Power conversion module

Abstract

To provide a power conversion module capable of improving power conversion efficiency.SOLUTION: A power conversion module 20 includes: semiconductor elements 51H, 51L constituting a first inverter connected to one end of a winding of a rotary electric machine; semiconductor elements 52H, 52L constituting a second inverter connected to the other end of the winding; a snubber circuit 62 connected in parallel with the second inverter; and a changeover switch 70. The changeover switch 70 is provided in a path connecting the first inverter and the second inverter, connects a DC power supply and the second inverter in a closed state, and cuts off the connection between the DC power supply and the second inverter in an open state. The changeover switch 70 is disposed at a position closer to the semiconductor elements 52H, 52L than to the semiconductor elements 51H, 51L.SELECTED DRAWING: Figure 5

Description

Technical Field

[0001] The disclosure in this specification relates to a power conversion module.

Background Art

[0002] Patent Document 1 discloses a power conversion module including a first inverter connected to one end of a winding of a rotating electrical machine, a second inverter connected to the other end of the winding, and a switching switch. The switching switch is arranged in a path connecting the first inverter and the second inverter, connects the DC power supply and the second inverter in the closed state, and cuts off the connection between the DC power supply and the second inverter in the open state. The description of the prior art document is incorporated herein by reference as an explanation of the technical elements in this specification.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] For inductance reduction, a configuration in which a snubber circuit is connected in parallel to the inverter is conceivable. However, in the open state of the switching switch, the capacitor of the snubber circuit connected in parallel to the second inverter may charge and discharge. That is, there is a problem that the power conversion efficiency is low. From the above viewpoints, or from other viewpoints not mentioned, further improvement of the power conversion module is required.

[0005] One disclosed object is to provide a power conversion module capable of improving power conversion efficiency.

Means for Solving the Problems

[0006] One aspect of the disclosure is a power conversion module, comprising The first semiconductor elements (51H, 51L) that constitute the first inverter (8) connected to one end of the winding of the rotating electrical machine (3), The second semiconductor elements (52H, 52L) that constitute the second inverter (9) connected to the other end of the winding, A changeover switch (70, 10) provided in the path connecting the first inverter and the second inverter, connecting the DC power supply (2) and the second inverter in a closed state, and cutting off the connection between the DC power supply and the second inverter in an open state, A snubber circuit (62, 11) connected in parallel to the second inverter, and the changeover switch is arranged at a position closer to the second semiconductor element than the first semiconductor element.

[0007] According to the disclosed power conversion module, the changeover switch is arranged closer to the second semiconductor element (second inverter). Thereby, the degree of freedom in layout is improved, and in the open state of the changeover switch, charging and discharging of the capacitor of the snubber circuit can be suppressed. Therefore, the power conversion efficiency can be improved.

[0008] In order to achieve their respective objects, the plurality of aspects disclosed in this specification employ different technical means. The reference numerals in parentheses described in the claims and in this section are for exemplarily showing the correspondence with the parts of the embodiments described later, and are not intended to limit the technical scope. The objects, features, and effects disclosed in this specification will become clearer by referring to the subsequent detailed description and the attached drawings.

Brief Description of the Drawings

[0009]

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Mode for Carrying Out the Invention

[0010] Hereinafter, a plurality of embodiments will be described with reference to the drawings. In each embodiment, corresponding components may be denoted by the same reference numerals, and redundant descriptions may be omitted. When only a part of the configuration is described in each embodiment, the configuration of other embodiments described previously can be applied to other parts of the said configuration. Also, not only the combinations of configurations explicitly shown in the description of each embodiment, but also the configurations of a plurality of embodiments can be partially combined with each other as long as there is no problem with the combination, even if not explicitly shown.

[0011] The power conversion module of this embodiment is applied to, for example, a moving body having a rotating electric machine as a drive source. The moving body is, for example, an electric vehicle such as a battery electric vehicle (BEV), a hybrid electric vehicle (HEV), a plug-in hybrid electric vehicle (PHEV), a flying body such as an electric vertical take-off and landing aircraft or a drone, a ship, a construction machine, an agricultural machine, or the like.

[0012] (First Embodiment) First, based on FIG. 1, the schematic configuration of the drive system of the moving body will be described.

[0013] <Drive System of Moving Body> As shown in FIG. 1, the drive system 1 of the 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 or a nickel-metal hydride battery. The DC power supply 2 may be one that converts AC power into DC and outputs it.

[0015] The rotating electric machine 3 is an open-winding type three-phase rotating electric machine with a neutral point released. 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 denoted as windings 3U, 3V, and 3W.

[0016] The rotating electrical machine 3 functions as, for example, a drive source of a moving body, that is, an electric motor. When the moving body is a vehicle, the rotating electrical machine 3 generates torque for driving drive wheels (not shown). The rotating electrical machine 3 is not limited to an electric motor. The rotating electrical machine 3 may be a motor generator having functions as an electric motor and as a generator, or may be a generator.

[0017] The power conversion circuit 4 performs power conversion between the DC power supply 2 and the rotating electrical machine 3. The drive system 1 is a power supply common system that supplies power from a common DC power supply 2 to two inverters 8 and 9 described later. The drive system 1 may include only one common DC power supply 2 as illustrated in FIG. 1, or may include a plurality of them. 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. When the power supply switch is turned on, power supply from the DC power supply 2 to the rotating electrical machine 3 becomes possible, and when the power supply switch is turned off, power supply from the DC power supply 2 to the rotating electrical machine 3 is cut off.

[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 illustrated in FIG. 1 includes power supply lines 5 and 6, smoothing capacitors 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 side 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 electrode side power line, a P line, or the like. The power supply line 6 is a low-potential side 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 electrode side power line, an N line, or the like. The power supply lines 5 and 6 are configured to include a bus bar, for example, a metal plate material.

[0020] The power line 5 has wirings 5A and 5B. The wirings 5A and 5B are parts of the wirings constituting the power line 5. The wirings 5A and 5B are the wirings that connect the inverter 8 and the inverter 9 among the power line 5. The wiring 5A is the wiring that connects the inverter 8 and the changeover switch 10 among the power line 5. The wiring 5B is the wiring that connects the changeover switch 10 and the inverter 9 among the power line 5.

[0021] The smoothing capacitor 7 mainly smoothes the DC voltage supplied from the DC power supply 2. The smoothing capacitor 7 is provided between the power lines 5 and 6. The positive electrode of the smoothing capacitor 7 is connected to the power 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 line 6 between the DC power supply 2 and the inverters 8 and 9. The smoothing capacitor 7 is connected in parallel to the inverters 8 and 9.

[0022] The inverters 8 and 9 are DC-AC conversion circuits. The inverter 8 corresponds to the first inverter, and the inverter 9 corresponds to the second inverter. The inverter 8 is configured to include 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 serially connected between the power lines 5 and 6 with the upper arm 8H on the power line 5 side.

[0023] The connection point between the upper arm 8H and the lower arm 8L is connected to the winding of the corresponding phase in the rotating electrical machine 3 via the output line 13. The inverter 8 has six arms. Each arm is configured to include a switching element. The number of switching elements constituting each arm is not particularly limited. It may be one or a plurality. In the case of a plurality, the plurality of switching elements connected in parallel to each other are driven on and off at the same timing by a common gate drive signal (drive voltage).

[0024] In the example shown in FIG. 1, an n-channel MOSFET 8S is adopted 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 line 5. In the lower arm 8L, the source terminal of the MOSFET 8S is connected to the power line 6. The source terminal of the MOSFET 8S in the upper arm 8H and the drain terminal of the MOSFET 8S in the lower arm 8L are connected to each other.

[0025] A freewheeling diode 8D is connected in anti-parallel to each of the MOSFETs 8S. The diode 8D may be the parasitic diode (body diode) of the MOSFET 8S or may be provided separately from the parasitic diode. The anode terminal of the diode 8D is connected to the source terminal of the corresponding MOSFET 8S, and the cathode terminal is connected to the drain terminal.

[0026] The inverter 9 has the same configuration as the inverter 8. The inverter 9 is configured to include upper and lower arm circuits 9HL for three phases. The upper and lower arm circuits 9HL have an upper arm 9H and a lower arm 9L. The upper arm 9H and the lower arm 9L are connected in series between the power lines 5 and 6 with the upper arm 9H on the power line 5 side.

[0027] The connection point between the upper arm 9H and the lower arm 9L is connected to the winding of the corresponding phase in the rotating electrical machine 3 via the output line 14. The inverter 9 also has six arms. Each arm is configured to include a switching element. The number of switching elements constituting each arm is not particularly limited. It may be one or a plurality.

[0028] In the example shown in FIG. 1, an n-channel type MOSFET 9S is adopted as the switching element constituting each arm. In the upper arm 9H, the drain terminal of the MOSFET 9S is connected to the power line 5. In the lower arm 9L, the source terminal of the MOSFET 9S is connected to the power 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 of the MOSFETs 9S.

[0029] As described above, the high-potential side terminals (drain terminals) of the upper arms 8H, 9H of the inverters 8, 9 are connected to the power line 5. The low-potential side terminals (source terminals) of the lower arms 8L, 9L are connected to the power line 6. The node, which is the connection point between the upper arm 8H and the lower arm 8L, is connected to one end of the winding of the corresponding phase via the output line 13, and the node between the upper arm 9H and the lower arm 9L is connected to the other end of the winding of the corresponding phase via the output line 14. Specifically, one end of the U-phase winding 3U is connected to the node U1 of the upper and lower arm circuits 8HL of the U-phase, and the other end of the U-phase winding 3U is connected to the node U2 of the upper and lower arm circuits 9HL of the U-phase. One end of the V-phase winding 3V is connected to the node V1 of the upper and lower arm circuits 8HL of the V-phase, and the other end of the V-phase winding 3V is connected to the node V2 of the upper and lower arm circuits 9HL of the V-phase. One end of the W-phase winding 3W is connected to the node W1 of the upper and lower arm circuits 8HL of the W-phase, and the other end of the W-phase winding 3W is connected to the node W2 of the upper and lower arm circuits 9HL of the W-phase.

[0030] Note that the switching elements constituting the inverters 8, 9 are not limited to the above-described MOSFETs. For example, an IGBT may be adopted. IGBT is an abbreviation for Insulated Gate Bipolar Transistor. Also in the case of an IGBT, a freewheeling diode is connected in anti-parallel. The types of the switching elements constituting the inverters 8, 9 may be the same or different. For example, one of the inverters 8, 9 may be constituted by a MOSFET and the other may be constituted by an IGBT. The types (materials) of the semiconductor substrates may be different.

[0031] The switching switch 10 is a semiconductor switch. The semiconductor switch is formed by forming a switching element on a semiconductor chip. The switching element is not particularly limited. It may have the same configuration as the switching element constituting at least one of the inverters 8 and 9, or may have a different configuration. The switching switch 10 is provided between the inverter 8 and the inverter 9 in at least one of the power lines 5 and 6. The switching switch 10 is provided on the power line. In the closed state, the switching switch 10 connects the high-potential-side terminal of the upper arm 9H of the inverter 9 and the smoothing capacitor 7 (DC power supply 2). In the open state, the switching switch 10 disconnects the connection between the high-potential-side terminal of the upper arm 9H and the smoothing capacitor 7 (DC power supply 2). The switching switch 10 may be referred to as a switch, a switching switch, or the like.

[0032] The switching element of the switching switch 10 illustrated in FIG. 1 is a MOSFET. A diode is connected in anti-parallel to the MOSFET. The diode is, for example, a parasitic diode. The drain terminal of the switching switch 10 (MOSFET) is connected to the wiring 5A, and the source terminal is connected to the wiring 5B. When the MOSFET is turned on and the switching switch 10 is in the closed state, the high-potential-side terminal of the upper arm 9H is electrically connected to the smoothing capacitor 7. When the MOSFET is turned off and the switching switch 10 is in the open state, the electrical connection between the high-potential-side terminal of the upper arm 9H and the smoothing capacitor 7 is disconnected.

[0033] Also, in the power conversion circuit 4, the switching switches 10 are provided for each phase with respect to the upper and lower arm circuits 9HL. The power conversion circuit 4 includes three switching switches 10. The drain terminals of each switching switch 10 are connected to the wiring 5A, and the source terminals are connected to the wiring 5B. One of the switching switches 10 is connected in series to the upper and lower arm circuits 9HL of the U phase. Another one of the switching switches 10 is connected in series to the upper and lower arm circuits 9HL of the V phase. Another one of the switching switches 10 is connected in series to the upper and lower arm circuits 9HL of the W phase. The source terminals of the three switching switches 10 are electrically connected to each other by the wiring 5B. The source terminals of the three switching switches 10 are commonly connected.

[0034] The snubber circuit 11 is connected in parallel to the inverter 9, that is, 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 the transient high voltage, so-called switching surge, generated during the switching of the switching elements (MOSFET 9S) that make up the upper and lower arm circuits 9HL. Thereby, the inverter 9 can perform high-speed switching.

[0035] The snubber circuit 11 has at least a capacitor 11C. The snubber circuit 11 may be, for example, a C snubber circuit having a capacitor, or an RC snubber circuit having a capacitor and a resistor. It may also be an RCD snubber circuit having a capacitor, a resistor, and a diode. The snubber circuit 11 shown in FIG. 1 is an RC snubber circuit in which the capacitor 11C and the resistor 11R are connected in series. One end of the snubber circuit 11 is connected to the power supply line 5. One end of the snubber circuit 11 is connected to the wiring 5A among the power supply lines 5. The other end of the snubber circuit 11 is connected to the power supply line 6. The snubber circuit 11 is electrically connected to the smoothing capacitor 7 and the DC power supply 2 without passing through the switching switch 10.

[0036] In the power conversion circuit 4 illustrated in FIG. 1, the snubber circuits 11 are provided for each phase with respect to the upper and lower arm circuits 9HL. The power conversion circuit 4 includes three snubber circuits 11 in addition to the three switching switches 10 described above. In each snubber circuit 11, one of the ends is connected to the wiring 5A, and the other end is connected to the power supply line 6. Each snubber circuit 11 has 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 circuits 9HL. Another one of the snubber circuits 11 is connected in parallel to the V-phase upper and lower arm circuits 9HL. Another one of the snubber circuits 11 is connected in parallel to the W-phase upper and lower arm circuits 9HL.

[0037] The snubber circuit 12 is connected in parallel to the inverter 8, that is, the upper and lower arm circuits 8HL. The snubber circuit 12 reduces the inductance of the upper and lower arm circuits 8HL. Thereby, the inverter 8 can perform high-speed switching. The snubber circuit 12 has 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 the capacitor 12C and the 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 11 is connected to the power supply line 6.

[0038] In the power conversion circuit 4 illustrated in FIG. 1, the snubber circuits 12 are provided for each phase with respect to the upper and lower arm circuits 8HL. The power conversion circuit 4 includes three snubber circuits 12. In each snubber circuit 12, one of the ends is connected to the power supply line 5, and the other end is connected to the power supply line 6. Each snubber circuit 12 has 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 circuits 8HL. Another one of the snubber circuits 12 is connected in parallel to the V-phase upper and lower arm circuits 8HL. Another one of the snubber circuits 12 is connected in parallel to the W-phase upper and lower arm circuits 8HL.

[0039] As illustrated in FIG. 1, the power conversion circuit 4 may further include a control unit (CTR) 15. The control unit 15 may be configured to include, for example, a processor, a memory, a storage, etc. The processor executes various processes by accessing the memory. The memory is a rewritable volatile storage medium. The memory is, for example, a RAM. RAM is an abbreviation for Random Access Memory. The storage is, for example, a rewritable non-volatile storage medium. A program executed by the processor is stored in the storage. The program constructs a plurality of functional units by causing the processor to execute a plurality of instructions. The processes executed by the control unit 15 may be realized by software processes in which the processor executes the above-described program, or may be realized by hardware processes using dedicated electronic circuits. It may also be realized by a combination of software processes and hardware processes.

[0040] The control unit 15 may have, for example, a drive command generation unit (not shown) and a drive circuit unit. The drive command generation unit controls the inverters 8 and 9. The drive command generation unit generates a drive command (command signal) for controlling the on / off of the MOSFETs 8S and 9S and outputs it to the drive circuit unit. The drive command generation unit generates a drive command based on drive requirements for the rotating electrical machine 3 such as a torque command value input from a higher-level ECU (not shown), and signals detected by various sensors. The various sensors may include a current sensor, a rotation angle sensor, a voltage sensor, etc. (not shown). The current sensor detects the phase current 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 electrical machine 3. The voltage sensor detects the voltage across the smoothing capacitor 7.

[0041] The drive command generation unit controls the changeover switch 10. The drive command generation unit generates a drive command for controlling the on / off state of the changeover switch 10 and outputs it to the drive circuit unit. The drive circuit unit may be referred to as a driver. The drive circuit unit can independently control the on / off states of the MOSFET 8S, MOSFET 9S, and the changeover switch 10 based on the drive command. For the sake of simplicity, in FIG. 1, the signal lines for transmitting drive signals from the control unit 15 to each switching element are omitted.

[0042] <Star connection drive and open connection drive> Next, based on FIGS. 2, 3, and 4, the star connection drive and the open connection drive will be described. FIG. 2 shows an example of an operating point map of a rotating electrical machine with the rotational speed on the horizontal axis and the torque on the vertical axis. FIG. 3 is a diagram showing the star connection drive. FIG. 4 is a diagram showing the open connection drive. For the sake of simplicity, in FIGS. 3 and 4, the control unit 15 is omitted.

[0043] As shown in FIG. 2, the drive region of the rotating electrical machine 3 is divided into two regions according to the rotational speed and the torque. One of the drive regions is the star connection drive region. The star connection drive region is the normal operating region. The other drive region is the open connection drive region. The open connection drive region is a region with higher rotation or higher torque than the star connection drive region.

[0044] When the operating point is in the star connection drive region, the control unit 15 executes the control of the star connection drive. The star connection drive is sometimes referred to as the Y drive. The control unit 15 controls the MOSFETs 8S, 9S and the switching switch 10 so that the windings 3U, 3V, 3W are in the star connection state. Specifically, as shown in FIG. 3, for all the switching switches 10, the MOSFETs are turned off and the switching switches 10 are set to the open state. Also, the inverter 9 is neutralized. As illustrated in FIG. 3, for example, the MOSFET 9S of the upper arm 9H of all phases may be turned on and the MOSFET 9S of the lower arm 9L of all phases may be turned off. The MOSFET 9S of the upper arm 9H of all phases may be turned off and the MOSFET 9S of the lower arm 9L of all phases may be turned on. Then, the MOSFET 8S of the inverter 8 is controlled according to the drive request or the like.

[0045] FIG. 3 shows one of the energization patterns in the star connection drive. The dashed-dotted arrow shown in FIG. 3 indicates an example of the current path. FIG. 3 shows the current path when the MOSFET 8S of the upper arm 8H of the U phase and the MOSFET 8S of the lower arm 8L of the W phase are turned on. In the example shown in FIG. 3, the upper arm 9H side of the inverter 9 is turned on and the lower arm 9L side is turned off. The current flows in the order of the upper arm 8H of the U phase → node U1 → U phase winding 3U → node U2 → upper arm 9H of the U phase → upper arm 9H of the W phase → node W2 → W phase winding 3W → node W1 → lower arm 8L of the W phase. In this way, in the star connection drive, the current flows without passing through the switching switch 10.

[0046] When the operating point is in the open - connection drive region, the control unit 15 executes the control of open - connection drive. The open - connection drive is sometimes referred to as H - drive. For example, for all the switching switches 10, the control unit 15 turns on the MOSFETs and closes the switching switches 10. The control unit 15 may close the corresponding - phase switching switch 10 at the timing when it turns on the MOSFET 9S of the upper arm 9H. Also, the control unit 15 releases the neutral point by the inverter 9. By releasing the neutral point, an open - connection circuit of the upper and lower arm circuits 8HL, 9HL of the U - phase through the U - phase winding 3U is formed. Similarly, an open - connection circuit of the upper and lower arm circuits 8HL, 9HL of the V - phase through the V - phase winding 3V is formed. An open - connection circuit of the upper and lower arm circuits 8HL, 9HL of the W - phase through the W - phase winding 3W is formed. The control unit 15 regards each phase as an independent open - connection circuit and controls the applied voltage for each phase.

[0047] Figure 4 shows one of the energization patterns in open - connection drive. The dashed - double - dotted - line arrow shown in Figure 4 indicates an example of the current path. In Figure 4, the current path when the MOSFET 8S of the lower arm 8L of the W - phase and the MOSFET 9S of the upper arm 9H of the W - phase are turned on is shown. The current flows in the order of switching switch 10→upper arm 9H of the W - phase→node W2→W - phase winding 3W→node W1→lower arm 8L of the W - phase. In this way, in open - connection drive, current flows through the switching switch 10.

[0048] As described above, the inverters 8, 9 can switch between star - connection drive and open - connection drive. By executing open - connection drive instead of star - connection drive, it is possible to output in a region of higher rotation speed or a region of higher torque.

[0049] <Power conversion module> Next, based on Figures 5, 6, and 7, the power conversion module will be described. Figure 5 is a plan view showing an example of the power conversion module. Figure 6 is a cross - sectional view taken along the line VI - VI of Figure 5. Figure 7 is a cross - sectional view taken along the line VII - VII of Figure 5.

[0050] Hereinafter, the thickness direction of the substrate is defined as the Z direction, and one direction orthogonal to the Z direction is defined as the X direction. The direction orthogonal to both the Z direction and the X direction is defined as the Y direction. Unless otherwise specified, the shape viewed from the Z direction in plan view, in other words, the shape along the XY plane defined by the X direction and the Y direction, is defined as the planar shape. Also, the plan view from the Z direction may be simply referred to as the plan view.

[0051] The power conversion module 20 provides at least a part of the above-described power conversion circuit 4. The power conversion module 20 includes a cooler 30, a substrate 40, a semiconductor element 50, a snubber circuit 60, a switching switch 70, a clip 80, and a main terminal 90. The power conversion module 20 may further include a capacitor device that provides the smoothing capacitor 7. The power conversion module 20 may further include a circuit board that provides the control unit 15. The power conversion module 20 may further include a sealing body that seals the semiconductor element 50, the snubber circuit 60, the switching switch 70, etc. The power conversion module 20 may be referred to as a semiconductor module, an inverter module, a power conversion device, etc.

[0052] The cooler 30 supports other elements that make up the power conversion module 20. The cooler 30 cools the circuit elements of the power conversion module 20, such as the semiconductor element 50 and the snubber circuit 60. The cooler 30 is formed using a metal material such as Al or Cu. The cooler 30 illustrated in FIG. 6 has a case 31 and a lid 32. The case 31 and the lid 32 form a flow path 33 in a state where the lid 32 is assembled to the case 31. The case 31 has, for example, a box shape with one surface open. The lid 32 is fixed to the case 31 so as to close the opening of the case 31. On the inner surface of the lid 32, fins 34, for example, a plurality of pin fins, are provided. The fins 34 are disposed in the flow path 33. The flow path 33 extends, for example, in the X direction.

[0053] The cooler 30 has an inlet pipe 35 and an outlet pipe 36 provided on the side wall of the case 31. In the example shown in FIG. 6, the inlet pipe 35 is attached to the side wall on the substrate 42 side in the X direction, and the outlet pipe 36 is attached to the side wall on the substrate 41 side. The refrigerant 37 is supplied to the flow path 33 through the inlet pipe 35. The refrigerant 37 that has flowed through the flow path 33 is discharged outside the cooler 30 through the outlet pipe 36. As the refrigerant 37, a phase-changing refrigerant such as water or ammonia, or a non-phase-changing refrigerant such as an ethylene glycol-based refrigerant may be used. For example, LLC may be used as the refrigerant 37. LLC is an abbreviation for long life coolant.

[0054] The cooler 30 has a front surface 301 and a back surface 302. The back surface 302 is the surface opposite to the front surface 301 in the Z direction. The substrate 40 is disposed on the front surface 301. The flow path 33 is provided so as to overlap the semiconductor element 50 and the snubber circuit 60 in a plan view so as to effectively cool the semiconductor element 50, the snubber circuit 60, etc. The flow path 33 is provided so as to overlap most of the substrate 40 in a plan view.

[0055] The cooler 30 is not limited to the configuration having the flow path 33 described above. As the cooler 30, for example, a heat dissipation member such as a heat sink may be used. A heat sink may sometimes be referred to as a heat dissipation plate, a cooling plate, etc. The heat dissipation member may include heat dissipation fins. When insulation of the substrate 40 with respect to the cooler 30 is not required, a bonding material such as solder or sintered Ag may be interposed between the substrate 40 and the cooler 30. That is, the substrate 40 may be bonded to the front surface 301 of the cooler 30. When insulation is required, an electrically insulating member may be disposed between the substrate 40 and the cooler 30. As the insulating member, for example, a ceramic plate or a resin sheet can be adopted. In order to enhance the thermal conductivity, a TIM such as silicone gel may be adopted. TIM is an abbreviation for Thermal Interface Material. Instead of the cooler 30, a support member that does not provide a cooling function may be used.

[0056] The substrate 40 provides a wiring function. The substrate 40 may be referred to as a wiring board, a printed circuit board, etc. A semiconductor element 50, a snubber circuit 60, and a switching switch 70 are mounted on the substrate 40. The substrate 40 has, for example, a substantially rectangular planar shape. The power conversion module 20 may include a single substrate 40 or a plurality of substrates 40. The substrate 40 includes a substrate 41 and a substrate 42. The substrate 41 corresponds to the first substrate, and the substrate 42 corresponds to the second substrate. The substrates 41 and 42 are arranged side by side in the X direction on one surface 301 of the cooler 30.

[0057] The substrate 41, together with the electronic components mounted on the substrate 41, constitutes the circuit on the inverter 8 side. The substrate 42, together with the electronic components mounted on the substrate 42, constitutes the circuit on the inverter 9 side. The substrate 41 has an insulating base material 411 and a conductor disposed on the insulating base material 411. The substrate 42 has an insulating base material 421 and a conductor disposed on the insulating base material 421. The insulating base materials 411 and 421 are formed using an electrical insulating material such as ceramic or resin.

[0058] The conductor is formed of a metal having good electrical conductivity and thermal conductivity such as Cu or Al as a material. The conductor may have a plating film such as Ni-based or Au on its surface. The conductor may be disposed only on one surface of the insulating base materials 411 and 421, or may be disposed on both the front and back surfaces. The back surfaces of the insulating base materials 411 and 421 are the surfaces on the cooler 30 side in the Z direction. The conductor may be disposed inside the insulating base materials 411 and 421. That is, the substrates 41 and 42 may be single-sided substrates, double-sided substrates, or multi-layer substrates of three or more layers including inner layer wiring. The conductor may include via conductors. The via conductor is formed by disposing a conductor such as plating in a through hole (via) formed in the insulating layer constituting the insulating base materials 411 and 421. The via conductor electrically connects the conductors disposed in different layers.

[0059] The exemplary substrate 41 has a conductor 412 disposed on one surface and a conductor 413 disposed on the back surface. The substrate 42 has a conductor 422 disposed on one surface and a conductor 423 disposed on the back surface. The conductors 413, 423 are electrically separated from the corresponding conductors 412, 422 by the insulating substrates 411, 421. The conductors 413, 423 provide, for example, a heat dissipation function. The substrates 41, 42 are arranged on the cooler 30 with the conductors 413, 423 facing the cooler 30 side.

[0060] The conductors 412, 422 are patterned. The patterned conductors 412, 422 provide a wiring function. That is, they form a circuit together with the mounted electronic components. The conductor 412 includes a P wiring 414, an N wiring 415, an O wiring 416, and a signal wiring 417. Each wiring is electrically separated by a predetermined interval (gap). The conductor 422 includes a P wiring 424, an N wiring 425, an O wiring 426, and signal wirings 427, 428. Each wiring is electrically separated by providing a predetermined interval. The P wirings 414, 424 may be referred to as a positive electrode wiring, a high-potential power supply line, etc. The N wirings 415, 425 may be referred to as a negative electrode wiring, a low-potential power supply line, etc. The O wirings 416, 426 may be referred to as an output wiring, etc.

[0061] The P wiring 414 is connected to the drain electrode (drain terminal) of the semiconductor element 51H. A P terminal 91 is joined to the P wiring 414. The P wiring 414 electrically connects the P terminal 91 and the semiconductor element 51H. The P wiring 414 is provided for each phase of the upper and lower arm circuits 8HL that constitute the inverter 8. The P wiring 414 generally extends in the Y direction. The three P wirings 414 are arranged side by side in the X direction with a predetermined interval. One end of the P wiring 414 is disposed near the end of the substrate 41 in the Y direction. A P terminal 91 is joined to one end of the P wiring 414. The other end of the P wiring 414 is located in the middle of the substrate 41 in the Y direction. The other end of the P wiring 414 is joined to the corresponding semiconductor element 51H (drain terminal).

[0062] The P wiring 424 is connected to the drain electrode (drain terminal) of the semiconductor element 52H. The P wiring 424 is electrically connected to the P terminal 91 via the P wiring 414. The P wiring 424 has wirings 424A, 424B, and 424C. The wirings 424A and 424B are provided for each phase of the upper and lower arm circuits 9HL constituting the inverter 9. The wiring 424A extends generally in the Y direction. One end of the wiring 424A is disposed near the end of the substrate 42 in the Y direction. The other end of the wiring 424A is located in the middle of the substrate 41 in the Y direction. The drain electrode (drain terminal) of the corresponding switching switch 70 is joined to the other end of the wiring 424A.

[0063] The wiring 424B extends in the Y direction while having a predetermined interval from the lower end of the corresponding wiring 424A. The wiring 424B is arranged side by side with the wiring 424A of the corresponding phase in the Y direction. The drain electrode (drain terminal) of the corresponding semiconductor element 52H is joined to the wiring 424B. The source electrode (source terminal) of the semiconductor element 52H is electrically connected to the wiring 424B via the clip 823. The three sets of wirings 424A and 424B are arranged side by side in the X direction with a predetermined interval. The wiring 424C is continuous with the end of the wiring 424A opposite to the end to which the switching switch 70 is connected. The wiring 424C is disposed near the end of the substrate 42 in the Y direction. The wiring 424C is disposed near the end on the side where the P terminal 91 and the N terminal 92 are arranged in the Y direction. The wiring 424C extends generally in the X direction. The wiring 424C commonly connects the wirings 424A provided for each phase. The wiring 424C is continuous with one end of the wiring 424A.

[0064] The N wiring 415 is electrically connected to the source electrode (source terminal) of the semiconductor element 51L via the clip 812. An N terminal 921 (92) is joined to the N wiring 415. The N wiring 415 electrically connects the N terminal 921 and the semiconductor element 51L. The N wiring 415 has wirings 415A and 415B. The wiring 415A extends generally in the Y direction. The wiring 415A has a length substantially equal to that of the P wiring 414 in the Y direction. The wiring 415A is arranged alternately with the P wiring 414 in the X direction and is disposed between the P wirings 414. That is, the N wiring 415 has two wirings 415A. In the X direction, the P wiring 414, the wiring 415A, the P wiring 414, the wiring 415A, and the P wiring 414 are arranged in this order.

[0065] One of the ends of the wiring 415A is disposed near the end of the substrate 41 in the Y direction. An N terminal 921 (92) is joined to one of the ends of the wiring 415A. The other wiring 415B is continuous with the other end of the wiring 415A. The wiring 415B is disposed in the middle of the substrate 41 in the Y direction. The wiring 415B is disposed between the P wiring 414 and the O wiring 416. The wiring 415B extends generally in the X direction. The wiring 415B extends from near one end to near the other end of the substrate 41 in the X direction. The wiring 415B commonly connects the wirings 415A. The clip 812 is connected to the wiring 415B.

[0066] The N wiring 425 is electrically connected to the source electrode (source terminal) of the semiconductor element 52L via the clip 822. The N terminal 922 (92) is joined to the N wiring 425. The N wiring 425 electrically connects the N terminal 922 and the semiconductor element 52L. The N wiring 425 is provided for each phase of the upper and lower arm circuits 9HL that constitute the inverter 9. The N wiring 425 extends generally in the Y direction. The three N wirings 425 are arranged side by side in the X direction with a predetermined interval. One of the ends of the N wiring 425 is arranged near the end of the substrate 42 in the Y direction. The N terminal 922 is joined to one of the ends of the N wiring 425. The other one of the ends of the N wiring 425 is located in the middle of the substrate 42 in the Y direction. The clip 822 is connected to the other one of the ends of the N wiring 425.

[0067] In the X direction, the N wiring 425 is arranged alternately with the P wiring 424 (wiring 424A, 424B). The N wiring 425 runs parallel to the wiring 424A, 424B (P wiring 424). Running parallel means a state of extending side by side with each other. The P wiring 424 is arranged at the end on the substrate 41 side in the X direction. The N wiring 425 is arranged side by side with the corresponding phase O wiring 426 in the Y direction.

[0068] The O wiring 416 is connected to the drain electrode (drain terminal) of the semiconductor element 51L. The O terminal 931 (93) is joined to the O wiring 416. The source terminal of the semiconductor element 51H is electrically connected to the O wiring 416 via the clip 811. The O wiring 416 electrically connects the source terminal of the semiconductor element 51H, the drain terminal of the semiconductor element 51L, and the O terminal 931. The O wiring 416 is provided for each phase. The O wiring 416 is arranged side by side with the corresponding phase P wiring 414 in the Y direction via the wiring 415B.

[0069] The O wiring 426 is connected to the drain electrode (drain terminal) of the semiconductor element 51L. The O terminal 932 (93) is joined to the O wiring 426. The source terminal of the semiconductor element 52H is electrically connected to the O wiring 426 via the clip 821. The O wiring 426 electrically connects the source terminal of the semiconductor element 52H, the drain terminal of the semiconductor element 52L, and the O terminal 932. The O wiring 426 is provided for each phase. The O wiring 426 is arranged side by side with the corresponding phase's P wiring 424 (wiring 424A, 424B) and N wiring 425 in the Y direction.

[0070] The signal wiring 417 electrically relays between the pads of the semiconductor elements 51H, 51L and signal terminals (not shown). The signal wiring 427 electrically relays between the pads of the semiconductor elements 52H, 52L and signal terminals (not shown). The signal wirings 417, 427 are electrically connected to the pads via, for example, bonding wires. The signal wirings 417, 427 are, for example, signal islands formed in the corresponding substrates 41, 42. For convenience, in FIG. 5, one signal wiring 417, 427 is shown for one semiconductor element 50.

[0071] In the substrate 41, the signal wiring 417 is arranged side by side with the corresponding semiconductor elements 51H, 51L in the Y direction. In the Y direction, the signal wiring 417 corresponding to the semiconductor element 51H is arranged at a position closer to the signal wiring 417 than the semiconductor element 51H with respect to the end portion on the P terminal 91 side in the substrate 41. The signal wiring 417 corresponding to the semiconductor element 51L is arranged at a position closer to the signal wiring 417 than the semiconductor element 51L with respect to the end portion on the O terminal 931 side in the substrate 41. In the substrate 42, the signal wiring 427 is arranged side by side with the corresponding semiconductor elements 52H, 52L in the X direction. In the X direction, the signal wiring 427 is arranged at a position closer to the substrate 41 than the corresponding semiconductor elements 52H, 52L.

[0072] The signal wiring 428 electrically relays between the pad of the switching switch 70 and a signal terminal (not shown). The signal wiring 428 is electrically connected to the pad, for example, via a bonding wire. The signal wiring 428 is, for example, an island for signals formed on the substrate 42. For the sake of convenience, in FIG. 5, one signal wiring 427 is shown for one semiconductor element 52H, 52L. The signal wiring 428 has the same arrangement as the signal wiring 427. On the substrate 42, the signal wiring 428 is arranged side by side with the corresponding switching switch 70 in the X direction. In the X direction, the signal wiring 428 is arranged at a position closer to the substrate 41 than the corresponding switching switch 70.

[0073] The semiconductor element 50 is an electronic component that provides the inverters 8, 9. The semiconductor element 50 is formed by forming vertical elements on a semiconductor substrate made of silicon (Si), a wide bandgap semiconductor having a wider bandgap than silicon, or the like. Examples of the wide bandgap semiconductor include silicon carbide (SiC), gallium nitride (GaN), gallium oxide (Ga2O3), and diamond. The semiconductor element 50 may be referred to as a power element, a semiconductor chip, or the like.

[0074] The vertical elements are configured to allow a main current to flow in the thickness direction of the semiconductor element 50 (semiconductor substrate). The semiconductor element 50 is arranged such that its thickness direction is substantially parallel to the Z direction. The semiconductor element 50 has main electrodes (main terminals) on both surfaces in the thickness direction. In the illustrated power conversion module 20, the semiconductor element 50 is formed by forming an n-channel MOSFET as a vertical element on a semiconductor substrate made of SiC. The semiconductor element 50 has a drain electrode (drain terminal) on the lower surface facing the substrate 40 and a source electrode (source terminal) on the upper surface opposite to the lower surface.

[0075] When the MOSFET is turned on, a current (main current) flows between the main terminals, that is, between the drain terminal and the source terminal. When 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 substantially the entire lower surface. The source terminal is formed on a part of the upper surface.

[0076] The semiconductor element 50 has a substantially rectangular planar shape. The semiconductor element 50 has pads, which are terminals for signals, on the upper surface. The pads are formed at positions different from the source terminal on the upper surface. The pads include at least gate pads.

[0077] The plurality of semiconductor elements 50 include semiconductor elements 51H that form the upper arm 8H, semiconductor elements 51L that form the lower arm 8L, semiconductor elements 52H that form the upper arm 9H, and semiconductor elements 52L that form the lower arm 9L. Each semiconductor element 50 includes three semiconductor elements 51H, 51L, 52H, and 52L. The semiconductor elements 51H, 51L, 52H, and 52L are provided for each phase. One semiconductor element 50 provides one arm. The U semiconductor elements 51H and 51L correspond to the first semiconductor element, and the semiconductor elements 52H and 52L correspond to the second semiconductor element. The semiconductor elements 51H and 52H may be referred to as upper arm elements. The semiconductor elements 51L and 52L may be referred to as lower arm elements.

[0078] The semiconductor elements 51H and 51L are mounted on the substrate 41. The semiconductor element 51H is arranged so as to overlap with the end on the O wiring 416 side in the P wiring 414 in plan view. The drain terminal of the semiconductor element 51H is joined to the P wiring 414 via a bonding material such as solder (not shown). The semiconductor element 51L is arranged so as to overlap with the O wiring 416 in plan view. The drain terminal of the semiconductor element 51L is joined to the O wiring 416 via a bonding material (not shown).

[0079] The semiconductor elements 51H of each phase are arranged side by side in the X direction. The semiconductor elements 51L of each phase are arranged side by side in the X direction. The semiconductor elements 51H and 51L of the corresponding phases are generally arranged side by side in the Y direction. The semiconductor elements 51H and 51L of the corresponding phases are arranged with a shift in the X direction so that only a part of them faces each other in the Y direction. The arrangement of the semiconductor elements 51H and 51L is shifted by 180 degrees around the Z axis, that is, they have an inverted positional relationship with each other. The pads of the semiconductor elements 51H and 51L are provided on the outer side, rather than on the inner side, that is, the side facing each other, in the Y direction. The Z axis is an axis parallel to the Z direction.

[0080] The semiconductor elements 52H and 52L are mounted on the substrate 42. The semiconductor element 52H is arranged so as to overlap the wiring 424B (P wiring 424) in a plan view. The drain terminal of the semiconductor element 52H is joined to the wiring 424B via a bonding material (not shown). The semiconductor element 52L is arranged so as to overlap the O wiring 426 in a plan view. The drain terminal of the semiconductor element 52L is joined to the O wiring 426 via a bonding material (not shown).

[0081] The semiconductor elements 52H of each phase are arranged side by side in the X direction. The semiconductor elements 52L of each phase are arranged side by side in the X direction. The semiconductor elements 52H and 52L of the corresponding phases are generally arranged side by side in the Y direction. The semiconductor elements 52H and 52L of the corresponding phases are arranged with a shift in the X direction so that only a part of them faces each other in the Y direction. The arrangement of the semiconductor elements 52H and 52L is common around the Z axis. The pads of the semiconductor elements 52H and 52L are provided on the substrate 41 side in the X direction.

[0082] The snubber circuit 60 is an electronic component that provides a snubber circuit. The snubber circuit 60 includes a snubber circuit 61 that provides the snubber circuit 12 and a snubber circuit 62 that provides the snubber circuit 11. For the sake of simplicity, FIGS. 5 and 6 show them in a simplified manner. The snubber circuits 61 and 62 may be referred to as snubber components. The snubber circuit 61 has at least a capacitor to provide the snubber circuit 12. The snubber circuit 61 is mounted on the substrate 41. The snubber circuit 61 is connected in parallel to the upper and lower arm circuits 8HL as described above. The snubber circuit 61 electrically bridges the P wiring 414 and the N wiring 415. In the illustrated power conversion module 20, the snubber circuit 61 is provided for each phase. The snubber circuit 61 electrically bridges the P wiring 414 and the wiring 415A. The snubber circuit 61 electrically bridges the P wiring 414 and the N wiring 415 at a position closer to the P terminal 91 and the N terminal 921 than the semiconductor element 51H. Two adjacent snubber circuits 61 are connected to the common wiring 415A. The snubber circuits 61 of each phase are arranged in the X direction.

[0083] The snubber circuit 62 has at least a capacitor to provide the snubber circuit 11. The snubber circuit 62 is mounted on the substrate 42. The snubber circuit 62 is connected in parallel to the upper and lower arm circuits 9HL as described above. The snubber circuit 62 electrically bridges the P wiring 424 and the N wiring 425. In the illustrated power conversion module 20, the snubber circuit 62 is provided for each phase. The snubber circuit 62 electrically bridges the wiring 424A and the N wiring 425. The snubber circuit 62 electrically bridges the P wiring 424 and the N wiring 425 at a position closer to the wiring 424C than the switching switch 70. The snubber circuits 62 of each phase are arranged in the X direction.

[0084] The switching switch 70 provides the switching switch 10 in the power conversion circuit 4. The switching switch 70 is formed by forming a switching element on a semiconductor substrate. In the exemplary power conversion module 20, the switching switch 70 has the same configuration as the semiconductor element 50. The switching switch 70 is formed by forming a MOSFET on a semiconductor substrate. A parasitic diode is connected in anti-parallel to the MOSFET.

[0085] The switching switch 70 is arranged closer to the inverter 9 (semiconductor elements 52H, 52L) than the inverter 8 (semiconductor elements 51H, 51L) in a plan view. In the exemplary power conversion module 20, the switching switch 70 is mounted on the substrate 42. The switching switch 70 is provided for each phase, similar to the snubber circuit 62. The switching switch 70 is arranged so as to overlap with the end on the wiring 424B side in the wiring 424A in a plan view. The drain terminal of the switching switch 70 is joined to the wiring 424A (P wiring 424) via a joining material (not shown). The switching switches 70 corresponding to each phase are arranged side by side in the X direction. The pads of the switching switch 70 are provided on the substrate 41 side in the X direction.

[0086] The clip 80 may be referred to as a bridging member, a relay member, a metal bridge, etc. The clip 80 is a metal plate material having a base material of a metal with good conductivity such as Cu or a Cu alloy. The clip 80 may be formed by punching out a metal plate with a predetermined thickness and performing press working. The clip 80 may be formed using a deformed material with different thicknesses in part. The clip 80 may be one having a film applied to the surface of the base material by surface treatment. The clip 80 may be provided with a plating film such as Ni or Au on the surface. The clip 80 may be provided with a Ni plating film containing P formed on the base material. The NiP film is formed, for example, by an electroless plating method. As the base material, Ag, Au, Al, Mg, etc. may be used instead of Cu. As the film added on the base material, Sn, Ag, etc. may be used instead of Ni or Au.

[0087] Clip 80 includes clip 811, 812, clip 821, 822, 823, 824, and clip 83. Clip 811 is connected to semiconductor element 51H. Clip 811 is provided individually for semiconductor element 51H. Clip 811 extends generally in the Y direction and electrically connects the source terminal of semiconductor element 51H and O wiring 416. Clip 812 is connected to semiconductor element 51L. Clip 812 is provided individually for semiconductor element 51L. Clip 812 extends generally in the Y direction and electrically connects the source terminal of semiconductor element 51L and wiring 415B of N wiring 415. Clips 811, 812, together with semiconductor elements 51H, 51L, and P wiring 414, N wiring 415, and O wiring 416, constitute inverter 8. Clips 811, 812 are mounted on substrate 41.

[0088] Clip 821 is connected to semiconductor element 52H. Clip 821 is provided individually for semiconductor element 52H. Clip 821 extends generally in the Y direction and electrically connects the source terminal of semiconductor element 52H and O wiring 426. Clip 822 is connected to semiconductor element 52L. Clip 822 is provided individually for semiconductor element 52L. Clip 822 extends generally in the Y direction and electrically connects the source terminal of semiconductor element 52L and N wiring 425. Clips 821, 822, together with semiconductor elements 52H, 52L, and P wiring 424, N wiring 425, and O wiring 426, constitute inverter 9. Clips 821, 822 are mounted on substrate 42.

[0089] Clip 823 is connected to the changeover switch 70. Clip 823 is provided individually for the changeover switch 70. Clip 823 extends generally in the Y direction and electrically connects the source terminal of the changeover switch 70 and the wiring 424B of the P wiring 424. Clip 823 functions as part of the P wiring 424. Clip 824 extends generally in the X direction. Clip 824 electrically connects adjacent wirings 424B. Clip 80 includes two clips 824. Clip 824 intersects the N wiring 425 three-dimensionally as shown in FIGS. 5 and 7. Clip 824 electrically connects adjacent wirings 424B across the N wiring 425. By means of clip 824, the low-potential side terminals of the changeover switch 70 are commonly connected. Clips 823 and 824 are mounted on the substrate 42. Clip 823 and the wiring 424B provide the wiring 5B. Clip 823 and the wiring 424B correspond to the second wiring.

[0090] Clip 83 electrically connects the P wiring 414 and the P wiring 424. Clip 83 electrically connects the inverter 8 and the inverter 9. Clip 83 extends generally in the X direction. Clip 83 bridges the substrate 41 and the substrate 42. Clip 83 and the wirings 424A and 424C provide the wiring 5A. Clip 83 and the wirings 424A and 424C correspond to the first wiring. Note that as the bridging member, an inner layer wiring of the substrate or a bonding wire may be employed.

[0091] The main terminal 90 is formed using a metal material with good conductivity such as Cu. The main terminal 90 is, for example, a plate material. The main terminal 90 is an external connection terminal that is electrically connected to the main terminal (main electrode) of the semiconductor element 50. The main terminal 90 includes a P terminal 91 and an N terminal 92 that are power supply terminals, and an O terminal 93.

[0092] The P terminal 91, together with the P wirings 414 and 424 and the clips 823 and 83, provides the above-described power line 5. The P terminal 91 is an external connection terminal connected to a capacitor device (not shown) that provides the smoothing capacitor 7. The P terminal 91 is electrically connected to the positive terminal of the smoothing capacitor 7. The P terminal 91 may be referred to as a positive terminal, a high-potential power supply terminal, etc. The P terminal 91 is joined to the P wiring 414. The P terminal 91 is mounted on the substrate 41. In the exemplary power conversion module 20, one end of the P terminal 91 branches into three, and each is joined to the P wiring 414 of the corresponding phase. The P terminal 91 extends generally in the Y direction from the joint with the P wiring 414. The P terminal 91 extends outward from the substrate 41 to a position that does not overlap with the cooler 30 in a plan view.

[0093] The N terminal 92, together with the N wirings 415 and 425 and the clips 812 and 822, provides the above-described power line 6. The N terminal 92 is an external connection terminal connected to a capacitor device that provides the smoothing capacitor 7. The N terminal 92 is electrically connected to the negative terminal of the smoothing capacitor 7. The N terminal 92 may be referred to as a negative terminal, a low-potential power supply terminal, etc. The N terminal 92 includes an N terminal 921 joined to the N wiring 415 and an N terminal 922 joined to the N wiring 425. The N terminal 921 is mounted on the substrate 41. The N terminal 922 is mounted on the substrate 42.

[0094] The exemplary power conversion module 20 includes one N terminal 921 and three N terminals 922. One end of the N terminal 921 branches into two, and each is joined to a corresponding wiring 415A (N wiring 415). The N terminal 921 extends generally in the Y direction from the joint with the wiring 415A. The N terminal 921 extends outward from the substrate 41 to a position that does not overlap with the cooler 30 in a plan view. The N terminals 922 are provided for each phase. The N terminal 922 is joined to the N wiring 425 of the corresponding phase. The N terminal 922 extends generally in the Y direction from the joint with the corresponding wiring 425. The N terminal 922 extends outward from the substrate 42 to a position that does not overlap with the cooler 30 in a plan view. As the N terminal 922, a configuration in which one end branches into three and each is joined to a corresponding N wiring 425 may be adopted.

[0095] The O terminal 93 is electrically connected to the windings 3U, 3V, 3W of the corresponding phase of the rotating electric machine 3. The O terminal 93 may be referred to as an output terminal, an AC terminal, etc. The O terminal 93 includes an O terminal 931 joined to the O wiring 416 and an O terminal 932 joined to the O wiring 426. The O terminal 931 is provided for each phase of the upper and lower arm circuits 8HL. The O terminal 931 provides the output line 13 together with the O wiring 416. The O terminal 931 extends generally in the Y direction from the joint with the O wiring 416, on the side opposite to the P terminal 91 and the N terminal 92. The O terminal 931 extends outward from the substrate 41 to a position that does not overlap with the cooler 30 in a plan view.

[0096] The O terminal 932 is provided for each phase of the upper and lower arm circuits 9HL. The O terminal 932 provides the output line 14 together with the O wiring 426. The O terminal 932 extends generally in the Y direction from the joint with the O wiring 426, on the side opposite to the P terminal 91 and the N terminal 92. The O terminal 932 extends outward from the substrate 42 to a position that does not overlap with the cooler 30 in a plan view.

[0097] <Summary of the First Embodiment> Figures 8 and 9 show a reference example of a power conversion device. Figure 8 shows an example of an energization pattern during star connection drive in the reference example. Figure 9 shows an energization pattern with a different timing from that in Figure 5 during star connection drive. In the reference example, an "r" is added to the end of the reference numerals of the related elements shown in this embodiment.

[0098] The control unit performs star connection drive while switching between a plurality of energization patterns. For example, the control unit performs star connection drive using a PWM control method. PWM is an abbreviation for Pulse Width Modulation. The plurality of energization patterns include the zero vector energization patterns shown in Figures 8 and 9. The energization pattern shown in Figure 8 is a pattern in which all of the upper arms 8Hr of the inverter 8r are turned on and all of the lower arms 8Lr are turned off among the zero vectors. The energization pattern shown in Figure 9 is a pattern in which all of the lower arms 8Lr of the inverter 8r are turned on and all of the upper arms 8Hr are turned off among the zero vectors.

[0099] As shown in Figures 8 and 9, in the power conversion circuit 4r of the reference example, the snubber circuit 11r connected in parallel to the inverter 9r is connected to the wiring 5Br that connects the changeover switch 10r and the inverter 9r among the power supply lines 5r. One end of the snubber circuit 11r is connected to the wiring 5Br of the power supply line 5r, and the other end is connected to the power supply line 6r. For convenience, in Figures 8 and 9, the smoothing capacitor and the snubber circuit connected in parallel to the inverter 8r are omitted. Also, the snubber circuit 11r is common to each phase of the inverter 9r.

[0100] In the example shown in Figures 8 and 9, the inverter 9r is neutralized by turning on all of the three-phase upper arms 9Hr of the inverter 9r. In this state, as shown in Figure 8, when all of the three-phase upper arms 8Hr of the inverter 8r are turned on, the voltage across both ends of the capacitor 11Cr becomes approximately equal to the supply voltage of the DC power supply 2r, that is, the power supply voltage Vdc. Also, as shown in Figure 9, when all of the three-phase lower arms 8Lr of the inverter 8r are turned on, the voltage across both ends of the capacitor 11Cr becomes approximately 0V (zero volts).

[0101] As described above, in order to perform star connection driving while switching a plurality of energization patterns, during star connection driving, the voltage across the capacitor 11Cr of the snubber circuit 11r fluctuates. The voltage across the capacitor 11Cr fluctuates in the range from 0V to Vdc. In this way, since the capacitor 11Cr is charged and discharged during star connection driving, the power conversion efficiency decreases. The resistor 11Rr of the snubber circuit 11r consumes the energy stored in the capacitor 11Cr and generates heat. This heat affects the capacitor 11Cr.

[0102] FIG. 10 schematically shows the arrangement of the semiconductor elements 52H, 52L, the snubber circuit 62, and the switching switch 70 in the power conversion module 20 according to the present embodiment. As shown in FIGS. 5 and 10, in the power conversion module 20, the switching switch 70 is arranged closer to the semiconductor elements 52H, 52L (inverter 9) than to the semiconductor elements 51H, 51L (inverter 8). Thereby, it is easy to connect the snubber circuit 62 to the wiring 424A (first wiring). That is, it is easy to connect the snubber circuit 11 to the wiring 5A. By connecting the snubber circuit 11 to the wiring 5A, the voltage across the capacitor 11C is clamped to the power supply voltage of the DC power supply 2 (the voltage across the smoothing capacitor 7). Therefore, during the OFF state (open state) of the switching switch 10, that is, during star connection driving, the charging and discharging operation of the capacitor 11C can be suppressed. Thus, the power conversion efficiency can be improved.

[0103] As illustrated, the power conversion module 20 may include two substrates 41 and 42. The semiconductor elements 51H and 51L (first semiconductor elements) may be mounted on the substrate 41 (first substrate), and the semiconductor elements 52H and 52L (second semiconductor elements), the snubber circuit 62, and the switching switch 70 may be mounted on the substrate 42 (second substrate). Since the semiconductor elements 52H and 52L, the snubber circuit 62, and the switching switch 70 that constitute the inverter 9 are mounted on the common substrate 42, the switching switch 70 can be positioned closer to the inverter 9. That is, the snubber circuit 62 can be easily connected by the wiring 424A. Therefore, a circuit configuration that can improve the power conversion efficiency can be easily realized. Further, warping can be suppressed by dividing the substrate into a plurality of parts.

[0104] As illustrated, the switching switch 70 may be disposed between the semiconductor elements 52H and 52L (second semiconductor elements) and the snubber circuit 62. Thereby, the physical size in the X direction can be reduced.

[0105] Furthermore, as shown in FIG. 11, as the second power supply line, a second upper power supply line connecting one end of the snubber circuit 62 and the semiconductor element 52H (second upper arm element), and a second lower power supply line connecting the semiconductor element 52L (second lower arm element) and the other end of the snubber circuit 62 are provided, and the second upper power supply line and the second lower power supply line may be arranged in parallel. One of the second upper power supply line and the second lower power supply line includes the switching switch 70. FIG. 11 is an enlarged view of the XI region shown by the two-dot chain line in FIG. 5 on the substrate 42. The broken line indicates a current loop including the snubber circuit 62. In the example shown in FIG. 11 (FIG. 5), the second upper power supply line includes the wirings 424A and 424B, the clip 823, and the switching switch 70. The second lower power supply line includes the clip 822 and the N wiring 425. By disposing the switching switch 70 between the snubber circuit 62 and the semiconductor elements 52H and 52L, and by arranging the above-described power supply lines in parallel, the area of the current loop can be reduced, and thus the wiring inductance can be reduced.

[0106] As illustrated, semiconductor elements 52H and 52L may be provided for each phase, and the switching switch 70 and the snubber circuit 62 may be provided for each phase. According to this, the area of the current loop formed by the semiconductor elements 52H and 52L, the snubber circuit 62, and the switching switch 70 can be made smaller than the configuration in which a single switching switch and a snubber circuit common to the three phases are provided. Therefore, the wiring inductance of the upper and lower arm circuits 9HL can be further reduced, and thus the power conversion efficiency can be improved.

[0107] Note that the total chip area of the three switching switches 70 can be made smaller than the chip area of a single switching switch common to the three phases. Also, the total capacitance of the capacitors of the three snubber circuits 62 can be made smaller than the capacitance of a single capacitor common to the three phases. Therefore, the size of the power conversion module 20 can be reduced.

[0108] As illustrated, the source terminals of the switching switches 70 provided for each phase may be commonly connected. That is, the source terminals may be electrically connected by a common wiring. Thereby, for example, even if one of the switching switches 70 fails, another switching switch 70 can be substituted. Note that a configuration in which they are not commonly connected may also be adopted.

[0109] As illustrated, the common wiring and the second power supply line that does not include the switching switch 70 may intersect three-dimensionally. For example, a clip 824 may be used as the common wiring, and the clip 824 may straddle the N wiring 425 which is the second power supply line. With such a three-dimensional arrangement that also utilizes the Z direction, the degree of freedom in layout is improved, and the size of the power conversion module 20 can be reduced. Note that as the common wiring, inner layer wiring of the substrate 42(40), bonding wires, or the like may be used.

[0110] As illustrated, in a configuration where the semiconductor elements 52H, 52L and the switching switch 70 are arranged in a predetermined direction, in a direction orthogonal to the predetermined direction, the signal wirings 427, 428 may be arranged on the side opposite to the second power supply line (N wiring 425) that does not include the switching switch 70, with respect to the corresponding semiconductor elements 52H, 52L and the switching switch 70. As shown in FIG. 5, the semiconductor elements 52H, 52L and the switching switch 70 are arranged in the Y direction. The semiconductor elements 52H, 52L and the corresponding signal wirings 427 are arranged in the X direction. The switching switch 70 and the signal wiring 428 are arranged in the X direction. Thereby, in the Y direction, the size of the substrate 42, and thus the size of the power conversion module 20, can be reduced.

[0111] Furthermore, the signal wiring 417 and the corresponding semiconductor elements 51H, 51L may be arranged in a predetermined direction. On the inverter 8 side, the switching switch 70 is not arranged. Therefore, the degree of freedom in arrangement in the Y direction is higher than that on the inverter 9 side. By adopting an arrangement different from that of the signal wirings 427, 428, specifically, an arrangement in which the signal wiring 417 and the semiconductor elements 51H, 51L are arranged in the Y direction, the size in the X direction can be reduced.

[0112] As illustrated, the above-described second upper power supply line and second lower power supply line may be alternately arranged in one direction. As the first power supply lines, a first upper power supply line to which the high-potential side terminal of the semiconductor element 51H (first upper arm element) is electrically connected, and a first lower power supply line to which the low-potential side terminal of the semiconductor element 51L (first lower arm element) is electrically connected are provided, and the first upper power supply line and the first lower power supply line may be alternately arranged in one direction. Then, among the second upper power supply line and the second lower power supply line, the second power supply line on which the switching switch is arranged, and among the first upper power supply line and the first lower power supply line, the first power supply line that is electrically connected to the second power supply line on which the switching switch is arranged may be arranged to face each other in one direction. The first upper power supply line includes the P wiring 414. The first lower power supply line includes the wiring 415A (N wiring 415).

[0113] In the example shown in FIG. 5, the P wiring 414 and the P wiring 424 (wiring 424A, 424B) face each other in the X direction and are adjacent to each other. According to this, the wiring (power line) electrically connecting the inverter 8 and the inverter 9 can be simplified. Therefore, the physical size in the X direction can be reduced.

[0114] <Modification example> In the present embodiment, an example in which the power conversion circuit 4 includes the snubber circuit 12 and the power conversion module 20 includes the snubber circuit 61 has been shown, but the present invention is not limited to this. A configuration that does not include the snubber circuit 61 may also be used.

[0115] The number of the substrates 40 is not limited to two. For example, as shown in FIG. 12, all the semiconductor elements 50, all the snubber circuits 60, and all the switching switches 70 may be mounted on a common (single) substrate 40. In this configuration, the wiring 424C (P wiring 424) is continuous with the P wiring 414. Therefore, the physical size in the X direction can be further reduced. Other configurations are the same as those shown in FIG. 5.

[0116] The number of the substrates 40 may be three or more. For example, as shown in FIG. 13, the power conversion module 20 may include three substrates 41, 42, and 43. In FIG. 13, the configuration of the substrate 42 shown in FIG. 5 is divided into the substrates 42 and 43. The substrate 42 provides a two-phase configuration together with the mounted electronic components. The substrate 43 provides the remaining one-phase configuration together with the mounted electronic components. The power conversion module 20 further includes clips 825 and 826. The clips 825 and 826 bridge the substrates 42 and 43. The clip 825 extends generally in the X direction and electrically connects the wiring 424B of the substrate 42 and the wiring 424B of the substrate 43. The clip 826 extends generally in the X direction and electrically connects the wiring 424C of the substrate 42 and the wiring 424C of the substrate 43. Other configurations are the same as those shown in FIG. 5.

[0117] Although an example in which the switching switch 10 and the snubber circuit 11 are provided for each phase has been shown, the present invention is not limited to this. Although an example in which the snubber circuit 12 is provided for each phase has been shown, the present invention is not limited to this. For example, as shown in FIG. 14, in the power conversion circuit 4, one switching switch 10 and one snubber circuit 11 may be provided for each of the three-phase upper and lower arm circuits 9HL constituting the inverter 9. The snubber circuit 11 is connected to the wiring 5A. One snubber circuit 12 may be provided for each of the three-phase upper and lower arm circuits 8HL constituting the inverter 8.

[0118] FIG. 15 shows a schematic configuration of the power conversion module 20 that provides the power conversion circuit 4 shown in FIG. 14. FIG. 15 corresponds to FIG. 10. As shown in FIG. 15, the snubber circuit 61 is commonly arranged for the three phases of the inverter 8. The snubber circuit 62 is commonly arranged for the three phases of the inverter 9. Similarly, the switching switch 70 is also commonly arranged for the inverter 9. Further, the switching switch 70 is arranged at a position closer to the inverter 9 than the inverter 8. The switching switch 70 is arranged between the snubber circuit 62 and the semiconductor elements 52H, 52L. The snubber circuit 62 and the switching switch 70 are provided on a substrate common to the semiconductor elements 52H, 52L and different from the substrate of the semiconductor elements 51H, 51L. The same effects as the configurations shown in FIGS. 5 and 10 can be achieved.

[0119] In the power conversion circuit 4, an example is shown in which the switching switch 10 is provided on the power line 5, but the present invention is not limited thereto. For example, as shown in FIG. 16, the switching switch 10 may be provided on the power line 6. The power line 6 has a wiring 6A connecting the inverter 8 and the switching switch 10, and a wiring 6B connecting the switching switch 10 and the inverter 9. The wiring 6A corresponds to the first wiring, and the wiring 6B corresponds to the second wiring. The source terminal of the switching switch 10 is connected to the wiring 6A, and the drain terminal is connected to the wiring 6B. The lower arm 9L (source terminal) of each phase is connected to the wiring 6B. One end of the snubber circuit 11 is connected to the power line 5, and the other end of the snubber circuit 11 is connected to the wiring 6A. Although not shown, the power conversion circuit 4 can be provided by the power conversion module 20 having the same configuration as that of FIG. 15.

[0120] (Second Embodiment) This embodiment is a modification example based on the preceding embodiment, and the description of the preceding embodiment can be incorporated herein. In the preceding embodiment, the switching switch 70 is arranged between the snubber circuit 62 and the semiconductor elements 52H and 52L. Instead, the snubber circuit 62 and the switching switch 70 may be arranged side by side.

[0121] FIG. 17 shows a power conversion module according to this embodiment. FIG. 17 corresponds to FIG. 10. In FIG. 17, the power conversion module 20 is schematically shown. Similar to the preceding embodiment, the switching switch 70 is arranged closer to the semiconductor elements 52H and 52L than to the semiconductor elements 51H and 51L. The snubber circuit 62 and the switching switch 70 are provided for each phase of the inverter 9, similar to the preceding embodiment.

[0122] The snubber circuits 62 and the switching switches 70 are arranged side by side in the X direction for each phase. The snubber circuits 62 and the switching switches 70 are arranged along the arrangement direction of the inverters 8 and 9. The snubber circuits 62 and the switching switches 70 are arranged side by side in the Y direction with respect to the semiconductor elements 52H and 52L of the corresponding phase. The power conversion module 20 illustrated in FIG. 17 includes two substrates 41 and 42. The substrates 41 and 42 are arranged side by side in the X direction. The semiconductor elements 51H and 51L and the snubber circuit 61 are mounted on the substrate 41. The semiconductor elements 52H and 52L, the snubber circuit 62, and the switching switch 70 are mounted on the substrate 42. Other configurations are the same as those of the power conversion module (see FIG. 10) shown in the previous embodiment.

[0123] <Summary of the Second Embodiment> As illustrated, the switching switch 70 and the snubber circuit 62 may be arranged side by side in the X direction (predetermined direction). The semiconductor elements 52H and 52L and the switching switch 70 and the snubber circuit 62 arranged side by side in the X direction may be arranged side by side in the Y direction (orthogonal direction). The switching switch 70 and the snubber circuit 62 may be arranged side by side along the arrangement direction of the inverters 8 and 9. With such an arrangement, the switching switch 70 can be brought closer to the semiconductor elements 52H and 52L (inverter 9) than to the semiconductor elements 51H and 51L (inverter 8). Therefore, the same effects as those of the configuration shown in the previous embodiment can be achieved. That is, the power conversion efficiency can be improved.

[0124] An example in which the switching switch 70 is on the inverter 8 side and the switching switch 70 and the snubber circuit 62 are arranged side by side has been shown. Instead of this, the snubber circuit 62 may be on the inverter 8 side and the switching switch 70 and the snubber circuit 62 may be arranged side by side.

[0125] Although an example including the substrates 41 and 42 has been shown, the present invention is not limited to this. As shown in FIGS. 12 and 13, a single substrate 40 may be provided, or three or more substrates 40 may be provided. The power conversion module 20 may be configured not to include the snubber circuit 61.

[0126] (Third Embodiment) This embodiment is a modification based on the preceding embodiment, and the description of the preceding embodiment can be incorporated by reference. In the preceding embodiment, the snubber circuit 62 and the switching switch 70 are arranged side by side along the X direction. Instead, the snubber circuit 62 and the switching switch 70 may be arranged side by side along the Y direction.

[0127] FIG. 18 shows the power conversion module according to this embodiment. FIG. 18 corresponds to FIG. 17. In FIG. 18, the power conversion module 20 is schematically shown. Similar to the preceding embodiment, the switching switch 70 is arranged closer to the semiconductor elements 52H and 52L than to the semiconductor elements 51H and 51L. The snubber circuit 62 and the switching switch 70 are provided for each phase of the inverter 9, as in the preceding embodiment.

[0128] The snubber circuit 62 and the switching switch 70 are arranged side by side in the Y direction for each phase. The snubber circuit 62 and the switching switch 70 are arranged along a direction orthogonal to the arrangement direction of the inverters 8 and 9. The snubber circuit 62 and the switching switch 70 are arranged side by side in the X direction with respect to the semiconductor elements 52H and 52L of the corresponding phase. The snubber circuit 62 and the switching switch 70 and the semiconductor elements 52H and 52L are alternately arranged in the X direction. In the example shown in FIG. 18, the snubber circuit 62 and the switching switch 70 are arranged at the end on the substrate 41 side of the substrate 42. Other configurations are the same as those of the power conversion module 20 (see FIG. 17) shown in the preceding embodiment.

[0129] <Summary of the Third Embodiment> As illustrated, the changeover switch 70 and the snubber circuit 62 may be arranged side by side in the Y direction (predetermined direction). The changeover switch 70 and the snubber circuit 62 arranged side by side in the Y direction with the semiconductor elements 52H and 52L may be arranged side by side in the X direction (orthogonal direction). The changeover switch 70 and the snubber circuit 62 may be arranged side by side along a direction orthogonal to the arrangement direction of the inverters 8 and 9. With such an arrangement, the changeover switch 70 can be brought closer to the semiconductor elements 52H and 52L (inverter 9) than to the semiconductor elements 51H and 51L (inverter 8). Therefore, the same effects as those of the configuration shown in the previous embodiment can be achieved. That is, the power conversion efficiency can be improved.

[0130] An example in which the snubber circuit 62 and the changeover switch 70 are arranged at the end on the substrate 41 side on the substrate 42 is shown. Instead of this, the semiconductor elements 52H and 52L may be arranged at the end on the substrate 41 side on the substrate 42.

[0131] Although an example including the substrates 41 and 42 is shown, the present invention is not limited to this. As shown in FIGS. 12 and 13, a single substrate 40 may be provided, or three or more substrates 40 may be provided. The power conversion module 20 may be configured not to include the snubber circuit 61.

[0132] (Fourth Embodiment) This embodiment is a modification based on the preceding embodiment, and the description of the preceding embodiment can be incorporated herein. In the preceding embodiment, the changeover switch 70 is arranged between the snubber circuit 62 and the semiconductor elements 52H and 52L. Instead of this, the snubber circuit 62 may be arranged between the changeover switch 70 and the semiconductor elements 52H and 52L.

[0133] FIG. 19 shows the power conversion module according to this embodiment. FIG. 19 corresponds to FIG. 10. In FIG. 19, the power conversion module 20 is schematically shown. Similar to the previous embodiment, the switching switch 70 is arranged closer to the semiconductor elements 52H and 52L than to the semiconductor elements 51H and 51L. The snubber circuit 62 and the switching switch 70 are provided for each phase of the inverter 9, as in the previous embodiment.

[0134] The snubber circuit 62 and the switching switch 70 are arranged side by side in the Y direction for each phase. The snubber circuit 62 and the switching switch 70 are arranged along a direction orthogonal to the arrangement direction of the inverters 8 and 9. The snubber circuit 62 and the switching switch 70 are arranged side by side in the Y direction with respect to the semiconductor elements 52H and 52L of the corresponding phase. The snubber circuit 62 is arranged between the switching switch 70 and the semiconductor elements 52H and 52L. Other configurations are the same as those of the power conversion module 20 (see FIG. 10) shown in the previous embodiment.

[0135] <Summary of the Fourth Embodiment> As illustrated, the snubber circuit 62 may be arranged between the semiconductor elements 52H and 52L and the switching switch 70. With such an arrangement, the switching switch 70 can be brought closer to the semiconductor elements 52H and 52L (inverter 9) than to the semiconductor elements 51H and 51L (inverter 8). Therefore, the same effects as those of the configuration shown in the previous embodiment can be achieved. That is, the power conversion efficiency can be improved.

[0136] Although an example including the substrates 41 and 42 is shown, the present invention is not limited thereto. As shown in FIGS. 12 and 13, a single substrate 40 may be provided, or three or more substrates 40 may be provided. The power conversion module 20 may be configured not to include the snubber circuit 61.

[0137] (Other Embodiments) The disclosure in this specification, drawings, etc. is not limited to the illustrated embodiments. The disclosure includes the illustrated embodiments and modifications by those skilled in the art based thereon. For example, the disclosure is not limited to the combination of parts and / or elements shown in the embodiments. The disclosure can be implemented by various combinations. The disclosure can have additional parts that can be added to the embodiments. The disclosure includes those in which parts and / or elements of the embodiments are omitted. The disclosure includes the replacement or combination of parts and / or elements between one embodiment and another. The technical scope disclosed is not limited to the description of the embodiments. Some of the technical scopes disclosed are indicated by the description of the claims and should be construed to include all changes within the meaning and scope equivalent to the description of the claims.

[0138] The disclosure in the specification, drawings, etc. is not limited by the description of the claims. The disclosure in the specification, drawings, etc. includes the technical idea described in the claims and extends to more diverse and extensive technical ideas than the technical idea described in the claims. Therefore, various technical ideas can be extracted from the disclosure in the specification, drawings, etc. without being restricted by the description of the claims.

[0139] When an element or layer is referred to as being "on," "connected to," "attached to," or "coupled to" another element or layer, it may be directly on, connected to, attached to, or coupled to the other element or layer, and there may also be intervening elements or intervening layers. In contrast, when an element is referred to as being "directly on," "directly connected to," "directly attached to," or "directly coupled to" another element or layer, there are no intervening elements or intervening layers. Other words used to describe the relationship between elements should be interpreted in a similar manner (e.g., "between" vs. "directly between," "adjacent" vs. "directly adjacent," etc.). As used in this specification, the term "and / or" includes any and all combinations of one or more of the associated listed items. That is, the description of A and / or B means at least one of A and B, and may include only A, only B, or both A and B.

[0140] Spatially relative terms such as "inside," "outside," "beneath," "below," "lower," "above," "upper," etc. are used herein to facilitate description of the relationship of one element or feature to another element or feature as illustrated. Spatially relative terms can be intended to encompass different orientations of the device during use or operation in addition to the orientation depicted in the drawings. For example, if the device in the figures is turned over, an element described as "beneath" or "under" another element or feature would then be oriented "above" the other element or feature. Thus, the term "beneath" can encompass both an orientation of above and below. The device may be oriented in other directions (rotated 90 degrees or other orientations), and the spatially relative descriptors used in this specification will be interpreted accordingly.

[0141] (Disclosure of Technical Idea) This specification discloses a plurality of technical ideas described in a plurality of clauses listed below. Some clauses may be described in a multiple dependent form that alternatively cites preceding clauses in subsequent clauses. Furthermore, some clauses may be described in a multiple dependent form that cites clauses in other multiple dependent forms. The clauses described in these multiple dependent forms define a plurality of technical ideas.

[0142] <Technical Idea 1> A first semiconductor element (51H, 51L) constituting a first inverter (8) connected to one end of the winding of a rotating electrical machine (3); A second semiconductor element (52H, 52L) constituting a second inverter (9) connected to the other end of the winding; A changeover switch (70, 10) provided in a path connecting the first inverter and the second inverter, connecting the DC power supply (2) and the second inverter in a closed state, and disconnecting the connection between the DC power supply and the second inverter in an open state; A snubber circuit (62, 11) connected in parallel with the second inverter; Comprising; The changeover switch is arranged at a position closer to the second semiconductor element than the first semiconductor element, a power conversion module.

[0143] <Technical Idea 2> A first wiring (83, 424A, 424C, 5A) connecting the first inverter and the changeover switch; A second wiring (823, 424B, 5B) connecting the changeover switch and the second inverter; Comprising; The snubber circuit is connected to the first wiring among the first wiring and the second wiring, the power conversion module described in Technical Idea 1.

[0144] <Technical Idea 3> a first substrate (41), a second substrate (42), further comprising: wherein the first semiconductor element is mounted on the first substrate, the power conversion module according to Technical Idea 1 or Technical Idea 2, wherein the second semiconductor element, the snubber circuit, and the switching switch are mounted on the second substrate.

[0145] <Technical Idea 4> the power conversion module according to any one of Technical Ideas 1 to 3, wherein the switching switch is disposed between the second semiconductor element and the snubber circuit.

[0146] <Technical Idea 5> wherein the second semiconductor element includes a second upper arm element (52H) and a second lower arm element (52L), as a second power supply line, a second upper power supply line (424A, 70, 823, 424B) connecting one end of the snubber circuit and the second upper arm element, and a second lower power supply line (822, 425) running parallel to the second upper power supply line and connecting the second lower arm element and the other end of the snubber circuit are provided, the power conversion module according to Technical Idea 4, wherein one of the second upper power supply line and the second lower power supply line includes the switching switch.

[0147] <Technical Idea 6> wherein the second upper arm element and the second lower arm element are provided for each phase, the power conversion module according to Technical Idea 5, wherein the switching switch and the snubber circuit are provided for each phase.

[0148] <Technical Idea 7> the power conversion module according to Technical Idea 6, further comprising a common wiring (824) for electrically connecting the low-potential side terminals of the switching switches provided for each phase to each other.

[0149] <Technical Idea 8> The power conversion module according to Technical Idea 7, wherein the second power line excluding the common wiring and the switching switch intersects three-dimensionally.

[0150] <Technical Idea 9> A signal wiring (427, 428) electrically connected to signal pads of the second semiconductor element and the switching switch is provided. The second semiconductor element and the switching switch are arranged side by side in a predetermined direction. The signal wiring is arranged side by side on the opposite side of the second power line excluding the switching switch with respect to the corresponding second semiconductor element and the switching switch in a direction orthogonal to the predetermined direction. The power conversion module according to any one of Technical Ideas 5 to 8.

[0151] <Technical Idea 10> A first signal wiring (417) electrically connected to a signal pad of the first semiconductor element is provided. The first signal wiring is a signal wiring different from the second signal wiring which is the signal wiring. The first signal wiring is arranged side by side with the corresponding first semiconductor element in the predetermined direction. The power conversion module according to Technical Idea 9.

[0152] <Technical Idea 11> The second upper power line and the second lower power line are alternately arranged in one direction. The first semiconductor element includes a plurality of first upper arm elements (51H) and a plurality of first lower arm elements (51L) provided for each phase. As a first power line, a plurality of first upper power lines (414) electrically connected to the high-potential side terminals of the first upper arm elements and a plurality of first lower power lines (415A) electrically connected to the low-potential side terminals of the first lower arm elements and alternately arranged with the first upper power lines in the one direction are provided. The switching switch is arranged on one of the second upper power line and the second lower power line. Among the second upper power line and the second lower power line, the second power line on which the switching switch is disposed and, among the first upper power line and the first lower power line, the first power line that is electrically connected to the second power line on which the switching switch is disposed face each other in the one direction, the power conversion module according to any one of technical concepts 6 to 10.

[0153] <Technical concept 12> The switching switch and the snubber circuit are arranged side by side in a predetermined direction. The switching switch and the snubber circuit arranged side by side in the predetermined direction and the second semiconductor element are arranged side by side in a direction orthogonal to the predetermined direction, the power conversion module according to any one of technical concepts 1 to 3.

[0154] <Technical concept 13> The switching switch and the snubber circuit are arranged side by side along the arrangement direction of the first inverter and the second inverter, the power conversion module according to technical concept 11.

[0155] <Technical concept 14> The switching switch and the snubber circuit are arranged side by side along a direction orthogonal to the arrangement direction of the first inverter and the second inverter, the power conversion module according to technical concept 11.

[0156] <Technical concept 15> The snubber circuit is disposed between the second semiconductor element and the switching switch, the power conversion module according to any one of technical concepts 1 to 3.

Description of reference numerals

[0157] 1... Drive system, 2... DC power supply, 3... Rotating electric machine, 3U, 3V, 3W... Windings, 4... Power conversion circuit, 5, 6... Power lines, 5A, 5B, 6A, 6B... Wires, 7... Smoothing capacitor, 8, 9... Inverters, 8HL, 9HL... Upper and lower arm circuits, 8D, 9D... Diodes, 8H, 9H... Upper arms, 8L, 9L... Lower arms, 8S, 9S... MOSFETs, 10... Switching switch, 11, 12... Snubber circuits, 11C, 12C... Capacitors, 11R, 12R... Resistors, 13, 14... Output lines, 15... Control unit, 20... Power conversion module, 30... Cooler, 301... One side, 302... Back side, 31... Case, 32... Cover, 33... Flow path, 34... Fins, 35... Inlet pipe, 36... Outlet pipe, 37... Refrigerant, 40, 41, 42, 43... Substrates, 411, 421... Insulating substrates, 412, 413, 422, 423... Conductors, 414, 424... P wirings, 424A, 424B, 424C... Wires, 415, 425... N wirings, 415A, 415B... Wires, 416, 426... O wirings, 417, 427, 428... Signal wirings, 50, 51H, 52H, 51L, 52L... Semiconductor elements, 60, 61, 62... Snubber circuits, 70... Switching switch, 80, 811, 812, 821, 822, 823, 824, 825, 826, 83... Clips, 90... Main terminals, 91... P terminals, 92, 921, 922... N terminals, 93, 931, 932... O terminals

Claims

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

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

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

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

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

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

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

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

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

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

11. The second upper power supply line and the second lower power supply line are alternately arranged in one direction, The first semiconductor element includes a plurality of first upper arm elements (51H) and a plurality of first lower arm elements (51L) provided for each phase, As a first power supply line, a plurality of first upper power supply lines (414) to which high potential side terminals of the first upper arm elements are electrically connected, and low potential side terminals of the first lower arm elements are electrically connected, and a plurality of first lower power supply lines (415A) alternately arranged with the first upper power supply lines in the one direction. The switching switch is arranged on one of the second upper power supply line and the second lower power supply line, Among the second upper power supply line and the second lower power supply line, the second power supply line on which the switching switch is arranged and the first power supply line electrically connected to the second power supply line on which the switching switch is arranged among the first upper power supply line and the first lower power supply line are opposed to each other in the one direction. The power conversion module according to claim 6.

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

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

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

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

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