 52H, 52L are arranged alternately in the X direction. In the example shown in FIG. 18 , the snubber circuits 62 and the changeover switches 70 are arranged at the end of the substrate 42 on the substrate 41 side. The other configurations are similar to those of the power conversion module 20 shown in the preceding embodiment (see FIG. 17 ).

[0130] Summary of the Third Embodiment As illustrated, the changeover switch 70 and the snubber circuit 62 may be arranged side by side in the Y direction (a predetermined direction). The changeover switch 70 and the snubber circuit 62, which are arranged side by side with the semiconductor elements 52H and 52L in the Y direction, may also be arranged side by side in the X direction (a direction perpendicular to the X direction). The changeover switch 70 and the snubber circuit 62 may also be arranged side by side in a direction perpendicular to the direction in which the inverters 8 and 9 are arranged. This arrangement allows the changeover switch 70 to be closer to the semiconductor elements 52H and 52L (inverter 9) than to the semiconductor elements 51H and 51L (inverter 8). Therefore, the same effects as those of the configurations described in the preceding embodiments can be achieved. In other words, power conversion efficiency can be improved.

[0131] In the example shown, the snubber circuit 62 and the changeover switch 70 are disposed at the end of the substrate 42 on the substrate 41 side. Alternatively, the semiconductor elements 52H and 52L may be disposed at the end of the substrate 42 on the substrate 41 side.

[0132] Although an example including the substrates 41 and 42 has been shown, this is not limiting. As shown in Figures 12 and 13, a single substrate 40 may be provided, or three or more substrates 40 may be provided. The power conversion module 20 may be configured without including the snubber circuit 61.

[0133] Fourth Embodiment This embodiment is a modification of the preceding embodiment, and the description of the preceding embodiment can be used. In the preceding embodiment, the changeover switch 70 is disposed between the snubber circuit 62 and the semiconductor elements 52H, 52L. Alternatively, the snubber circuit 62 may be disposed between the changeover switch 70 and the semiconductor elements 52H, 52L.

[0134] Fig. 19 shows a power conversion module according to this embodiment. Fig. 19 corresponds to Fig. 10 . Fig. 19 schematically shows a power conversion module 20. As in the previous embodiment, the changeover switch 70 is disposed closer to the semiconductor elements 52H and 52L than to the semiconductor elements 51H and 51L. As in the previous embodiment, a snubber circuit 62 and a changeover switch 70 are provided for each phase of the inverter 9.

[0135] The snubber circuits 62 and the changeover switches 70 are arranged in the Y direction for each phase. The snubber circuits 62 and the changeover switches 70 are arranged in a direction perpendicular to the arrangement direction of the inverters 8, 9. The snubber circuits 62 and the changeover switches 70 are arranged in the Y direction relative to the semiconductor elements 52H, 52L of the corresponding phase. The snubber circuit 62 is arranged between the changeover switch 70 and the semiconductor elements 52H, 52L. The other configurations are similar to those of the power conversion module 20 shown in the preceding embodiment (see FIG. 10 ).

[0136] Summary of the Fourth Embodiment As illustrated, the snubber circuit 62 may be disposed between the semiconductor elements 52H, 52L and the changeover switch 70. This arrangement allows the changeover switch 70 to be closer to the semiconductor elements 52H, 52L (inverter 9) than to the semiconductor elements 51H, 51L (inverter 8). This provides the same effects as the configurations described in the preceding embodiments. In other words, it is possible to improve power conversion efficiency.

[0137] Although an example including the substrates 41 and 42 has been shown, this is not limiting. As shown in Figures 12 and 13, a single substrate 40 may be provided, or three or more substrates 40 may be provided. The power conversion module 20 may be configured without including the snubber circuit 61.

[0138] (Other Embodiments) The disclosure in this specification and drawings, etc. is not limited to the exemplified embodiments. The disclosure encompasses the exemplified embodiments and modifications thereto by those skilled in the art. For example, the disclosure is not limited to the combinations of parts and / or elements shown in the embodiments. The disclosure can be implemented in various combinations. The disclosure can have additional parts that can be added to the embodiments. The disclosure encompasses the omission of parts and / or elements from the embodiments. The disclosure encompasses the substitution or combination of parts and / or elements between one embodiment and another embodiment. The disclosed technical scope is not limited to the description of the embodiments. Some disclosed technical scopes are defined by the claims, and should be interpreted as including all modifications within the meaning and scope equivalent to the claims.

[0139] The disclosure in the specification, drawings, etc. is not limited by the claims. The disclosure in the specification, drawings, etc. encompasses the technical ideas described in the claims, and extends to more diverse and broader technical ideas than the technical ideas described in the claims. Therefore, various technical ideas can be extracted from the disclosure in the specification, drawings, etc. without being bound by the claims.

[0140] When an element or layer is referred to as being "on," "coupled," "connected," or "bonded," it may be directly coupled, connected, or bonded to another element or layer, and intervening elements or layers may be present. In contrast, when an element is referred to as being "directly on," "directly coupled," "directly connected," or "directly bonded" to another element or layer, no intervening elements or layers are present. Other terms used to describe relationships between elements should be construed in a similar manner (e.g., "between" vs. "directly between," "adjacent" vs. "directly adjacent," etc.). As used in this specification, the term "and / or" includes any and all combinations of one or more of the associated listed items. That is, a reference to A and / or B means at least one of A and B, and can include A only, B only, or both A and B.

[0141] Spatially relative terms such as "inside," "outside," "back," "below," "low," "top," "top," and the like are used herein to facilitate the description of one element or feature's relationship to other elements or features, as illustrated. Spatially relative terms may be intended to encompass different orientations of the device during use or operation in addition to the orientation depicted in the figures. For example, if the device in the figures were turned over, elements described as "below" or "directly below" other elements or features would then be oriented "above" the other elements or features. Thus, the term "bottom" can encompass both an orientation of top and bottom. The device may also be oriented in other ways (rotated 90 degrees or at other orientations), and the spatially relative descriptors used in this specification would be interpreted accordingly.

[0142] (Disclosure of Technical Ideas) This specification discloses multiple technical ideas described in the following multiple clauses. Some clauses may be described in a multiple dependent form, with the subsequent clause alternatively referring to the preceding clause. Furthermore, some clauses may be described in a multiple dependent form, with the subsequent clause referring to another multiple dependent clause. These multiple dependent clauses define multiple technical ideas.

[0143] <Technical Idea 1> A power conversion module comprising: a first semiconductor element (51H, 51L) constituting a first inverter (8) connected to one end of a winding of a rotating electric machine (3); a second semiconductor element (52H, 52L) constituting a second inverter (9) connected to the other end of the winding; a changeover switch (70, 10) provided in a path connecting the first inverter and the second inverter, the changeover switch connecting a DC power source (2) and the second inverter in a closed state and cutting off the connection between the DC power source and the second inverter in an open state; and a snubber circuit (62, 11) connected in parallel to the second inverter, wherein the changeover switch is positioned closer to the second semiconductor element than to the first semiconductor element.

[0144] <Technical Idea 2> A power conversion module according to Technical Idea 1, comprising: a first wiring (83, 424A, 424C, 5A) connecting the first inverter and the changeover switch; and a second wiring (823, 424B, 5B) connecting the changeover switch and the second inverter, wherein the snubber circuit is connected to the first wiring of the first wiring and the second wiring.

[0145] <Technical Idea 3> The power conversion module according to Technical Idea 1 or Technical Idea 2, further comprising: a first substrate (41); and a second substrate (42), wherein the first semiconductor element is mounted on the first substrate; and the second semiconductor element, the snubber circuit, and the changeover switch are mounted on the second substrate.

[0146] <Technical Concept 4> The power conversion module according to any one of Technical Concepts 1 to 3, wherein the changeover switch is disposed between the second semiconductor element and the snubber circuit.

[0147] <Technical Idea 5> The power conversion module according to Technical Idea 4, wherein the second semiconductor element includes a second upper arm element (52H) and a second lower arm element (52L), and the second power supply line includes a second upper power supply line (424A, 70, 823, 424B) connecting one end of the snubber circuit and the second upper arm element, and a second lower power supply line (822, 425) running parallel to the second upper power supply line and connecting the second lower arm element and the other end of the snubber circuit, and one of the second upper power supply line and the second lower power supply line includes the change-over switch.

[0148] <Technical Concept 6> The power conversion module according to Technical Concept 5, wherein the second upper arm element and the second lower arm element are provided for each phase, and the changeover switch and the snubber circuit are provided for each phase.

[0149] <Technical Concept 7> The power conversion module according to Technical Concept 6, further comprising a common wiring (824) for electrically connecting the low potential side terminals of the changeover switches provided for each phase to each other.

[0150] <Technical Concept 8> The power conversion module according to Technical Concept 7, wherein the common wiring and the second power supply line not including the changeover switch intersect three-dimensionally.

[0151] <Technical Idea 9> A power conversion module according to any one of Technical Ideas 5 to 8, comprising signal wiring (427, 428) electrically connected to signal pads of the second semiconductor elements and the changeover switches, the second semiconductor elements and the changeover switches being arranged side by side in a predetermined direction, and the signal wiring being arranged side by side with the corresponding second semiconductor elements and the changeover switches in a direction perpendicular to the predetermined direction, on the opposite side of the second power line not including the changeover switch.

[0152] <Technical Idea 10> A power conversion module according to Technical Idea 9, comprising a first signal wiring (417) electrically connected to a signal pad of the first semiconductor element, the first signal wiring being a signal wiring separate from a second signal wiring which is also the signal wiring, and the first signal wiring being arranged alongside the corresponding first semiconductor element in the predetermined direction.

[0153] the second upper power line and the second lower power line are alternately arranged in one direction; the first semiconductor element includes a plurality of first upper arm elements (51H) and a plurality of first lower arm elements (51L) provided for each phase; first power lines include a plurality of first upper power lines (414) to which high potential side terminals of the first upper arm elements are electrically connected, and a plurality of first lower power lines (415A) to which low potential side terminals of the first lower arm elements are electrically connected, and which are alternately arranged with the first upper power lines in the one direction; the changeover switch is arranged on one of the second upper power line and the second lower power line; and the second power line of the second upper power line and the second lower power line, on which the changeover switch is arranged, and the first power line of the first upper power line and the first lower power line, which is electrically connected to the second power line on which the changeover switch is arranged, face each other in the one direction.

[0154] <Technical Idea 12> A power conversion module according to any one of Technical Ideas 1 to 3, wherein the changeover switch and the snubber circuit are arranged side by side in a predetermined direction, and the changeover switch and the snubber circuit arranged side by side in the predetermined direction, and the second semiconductor element are arranged side by side in a direction perpendicular to the predetermined direction.

[0155] <Technical Concept 13> The power conversion module according to Technical Concept 11, wherein the changeover switch and the snubber circuit are arranged in a direction in which the first inverter and the second inverter are arranged.

[0156] <Technical Concept 14> The power conversion module according to Technical Concept 11, wherein the changeover switch and the snubber circuit are arranged in a direction perpendicular to the arrangement direction of the first inverter and the second inverter.

[0157] <Technical Concept 15> The power conversion module according to any one of Technical Concepts 1 to 3, wherein the snubber circuit is disposed between the second semiconductor element and the changeover switch.

Claims

1. A power conversion module comprising: a first semiconductor element (51H, 51L) constituting a first inverter (8) connected to one end of a winding of a rotating electrical machine (3); a second semiconductor element (52H, 52L) constituting a second inverter (9) connected to the other end of the winding; a switching switch (70, 10) provided in a path connecting the first inverter and the second inverter, connecting the DC power supply (2) and the second inverter in a closed state, and disconnecting the connection between the DC power supply and the second inverter in an open state; and a snubber circuit (62, 11) connected in parallel to the second inverter, wherein the switching switch is arranged at a position closer to the second semiconductor element than the first semiconductor element.

2. The power conversion module according to claim 1, further comprising: a first wiring (83, 424A, 424C, 5A) connecting the first inverter and the switching switch; and a second wiring (823, 424B, 5B) connecting the switching switch and the second inverter, wherein the snubber circuit is connected to the first wiring among the first wiring and the second wiring.

3. The power conversion module according to claim 1, further comprising: a first substrate (41); and a second substrate (42), wherein the first semiconductor element is mounted on the first substrate, and the second semiconductor element, the snubber circuit, and the switching switch are mounted on the second substrate.

4. The power conversion module according to any one of claims 1 to 3, wherein the switching switch is arranged between the second semiconductor element and the snubber circuit.

5. The second semiconductor element includes a second upper arm element (52H) and a second lower arm element (52L), and as second power supply lines, a second upper power supply line (424A, 70, 823, 424B) connecting one end of the snubber circuit and the second upper arm element, and a second lower power supply line (822, 425) running parallel to the second upper power supply line and connecting the second lower arm element and the other end of the snubber circuit are provided, and one of the second upper power supply line and the second lower power supply line includes the switching switch. The power conversion module according to claim 4.

6. The power conversion module according to claim 5, wherein the second upper arm element and the second lower arm element are provided for each phase, and the switching switch and the snubber circuit are provided for each phase.

7. The power conversion module according to claim 6, having a common wiring (824) for electrically connecting the terminals on the low potential side of the switching switches provided for each phase to each other.

8. The power conversion module according to claim 7, wherein the common wiring and the second power supply line not including the switching switch are three-dimensionally intersecting.

9. The power conversion module according to claim 5, comprising signal wirings (427, 428) electrically connected to pads for signals of the second semiconductor element and the switching switch, the second semiconductor element and the switching switch being arranged side by side in a predetermined direction, and the signal wirings being arranged side by side on the side opposite to the second power supply line not including the switching switch with respect to the corresponding second semiconductor element and the switching switch in a direction orthogonal to the predetermined direction.

10. The power conversion module according to claim 9, comprising a first signal wiring (417) electrically connected to a pad for a signal of the first semiconductor element, the first signal wiring being a signal wiring different from the second signal wiring which is the signal wiring, and the first signal wiring being arranged side by side with the corresponding first semiconductor element in the predetermined direction.

11. The second upper power supply line and the second lower power supply line are alternately arranged in one direction, the first semiconductor element includes a plurality of first upper arm elements (51H) and a plurality of first lower arm elements (51L) provided for each phase, as the first power supply line, a plurality of first upper power supply lines (414) to which the terminals on the high potential side of the first upper arm elements are electrically connected, and a plurality of first lower power supply lines (415A) to which the terminals on the low potential side of the first lower arm elements are electrically connected and which are alternately arranged with the first upper power supply lines in the one direction, the switching switch is arranged on one of the second upper power supply line and the second lower power supply line, and among the second upper power supply line and the second lower power supply line, the second power supply line on which the switching switch is arranged and the first power supply line electrically connected to the second power supply line on which the switching switch is arranged among the first upper power supply line and the first lower power supply line face each other in the one direction.

12. The changeover switch and the snubber circuit are arranged side by side in a predetermined direction, and the changeover switch and the snubber circuit arranged side by side in the predetermined direction and the second semiconductor element are arranged side by side in a direction orthogonal to the predetermined direction. The power conversion module according to any one of claims 1 to 3.

13. The changeover switch and the snubber circuit are arranged side by side along the arrangement direction of the first inverter and the second inverter. The power conversion module according to claim 11.

14. The changeover switch and the snubber circuit are arranged side by side along a direction orthogonal to the arrangement direction of the first inverter and the second inverter. The power conversion module according to claim 11.

15. The snubber circuit is arranged between the second semiconductor element and the changeover switch. The power conversion module according to any one of claims 1 to 3.

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