Power conversion module

Abstract

A semiconductor element (60) has upper arm elements (61H, 62H) and lower arm elements (61L, 62L) provided for each phase. Wirings have P wirings (101, 103, 105, 106, 514, 524, 534, 931) connected to the high potential side terminals of the upper arm elements, and N wirings (102, 104, 107, 108, 515, 525, 535, 912, 922, 932) connected to the low potential side terminals of the lower arm elements. The P wirings include a plurality of first wirings (514) arranged in a predetermined direction, and second wirings (101, 103) electrically connecting the plurality of first wirings. The N wirings include a plurality of first wirings (515B, 525B) arranged in a predetermined direction, and second wirings (102, 104, 515A, 525A) electrically connecting the plurality of first wirings.

Description

Power Conversion Module CROSS-REFERENCE TO RELATED APPLICATIONS

[0001] This application is based on Patent Application No. 2024-8244 filed in Japan on January 23, 2024, the contents of which 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] In Patent Document 1, a changeover switch is disposed between a power supply terminal, which is an external connection terminal of the first inverter, and a power supply terminal, which is an external connection terminal of the second inverter, and each of the power supply terminals is electrically connected to the changeover switch by a bus bar. This increases the wiring length, which results in an increase in inductance. Further improvements are needed in power conversion modules in terms of the above and other aspects not mentioned.

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

[0007] One aspect of the disclosure is a power conversion module comprising: wiring; a plurality of semiconductor elements which, together with the wiring, constitute a first inverter connected to one end of a winding of a rotating electric machine and a second inverter connected to the other end of the winding; and a changeover switch which 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, wherein the semiconductor elements have upper arm elements and lower arm elements provided for each phase, and the wiring has P wiring electrically connected to the high potential side terminal of the upper arm element and N wiring electrically connected to the low potential side terminal of the lower arm element, and at least one of the P wiring and N wiring is provided in plurality corresponding to the semiconductor elements and includes first wiring arranged in a predetermined direction and second wiring electrically connecting the plurality of first wirings.

[0008] The disclosed power conversion module modularizes wiring, semiconductor devices, and changeover switches. The wiring includes second wiring that electrically connects multiple first wirings arranged in a predetermined direction, corresponding to the semiconductor devices provided for each phase. In this way, the multiple first wirings are connected within the module, thereby shortening the wiring length and reducing inductance.

[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] 7 is a diagram illustrating a power conversion circuit and a drive system. FIG. 8 is a diagram illustrating an example of an operating point map of a rotating electric machine. FIG. 9 is a diagram illustrating star connection drive. FIG. 10 is a diagram illustrating open connection drive. FIG. 11 is a circuit diagram illustrating a state in which an external device is connected. FIG. 12 is a diagram illustrating a connection structure between a power conversion module and an external device. FIG. 13 is a plan view illustrating a power conversion module according to a first embodiment. FIG. 14 is a diagram in which a cooler and a housing are omitted compared to FIG. 7. FIG. 15 is a cross-sectional view taken along line IX-IX in FIG. 7. FIG. 16 is a cross-sectional view taken along line XX in FIG. 15. FIG. 16 is a diagram illustrating a reference example. FIG. 17 is a diagram illustrating a power conversion circuit provided by a power conversion module according to a second embodiment. FIG. 18 is a diagram illustrating a power conversion module. FIG. 19 is a diagram illustrating a power conversion circuit provided by a power conversion module according to a third embodiment. FIG. 19 is a diagram illustrating a power conversion module. FIG. 19 is a diagram illustrating a power conversion circuit provided by a power conversion module according to a fourth embodiment. FIG. 19 is a diagram illustrating a power conversion module.

[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 source 2 and the rotating electric machine 3. The drive system 1 is a common power source system in which a common DC power source 2 supplies power to two inverters 8 and 9 (described later) to drive the rotating electric machine 3. The drive system 1 may include only one common DC power source 2 as illustrated in FIG. 1 , or may include multiple common DC power sources 2. The drive system 1 may include a power supply switch (not shown), such as an SMR, between the DC power source 2 and the power conversion circuit 4. SMR is an abbreviation for System Main Relay. Turning on the power supply switch enables power supply from the DC power source 2 to the rotating electric machine 3, and turning off the power supply switch cuts off the power supply from the DC power source 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-side power supply line, a P line, or the like. The power supply line 5 has a wiring 5A. The wiring 5A is a part of the wiring that constitutes the power supply line 5. The wiring 5A is a part of the power supply line 5 that connects the inverter 8 and the inverter 9. 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-side power supply line, an N line, or the like. The power supply line 6 has a wiring 6A. The wiring 6A is a part of the wiring that constitutes the power supply line 6. The wiring 6A is a part of the power supply line 6 that connects the inverter 8 and the inverter 9. The power supply lines 5, 6 are configured to include a bus bar that is, for example, a metal plate.

[0021] 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.

[0022] The inverters 8 and 9 are DC-AC conversion circuits. 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.

[0023] 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).

[0024] 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.

[0025] 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.

[0026] 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.

[0027] 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.

[0028] 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.

[0029] 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.

[0030] The switching elements constituting the inverters 8 and 9 are not limited to the MOSFETs described above. 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 also connected in anti-parallel.

[0031] 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. 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 cuts off the connection between the high-potential side terminal of the upper arm 9H and the smoothing capacitor 7 (DC power supply 2). The changeover switch 10 may also be called a switch, an open / close switch, etc.

[0032] 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 changeover switch 10 includes changeover switches 10A and 10B. The changeover switch 10A is arranged on wiring 5A of the power supply line 5. The changeover switch 10A is arranged on wiring 5A so that the drain terminal of the MOSFET is on the inverter 8 side and the source terminal is on the inverter 9 side. In other words, the changeover switch 10A is arranged so that the forward direction of the diode is from the inverter 9 to the inverter 8.

[0033] The changeover switch 10B is disposed on the wiring 6A of the power supply line 6. The changeover switch 10B is disposed on the wiring 6A so that the drain terminal of the MOSFET is on the inverter 9 side and the source terminal is on the inverter 8 side. In other words, the changeover switch 10B is disposed so that the forward direction of the diode is from the inverter 8 to the inverter 9. When the MOSFET is turned on and the changeover switch 10 is closed, the inverter 9 is electrically connected to the smoothing capacitor 7 (DC power supply 2). When the MOSFET is turned off and the changeover switch 10 is opened, the electrical connection between the inverter 9 and the smoothing capacitor 7 is interrupted.

[0034] 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.

[0035] 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. Another end of the snubber circuit 11 is connected to a portion of the wiring 5A that connects the selector switch 10 and the inverter 9. The other end of the snubber circuit 11 is connected to the power supply line 6.

[0036] 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. One end of each snubber circuit 11 is connected to the power supply line 5, and the other end is connected to the power supply 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.

[0037] 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.

[0038] 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.

[0039] As illustrated in FIG. 1 , the power conversion circuit 4 may 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.

[0040] 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.

[0041] The drive command generation unit controls the changeover switch 10 (10A, 10B). 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 in FIG. 1 .

[0042] <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.

[0043] 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.

[0044] 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 and 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 control unit 15 turns off the MOSFETs of the changeover switch 10 (10A, 10B) and opens the changeover switch 10. The control unit 15 also neutralizes the inverter 9. 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 control unit 15 then controls the MOSFETs 8S of the inverter 8 according to drive requirements, etc.

[0045] 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.

[0046] 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. The control unit 15 turns on the MOSFET of the changeover switch 10 (10A, 10B) to close the changeover switch 10. 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.

[0047] 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.

[0048] As described above, the power conversion circuit 4 is configured to be switchable between star connection drive and open connection drive. The power conversion circuit 4 is configured to be able to execute star connection drive. The power conversion circuit 4 is configured to be able to execute open connection drive. By executing open connection drive instead of star connection drive, it is possible to output a higher rotation range or a higher torque range.

[0049] <Charging Using a Power Conversion Circuit> Next, charging using the power conversion circuit 4 will be described with reference to Fig. 5. Fig. 5 shows a circuit configuration showing a state in which an external device is connected. In Fig. 5, the external device is shown in a simplified form.

[0050] As shown in FIG. 5 , the external device 16 is connected to the power supply lines 5 and 6. The external device 16 is connected in parallel to the DC power supply 2. The external device 16 is an element separate from the elements constituting the drive system 1. The external device 16 may be, for example, an element external to a moving body (vehicle). An example of the external device 16 is a charger. The charger charges the DC power supply 2. The voltage supplied by the external device 16 is lower than the power supply voltage of the DC power supply 2. For example, the DC power supply 2 is 800 V, and the external device 16 (charger) is 400 V. In the rotating electric machine 3 and the power conversion circuit 4, the windings 3U, 3V, and 3W of the rotating electric machine 3 and the upper and lower arm circuit 8HL constituting the inverter 8 function as a boost circuit.

[0051] The external device 16 is connected to the drive system 1 (power conversion circuit 4), for example, while the vehicle is stopped. When the external device 16 is connected, the control unit 15 controls the inverters 8 and 9 and the selector switch 10 to boost the supply voltage of the external device 16 and charge the DC power supply 2. The boost operation may use one phase or multiple phases (multi-phase). The control unit 15 turns off the MOSFET of the selector switch 10. In this state, the control unit 15 turns on the upper arm 9H of the inverter 9 and controls the on / off of the upper and lower MOSFETs 8S of the upper and lower arm circuit 8HL in the corresponding phase.

[0052] The external device 16 may be a DC power supply (external power supply) separate from the DC power supply 2. The external power supply may be, for example, a secondary battery or may include a DC-AC conversion circuit. The DC power supply 2 charges the external device 16. The power supply voltage of the external device 16 is lower than the power supply voltage of the DC power supply 2. In the rotating electric machine 3 and the power conversion circuit 4, the windings 3U, 3V, and 3W of the rotating electric machine 3 and the upper arm 8H of the inverter 8 function as a step-down circuit.

[0053] When an external device 16 is connected to the drive system 1, the control unit 15 controls the inverters 8, 9 and the selector switch 10 to step down the power supply voltage of the DC power supply 2 and charge the external device 16. In the step-down operation, one phase or multiple phases (multi-phase) may be used. The control unit 15 turns off the MOSFET of the selector switch 10. In this state, the control unit 15 turns on the upper arm 9H of the inverter 9 and controls the on / off of the MOSFET 8S of the upper arm 8H of the corresponding phase. The MOSFET 8S of the lower arm 8L of the corresponding phase is turned off. When the MOSFET 8S of the upper arm 8H is turned off, current flows through the diode of the lower arm 8L of the corresponding phase.

[0054] Fig. 6 shows an example of an external device connection structure corresponding to the circuit configuration shown in Fig. 5. Fig. 6 shows a connection structure between a power conversion module and an external device. Fig. 6 shows a simplified representation of the external device. Fig. 6 also shows directions (X direction and Y direction) that will be described later.

[0055] The power conversion module 20 shown in Figure 6 provides the main components of the power conversion circuit 4. The power conversion module 20 provides inverters 8 and 9, a changeover switch 10, and snubber circuits 11 and 12. The power conversion module 20 includes two circuit units 201 and 202, as described below. The power conversion module 20 includes a charging terminal 113 connected to the circuit unit 202. The power supply device 21 provides the DC power supply 2. The capacitor device 22 provides the smoothing capacitor 7. The external device 23 provides the external device 16.

[0056] The positive electrode of the power supply device 21 is electrically connected to the positive terminal of the capacitor device 22 via the P bus bar 24P. The negative electrode of the power supply device 21 is electrically connected to the negative terminal of the capacitor device 22 via the N bus bar 24N. The positive terminal of the capacitor device 22 is electrically connected to the power conversion module 20 via the P bus bar 25P. The negative terminal of the capacitor device 22 is electrically connected to the power conversion module 20 via the N bus bar 25N. The positive terminal of the external device 23 is electrically connected to the charging terminal 113 of the power conversion module 20 via the P bus bar 26P. The negative terminal of the external device 23 is electrically connected to, for example, the N bus bar 24N via the N bus bar 26N. The negative terminal of the external device 23 is connected to a position closer to the power supply device 21 than the capacitor device 22. This reduces inductance. Note that the conductive member electrically connecting corresponding elements is not limited to a bus bar. A cable, a terminal, or the like may also be used.

[0057] <Power Conversion Module> Next, the structure of a power conversion module will be described with reference to Figs. 7, 8, 9, and 10. Fig. 7 is a plan view showing an example of a power conversion module. For convenience, the sealing body is omitted from Fig. 7. Fig. 8 is a view of the power conversion module with the cooler, housing, and sealing body omitted. In other words, it is a diagram showing circuit elements of the power conversion module. Fig. 9 is a cross-sectional view taken along line IX-IX in Fig. 7. Fig. 10 is a cross-sectional view taken along line XX in Fig. 7.

[0058] 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.

[0059] The power conversion module 20 provides at least a part of the power conversion circuit 4 described above. The power conversion module 20 includes a cooler 30, a housing 40, a substrate 50, a semiconductor element 60, a snubber component 70, a changeover switch 80, a clip 90, a bus bar 100, and a main terminal 110. The power conversion module 20 may further include a circuit board that provides a control unit 15. The power conversion module 20 may also be referred to as a semiconductor module, an inverter module, a power conversion device, or the like. A circuit is formed by wiring members including the conductors of the substrate 50, the clip 90, and the bus bar 100, and electronic components including the semiconductor element 60, the snubber component 70, and the changeover switch 80 mounted on the substrate 50. The main terminal 110 is a terminal for external connection connected to the circuit.

[0060] 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 60 and the snubber component 70. The cooler 30 is formed using a metal material such as Al or Cu. The illustrated cooler 30 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.

[0061] 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. 9 , the inlet pipe 35 is attached to the side wall on the substrate 52 side in the X direction, and the outlet pipe 36 is attached to the side wall on the substrate 51 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. A phase-change refrigerant such as water or ammonia, or a phase-non-change refrigerant such as an ethylene glycol-based refrigerant may be used as the refrigerant 37. For example, LLC may be used as the refrigerant 37. LLC is an abbreviation for long life coolant.

[0062] 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 50 is disposed on the one surface 301. The flow path 33 is provided so as to overlap the semiconductor element 60 and the snubber component 70 in a plan view in order to effectively cool the semiconductor element 60, the snubber component 70, and the like. The flow path 33 is provided so as to overlap most of the substrate 50 in a plan view.

[0063] 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 50 from the cooler 30 is not required, a bonding material such as solder or sintered Ag may be interposed between the substrate 50 and the cooler 30. In other words, the substrate 50 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 50 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 is an abbreviation for Thermal Interface Material. A support member that does not provide cooling function may be used instead of the cooler 30.

[0064] The housing 40 is formed using an electrically insulating material such as resin. The housing 40 may be, for example, a resin molded body. The housing 40 may hold some of the elements of the power conversion module 20. Some of the elements may be integrally molded with the housing 40 as an insert part. The housing 40 may be fixed to the cooler 30. The housing 40 may be fixed to a case (not shown) that houses the power conversion module 20 together with the cooler 30. When arranged on one side of the cooler 30, the housing 40, together with the cooler 30, provides a space for accommodating electronic components such as the substrate 50 and the semiconductor element 60 mounted on the substrate 50.

[0065] The illustrated housing 40 includes a frame body 41 and a partition wall 42. The frame body 41 has a predetermined height in the Z direction and is annular so as to surround the substrate 50 in a plan view in the Z direction. The frame body 41 is sometimes referred to as an annular wall portion. The frame body 41 may be an approximately rectangular annular portion. The rectangular annular frame body 41 has four walls 411, 412, 413, and 414.

[0066] The wall portions 411 and 412 extend generally in the X direction. The wall portions 411 and 412 are disposed opposite each other with a predetermined gap in the Y direction. The wall portion 411 is disposed on one end side of the substrate 50 in the Y direction, and the wall portion 412 is disposed on the other end side of the substrate 50. The wall portions 413 and 414 extend in the Y direction. The wall portion 413 is continuous with the wall portions 411 and 412 at one end side in the X direction. The wall portion 414 is continuous with the wall portions 411 and 412 at the other end side in the X direction.

[0067] The partition wall 42 has a predetermined height in the Z direction and is connected to the frame body 41. The partition wall 42 divides the area defined by the frame body 41. The partition wall 42 may divide the area into multiple areas, for example, corresponding to the number of substrates 50. The partition wall 42 is sometimes referred to as a partition wall. The partition wall 42 may extend in a predetermined direction, with both ends connected to the frame body 41. The illustrated housing 40 has two partition walls 42. The partition walls 42 extend in the Y direction, similar to the wall portions 413 and 414. One end of each partition wall 42 is connected to the wall portion 411, and the other end is connected to the wall portion 412. The two partition walls 42 and the wall portions 413 and 414 are aligned in the X direction at a predetermined interval. The partition walls 42 divide the opposing area of ​​the frame body 41 into three areas. A substrate 50 is housed in each of the three divided areas.

[0068] As illustrated, a seal 43 may be disposed in the accommodation space formed by the housing 40 and the cooler 30. The seal 43 is disposed in the accommodation space and seals the substrate 50, electronic components mounted on the substrate 50, and the like. The seal 43 is, for example, a gel or potting resin. The seal 43 fills the accommodation space so as not to exceed the upper end of the frame 41. Because the accommodation space is divided into multiple regions by the partition walls 42 as described above, the influence of stress due to expansion and contraction of the seal 43 on the electronic components mounted on the substrate 50 and the electrical connection structure can be reduced compared to a configuration without division.

[0069] The substrate 50 provides a wiring function. The substrate 50 may also be referred to as a wiring substrate, a printed circuit board, or the like. A semiconductor element 60, a snubber component 70, and a changeover switch 80 are mounted on the substrate 50. The substrate 50 has, for example, a substantially rectangular shape in plan view. The power conversion module 20 may include a single substrate 50 or multiple substrates 50. The illustrated substrate 50 includes three substrates 51, 52, and 53.

[0070] The substrate 51, together with the electronic components mounted on the substrate 51, constitutes a circuit on the inverter 8 side. The substrate 52, together with the electronic components mounted on the substrate 52, constitutes a circuit on the inverter 9 side. The substrate 51 has an insulating substrate 511 and a conductor arranged on the insulating substrate 511. The substrate 52 has an insulating substrate 521 and a conductor arranged on the insulating substrate 521. The substrate 53 has an insulating substrate 531 and a conductor arranged on the insulating substrate 531. The insulating substrates 511, 521, and 531 are formed using an electrically insulating material such as ceramic or resin.

[0071] 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 or Au on their surfaces. The conductors may be disposed on only one surface of the insulating substrates 511, 521, and 531, or on both one surface and the back surface. The back surfaces of the insulating substrates 511, 521, and 531 are the surfaces facing the cooler 30 in the Z direction. The conductors may be disposed inside the insulating substrates 511, 521, and 531. In other words, the substrates 51, 52, and 53 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 constitute the insulating substrates 511, 521, and 531. The via conductors electrically connect conductors disposed on different layers.

[0072] The substrates 51 and 52 have a common structure. Substrates with the same specifications are used as the substrates 51 and 52. The substrates 51 and 52 are made of the same material and have the same planar shapes. The conductor patterns are also the same. The substrate 53 has a structure different from the substrates 51 and 52. The substrates 51, 52, and 53 all have a substantially rectangular shape in plan view. The planar shapes of the substrates 51 and 52 and the substrate 53 are different. In the Y direction, the length of the substrates 51 and 52 is substantially equal to the length of the substrate 53. In the X direction, the length of the substrate 53 is shorter than the length of the substrates 51 and 52. The conductor patterns of the substrates 51 and 52 and the substrate 53 are different. The power conversion module 20 includes two types of substrates 50, a total of three substrates 50.

[0073] The substrates 51, 52, and 53 are arranged on one surface 301 of the cooler 30. The substrates 51, 52, and 53 are lined up in the X direction. The substrate 53 is arranged between the substrates 51 and 52. In the X direction, the substrates 51, 53, and 52 are lined up in this order. The substrates 51 and 52 are arranged in the same orientation relative to the cooler 30.

[0074] The illustrated substrate 51 has a conductor 512 arranged on one surface and a conductor 513 arranged on the back surface. The substrate 52 has a conductor 522 arranged on one surface and a conductor 523 arranged on the back surface. The substrate 53 has a conductor 532 arranged on one surface and a conductor 533 arranged on the back surface. The conductors 513, 523, and 533 are electrically isolated from the corresponding conductors 512, 522, and 532 by insulating substrates 511, 521, and 531. The conductors 513, 523, and 533 provide, for example, a heat dissipation function. The substrates 51, 52, and 53 are arranged in the cooler 30 with the conductors 513, 523, and 533 facing the cooler 30.

[0075] The conductors 512, 522, and 532 are patterned. The patterned conductors 512, 522, and 532 provide wiring functions. In other words, they form a circuit together with the mounted electronic components. The conductors 512 of the substrate 51 include P wiring 514, N wiring 515, O wiring 516, and signal wiring 517. Each wiring is electrically separated by a predetermined gap. The P wiring 514 and N wiring 515 are power wiring. The P wiring 514 may be referred to as a positive wiring or a high-potential power line. The N wiring 515 may be referred to as a negative wiring or a low-potential power line. The O wiring 516 may be referred to as an output wiring.

[0076] The P wiring 514 is connected to the drain electrode (drain terminal) of the semiconductor element 61H. A P bus bar 101, to which the P terminal 111 is connected, is joined to the P wiring 514. The P wiring 514 electrically connects the P terminal 111 and the semiconductor element 61H. A P wiring 514 is provided for each phase of the upper and lower arm circuits 8HL that constitute the inverter 8. The P wiring 514 extends generally in the Y direction. Three P wirings 514 are lined up in the X direction at a predetermined interval. The P wiring 514 includes wirings 514A, 514B, and 514C. The wiring 514A extends in the Y direction. Wiring 514B is connected to one end of wiring 514A, and wiring 514C is connected to the other end.

[0077] The wiring 514B is disposed near the end of the substrate 51 in the Y direction. The wiring 514B extends in the X direction from the wiring 514A. The P bus bar 101 is joined to the wiring 514B. The wiring 514C is located in the middle of the substrate 51 in the Y direction. The wiring 514C extends in the X direction from the wiring 514A at the end opposite to the wiring 514B. The corresponding semiconductor element 61H (drain terminal) is joined to the wiring 514C.

[0078] Of the three P wirings 514 lined up in the X direction, the P wiring 514 located at the end closest to the substrate 52 and the P wiring 514 located in the middle are arranged in the same direction. Of these two P wirings 514, wirings 514B and 514C extend from wiring 514A in a direction away from the substrate 52. The remaining P wiring 514 is arranged in a mirror image of the other two, that is, in a line-symmetrical arrangement with respect to a virtual line substantially parallel to the Y direction. In this P wiring 514, wirings 514B and 514C extend from wiring 514A in a direction approaching the substrate 52.

[0079] The N wiring 515 is electrically connected to the source electrode (source terminal) of the semiconductor element 61L via a clip 912. An N bus bar 102, to which the N terminals 112 are connected, is joined to the N wiring 515. The N wiring 515 electrically connects the N terminals 112 and the semiconductor element 61L. The N wiring 515 has wirings 515A and 515B. The wiring 515A is arranged in the middle of the substrate 51 in the Y direction. The wiring 515A is arranged between the P wiring 514 and the O wiring 516. The wiring 515A extends generally in the X direction. The wiring 515A extends from near one end of the substrate 51 to near the other end in the X direction. The three-phase semiconductor elements 61L are commonly connected to the wiring 515A via the corresponding clips 912.

[0080] The wiring 515B extends roughly in the Y direction. The wiring 515B has a length in the Y direction that is roughly equal to that of the P wiring 514 (wiring 514A). The wiring 515B is arranged alternately with the P wiring 514 in the X direction and between the P wirings 514. In other words, the N wiring 515 has two wirings 515B. In the X direction, the wirings are arranged in the following order: P wiring 514, wiring 515B, P wiring 514, wiring 515B, P wiring 514. One of the ends of the wiring 515B is arranged near the end of the substrate 51 in the Y direction. The N bus bar 102 is joined to one of the ends of the wiring 515B. The wiring 515A is connected to the other end of the wiring 515B.

[0081] The O wiring 516 is connected to the drain electrode (drain terminal) of the semiconductor element 61L. The O terminal 115 is joined to the O wiring 516. The source terminal of the semiconductor element 61H is electrically connected to the O wiring 516 via a clip 911. The O wiring 516 electrically connects the source terminal of the semiconductor element 61H, the drain terminal of the semiconductor element 61L, and the O terminal 115. The O wiring 516 is provided for each phase. The O wiring 516 is aligned in the Y direction with the P wiring 514 of the corresponding phase via wiring 515A. The O wiring 516 is generally L-shaped in plan view.

[0082] The signal wiring 517 electrically connects the pads of the semiconductor elements 61H and 61L to signal terminals (not shown). The signal wiring 517 is electrically connected to the pads via, for example, bonding wires. The signal wiring 517 is, for example, a signal island formed on the corresponding substrate 51. For convenience, FIG. 5 shows one signal wiring 517 for each semiconductor element 61H, 61L. The signal wiring 517 is aligned with the corresponding semiconductor element 61H in the Y direction. The signal wiring 517 corresponding to the semiconductor element 61H is arranged closer to the wiring 514B than the semiconductor element 61H. The signal wiring 517 is aligned with the corresponding semiconductor element 61L in the X direction. The signal wiring 517 corresponding to the semiconductor element 61L is arranged closer to the substrate 52 than the semiconductor element 61L.

[0083] As described above, the substrate 52 has the same configuration as the substrate 51. The substrate 52 is disposed in the same orientation as the substrate 51 with respect to the cooler 30. The conductor 522 of the substrate 52 is patterned in the same manner as the conductor 512. The conductor 522 includes a P wiring 524, an N wiring 525, an O wiring 526, and a signal wiring 527. The P wiring 524 has the same configuration as the P wiring 514. The P wiring 524 has wirings 524A, 524B, and 524C. The N wiring 525 has the same configuration as the N wiring 515. The N wiring 525 has wirings 525A and 525B. The P wiring 524 and the N wiring 525 are power supply wirings. The O wiring 526 has the same configuration as the O wiring 516. The signal wiring 527 has the same configuration as the signal wiring 517.

[0084] The conductor 532 of the substrate 53 includes a P wiring 534, an N wiring 535, and a signal wiring 537. The P wiring 534 and the N wiring 535 are power wirings that connect the inverter 8 and the inverter 9. The P wiring 534 connects the P wiring 514 of the substrate 51 with the P wiring 524 of the substrate 52. The P wiring 534 extends generally in the direction in which the substrates 51 and 52 are arranged, i.e., in the X direction. The P wiring 534 is divided into two in the extension direction. The P bus bar 105 and the changeover switch 81 are joined to the P wiring 534 on the substrate 51 side. The clip 931 and the P bus bar 106 are joined to the P wiring 534 on the substrate 52 side.

[0085] The N wiring 535 connects the N wiring 515 of the substrate 51 and the N wiring 525 of the substrate 52. The N wiring 535 extends generally in the X direction. The N wiring 535 is divided into two in the extension direction. The N bus bar 107 and the clip 932 are joined to the N wiring 535 on the substrate 51 side. The changeover switch 82 and the N bus bar 108 are joined to the N wiring 535 on the substrate 52 side. The N wiring 535 and the N wirings 515 and 525 (wirings 515A and 525A) are arranged on an imaginary line that is generally parallel to the X direction. The N wiring 535 and the P wiring 534 are arranged so as to be shifted in the Y direction. The connection position between the N wiring 535 and the N wirings 515 and 525 is shifted in the Y direction with respect to the connection position between the P wiring 534 and the P wirings 514 and 524.

[0086] The signal wiring 537 electrically connects the pad of the changeover switch 80 to a signal terminal (not shown). The signal wiring 537 is electrically connected to the pad via, for example, a bonding wire. The signal wiring 537 is, for example, a signal island formed on the corresponding substrate 53. For convenience, one signal wiring 537 is shown for one changeover switch 80 in FIG. 5. The signal wiring 537 is aligned with the changeover switch 80 in the Y direction. The signal wiring 537 is arranged on the opposite side of the N wiring 535 with respect to the changeover switch 81. The signal wiring 537 is arranged on the P wiring 534 side with respect to the changeover switch 82.

[0087] The semiconductor element 60 is an electronic component that provides the inverters 8 and 9. The semiconductor element 60 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 60 may also be called a power element, a semiconductor chip, or the like.

[0088] The vertical element is configured to pass a main current in the thickness direction of the semiconductor element 60 (semiconductor substrate). The semiconductor element 60 is arranged so that its thickness direction is approximately parallel to the Z direction. The semiconductor element 60 has main electrodes (main terminals) on both sides in the thickness direction. In the illustrated power conversion module 20, the semiconductor element 60 is formed by forming an n-channel MOSFET as a vertical element on a semiconductor substrate made of SiC. The semiconductor element 60 has a drain electrode (drain terminal) on its bottom surface facing the substrate 50 (51, 52) and a source electrode (source terminal) on its top surface opposite the bottom surface.

[0089] 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.

[0090] The semiconductor element 60 has a generally rectangular shape in plan view. The semiconductor element 60 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.

[0091] The multiple semiconductor elements 60 include a semiconductor element 61H that constitutes the upper arm 8H, a semiconductor element 61L that constitutes the lower arm 8L, a semiconductor element 62H that constitutes the upper arm 9H, and a semiconductor element 62L that constitutes the lower arm 9L. The semiconductor elements 60 include three semiconductor elements each, 61H, 61L, 62H, and 62L. The semiconductor elements 61H, 61L, 62H, and 62L are provided for each phase. One semiconductor element 60 provides one arm. In the following, the semiconductor elements 61H and 62H may refer to upper arm elements. The semiconductor elements 61L and 62L may be referred to as lower arm elements.

[0092] The semiconductor elements 61H and 61L are mounted on the substrate 51. The semiconductor element 61H is arranged so as to overlap with the wiring 514C of the P wiring 514 in a plan view. The drain terminal of the semiconductor element 61H is joined to the P wiring 514 via a bonding material such as solder (not shown). The semiconductor element 61L is arranged so as to overlap with the O wiring 516 in a plan view. The drain terminal of the semiconductor element 61L is joined to the O wiring 516 via a bonding material (not shown).

[0093] The semiconductor elements 61H of each phase are aligned in the X direction. The semiconductor elements 61L of each phase are aligned in the X direction. The semiconductor elements 61H, 61L of corresponding phases are aligned roughly in the Y direction. The semiconductor elements 61H, 61L of corresponding phases are arranged offset in the X direction so that only a portion of them face each other in the Y direction. The semiconductor elements 61H, 61L are arranged offset by 90 degrees around an axis approximately parallel to the Z direction. The pads of the semiconductor element 61H are arranged on the wiring 514B side in the Y direction. The pads of the semiconductor element 61L are arranged on the substrate 52 side in the X direction.

[0094] The semiconductor elements 62H and 62L are mounted on the substrate 52. The semiconductor element 62H has the same structure as the semiconductor element 61H. That is, semiconductor elements with the same specifications are used as the semiconductor elements 61H and 62H. The arrangement of the semiconductor element 62H on the substrate 52 is the same as the arrangement of the semiconductor element 61H on the substrate 51. The semiconductor element 62L has the same structure as the semiconductor element 61L. That is, semiconductor elements with the same specifications are used as the semiconductor elements 61L and 62L. The arrangement of the semiconductor element 62L on the substrate 52 is the same as the arrangement of the semiconductor element 61L on the substrate 51. The semiconductor elements 61H, 61L, 62H, and 62L have common specifications.

[0095] The semiconductor element 62H is disposed so as to overlap with the wiring 524C in a plan view. The drain terminal of the semiconductor element 62H is bonded to the wiring 524C via a bonding material (not shown). The semiconductor element 62L is disposed so as to overlap with the O wiring 526 in a plan view. The drain terminal of the semiconductor element 62L is bonded to the O wiring 526 via a bonding material (not shown).

[0096] The semiconductor elements 62H of each phase are aligned in the X direction. The semiconductor elements 62L of each phase are aligned in the X direction. The semiconductor elements 62H, 62L of corresponding phases are aligned roughly in the Y direction. The semiconductor elements 62H, 62L of corresponding phases are arranged offset in the X direction so that only a portion of them face each other in the Y direction. The semiconductor elements 62H, 62L are arranged offset by 90 degrees around an axis approximately parallel to the Z direction. The pads of the semiconductor element 62H are arranged on the wiring 524B side in the Y direction. The pads of the semiconductor element 62L are arranged on the opposite side of the substrate 51 in the X direction.

[0097] The snubber component 70 is an electronic component that provides a snubber circuit. The snubber component 70 includes a snubber component 71 that provides the snubber circuit 12 and a snubber component 72 that provides the snubber circuit 11. For convenience, FIGS. 7 to 9 show a simplified illustration. The snubber component 71 has at least a capacitor to provide the snubber circuit 12. The snubber component 71 is mounted on the substrate 51. As described above, the snubber component 71 is connected in parallel to the upper and lower arm circuits 8HL. The snubber component 71 electrically bridges the P wiring 514 and the N wiring 515. In the illustrated power conversion module 20, a snubber component 71 is provided for each phase. The snubber component 71 electrically bridges the wiring 514A and the wiring 515B. The snubber component 71 electrically bridges the P wiring 514 and the N wiring 515 at a position closer to the wiring 514B than the semiconductor element 61H. Of the two wirings 515B, one snubber component 71 is connected to the wiring 515B closer to the substrate 52, and two snubber components 71 are commonly connected to the wiring 515B farther from the substrate 52. The snubber components 71 for each phase are aligned in the X direction.

[0098] The snubber component 72 has the same structure as the snubber component 71. That is, snubber components with the same specifications are used for the snubber components 71 and 72. The arrangement of the snubber components 72 on the substrate 52 is the same as the arrangement of the snubber components 71 on the substrate 51. In the illustrated power conversion module 20, the snubber component 72 is provided for each phase. The snubber component 72 electrically bridges the wiring 524A and the wiring 525B. The snubber component 72 electrically bridges the P wiring 524 and the N wiring 525 at a position closer to the wiring 524B than the semiconductor element 62H. Of the two wirings 525B, one snubber component 72 is connected to the wiring 525B farther from the substrate 51, and two snubber components 72 are commonly connected to the wiring 525B farther from the substrate 51. The snubber components 72 for each phase are lined up in the X direction.

[0099] The changeover switch 80 functions as the changeover switch 10 in the power conversion circuit 4. The changeover switch 80 is formed by forming a switching element on a semiconductor substrate. In the illustrated power conversion module 20, the changeover switch 80 has a configuration similar to that of the semiconductor element 60. The changeover switch 80 is formed by forming a MOSFET on the semiconductor substrate. A parasitic diode is connected in antiparallel to the MOSFET.

[0100] In the illustrated power conversion module 20, the changeover switch 80 is mounted on the substrate 53. The changeover switch 80 includes changeover switches 81 and 82. The changeover switches 81 and 82 are aligned approximately in the Y direction. The changeover switch 81 is provided on the P wiring 534. The changeover switch 81 is arranged so as to overlap with the P wiring 534 on the substrate 51 side in a plan view. The drain terminal of the changeover switch 81 is joined to the P wiring 534. The source terminal of the changeover switch 81 is connected to the N wiring 535 on the substrate 52 side via a clip 931. The pad of the changeover switch 81 is arranged on the side of the corresponding signal wiring 537 in the Y direction.

[0101] The changeover switch 82 is provided on the N wiring 535. The changeover switch 82 is arranged so as to overlap with the N wiring 535 on the substrate 52 side in a plan view. The drain terminal of the changeover switch 82 is joined to the N wiring 535. The source terminal of the changeover switch 82 is connected to the N wiring 535 on the substrate 51 side via a clip 932. The pad of the changeover switch 82 is arranged on the side of the corresponding signal wiring 537 in the Y direction.

[0102] The clip 90 bridges the electronic component and the conductor (wiring). The clip 90 may also be referred to as a bridging member, relay member, metal bridge, etc. The clip 90 is a metal plate material whose base material is a metal with good conductivity, such as Cu or a Cu alloy. The clip 90 may be formed by punching and pressing a metal plate of a predetermined thickness. The clip 90 may also be formed using a profiled material with a varying thickness in some areas. The clip 90 may have a film applied to the surface of the base material by surface treatment. The clip 90 may have a plating film of Ni, Au, or the like on its surface. The clip 90 may have a Ni plating 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.

[0103] The clips 90 include clips 911 and 912 mounted on the substrate 51, clips 921 and 922 mounted on the substrate 52, and clips 931 and 932 mounted on the substrate 53. The clip 911 is connected to the semiconductor element 61H. The clip 911 is provided individually for the semiconductor element 61H. The clip 911 extends generally in the Y direction and electrically connects the source terminal of the semiconductor element 61H to the O wiring 516. The clip 912 is connected to the semiconductor element 61L. The clip 912 is provided individually for the semiconductor element 61L. The clip 912 extends generally in the Y direction and electrically connects the source terminal of the semiconductor element 61L to the wiring 515A of the N wiring 515. The clips 911 and 912, together with the semiconductor elements 61H and 61L, the P wiring 514, the N wiring 515, and the O wiring 516, constitute the inverter 8.

[0104] The clip 921 has the same structure as the clip 911. That is, clips with the same specifications are used as the clips 911 and 921. The arrangement of the clip 921 on the substrate 52 is the same as the arrangement of the clip 911 on the substrate 51. In the illustrated power conversion module 20, the clip 922 has the same structure as the clip 912. That is, clips with the same specifications are used as the clips 912 and 922. The arrangement of the clip 922 on the substrate 52 is the same as the arrangement of the clip 912 on the substrate 51.

[0105] In the illustrated power conversion module 20, a clip 921 is connected to the semiconductor element 62H. The clip 921 is provided individually for each semiconductor element 62H. The clip 921 extends generally in the Y direction and electrically connects the source terminal of the semiconductor element 62H to the O wiring 526. A clip 922 is connected to the semiconductor element 62L. The clip 922 is provided individually for each semiconductor element 62L. The clip 922 extends generally in the Y direction and electrically connects the source terminal of the semiconductor element 62L to the wiring 525A of the N wiring 525. The clips 921 and 922, together with the semiconductor elements 62H and 62L, the P wiring 524, the N wiring 525, and the O wiring 526, constitute the inverter 9.

[0106] The clip 931 is connected to the changeover switch 81. The clip 931 extends generally in the X direction. The clip 931 electrically connects the source terminal of the changeover switch 81 mounted on the P wiring 534 on the substrate 51 side to the P wiring 534 on the substrate 52 side. The clip 932 is connected to the changeover switch 82. The clip 932 extends generally in the X direction. The clip 932 electrically connects the source terminal of the changeover switch 82 mounted on the N wiring 535 on the substrate 52 side to the N wiring 535 on the substrate 51 side.

[0107] The busbar 100 electrically connects the conductors (wiring) of the substrate 50. The busbar 100 electrically connects the conductors and the main terminals 110. The busbar 100 may also be referred to as a lead, a wiring member, or the like. The busbar 100 is a plate material formed using a metal material with good conductivity, such as Cu. In the illustrated power conversion module 20, the busbar 100 is held in the housing 40. The busbar 100 includes a P busbar 101 and an N busbar 102 mounted on the substrate 51, and a P busbar 103 and an N busbar 104 mounted on the substrate 52.

[0108] The P bus bar 101 commonly connects the P wiring 514 provided for each phase. The connection portion of the P bus bar 101 with the substrate 51 branches into three, each of which is joined to a corresponding wiring 514B. A P terminal 111 is connected to the end of the P bus bar 101 opposite the substrate 51 in the Y direction. The N bus bar 102 commonly connects multiple wirings 515B. The connection portion of the N bus bar 102 with the substrate 51 branches into two, each of which is joined to a corresponding wiring 515B. An N terminal 112 is connected to the end of the N bus bar 102 opposite the substrate 51 in the Y direction.

[0109] The P bus bar 103 has the same structure as the P bus bar 101. That is, bus bars with the same specifications are used for the P bus bars 101 and 103. The arrangement of the P bus bar 103 on the substrate 52 is the same as the arrangement of the P bus bar 101 on the substrate 51. The N bus bar 104 has the same structure as the N bus bar 102. That is, bus bars with the same specifications are used for the N bus bars 102 and 104. The arrangement of the N bus bar 104 on the substrate 52 is the same as the arrangement of the N bus bar 102 on the substrate 51.

[0110] The P bus bar 103 commonly connects the P wiring 524 provided for each phase. The connection portion of the P bus bar 103 with the substrate 52 branches into three, each of which is joined to the corresponding wiring 524B. A charging terminal 113 is connected to the end of the P bus bar 103 opposite the substrate 52 in the Y direction. The N bus bar 104 commonly connects multiple wirings 525B. The connection portion of the N bus bar 104 with the substrate 52 branches into two, each of which is joined to the corresponding wiring 525B.

[0111] The P bus bars 101, 103 and the N bus bars 102, 104 are held (inserted) in the wall portion 411 of the frame 41. The board connection portions of the P bus bars 101, 103 and the N bus bars 102, 104 protrude from the wall portion 411 into the accommodation space and are joined to the corresponding wiring.

[0112] The bus bar 100 further includes P bus bars 105 and 106 and N bus bars 107 and 108. The P bus bar 105 extends in the X direction in a plan view. One end of the P bus bar 105 is joined to the P wiring 514 (wiring 514A) closest to the substrate 52, and the other end is joined to the P wiring 534. The P bus bar 106 extends in the X direction in a plan view. One end of the P bus bar 106 is joined to the P wiring 524 (wiring 524A) closest to the substrate 51, and the other end is joined to the P wiring 534. The N bus bar 107 extends in the X direction in a plan view. One end of the N bus bar 107 is joined to the end of the N wiring 515 (wiring 515A) on the substrate 52 side, and the other end is joined to the N wiring 535. The N bus bar 108 extends in the X direction in a plan view. One end of the N bus bar 108 is joined to the end of the N wiring 525 (wiring 525A) on the substrate 51 side, and the other end is joined to the N wiring 535.

[0113] P bus bar 105 and N bus bar 107 are held by partition wall 42 located between substrates 51 and 53. P bus bar 106 and N bus bar 108 are held by partition wall 42 located between substrates 52 and 53. The substrate connection portions of P bus bars 105 and 106 and N bus bars 107 and 108 protrude from partition wall 42 into the accommodation space and are joined to the corresponding wiring.

[0114] Like the bus bar 100, the main terminal 110 is a plate material formed using a metal material with good conductivity, such as Cu. The main terminal 110 is an external connection terminal that is electrically connected to the main terminal (main electrode) of the semiconductor element 60. The main terminal 110 includes a P terminal 111 and an N terminal 112 that are power supply terminals, a charging terminal 113, and O terminals 115 and 116. In FIG. 8 , the boundary between the bus bar 100 and the main terminal 110 is indicated by a two-dot chain line.

[0115] The power supply terminal is an external connection terminal electrically connected to the above-described capacitor device 22 (smoothing capacitor 7). The P terminal 111 is an external connection terminal connected to the positive terminal of the capacitor device 22 via the P bus bar 25P. The P terminal 111 is connected to the P bus bar 101. The P terminal 111 may be connected to the P bus bar 101 continuously and integrally, or may be connected by joining. The P terminal 111 may also be referred to as a positive terminal, a high-potential power supply terminal, or the like. The P terminal 111 is mounted on the substrate 51 via the P bus bar 101. The P terminal 111 extends outward in the Y direction from the wall portion 411 of the frame 41 to a position where it does not overlap with the cooler 30 in a plan view.

[0116] The N terminal 112 is an external connection terminal connected to the negative terminal of the capacitor device 22 via the N bus bar 25N. The N terminal 112 is connected to the N bus bar 102. The N terminal 112 may be connected to the N bus bar 102 continuously and integrally, or may be connected by joining. The N terminal 112 may also be referred to as a negative terminal, a low-potential power supply terminal, or the like. The N terminal 112 is mounted on the substrate 51 via the N bus bar 102. The N terminal 112 extends outward in the Y direction from the wall portion 411 of the frame 41 to a position where it does not overlap with the cooler 30 in a plan view. The N terminal 112 is located closer to the substrate 52 in the X direction than the P terminal 111.

[0117] The charging terminal 113 is an external connection terminal that is connected to the positive terminal of the external device 23 via the P bus bar 26P. The charging terminal 113 is connected to the P bus bar 103. The charging terminal 113 is sometimes referred to as a P terminal because it is electrically connected to the P wiring 524 via the P bus bar 103. The charging terminal 113 may be connected integrally and continuously with the P bus bar 103, or may be connected by joining. The charging terminal 113 is mounted on the substrate 52 via the P bus bar 103. The charging terminal 113 extends outward in the Y direction from the wall portion 411 of the frame 41 to a position where it does not overlap with the cooler 30 in a plan view.

[0118] In a plan view, the position of the charging terminal 113 relative to the substrate 52 is different from the position of the P terminal 111 relative to the substrate 51. The connection position of the charging terminal 113 relative to the P bus bar 103 is different from the connection position of the P terminal 111 relative to the P bus bar 101. As shown in Figures 7 and 8 , the P terminal 111 is connected to the vicinity of the end of the P bus bar 101 on the wall portion 413 side. The charging terminal 113 is connected to the vicinity of the end of the P bus bar 103 on the wall portion 414 side. In the X direction, the P terminal 111, the N terminal 112, and the charging terminal 113 are lined up in this order. In other words, the charging terminal 113 is located at one end in the arrangement direction, and the P terminal 111 is located at the other end.

[0119] The O terminals 115, 116 are electrically connected to the windings 3U, 3V, 3W of the corresponding phases of the rotating electric machine 3. The O terminals 115, 116 may also be referred to as output terminals, AC terminals, etc. The O terminal 115 is joined to the O wiring 516. An O terminal 115 is provided for each phase of the upper and lower arm circuits 8HL. The O terminal 115, together with the O wiring 516, provides the output line 13. The O terminal 115 extends generally in the Y direction from the joint with the O wiring 516. The O terminal 115 extends outward in the Y direction from the wall portion 412 of the frame body 41 to a position where it does not overlap with the cooler 30 in a plan view.

[0120] The O terminal 116 is joined to the O wiring 526. The O terminal 116 is provided for each phase of the upper and lower arm circuits 9HL. The O terminal 116, together with the O wiring 526, provides the output line 14. The O terminal 116 extends generally in the Y direction from the joint with the O wiring 526. The O terminal 116 extends outward in the Y direction from the wall portion 412 to a position where it does not overlap with the cooler 30 in a plan view. In the illustrated power conversion module 20, the O terminal 116 has the same structure as the O terminal 115. In other words, external connection terminals with the same specifications are used as the O terminals 115 and 116. The arrangement of the O terminal 116 on the substrate 52 is the same as the arrangement of the O terminal 115 on the substrate 51.

[0121] The power conversion module 20 includes two circuit units 201 and 202 that provide a power conversion circuit 4. The circuit unit 201 includes a substrate 51 and components mounted on the substrate 51. The components mounted on the substrate 51 in the circuit unit 201 include semiconductor elements 61H and 61L, a snubber component 71, clips 911 and 912, a P bus bar 101, and an N bus bar 102. The circuit unit 201 provides an inverter 8 and a snubber circuit 12. The circuit unit 202 includes a substrate 52 and components mounted on the substrate 52. The components mounted on the substrate 52 in the circuit unit 202 include semiconductor elements 62H and 62L, a snubber component 72, clips 921 and 922, a P bus bar 103, and an N bus bar 104. The circuit unit 202 provides an inverter 9 and a snubber circuit 11.

[0122] As described above, the elements that constitute the circuit units 201 and 202 and that are related to each other have a common structure. Furthermore, the layout of the components mounted on the board 52 is substantially the same as the layout of the components mounted on the board 51. Therefore, the circuit units 201 and 202 have a common structure. Circuit units with the same specifications are used as the circuit units 201 and 202. Note that "common" or "identical" may include errors on the order of manufacturing variations.

[0123] Summary of First Embodiment The power conversion module 20 according to this embodiment includes wiring, a plurality of semiconductor elements 60 constituting an inverter 8 serving as a first inverter and an inverter 9 serving as a second inverter, and a changeover switch 80. The semiconductor elements 60 include upper arm elements 61H, 62H and lower arm elements 61L, 62L, each of which is provided for each phase. The wiring includes P wiring electrically connected to the high-potential terminals (drain terminals) of the upper arm elements 61H, 62H and N wiring electrically connected to the low-potential terminals (source terminals) of the lower arm elements 61L, 62L. At least one of the P wiring and N wiring is provided in plurality corresponding to the semiconductor elements 60, and includes first wiring arranged in a predetermined X direction and second wiring electrically connecting the plurality of first wirings arranged in the predetermined direction.

[0124] 8 , the wiring includes conductors 512, 522, and 532 on substrates 51, 52, and 53, clip 90, and bus bar 100. P wiring includes P wirings 514, 524, and 534, P bus bars 101, 103, 105, and 106, and clip 931, which are formed on substrate 50. N wiring includes N wirings 515, 525, and 535, N bus bars 102, 104, 107, and 108, and clips 912, 922, and 932, which are formed on substrate 50. The first wiring includes P wirings 514 and 524 and wirings 515B and 525B of N wirings 515 and 525. The second wiring includes wirings 515A and 525A of N wirings 515 and 525, P bus bars 101 and 103, and N bus bars 102 and 104.

[0125] As described above, the power conversion module 20 modularizes the wiring, semiconductor elements 60, and changeover switches 80. The wiring includes a plurality of first wirings arranged in a predetermined direction corresponding to the semiconductor elements 60 provided for each phase, and a second wiring that commonly connects the plurality of first wirings. Because the plurality of first wirings are connected within the module, the wiring length of at least one of the P wiring and the N wiring can be shortened, thereby reducing inductance. In particular, in this embodiment, the P wiring includes P wirings 514 and 524 as the first wiring and P bus bars 101 and 103 as the second wiring. Furthermore, the N wiring includes wirings 515B and 525B as the first wiring and wirings 515A and 525A and N bus bars 102 and 104 as the second wiring. Therefore, the wiring length of both the P wiring and the N wiring can be shortened, thereby reducing inductance.

[0126] As illustrated, the P wiring may have a first P wiring, and the N wiring may have a first N wiring, as the first wiring. The first P wiring and the first N wiring may be arranged alternately in the X direction, which is a predetermined direction. In the example shown in FIG. 8 , the first P wiring includes P wirings 514 and 524, and the first N wiring includes wirings 515B and 525B. The P wiring 514 and the wiring 515B are arranged alternately in the X direction. The P wiring 524 and the wiring 525B are arranged alternately in the X direction. By running the first P wiring and the first N wiring parallel to each other, inductance can be further reduced.

[0127] As illustrated, one of the first P wirings and the first N wirings may have the same number of wirings as the number of phases, and the other of the first P wirings and the first N wirings may have the number of wirings obtained by subtracting one from the number of phases. In the example shown in FIG. 8 , on the inverter 8 side, there are three P wirings 514 that are the first P wirings and two wirings 515B that are the first N wirings. Also, on the inverter 9 side, there are three P wirings 524 that are the first P wirings and two wirings 525B that are the first N wirings. This allows the size of the power conversion module 20 to be reduced in the X direction, which is the arrangement direction, while reducing inductance by running the wirings parallel to one another.

[0128] As illustrated, the wiring constituting the inverters 8 and 9 may each include a first P wiring and a first N wiring, and the first P wirings or the first N wirings may be arranged to face each other in the X direction. The changeover switch 80 may then be electrically connected to each of the first P wirings arranged to face each other, or each of the first N wirings arranged to face each other. In the example shown in FIG. 8 , the changeover switch 81 is electrically connected to each of the P wirings 514 and 524 arranged to face each other. This can shorten the connection distance between the P wiring constituting the inverter 8 and the changeover switch 81, and the connection distance between the P wiring constituting the inverter 9 and the changeover switch 81, for example. In other words, the inductance can be further reduced.

[0129] As illustrated, the P wiring may have a second P wiring, and the N wiring may have a second N wiring as the second wiring. The second P wiring and the second N wiring may be arranged side by side in a direction perpendicular to a predetermined direction, i.e., a direction perpendicular to the X direction. In the example shown in FIG. 8 , the second P wiring includes P bus bars 101 and 103. The second N wiring includes wiring 515A and 525A and N bus bars 102 and 104. The P bus bar 101 and the N bus bar 102 are arranged side by side in the Z direction. The P bus bar 103 and the N bus bar 104 are arranged side by side in the Z direction. The P bus bar 101 and the wiring 515A are arranged side by side in the Y direction. The P bus bar 103 and the wiring 525A are arranged side by side in the Y direction. In particular, the P bus bar 101 and the N bus bar 102 face each other in the Z direction. The P bus bar 103 and the N bus bar 104 face each other in the Z direction. In other words, they run side by side, which makes it possible to further reduce inductance.

[0130] As illustrated, the second wiring electrically connects the plurality of first wirings in the inverters 8 and 9 and may include connecting wiring extending in the X direction, which is a predetermined direction, to connect the inverters 8 and 9. In the example shown in FIG. 8 , the connecting wiring includes wirings 515A and 525A, N wiring 535, N bus bars 107 and 108, and clip 932. This makes it easy to connect the plurality of first wirings to the connecting wiring (second wiring). Furthermore, the connection distance between the inverters 8 and 9 can be shortened. This further reduces inductance. Furthermore, the size in the X direction can be reduced.

[0131] As illustrated, the wiring may include O wirings 516 and 526 electrically connected to the low-potential terminals (source terminals) of the upper arm elements 61H and 62H and the high-potential terminals (drain terminals) of the lower arm elements 61L and 62L. Furthermore, connecting wirings may be arranged between the first P wiring and the first N wiring and the O wiring in the orthogonal Y direction. In the example shown in FIG. 8 , connecting wirings are arranged between the P wiring 514 and the wiring 515B and the O wiring 516. The connecting wirings are arranged between the P wiring 524 and the wiring 525B and the O wiring 526. This arrangement allows the first P wiring and the first N wiring (first wirings), the connecting wiring (second wirings), and the O wiring to be aligned in the Y direction. This facilitates connecting multiple first N wirings to the connecting wiring including the second N wiring. This reduces inductance. Furthermore, it is easy to connect the low-potential terminals (source terminals) of the upper arm elements 61H and 62H to the O wirings 516 and 526. Lower arm elements 61L and 62L can be easily connected to the N wiring, and the size in the Y direction can be reduced.

[0132] As illustrated, the power supply terminals may include only the P terminal 111 and the N terminal 112. By providing a changeover switch 82 (10B) on the N wiring 535 connecting the inverters 8 and 9, the N terminal connecting the inverter 9 to the smoothing capacitor 7 (capacitor device 22) becomes unnecessary, and the N terminal can be eliminated. This simplifies the configuration.

[0133] 11 and 12 show a reference example of a power conversion circuit. Fig. 11 shows an example of a current conduction pattern when star-connected driving is performed in the reference example. Fig. 12 shows a current conduction pattern with timing different from that in Fig. 4 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.

[0134] 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. 11 and 12. The current conduction pattern shown in FIG. 11 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. The power supply line 5r has a wiring 5A1r connecting the inverter 8 and the selector switch 10r and a wiring 5A2r connecting the selector switch 10r and the inverter 9r.

[0135] As shown in Figures 11 and 12, 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 5A2r 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 5A2r of the power line 5r, and the other end is connected to a power line 6r. For convenience, Figures 11 and 12 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.

[0136] In the examples shown in Figures 11 and 12, all three-phase upper arms 9Hr of inverter 9r are turned on to neutralize inverter 9r. In this state, as shown in Figure 11, when all three-phase upper arms 8Hr of inverter 8r are turned on, the voltage across capacitor 11Cr becomes approximately equal to the supply voltage of DC power supply 2r, i.e., power supply voltage Vdc. Furthermore, as shown in Figure 12, when all three-phase lower arms 8Lr of inverter 8r are turned on, the voltage across capacitor 11Cr becomes approximately 0 V (zero volts).

[0137] 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.

[0138] As shown in the example, in a configuration in which the changeover switch 82 (10B) is provided on the N wiring 535, the MOSFET of the changeover switch 10B is off, i.e., the changeover switch 10 is in an open state, during star connection drive. As a result, the potential on the negative electrode side of the capacitor 11C provided in the snubber circuit 11 becomes a floating potential. Therefore, fluctuations in the voltage across the capacitor 11C can be suppressed during star connection drive. In other words, charging and discharging of the capacitor 11C can be suppressed, improving power conversion efficiency. Furthermore, the resistor 11R generates heat due to charging and discharging, and the capacitor 11C is prevented from being affected by the heat. This configuration is suitable not only for open connection drive but also for star connection drive.

[0139] In this embodiment, the clip 90 is used as an example of the bridging member, but the present invention is not limited to this. A bonding wire or the like may be used instead of the clip 90. However, using the clip 90 can reduce inductance.

[0140] 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 10 is provided on the power supply lines 5 and 6. Alternatively, the changeover switch 10 may be provided only on the power supply line 5.

[0141] <Power Conversion Circuit> Fig. 13 shows a power conversion circuit 4 provided by a power conversion module 20 according to this embodiment. In the power conversion circuit 4 shown in Fig. 13, the changeover switch 10 is arranged only on the power supply line 5 (wiring 5A). It is not arranged on the power supply line 6. The changeover switch 10 is arranged so that the drain terminal of the MOSFET is on the inverter 8 side and the source terminal is on the inverter 9 side. The rest of the configuration is the same as that of the power conversion circuit shown in the preceding embodiment (see Fig. 1).

[0142] <Power Conversion Module> Fig. 14 is a diagram of the power conversion module 20 according to this embodiment, with the cooler 30, housing 40, and sealing body 43 omitted. Fig. 14 corresponds to Fig. 8. Although not shown, the power conversion module 20 includes the cooler 30, housing 40, and sealing body 43, similar to the preceding embodiment.

[0143] The power conversion module 20 provides the power conversion circuit 4 shown in Fig. 13. In the power conversion module 20, the changeover switch 80 is arranged on the P wiring 534. It is not arranged on the N wiring 535. The power conversion module 20 has a configuration in which the changeover switch 82, the clip 932, and the signal wiring 537 corresponding to the changeover switch 82 are eliminated from the configuration shown in the preceding embodiment. The N wiring 535 is not divided into two, but extends from near one end of the substrate 53 to near the other end.

[0144] The power conversion module 20 includes an N-terminal 114 as a power supply terminal. Like the N-terminal 112, the N-terminal 114 is an external connection terminal connected to the negative terminal of the capacitor device 22. The N-terminal 114 is connected to the N-bus bar 104. The N-terminal 114 may be connected to the N-bus bar 104 continuously and integrally, or may be connected by joining. The N-terminal 114 is mounted on the substrate 52 via the N-bus bar 104. The N-terminal 114 extends outward in the Y-direction from the wall portion 411 of the frame 41 to a position where it does not overlap with the cooler 30 in a plan view. In a plan view, the position of the N-terminal 114 relative to the substrate 52 is different from the position of the N-terminal 112 relative to the substrate 51. The P-terminal 111, the N-terminal 112, the N-terminal 114, and the charging terminal 113 are arranged in this order in the X-direction. The rest of the configuration is the same as that of the power conversion module 20 shown in the preceding embodiment (see FIGS. 7 to 9 ).

[0145] Summary of Second Embodiment The power conversion module 20 of this embodiment can achieve the same effects as the configurations described in the preceding embodiments. In the example shown in FIG. 14 , the P wiring includes P wirings 514, 524, and 534, P bus bars 101, 103, 105, and 106, and clip 931. The N wiring includes N wirings 515, 525, and 535, N bus bars 102, 104, 107, and 108, and clips 912 and 922. The first wiring includes P wirings 514 and 524 and wirings 515B and 525B of the N wirings 515 and 525. The second wiring includes wirings 515A and 525A of the N wirings 515 and 525, P bus bars 101 and 103, and N bus bars 102 and 104. The first P wiring includes P wirings 514 and 524, and the first N wiring includes wirings 515B and 525B. The second P wiring includes P bus bars 101 and 103, and the second N wiring includes wirings 515A and 525A and N bus bars 102 and 104. The connecting wiring includes wirings 515A and 525A, N wiring 535, and N bus bars 107 and 108.

[0146] As illustrated, the changeover switch 80 may be provided on either the P wiring 534 or the N wiring 535. In the example shown in FIG. 14 , the changeover switch 80 is provided on the P wiring 534, but not on the N wiring 535. By providing the N terminal 114, the inverter 9 is connected to the capacitor device 22 without going through the N wirings 515 and 535. This makes it possible to reduce wiring inductance. Since the changeover switch 10 is not provided on the power supply line 6, only open connection driving may be performed.

[0147] 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 component 72 is mounted on the substrate 52 common to the semiconductor elements 62H and 62L that constitute the inverter 9. Alternatively, the snubber component 72 may be mounted on the substrate 53. Furthermore, the connection position of the snubber circuit 11 may be different from that of the preceding embodiment.

[0148] 15 shows a power conversion circuit 4 provided by the power conversion module 20 according to this embodiment. In the power conversion circuit 4, the changeover switch 10 is arranged only on the power supply line 5, as in the configuration shown in the second embodiment, and is not arranged on the power supply line 6. The changeover switch 10 is arranged so that the drain terminal of the MOSFET is on the inverter 8 side and the source terminal is on the inverter 9 side.

[0149] The snubber circuits 11 are not provided for each phase of the upper and lower arm circuits 9HL, but are provided collectively. A common snubber circuit 11 is connected in parallel to the three-phase upper and lower arm circuits 9HL. The power supply line 5 has a wiring 5A1 connecting the inverter 8 and the changeover switch 10, and a wiring 5A2 connecting the changeover switch 10 and the inverter 9. The wirings 5A1 and 5A2 correspond to the wiring 5A shown in the previous embodiment. One of the ends of the snubber circuit 11 is connected to the wiring 5A1 of the wirings 5A1 and 5A2. The other end is connected to the power supply line 6. The other configuration is similar to that of the power conversion circuit shown in the previous embodiment (see FIG. 13 ).

[0150] <Power Conversion Module> Fig. 16 is a diagram of the power conversion module 20 according to this embodiment, with the cooler 30, housing 40, and sealing body 43 omitted. Fig. 16 corresponds to Fig. 8. Although not shown, the power conversion module 20 includes the cooler 30, housing 40, and sealing body 43, similar to the preceding embodiment.

[0151] The power conversion module 20 provides the power conversion circuit 4 shown in Fig. 15. Similar to the configuration shown in the second embodiment, the power conversion module 20 includes a changeover switch 80 arranged on the P wiring 534. The power conversion module 20 includes an N terminal 114 as a power supply terminal.

[0152] The snubber component 72 is mounted on the substrate 53, not on the substrate 52. The circuit unit 202 has a structure in which the snubber component 72 is removed from the configuration shown in the preceding embodiment. On the substrate 52, the P wiring 524 and the N wiring 525 (wiring 525B) are aligned in the X direction. The P wiring 524 and the N wiring 525 run parallel to each other.

[0153] The substrate 53 has a P wiring 534 having wirings 534A and 534B. The wiring 534A electrically connects the inverter 8 and the drain terminal of the changeover switch 80. The wiring 534B electrically connects the source terminal of the changeover switch 80 and the inverter 9. The wiring 534A provides wiring 5A1, and the wiring 534B provides wiring 5A2.

[0154] The P bus bar 105 is joined to one end of the wiring 534A, and the drain terminal of the changeover switch 80 is joined to the other end. A clip 931 is joined to one end of the wiring 534B, and the P bus bar 106 is joined to the other end. The snubber component 72 is connected to a position on the wiring 534A between the joint portion of the P bus bar 105 and the joint portion of the changeover switch 80. The snubber component 72 is connected to the wiring 534A and the N wiring 535. The snubber component 72 is aligned with the changeover switch 80 in the Y direction. The rest of the configuration is the same as that of the power conversion module 20 shown in the preceding embodiment (see FIG. 14 ).

[0155] Summary of the Third Embodiment The power conversion module 20 of this embodiment can achieve the same effects as the configurations described in the preceding embodiments. In the example shown in FIG. 16 , the P wiring includes P wirings 514, 524, and 534, P bus bars 101, 103, 105, and 106, and clip 931. The N wiring includes N wirings 515, 525, and 535, N bus bars 102, 104, 107, and 108, and clips 912 and 922. The first wiring includes P wirings 514 and 524 and wirings 515B and 525B of the N wirings 515 and 525. The second wiring includes wirings 515A and 525A of the N wirings 515 and 525, P bus bars 101 and 103, and N bus bars 102 and 104. The first P wiring includes P wirings 514 and 524, and the first N wiring includes wirings 515B and 525B. The second P wiring includes P bus bars 101 and 103, and the second N wiring includes wirings 515A and 525A and N bus bars 102 and 104. The connecting wiring includes wirings 515A and 525A, N wiring 535, and N bus bars 107 and 108.

[0156] As illustrated, the changeover switch 80 may be disposed on one of the P wiring 534 and the N wiring 535 (power supply wiring). The snubber component 72 may be connected to a portion of the power supply wiring that connects the changeover switch 80 to the inverter 8. In the example shown in FIG. 16 , the changeover switch 80 is disposed on the P wiring 534, but not on the N wiring 535. By providing the N terminal 114, the inverter 9 is connected to the capacitor device 22 without going through the N wirings 515 and 535. This allows for reduced wiring inductance.

[0157] Furthermore, snubber component 72 is connected to wiring 534A. As a result, during star connection driving, the voltage across capacitor 11C is clamped to the power supply voltage of DC power supply 2 (voltage across smoothing capacitor 7). Therefore, during star connection driving, the charge / discharge operation of capacitor 11C can be suppressed, improving power conversion efficiency. Even without providing selector switch 80 on N wiring 535, the charge / discharge operation of capacitor 11C can be suppressed during star connection driving.

[0158] Fourth 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 component 72 is mounted on the substrate 53 and connected to the wiring 534A. Alternatively, the snubber component 72 may be connected to the wiring 534B.

[0159] <Power Conversion Circuit> Fig. 17 shows a power conversion circuit 4 provided by a power conversion module 20 according to this embodiment. In the power conversion circuit 4, the changeover switch 10 is arranged only on the power supply line 5, not on the power supply line 6, as in the configuration shown in the third embodiment. The snubber circuits 11 are not provided for each phase of the upper and lower arm circuits 9HL, but are provided collectively. A common snubber circuit 11 is connected in parallel to the three-phase upper and lower arm circuits 9HL. One end of the snubber circuit 11 is connected to the wiring 5A2 of the wirings 5A1 and 5A2. The other end is connected to the power supply line 6. The other configuration is the same as that of the power conversion circuit shown in the preceding embodiment (see Fig. 15).

[0160] <Power Conversion Module> Fig. 18 is a diagram of the power conversion module 20 according to this embodiment, with the cooler 30, housing 40, and sealing body 43 omitted. Fig. 18 corresponds to Fig. 8. Although not shown, the power conversion module 20 includes the cooler 30, housing 40, and sealing body 43, similar to the preceding embodiment.

[0161] The power conversion module 20 provides the power conversion circuit 4 shown in FIG. 17 . The power conversion module 20 has substantially the same configuration as that shown in the third embodiment. The snubber component 72 is mounted on the substrate 53. The snubber component 72 is connected to the wiring 534B at a position between the joint portion of the clip 931 and the joint portion of the P bus bar 106. The snubber component 72 is connected to the wiring 534B and the N wiring 535. The snubber component 72 is aligned with the changeover switch 80 in the Y direction. The other configurations are the same as those of the power conversion module 20 shown in the preceding embodiment (see FIG. 16 ).

[0162] Summary of Fourth Embodiment The power conversion module 20 of this embodiment can achieve the same effects as the configurations described in the preceding embodiments. In the example shown in FIG. 18 , the P wiring includes P wirings 514, 524, and 534, P bus bars 101, 103, 105, and 106, and clip 931. The N wiring includes N wirings 515, 525, and 535, N bus bars 102, 104, 107, and 108, and clips 912 and 922. The first wiring includes P wirings 514 and 524 and wirings 515B and 525B of the N wirings 515 and 525. The second wiring includes wirings 515A and 525A of the N wirings 515 and 525, P bus bars 101 and 103, and N bus bars 102 and 104. The first P wiring includes P wirings 514 and 524, and the first N wiring includes wirings 515B and 525B. The second P wiring includes P bus bars 101 and 103, and the second N wiring includes wirings 515A and 525A and N bus bars 102 and 104. The connecting wiring includes wirings 515A and 525A, N wiring 535, and N bus bars 107 and 108.

[0163] As illustrated, the changeover switch 80 may be disposed on one of the P wiring 534 and the N wiring 535 (power supply wiring). In the example shown in FIG. 18 , the changeover switch 80 is disposed on the P wiring 534, but not on the N wiring 535. By providing the N terminal 114, the inverter 9 is connected to the capacitor device 22 without going through the N wirings 515 and 535. This reduces the wiring inductance. Since the changeover switch 10 is not provided on the power supply line 6 and the snubber circuit 11 is connected to the wiring 5A2, only open connection driving may be performed.

[0164] (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.

[0165] 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.

[0166] 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.

[0167] 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.

[0168] (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.

[0169] <Technical Idea 1> A rotating electric machine (100) comprising: wiring (90, 100, 512, 522, 532); a plurality of semiconductor elements (60) which, together with the wiring, constitute a first inverter (8) connected to one end of a winding of a rotating electric machine (3) and a second inverter (9) connected to the other end of the winding; and a changeover switch (80) which connects a DC power source (2) 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, wherein the semiconductor elements have upper arm elements (61H, 62H) and lower arm elements (61L, 62L) provided for each phase, the wiring includes P wiring (101, 103, 105, 106, 514, 524, 534, 931) electrically connected to a high potential side terminal of the upper arm element, and N wiring (102, 104, 107, 108, 515, 525, 535, 912, 922, 932) electrically connected to a low potential side terminal of the lower arm element, and at least one of the P wiring and the N wiring is provided in plurality corresponding to the semiconductor element, and includes first wiring (514, 515B, 524, 525B) arranged in a predetermined direction, and second wiring (101, 102, 103, 104, 515A, 525A) electrically connecting the plurality of first wirings.

[0170] <Technical Idea 2> The P wiring has first P wiring (514, 524) which is the first wiring, the N wiring has first N wiring (515B, 525B) which is the first wiring, and the first P wiring and the first N wiring are arranged alternately in the predetermined direction, in the power conversion module described in Technical Idea 1.

[0171] <Technical Idea 3> The power conversion module according to Technical Idea 2, wherein one of the first P wirings and the first N wirings has a number of wirings equal to the number of phases, and the other of the first P wirings and the first N wirings has a number of wirings obtained by subtracting 1 from the number of phases.

[0172] <Technical Idea 4> The power conversion module according to Technical Idea 3, wherein the wiring constituting the first inverter has the first P wiring and the first N wiring, the wiring constituting the second inverter has the first P wiring and the first N wiring, the first P wirings or the first N wirings face each other in the predetermined direction, and the changeover switch is electrically connected to each of the first P wirings or each of the first N wirings that are arranged facing each other.

[0173] <Technical Idea 5> A power conversion module according to any one of Technical Ideas 1 to 4, wherein the P wiring has a second P wiring (101, 103) that is the second wiring, the N wiring has a second N wiring (102, 104, 515A, 525A) that is the second wiring, and the second P wiring and the second N wiring are arranged side by side in an orthogonal direction that is orthogonal to the predetermined direction.

[0174] <Technical Idea 6> The power conversion module according to any one of Technical Ideas 1 to 5, wherein the second wiring electrically connects the plurality of first wirings in the first inverter and the second inverter, and includes connecting wiring (107, 108, 515A, 525A, 535, 932) extending in the predetermined direction to connect the first inverter and the second inverter.

[0175] <Technical Idea 7> The power conversion module according to Technical Idea 6, wherein the wiring has an O wiring (516, 526) electrically connected to a low potential side terminal of the upper arm element and a high potential side terminal of the lower arm element, and the connecting wiring is arranged between a first P wiring and a first N wiring and the O wiring in an orthogonal direction perpendicular to the predetermined direction.

Claims

1. Wiring (90, 100, 512, 522, 532), a plurality of semiconductor elements (60) that, together with the wiring, constitute a first inverter (8) connected to one end of the winding of a rotating electrical machine (3) and a second inverter (9) connected to the other end of the winding, and a switching switch (80) that connects the DC power supply (2) and the second inverter in a closed state and disconnects the connection between the DC power supply and the second inverter in an open state. The semiconductor elements have an upper arm element (61H, 62H) and a lower arm element (61L, 62L) provided for each phase. The wiring includes a P wiring (101, 103, 105, 106, 514, 524, 534, 931) electrically connected to the high-potential side terminal of the upper arm element and an N wiring (102, 104, 107, 108, 515, 525, 535, 912, 922, 932) electrically connected to the low-potential side terminal of the lower arm element. At least one of the P wiring and the N wiring is provided in a plurality corresponding to the semiconductor elements, and includes a first wiring (514, 515B, 524, 525B) arranged in a predetermined direction and a second wiring (101, 102, 103, 104, 515A, 525A) electrically connecting the plurality of first wirings, which is a power conversion module.

2. The P wiring has a first P wiring (514, 524) that is the first wiring, the N wiring has a first N wiring (515B, 525B) that is the first wiring, and the first P wiring and the first N wiring are alternately arranged in the predetermined direction. The power conversion module according to claim 1.

3. One of the first P wiring and the first N wiring has a number of wirings equal to the number of phases, and the other of the first P wiring and the first N wiring has a number of wirings obtained by subtracting 1 from the number of phases. The power conversion module according to claim 2.

4. The wiring constituting the first inverter has the first P wiring and the first N wiring, the wiring constituting the second inverter has the first P wiring and the first N wiring, the first P wirings or the first N wirings face each other in the predetermined direction, and the switching switch is electrically connected to each of the first P wirings or the first N wirings that are arranged opposite to each other. The power conversion module according to claim 3.

5. The P wiring has second P wirings (101, 103) that are the second wiring, the N wiring has second N wirings (102, 104, 515A, 525A) that are the second wiring, and the second P wiring and the second N wiring are arranged side by side in an orthogonal direction orthogonal to the predetermined direction. The power conversion module according to any one of claims 1 to 4.

6. The second wiring includes connecting wirings (107, 108, 515A, 525A, 535, 932) that electrically connect the plurality of first wirings in the first inverter and the second inverter and extend in the predetermined direction to connect the first inverter and the second inverter. The power conversion module according to claim 5.

7. The wiring has O wirings (516, 526) electrically connected to the low-potential-side terminals of the upper-arm elements and the high-potential-side terminals of the lower-arm elements, and the connecting wiring is arranged between the first P wiring and the first N wiring and the O wiring in the orthogonal direction. The power conversion module according to claim 6.

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