Power conversion module

Abstract

To provide a power conversion module which can suppress a failure of a semiconductor device.SOLUTION: A power conversion module comprises a plurality of bridge members 90. Each bridge member 90 comprises: clips 91, 92, 93, 94; and bonding wires 95, 96. The clip 91 bridges a semiconductor device 61H and an O-wire 516. The clip 92 bridges a semiconductor device 61L and an N-wire 515. The clip 93 bridges a semiconductor device 62H and an O-wire 526. The clip 94 bridges a semiconductor device 62L and an N-wire 525. The bonding wire 95 bridges a changeover switch 81 and a P-wire 534. The bonding wire 96 bridges a changeover switch 82 and an N-wire 535. The bonding wire 95, 96 as second bridge members are easier to melt than the clips 91, 92, 93, 94 as first bridge members.SELECTED DRAWING: Figure 8

Description

[Technical Field]

[0001] The disclosure herein relates to power conversion modules. [Background technology]

[0002] 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 cuts off the connection between the DC power source and the second inverter in an open state. The contents of the prior art documents are incorporated by reference as explanations of the technical elements in this specification. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Publication No. 2022-177342 Summary of the Invention [Problem to be solved by the invention]

[0004] 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. Therefore, if a short circuit occurs between the top and bottom of the second inverter, or if a short circuit occurs in the power line on the second inverter side of the changeover switch, a large current may flow through the changeover switch, causing damage to the semiconductor elements. Further improvements are required in power conversion modules from the above-mentioned perspectives and other perspectives not mentioned.

[0005] One disclosed object is to provide a power conversion module that can suppress failure of semiconductor elements. [Means for solving the problem]

[0006] One aspect of the disclosure is a power conversion module, comprising: First wiring (515, 516, 525, 526), ​​second wiring (534, 535), and wiring (512, 522, 532) including the first wiring (515, 516, 525, 526), a plurality of semiconductor elements (60) including first semiconductor elements (61H, 61L) constituting a first inverter (8) connected to one end of a winding of the rotating electric machine (3) and second semiconductor elements (62H, 62L) constituting a second inverter (9) connected to the other end of the winding; a changeover switch (80) which is a semiconductor switch provided in a power supply path connecting the first inverter and the second inverter, connecting the DC power supply (2) and the second inverter in a closed state, and disconnecting the DC power supply and the second inverter in an open state; a plurality of bridging members (90) including first bridging members (91, 92, 93, 94) that connect the semiconductor element and the first wiring, and second bridging members (95, 96, 97, 98) that connect the changeover switch and the second wiring; Equipped with The second bridging member is more likely to melt than the first bridging member.

[0007] According to the disclosed power conversion module, when a large current flows through the current path due to an upper / lower short circuit of the second inverter, the second bridging member melts and cuts off the large current, thereby preventing breakdown of the semiconductor element.

[0008] 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. [Brief explanation of the drawings]

[0009] [Figure 1]FIG. 2 illustrates a power conversion circuit and a drive system. [Figure 2] FIG. 4 is a diagram showing an example of an operating point map of the rotating electric machine. [Figure 3] FIG. 1 is a diagram showing a star-connected drive. [Figure 4] FIG. 10 is a diagram illustrating an open connection drive. [Figure 5] FIG. 2 is a circuit diagram showing a state in which an external device is connected. [Figure 6] 1 is a diagram showing a connection structure between a power conversion module and an external device. FIG. [Figure 7] 1 is a plan view showing a power conversion module according to a first embodiment. [Figure 8] This is a diagram in which the cooler and housing are omitted from FIG. 7. [Figure 9] FIG. 8 is a cross-sectional view taken along line IX-IX in FIG. 7. [Figure 10] FIG. 8 is a cross-sectional view taken along line XX in FIG. [Figure 11] FIG. 10 is a diagram illustrating a reference example. [Figure 12] FIG. 10 is a diagram illustrating a reference example. [Figure 13] FIG. 10 is a plan view showing a power conversion module according to a second embodiment. [Figure 14] FIG. [Figure 15] FIG. 10 is a diagram illustrating a power conversion circuit provided by a power conversion module according to a third embodiment. [Figure 16] FIG. 2 is a plan view showing the power conversion module. DETAILED DESCRIPTION OF THE INVENTION

[0010] 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.

[0011] The power conversion module of this embodiment is applied to, for example, a mobile body using a rotating electric machine as a drive source, 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, an agricultural machine, etc.

[0012] (First embodiment) First, the schematic configuration of a drive system for a moving body will be described with reference to FIG.

[0013] <Drive systems for moving objects> 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.

[0014] 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 convert AC power into DC and output it.

[0015] The rotating electric machine 3 is a three-phase rotating electric machine of an open winding type 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.

[0016] 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.

[0017] The power conversion circuit 4 converts power between the DC power supply 2 and the rotating electric machine 3. The drive system 1 is a common power supply system in which a common DC power supply 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 supply 2 as shown in FIG. 1, or multiple common DC power supplies 2. The drive system 1 may include a power supply switch (not shown), such as an SMR, between the DC power supply 2 and the power conversion circuit 4. SMR is an abbreviation for System Main Relay. Turning the power supply switch on enables power supply from the DC power supply 2 to the rotating electric machine 3, and turning the power supply switch off cuts off the power supply from the DC power supply 2 to the rotating electric machine 3.

[0018] <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 shown in Fig. 1 includes power lines 5 and 6, a smoothing capacitor 7, inverters 8 and 9, a changeover switch 10, and snubber circuits 11 and 12.

[0019] 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, P line, etc. 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, N line, etc. 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.

[0020] 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.

[0021] 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 circuits 8HL have 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.

[0022] 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 configuring 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).

[0023] 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.

[0024] 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.

[0025] 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 circuit 9HL has 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.

[0026] 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.

[0027] In the example shown in Fig. 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 anti-parallel to each MOSFET 9S.

[0028] 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 line 5. The low-potential terminals (source terminals) of the lower arms 8L, 9L are connected to the power 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 a 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 a W-phase upper and lower arm circuit 9HL.

[0029] The switching elements constituting the inverters 8 and 9 are not limited to the MOSFETs described above. For example, IGBTs may be used. IGBT stands for Insulated Gate Bipolar Transistor. In the case of an IGBT, a freewheeling diode is also connected in anti-parallel.

[0030] The changeover switch 10 is a semiconductor switch. A semiconductor switch has a switching element formed on a semiconductor chip. The switching element is not particularly limited and 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 or an open / close switch.

[0031] The switching element of the changeover switch 10 illustrated in FIG. 1 is a MOSFET 10S. A diode 10D is connected in anti-parallel to the MOSFET 10S. The diode 10D is, for example, a parasitic diode. The changeover switch 10 includes changeover switches 10A and 10B. The changeover switch 10A is arranged on a wiring 5A of a power supply line 5. The changeover switch 10A is arranged on the wiring 5A so that the drain terminal of the MOSFET 10S is on the inverter 8 side and the source terminal is on the inverter 9 side. In other words, the forward direction of the diode 10D is from the inverter 9 to the inverter 8.

[0032] The changeover switch 10B is arranged on the wiring 6A of the power supply line 6. The changeover switch 10B is arranged on the wiring 6A so that the drain terminal of the MOSFET 10S is on the inverter 9 side and the source terminal is on the inverter 8 side. In other words, the changeover switch 10B is arranged so that the forward direction of the diode 10D is from the inverter 8 to the inverter 9. When the MOSFET 10S 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 10S is turned off and the changeover switch 10 is opened, the electrical connection between the inverter 9 and the smoothing capacitor 7 is interrupted.

[0033] 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 a transient high voltage, or so-called switching surge, that occurs 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.

[0034] 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, an RC snubber circuit including a capacitor and a resistor, or an RCD snubber circuit including a capacitor, a resistor, and a diode. The snubber circuit 11 shown in FIG. 1 is an RC snubber circuit in which a capacitor 11C and a resistor 11R are connected in series. One end of the snubber circuit 11 is connected to the power supply line 5. One end of the snubber circuit 11 may be connected to a portion of the wiring 5A connecting the inverter 8 and the changeover switch 10, or may be connected to a portion connecting the changeover switch 10 and the inverter 9. The other end of the snubber circuit 11 is connected to the power supply line 6. The illustrated snubber circuit 11 is connected to a portion of the wiring 5A connecting the changeover switch 10 and the inverter 9.

[0035] 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.

[0036] 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.

[0037] 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.

[0038] 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, and a storage. 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 a rewritable non-volatile storage medium such as ROM or flash. ROM is an abbreviation for Read Only Memory. 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.

[0039] 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 sensor detects the rotation angle of the rotor of the rotating electric machine 3. The voltage sensor detects the voltage across the smoothing capacitor 7.

[0040] The drive command generation unit controls the changeover switch 10 (10A, 10B). The drive command generation unit generates a drive command for controlling the on / off of the MOSFET 10S and outputs it to the drive circuit unit. The drive circuit unit is sometimes called a driver. The drive circuit unit can independently control the on / off of the MOSFETs 8S, 9S, and 10S based on the drive command. For convenience, signal lines for transmitting drive signals from the control unit 15 to each switching element are omitted in FIG. 1.

[0041] <Star connection drive and open connection drive> Next, star connection driving and open connection driving 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 driving. Figure 4 is a diagram showing open connection driving. For convenience, the control unit 15 is omitted from Figures 3 and 4.

[0042] As shown in FIG. 2, the driving range of the rotating electric machine 3 is divided into two ranges based on the rotation speed and torque. One of the driving ranges is the star connection driving range. The star connection driving range is the range normally used in, for example, a typical vehicle. The other driving range is the open connection driving range. The open connection driving range is a range with higher rotation speeds or higher torque than the star connection driving range.

[0043] When the operating point is in the star connection drive region, the control unit 15 executes star connection drive control. Star connection drive is sometimes referred to as Y drive. The control unit 15 controls the MOSFETs 8S, 9S, and 10S 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 MOSFET 10S 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.

[0044] 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.

[0045] 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 10S 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.

[0046] FIG. 4 shows one current conduction pattern in open-connection driving. The two-dot chain arrow in FIG. 4 indicates one example of a current path. FIG. 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 driving, current flows via changeover switch 10.

[0047] 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 speed range or a higher torque range.

[0048] <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.

[0049] 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.

[0050] 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 so as to boost the supply voltage of the external device 16 and charge the DC power supply 2. In the boost operation, one phase or multiple phases (multi-phase) may be used. The control unit 15 turns off the MOSFET 10S 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.

[0051] External device 16 may be a DC power supply (external power supply) separate from DC power supply 2. The external power supply may be, for example, a secondary battery or may include a DC-AC conversion circuit. DC power supply 2 charges external device 16. The power supply voltage of external device 16 is lower than the power supply voltage of DC power supply 2. In rotating electric machine 3 and power conversion circuit 4, windings 3U, 3V, 3W of rotating electric machine 3 and upper arm 8H of inverter 8 function as a step-down circuit.

[0052] When an external device 16 is connected to the drive system 1, the control unit 15 controls the inverters 8 and 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 10S 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, a current flows through the diode of the lower arm 8L of the corresponding phase.

[0053] 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 view of the external device. Fig. 6 also shows directions (X direction and Y direction) that will be described later.

[0054] The power conversion module 20 shown in FIG. 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.

[0055] 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. It may be a cable, a terminal, or the like.

[0056] <Power conversion module> Next, the structure of a power conversion module will be described with reference to Figures 7, 8, 9, and 10. Figure 7 is a plan view showing an example of a power conversion module. For convenience, the sealing body is omitted from Figure 7. Figure 8 is a diagram showing the power conversion module without the cooler, housing, and sealing body. In other words, it is a diagram showing the circuit elements of the power conversion module. Figure 9 is a cross-sectional view taken along line IX-IX in Figure 7. Figure 10 is a cross-sectional view taken along line XX in Figure 7.

[0057] In the following, the thickness direction of the substrate is referred to as the Z direction, and the 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 sometimes be simply referred to as the planar view.

[0058] The power conversion module 20 provides at least a part of the above-described power conversion circuit 4. The power conversion module 20 includes a cooler 30, a housing 40, a substrate 50, a semiconductor element 60, a snubber component 70, a changeover switch 80, a bridging member 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 bridging member 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.

[0059] 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 has 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.

[0060] 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.

[0061] 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.

[0062] The cooler 30 is not limited to the configuration having the flow path 33 described above. A heat dissipation member such as a heat sink may be used as the cooler 30. A heat sink is sometimes referred to as a heat sink or a 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 a cooling function may be used instead of the cooler 30.

[0063] 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 the housing 40 is arranged on one side of the cooler 30, it provides, together with the cooler 30, a space for accommodating electronic components such as the substrate 50 and the semiconductor element 60 mounted on the substrate 50.

[0064] 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 may be 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.

[0065] The wall portions 411 and 412 extend substantially 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.

[0066] 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, and both ends thereof may be 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.

[0067] As illustrated, a seal 43 may be disposed in the storage space formed by the housing 40 and the cooler 30. The seal 43 is disposed in the storage 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 a potting resin. The seal 43 fills the storage space so as not to exceed the upper end of the frame 41. Because the storage space is divided into multiple regions by the partition walls 42 as described above, the impact 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.

[0068] The substrate 50 provides a wiring function. The substrate 50 may also be referred to as a wiring board, 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 planar shape. 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.

[0069] Substrate 51, together with electronic components mounted on substrate 51, constitutes a circuit on the inverter 8 side. Substrate 52, together with electronic components mounted on substrate 52, constitutes a circuit on the inverter 9 side. Substrate 51 has an insulating substrate 511 and a conductor arranged on insulating substrate 511. Substrate 52 has an insulating substrate 521 and a conductor arranged on insulating substrate 521. Substrate 53 has an insulating substrate 531 and a conductor arranged on insulating substrate 531. Insulating substrates 511, 521, and 531 are formed using an electrically insulating material such as ceramic or resin.

[0070] 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, Au, or the like on their surfaces. The conductors may be arranged 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 arranged inside the insulating substrates 511, 521, and 531. That is, 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 arranging 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 arranged on different layers.

[0071] The illustrated substrates 51 and 52 have a common structure. Substrates with the same specifications are used for 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 different structure from the substrates 51 and 52. The substrates 51, 52, and 53 all have a substantially rectangular planar shape. 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.

[0072] 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 are lined up in the order of substrate 51, substrate 53, and substrate 52. The substrates 51 and 52 are arranged facing the same direction relative to the cooler 30.

[0073] The illustrated substrate 51 has a conductor 512 arranged on one side and a conductor 513 arranged on the back side. The substrate 52 has a conductor 522 arranged on one side and a conductor 523 arranged on the back side. The substrate 53 has a conductor 532 arranged on one side and a conductor 533 arranged on the back side. 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.

[0074] The conductors 512, 522, and 532 are patterned. The patterned conductors 512, 522, and 532 provide wiring functions. That is, together with the mounted electronic components, they form a circuit. The conductors 512 of the substrate 51 include a P wiring 514, an N wiring 515, an O wiring 516, and a signal wiring 517. Each wiring is electrically separated by a predetermined gap. The P wiring 514 and the N wiring 515 are power wirings. 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.

[0075] 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. The 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 approximately in the Y direction. The three P wirings 514 are lined up in the X direction at a predetermined interval. The P wiring 514 has wirings 514A, 514B, and 514C. The wiring 514A extends in the Y direction. The wiring 514B is connected to one end of the wiring 514A, and the wiring 514C is connected to the other end.

[0076] Wiring 514B is disposed near an end of substrate 51 in the Y direction. Wiring 514B extends in the X direction from wiring 514A. P bus bar 101 is joined to wiring 514B. Wiring 514C is located in the middle of substrate 51 in the Y direction. Wiring 514C extends in the X direction from wiring 514A at the end opposite to wiring 514B. A corresponding semiconductor element 61H (drain terminal) is joined to wiring 514C.

[0077] Of the three P wirings 514 lined up in the X direction, the P wiring 514 arranged at the end closest to the substrate 52 and the P wiring 514 arranged 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 an imaginary 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.

[0078] The N wiring 515 is electrically connected to the source electrode (source terminal) of the semiconductor element 61L via a clip 92. 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 corresponding clips 92.

[0079] The wiring 515B extends roughly in the Y direction. The wiring 515B has roughly the same length in the Y direction as 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. That is, 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 other end of the wiring 515B is connected to the wiring 515A.

[0080] 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 91. 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.

[0081] 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.

[0082] 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.

[0083] Conductor 532 of substrate 53 includes P wiring 534, N wiring 535, and signal wiring 537. P wiring 534 and N wiring 535 are power wiring that connect inverter 8 and inverter 9. P wiring 534 connects P wiring 514 of substrate 51 and P wiring 524 of substrate 52. P wiring 534 extends generally in the direction in which substrates 51 and 52 are arranged, i.e., in the X direction. P wiring 534 is divided into two in the extension direction. P bus bar 105 and changeover switch 81 are joined to P wiring 534 on the substrate 51 side. Bonding wire 95 and P bus bar 106 are joined to P wiring 534 on the substrate 52 side.

[0084] N wiring 535 connects N wiring 515 of substrate 51 and N wiring 525 of substrate 52. N wiring 535 extends roughly in the X direction. N wiring 535 is divided into two in the extension direction. N bus bar 107 and bonding wire 96 are joined to N wiring 535 on the substrate 51 side. Changeover switch 82 and N bus bar 108 are joined to N wiring 535 on the substrate 52 side. N wiring 535 and N wirings 515, 525 (wirings 515A, 525A) are arranged on an imaginary line roughly parallel to the X direction. N wiring 535 and P wiring 534 are arranged to be shifted in the Y direction. The connection position of N wiring 535 and N wirings 515, 525 is shifted in the Y direction from the connection position of P wiring 534 and P wirings 514, 524.

[0085] 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.

[0086] 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.

[0087] 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.

[0088] 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.

[0089] 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.

[0090] 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.

[0091] Semiconductor elements 61H and 61L are mounted on substrate 51. Semiconductor element 61H is arranged to overlap wiring 514C of P wiring 514 in a plan view. The drain terminal of semiconductor element 61H is joined to P wiring 514 via a bonding material such as solder (not shown). Semiconductor element 61L is arranged to overlap O wiring 516 in a plan view. The drain terminal of semiconductor element 61L is joined to O wiring 516 via a bonding material (not shown).

[0092] 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 portions 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.

[0093] Semiconductor elements 62H and 62L are mounted on the substrate 52. Semiconductor element 62H has the same structure as semiconductor element 61H. That is, semiconductor elements with the same specifications are used as semiconductor elements 61H and 62H. The arrangement of semiconductor element 62H on substrate 52 is the same as the arrangement of semiconductor element 61H on substrate 51. Semiconductor element 62L has the same structure as semiconductor element 61L. That is, semiconductor elements with the same specifications are used as semiconductor elements 61L and 62L. The arrangement of semiconductor element 62L on substrate 52 is the same as the arrangement of semiconductor element 61L on substrate 51. Semiconductor elements 61H, 61L, 62H, and 62L have common specifications.

[0094] 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).

[0095] 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 portions 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.

[0096] 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 10 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.

[0097] The snubber component 72 has the same structure as the snubber component 71. That is, snubber components with the same specifications are used as the snubber components 71, 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.

[0098] 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 is formed by forming a MOSFET on the semiconductor substrate. A parasitic diode is connected in antiparallel to the MOSFET.

[0099] 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.

[0100] 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.

[0101] The bridging member 90 bridges the electronic component and the conductor (wiring). The bridging member 90 electrically connects the electronic component and the conductor by bridging. The bridging member 90 is sometimes called a relay member or the like. The bridging member 90 is, for example, a clip or a bonding wire.

[0102] The clip is a metal plate made of a metal with good conductivity, such as Cu or a Cu alloy. The clip may be formed by punching and pressing a metal plate of a predetermined thickness. The clip may be formed using a profiled material with a different thickness in some areas. The clip may have a film applied to the surface of the base material by surface treatment. The clip may have a plated film of Ni, Au, or the like on its surface. The clip may have a Ni plated film containing P formed on the base material. The NiP film is formed, for example, by electroless plating. Ag, Au, Al, Mg, or the like may be used as the base material instead of Cu. Sn, Ag, or the like may be used as the film applied to the base material instead of Ni or Au. The bonding wire is a wire made of a metal, such as Cu or Al, for example.

[0103] The illustrated bridging member 90 includes clips 91, 92, 93, and 94 and bonding wires 95 and 96. The clips 91, 92, 93, and 94 are plate materials containing Cu. The clips 91 and 92 are mounted on the substrate 51. The clip 91 is connected to the semiconductor element 61H. The clip 91 is provided individually for the semiconductor element 61H. The clip 91 extends generally in the Y direction and electrically connects the source terminal of the semiconductor element 61H to the O wiring 516. The clip 92 is connected to the semiconductor element 61L. The clip 92 is provided individually for the semiconductor element 61L. The clip 92 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 91 and 92, 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] Clips 93 and 94 are mounted on board 52. Clip 93 has the same structure as clip 91. That is, clips with the same specifications are used for clips 91 and 93. The arrangement of clip 93 on board 52 is the same as the arrangement of clip 91 on board 51. Clip 94 has the same structure as clip 92. That is, clips with the same specifications are used for clips 92 and 94. The arrangement of clip 94 on board 52 is the same as the arrangement of clip 92 on board 51.

[0105] The clip 93 is connected to the semiconductor element 62H. The clip 93 is provided individually for each semiconductor element 62H. The clip 93 extends generally in the Y direction and electrically connects the source terminal of the semiconductor element 62H to the O wiring 526. The clip 94 is connected to the semiconductor element 62L. The clip 94 is provided individually for each semiconductor element 62L. The clip 94 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 93 and 94, together with the semiconductor elements 62H and 62L, the P wiring 524, the N wiring 525, and the O wiring 526, configure the inverter 9.

[0106] The bonding wires 95 and 96 are Cu wires. The cross-sectional areas of the bonding wires 95 and 96 are smaller than the smallest cross-sectional areas of the clips 91, 92, 93, and 94. The cross-sectional areas are the areas of the planes perpendicular to the extension direction of the respective bonding wires. The bonding wire 95 is connected to the changeover switch 81. The bonding wire 95 extends generally in the X direction in a plan view. The bonding wire 95 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 bonding wire 96 is connected to the changeover switch 82. The bonding wire 96 extends generally in the X direction in a plan view. The bonding wire 96 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] P bus bar 101 commonly connects P wiring 514 provided for each phase. The portion of P bus bar 101 that connects to substrate 51 is branched into three, and each is joined to a corresponding wiring 514B. A P terminal 111 is connected to the end of P bus bar 101 opposite substrate 51 in the Y direction. N bus bar 102 commonly connects multiple wirings 515B. The portion of N bus bar 102 that connects to substrate 51 is branched into two, and each is joined to a corresponding wiring 515B. An N terminal 112 is connected to the end of N bus bar 102 opposite substrate 51 in the Y direction.

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

[0110] P bus bar 103 commonly connects P wiring 524 provided for each phase. The portion of P bus bar 103 that connects to substrate 52 is branched into three, and each is joined to a corresponding wiring 524B. Charging terminal 113 is connected to the end of P bus bar 103 on the opposite side from substrate 52 in the Y direction. N bus bar 104 commonly connects multiple wirings 525B. The portion of N bus bar 104 that connects to substrate 52 is branched into two, and each is joined to a corresponding wiring 525B.

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

[0112] Bus bar 100 further includes P bus bars 105 and 106 and N bus bars 107 and 108. P bus bar 105 extends in the X direction in a plan view. One end of P bus bar 105 is joined to P wiring 514 (wiring 514A) closest to substrate 52, and the other end is joined to P wiring 534. P bus bar 106 extends in the X direction in a plan view. One end of P bus bar 106 is joined to P wiring 524 (wiring 524A) closest to substrate 51, and the other end is joined to P wiring 534. N bus bar 107 extends in the X direction in a plan view. One end of N bus bar 107 is joined to the end of N wiring 515 (wiring 515A) on the substrate 52 side, and the other end is joined to N wiring 535. N bus bar 108 extends in the X direction in a plan view. One end of N bus bar 108 is joined to the end of N wiring 525 (wiring 525A) on the substrate 51 side, and the other end is joined to 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 busbar 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 busbar 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 body 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 charging terminal 113 relative to substrate 52 is different from the position of P terminal 111 relative to substrate 51. The connection position of charging terminal 113 relative to P bus bar 103 is different from the connection position of P terminal 111 relative to P bus bar 101. As shown in FIGS. 7 and 8, P terminal 111 is connected to the vicinity of the end of P bus bar 101 on the wall portion 413 side. Charging terminal 113 is connected to the vicinity of the end of P bus bar 103 on the wall portion 414 side. In the X direction, P terminal 111, N terminal 112, and charging terminal 113 are lined up in this order. In other words, charging terminal 113 is located at one end in the arrangement direction, and 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 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 substantially 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. That is, external connection terminals with the same specifications are used as the O terminals 115, 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 circuit unit 201 includes, as components mounted on the substrate 51, semiconductor elements 61H and 61L, a snubber component 71, clips 91 and 92, 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 circuit unit 202 includes, as components mounted on the substrate 52, semiconductor elements 62H and 62L, a snubber component 72, clips 93 and 94, 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 the First Embodiment> The power conversion module 20 of this embodiment includes wiring including first wiring and second wiring, multiple semiconductor elements 60 including a first semiconductor element constituting a first inverter and a second semiconductor element constituting a second inverter, a changeover switch 80, and a bridging member 90. The bridging member 90 includes a first bridging member connecting the semiconductor elements 60 to the first wiring and a second bridging member connecting the changeover switch 80 to the second wiring. In the illustrated example, N wirings 515 and 525 and O wirings 516 and 526 correspond to the first wiring, and P wiring 534 and N wiring 535 correspond to the second wiring. Inverter 8 corresponds to the first inverter, and inverter 9 corresponds to the second inverter. Semiconductor elements 61H and 61L correspond to the first semiconductor element, and semiconductor elements 62H and 62L correspond to the second semiconductor element. Clips 91, 92, 93, and 94 correspond to the first bridging member, and bonding wires 95 and 96 correspond to the second bridging member.

[0124] The second bridging members are configured to melt and break due to heat (Joule heat) generated during current flow more easily than the first bridging members. Therefore, if a short circuit occurs between the top and bottom of the inverter 9 or in a portion of the power lines 5, 6 closer to the inverter 9 than the selector switch 10 during open-circuit operation, causing a large current to flow through the current path via the selector switch 80, at least one of the second bridging members melts and cuts off the large current. In other words, the second bridging members function as eFuses. Therefore, it is possible to prevent the semiconductor element 60 from failing due to a short circuit.

[0125] As shown in the example, clips 91, 92, 93, and 94, which are metal plates, may be used as the first bridging members, and bonding wires 95 and 96 may be used as the second bridging members. The bonding wires 95 and 96 include portions whose cross-sectional area is smaller than the minimum cross-sectional area of ​​each of the clips 91, 92, 93, and 94. For example, the bonding wires 95 and 96 have a cross-sectional area smaller than the minimum cross-sectional area of ​​each of the clips 91, 92, 93, and 94 over their entire length. Because the second bridging member with a smaller cross-sectional area has a higher resistance and thus Joule heat, at least one of the second bridging members will melt due to a large current. This can prevent the semiconductor element 60 from failing.

[0126] As shown in the example, the primary metal of the first bridging member and the primary metal of the second bridging member may be the same. In the example, clips 91, 92, 93, and 94 are Cu clips, and bonding wires 95 and 96 are Cu wires. Even if the primary metals are the same, the second bridging member, which has a smaller cross-sectional area, will melt down due to a large current. This can prevent the semiconductor element 60 from failing.

[0127] As shown in the example, the wiring may be arranged on one surface of insulating base materials 511, 521, 531 on substrate 50, and bridging member 90 may be connected to the surface of semiconductor element 60 and changeover switch 80 opposite to the substrate mounting surface. Since semiconductor element 60, changeover switch 80, and bridging member 90 are mounted on substrate 50, the module structure can be simplified.

[0128] As illustrated, the power supply terminals may include only the P terminal 111 and the N terminal 112. By providing the 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.

[0129] 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 of the symbols.

[0130] 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 Figures 11 and 12. The current conduction pattern shown in Figure 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 Figure 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 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.

[0131] 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.

[0132] 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).

[0133] As described above, star connection driving is performed while switching between multiple current patterns, so the voltage across capacitor 11Cr of snubber circuit 11r fluctuates during star connection driving. The voltage across capacitor 11Cr fluctuates between 0 V and Vdc. As a result, capacitor 11Cr is charged and discharged during star connection driving, resulting in low power conversion efficiency. Resistor 11Rr of snubber circuit 11r consumes the energy stored in capacitor 11Cr and generates heat. This heat affects capacitor 11Cr.

[0134] 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 driving. 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, during star connection driving, fluctuations in the voltage across the capacitor 11C can be suppressed. 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 can be prevented from being affected by the heat. This configuration is suitable not only for open connection driving but also for star connection driving.

[0135] <Modification> Although the example in which the substrate 50 provides wiring has been described, the present invention is not limited to this. Instead of the substrate 50, a metal plate such as a lead frame may be used.

[0136] There is no particular limitation on the number of bonding wires connected to the changeover switch 80 as the bridging member 90. As illustrated, one bonding wire may be connected to one changeover switch 80, or multiple bonding wires may be connected. It is sufficient that the total cross-sectional area of ​​the bonding wires connected to one changeover switch 80 is smaller than the cross-sectional area of ​​the clip (metal plate) connected to the semiconductor element 60.

[0137] While the clips 91, 92, 93, and 94 are made of Cu clips and the bonding wires 95, 96 are made of Cu wires, this is not limiting. Alternatively, the bonding wires 95, 96 may be made of a material with a lower melting point than the clips 91, 92, 93, and 94. For example, the clips 91, 92, 93, and 94 may be made of Cu clips, and the bonding wires 95, 96 may be made of Al wires. In this manner, the clips 91, 92, 93, and 94 may be made of different materials from the bonding wires 95, 96. The melting point of Al is approximately 660°C, which is lower than the melting point of Cu, approximately 1084°C. Due to this synergistic effect, at least one of the bonding wires 95, 96 (second bridging members) melts more quickly when a large current flows due to a short circuit. This effectively protects the semiconductor element 60 from short circuits.

[0138] (Second embodiment) This embodiment is a modification based on the previous embodiment, and the description of the previous embodiment can be used. In the previous embodiment, bonding wires 95 and 96 are used as the second bridging members. Instead, a clip may be used as the second bridging member, similar to the first bridging member.

[0139] Fig. 13 is a diagram of the power conversion module 20 according to this embodiment, with the cooler 30, the housing 40, and the sealing body 43 omitted. Fig. 13 corresponds to Fig. 8. Although not shown, the power conversion module 20 includes the cooler 30, the housing 40, and the sealing body 43, similar to the preceding embodiment.

[0140] The power conversion module 20 provides a power conversion circuit 4 (see FIG. 1 ) similar to that of the previous embodiment. The illustrated bridging member 90 includes clips 91, 92, 93, 94, 97, and 98. As in the previous embodiment, the clips 91, 92, 93, and 94 are connected to the corresponding semiconductor elements 60. The clips 97 and 98 are connected to the changeover switch 80. The clip 97 is connected to the changeover switch 81. The clip 97 extends generally in the X direction in a plan view. The clip 97 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 98 is connected to the changeover switch 82. The clip 98 extends generally in the X direction in a plan view. The clip 98 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.

[0141] The clips 97 and 98 each have a fusible portion 99. The fusible portion 99 melts when current is applied, interrupting the electrical path. The fusible portion 99 generates heat and melts when current is applied. The fusible portion 99 melts when a large current flows due to a short circuit, protecting normal circuit elements, such as normal semiconductor elements 60. The fusible portion 99 is sometimes referred to as a fuse or a disconnecting portion. The fusible portion 99 is a portion of the clips 97 and 98 that has a narrower current path, i.e., a smaller cross-sectional area, than other portions. The fusible portion 99 has a smaller cross-sectional area than the smallest cross-sectional area of ​​the clips 91, 92, 93, and 94. The illustrated clips 97 and 98 are Cu clips, like the clips 91, 92, 93, and 94. The fusible portion 99 has a narrower length in the Y direction, i.e., a narrower width, due to a notch. The rest of the configuration is the same as that shown in the preceding embodiment.

[0142] <Summary of the second embodiment> As illustrated, clips 91, 92, 93, and 94 may be used as the first bridging member, and clips 97 and 98 may be used as the second bridging member. By configuring clips 97 and 98 to include fusion portions 99 that are portions with a smaller cross-sectional area than the smallest cross-sectional areas of clips 91, 92, 93, and 94, the fusion portions 99 will fuse when a large current flows due to a short circuit. This will block the large current, preventing the semiconductor element 60 from breaking down.

[0143] As shown in the example, the main metal of clips 91, 92, 93, and 94 may be the same as the main metal of clips 97 and 98. Even if a common material is used, clips 97 and 98 (fusing portions 99) with a smaller cross-sectional area have a larger resistance and therefore Joule heat, so at least one of clips 97 and 98 will fuse. This simplifies the configuration and prevents the semiconductor element 60 from failing.

[0144] <Modification> Although the example in which the width of the clips 97 and 98 is locally narrowed to form the fusion portion 99 has been shown, the present invention is not limited to this. For example, as shown in Fig. 14, the thickness of the clip 97 may be locally thinned to form the fusion portion 99.

[0145] While the clips 91, 92, 93, and 94 are made of Cu, and the clips 97 and 98 are made of Cu, this is not limiting. Clips 97 and 98 may be made of a material with a lower melting point than clips 91, 92, 93, and 94. For example, clips 91, 92, 93, and 94 may be made of Cu, and clips 97 and 98 may be made of Al. In this manner, clips 91, 92, 93, and 94 may be made of different materials from clips 97 and 98. Even if clips 91, 92, 93, and 94 share a common structure, Al has a lower melting point than Cu, so at least one of clips 97 and 98 (second bridging member) melts faster when a large current flows due to a short circuit. This effectively protects the semiconductor element 60 from short circuits.

[0146] (Third embodiment) This embodiment is a modification based on the previous embodiment, and the description of the previous embodiment can be used. In the previous 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.

[0147] <Power conversion circuit> FIG. 15 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. 15, the changeover switch 10 is arranged only on the power line 5 (wiring 5A). It is not arranged on the power line 6. The changeover switch 10 is arranged so that the drain terminal of the MOSFET 10S is on the inverter 8 side and the source terminal is on the inverter 9 side. The other configurations are the same as those of the power conversion circuit shown in the preceding embodiment (see FIG. 1).

[0148] <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.

[0149] The power conversion module 20 provides the power conversion circuit 4 shown in FIG. 15 . In the power conversion module 20, the changeover switch 80 is arranged on the P wiring 534. The changeover switch 80 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. The bonding wire 95 extends generally in the X direction in a plan view. The bonding wire 95 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.

[0150] 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 other configurations are the same as those of the power conversion module 20 described in the preceding embodiment.

[0151] <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. For example, the bonding wire 95 includes a portion whose cross-sectional area is smaller than the minimum cross-sectional area of ​​each of the clips 91, 92, 93, and 94. Therefore, when a large current flows due to a short circuit, the bonding wire 95 melts. This interrupts the large current and prevents the semiconductor element 60 from failing. In particular, if a bonding wire 95 with a lower melting point than the clips 91, 92, 93, and 94 is used, the bonding wire 95 melts quickly when a large current flows, thereby enhancing the interruption effect. Note that a clip 97 may be used instead of the bonding wire 95. The clip 97 may have a fusible portion 99.

[0152] 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. 16, 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 inductance. Since the changeover switch 10 is not provided on the power supply line 6, only open connection driving may be performed.

[0153] (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.

[0154] 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.

[0155] 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 the associated listed item or items. That is, 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.

[0156] 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 be otherwise oriented (rotated 90 degrees or at other orientations), and the spatially relative descriptors used in this specification would be interpreted accordingly.

[0157] (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.

[0158] 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.

[0159] 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 the associated listed item or items. That is, 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.

[0160] 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 be otherwise oriented (rotated 90 degrees or at other orientations), and the spatially relative descriptors used in this specification would be interpreted accordingly.

[0161] (Disclosure of technical ideas) This specification discloses multiple technical ideas described in the following multiple clauses. Some clauses may be written in a multiple dependent form, with the subsequent clause referring to the preceding clause as an alternative. Furthermore, some clauses may be written in a multiple dependent form, referring to another multiple dependent clause. These multiple dependent clauses define multiple technical ideas.

[0162] <Technical philosophy 1> First wiring (515, 516, 525, 526), ​​second wiring (534, 535), and wiring (512, 522, 532) including the first wiring (515, 516, 525, 526), a plurality of semiconductor elements (60) including first semiconductor elements (61H, 61L) constituting a first inverter (8) connected to one end of a winding of the rotating electric machine (3), and second semiconductor elements (62H, 62L) constituting a second inverter (9) connected to the other end of the winding; a changeover switch (80) which is a semiconductor switch provided in a power supply path connecting the first inverter and the second inverter, connecting a DC power supply (2) and the second inverter in a closed state, and disconnecting the DC power supply and the second inverter in an open state; a plurality of bridging members (90) including first bridging members (91, 92, 93, 94) connecting the semiconductor element and the first wiring, and second bridging members (95, 96, 97, 98) connecting the changeover switch and the second wiring; Equipped with The second bridging member is more likely to melt than the first bridging member.

[0163] <Technical philosophy 2> the first bridging member is a metal plate material, The power conversion module according to Technical Idea 1, wherein the second bridging member is a bonding wire.

[0164] <Technical philosophy 3> The power conversion module according to Technical Concept 1 or 2, wherein the second bridging member includes a portion having a cross-sectional area smaller than the smallest cross-sectional area of ​​the portion of the first bridging member.

[0165] <Technical philosophy 4> The power conversion module according to Technical Concept 3, wherein the main metal of the first bridging member and the main metal of the second bridging member are the same.

[0166] <Technical philosophy 5> The power conversion module according to any one of Technical Concepts 1 to 3, wherein the melting point of the second bridging member is lower than the melting point of the first bridging member.

[0167] <Technical philosophy 6> The power conversion module according to any one of Technical Concepts 1 to 3, wherein the first bridging member and the second bridging member are made of different materials.

[0168] <Technical philosophy 7> The wiring is disposed on one surface of an insulating base material (511, 521, 531) in the substrate (50), The power conversion module according to any one of Technical Concepts 1 to 6, wherein the bridging member is connected to a surface of the semiconductor element and the changeover switch opposite to a surface where the semiconductor element and the changeover switch are mounted on a board. [Explanation of symbols]

[0169] 1... drive system, 2... DC power supply, 3... rotating electric machine, 3U, 3V, 3W... winding, 4... power conversion circuit, 5, 6... power line, 5A, 6A... wiring, 7... smoothing capacitor, 8, 9... inverter, 8HL, 9HL... upper and lower arm circuits, 8D, 9D... diode, 8H, 9H... upper arm, 8L, 9L... lower arm, 8S, 9S... MOSFET, 10, 10A, 10B... changeover switch, 10D... diode, 10S... MOSFET, 11, 12... snubber circuit, 11C, 12C... capacitor, 11R , 12R...resistor, 13, 14...output line, 15...control unit, 16...external device, 20...power conversion module, 201, 202...circuit unit, 21...power supply device, 22...capacitor device, 23...external device, 24N, 25N, 26N...N bus bar, 24P, 25P, 26P...P bus bar, 30...cooler, 301...one side, 302...rear side, 31...case, 32...lid, 33...flow path, 34...fin, 35...inlet pipe, 36...exhaust pipe, 37...refrigerant, 40...housing, 41...frame body, 411, 412 , 413, 414...wall portion, 42...partition wall, 43...sealing body, 50, 51, 52, 53...substrate, 511, 521, 531...insulating base material, 512, 513, 522, 523, 532, 533...conductor, 514, 524, 534...P wiring, 514A, 514B, 514C, 524A, 524B, 524C, 534A, 534B...wiring, 515, 525, 535...N wiring, 515A, 515B, 525A, 525B...wiring, 516, 526...O wiring, 517, 527, 537...signal wiring , 60, 61H, 61L, 62H, 62L...Semiconductor element, 70, 71, 72...Snubber component, 80, 81, 82...Changeover switch, 90...Bridging member, 91, 92, 93, 94, 97, 98...Clip, 95, 96...Bonding wire, 99...Fusing part, 100...Bus bar, 101, 103, 105, 106...P bus bar, 102, 104, 107, 108...N bus bar, 110...Main terminal, 111...P terminal, 112, 114...N terminal, 113...Charging terminal, 115, 116...O terminal

Claims

1. First wiring (515, 516, 525, 526), ​​second wiring (534, 535), and wiring (512, 522, 532) including the first wiring (515, 516, 525, 526), a plurality of semiconductor elements (60) including first semiconductor elements (61H, 61L) constituting a first inverter (8) connected to one end of a winding of a rotating electric machine (3), and second semiconductor elements (62H, 62L) constituting a second inverter (9) connected to the other end of the winding; a changeover switch (80) which is a semiconductor switch provided in a power supply path connecting the first inverter and the second inverter, connecting a DC power supply (2) and the second inverter in a closed state, and disconnecting the DC power supply and the second inverter in an open state; a plurality of bridging members (90) including first bridging members (91, 92, 93, 94) connecting the semiconductor element and the first wiring, and second bridging members (95, 96, 97, 98) connecting the changeover switch and the second wiring; Equipped with The second bridging member is more likely to melt than the first bridging member.

2. the first bridging member is a metal plate material, The power conversion module according to claim 1 , wherein the second bridging member is a bonding wire.

3. The power conversion module according to claim 1 or 2, wherein the second bridging member includes a portion having a cross-sectional area smaller than a minimum cross-sectional area of ​​the first bridging member.

4. The power conversion module according to claim 3 , wherein a main metal of the first bridging member and a main metal of the second bridging member are the same.

5. The power conversion module according to claim 1 or 2, wherein the melting point of the second bridging member is lower than the melting point of the first bridging member.

6. The power conversion module according to claim 1 or 2, wherein the first bridging member and the second bridging member are made of different materials.

7. The wiring is disposed on one surface of an insulating base material (511, 521, 531) in the substrate (50), 3. The power conversion module according to claim 1, wherein the bridging member is connected to a surface of the semiconductor element and the changeover switch opposite to a surface where the semiconductor element and the changeover switch are mounted on the board.

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