JP5315073B2 - Power converter - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a power converter capable of attaining miniaturization thereof while maintaining cooling performance by improving the rigidity of a metallic base. <P>SOLUTION: The metallic base 304 attached to a power module 300 has semiconductor devices 328, 330, 156, 166 mounted on one surface thereof and has the other surface fixed to cover an opening formed in a cooling water flow path 19 of a cooling jacket 19A. The metallic base plate 304 has thick portions 304a, 304b which are a mounting area mounted with the semiconductor devices and a fixed area for pressing and fixing an O-ring 800 on the cooling jacket 19A. Besides, the thickness of the mounting area is defined according to the radiation quantity for radiating the heat generated from the semiconductor device into refrigerant, and the rigidity of the thickness portions 304a, 304b is defined to be higher than that of the mounting area. Thus, deformation of a seal portion of the metallic base 304 due to a cooling water pressure can be restrained, sealing performance by the O-ring 800 can be ensured while maintaining radiation performance in the same way as a conventional one, and the size of the apparatus can be reduced. <P>COPYRIGHT: (C)2010,JPO&amp;INPIT

Description

  The present invention relates to a power conversion device that directly cools a metal base plate on which a semiconductor element is mounted with a refrigerant.

  Conventionally, a heat radiation fin is formed on a metal base to which a power semiconductor element is fixed, and the fin is brought into direct contact with the cooling water in the cooling water channel portion so that heat generated in the power semiconductor element is radiated to the cooling water. A power module having a simple structure is known (see, for example, Patent Document 1). The power module is attached to the cooling water channel portion so as to cover the cooling water channel opening with the heat radiating surface on which the fins are formed. A seal member is provided between the back surface of the metal base (the surface on the cooling water channel side) and the cooling water channel part to prevent refrigerant leakage from the cooling water channel part, and the power module is a screw component such as a bolt or screw. By sealing to a cooling water channel part by this, sealing with a sealing member is performed.

JP 2007-295765 A

  Incidentally, on the metal base, a space for arranging mounting parts such as power semiconductor elements is necessary, but it is also necessary to secure a fastening seat surface for fixing bolts and a tool space for tightening the bolts. On the other hand, in order to ensure the sealing performance of the seal member, it is necessary to set the bolt interval at the time of bolt fixing to a predetermined interval or less according to the refrigerant pressure, the rigidity of the base metal, and the like. For this reason, there is a problem that the area other than the component mounting area is increased and the power module is increased in size.

Power converter according to a first aspect of the present invention, a cooling jacket opening and is formed where part of the flow path and a flow path through which the refrigerant flows is exposed, the semiconductor element and the lower arm upper arm constituting the inverter circuit comprising a use semiconductor device, a semiconductor element for converting a DC power and AC power together, along with the semi-conductor element is mounted on one surface of the plate-like member, so that the other face closes the apertures A metal base plate that is fixed to the cooling jacket and contacts the refrigerant, and a seal member that is sandwiched between the metal base plate and the cooling jacket and seals leakage of the refrigerant from the opening. The metal base plate includes a mounting region on which a semiconductor element is mounted , a first mounting region for the upper arm semiconductor device, and a second mounting region for the lower arm semiconductor device, and a seal member. Press And a fixing region for fixing to the cooling jacket, and a first fin forming region and the second fin forming region corresponding to each of the first mounting area and the second mounting region, the metal base plate is a metal with a temperature cycle stress generated in the base plate is made from a material having a Vickers hardness not reaching the yield stress, determined according to the heat generated the thickness of the mounting area from the semiconductor element to the heat radiation amount for radiating the refrigerant further, the mounting area A fin forming region is provided on the other surface of the substrate, a plurality of cooling fins protruding into the flow path are formed in the fin forming region, the thickness of the fixing region is set larger than the thickness of the mounting region, and the rigidity of the fixing region is increased. It is characterized by being set larger than the rigidity of the mounting area.
A power conversion device according to a second aspect of the present invention is the power conversion device according to the first aspect, wherein the mounting region has a thickness of 3 to 4 mm.
A power converter according to a third aspect of the present invention is the power converter according to the first or second aspect, wherein the mounting region, the fixed region, and the cooling fin are integrally formed by forging the metal plate material. To do.
A power converter according to a fourth aspect of the present invention is the power converter according to the first or second aspect, wherein the mounting region, the fixed region, and the cooling fin are integrally molded by a metal powder injection molding method.
A power conversion device according to a fifth aspect of the present invention is the power conversion device according to any one of the first to fourth aspects, wherein the metal-based substrate has a rectangular shape, and a rectangular frame region at a periphery of the rectangular region. The fixed area is formed, and the four corners of the rectangular frame area are fastened to the cooling jacket by fastening parts.

  According to the present invention, it is possible to reduce the size of the apparatus while maintaining the cooling performance by improving the rigidity of the metal base.

It is a figure which shows the control block of a hybrid vehicle. It is a figure explaining the electric circuit structure of an inverter apparatus. It is a perspective view which shows the external appearance of a power converter device. It is a disassembled perspective view which shows the internal structure of a power converter device. It is the figure which attached the cooling water inlet piping and the outlet piping to the aluminum casting of the housing | casing which has a cooling water flow path, (a) is a perspective view of a housing | casing, (b) is a top view of a housing | casing, (c) is It is a bottom view of a housing | casing. It is detail drawing of the bottom view of a housing | casing. It is AA sectional drawing of FIG. It is a figure which shows a power module, (a) is an upper perspective view, (b) is a top view. It is a perspective view which shows the lower surface side of a power module. It is sectional drawing of a power module. It is a figure which shows a 1st modification, and is a perspective view of a power module case and a metal base. It is a figure which shows a 1st modification, and is a perspective view which shows the lower surface side of a power module. It is a figure which shows the deformation amount of the seal part of a metal base by water pressure. It is a figure which shows the deformation | transformation amount of the seal part center position when the dimension N is changed. It is a figure which shows a 2nd modification, and is a perspective view of a power module case and a metal base. It is a figure which shows a 2nd modification, (a) is CC sectional drawing of FIG. 15, (b) is DD sectional drawing of FIG. It is a figure which shows a 3rd modification, and is a perspective view of a power module case and a metal base. It is a figure which shows a 3rd modification, and is a perspective view which shows the lower surface side of a power module. It is a figure which shows the cross section of a power module, (a) is EE sectional drawing of FIG. 17, (b) is FF sectional drawing. It is a graph which shows the correlation with the temperature cycle lifetime explaining the dimension shape of a metal material, and the thickness of a metal base. It is a graph which shows the correlation with the Vickers hardness of a metal material, and a yield stress.

  A power converter according to an embodiment of the present invention will be described below in detail with reference to the drawings. The power conversion device according to the embodiment of the present invention can be applied to a hybrid vehicle or a pure electric vehicle. Here, as a representative example, a control configuration and a circuit configuration of the power conversion device when the power conversion device according to the embodiment of the present invention is applied to a hybrid vehicle will be described with reference to FIGS. 1 and 2.

  The power conversion device according to the embodiment of the present invention is used in a vehicle-mounted power conversion device for a vehicle-mounted electrical system mounted on an automobile, in particular, a vehicle drive electrical system, and has a very severe mounting environment and operational environment. The inverter device will be described as an example. A vehicle drive inverter device is provided in a vehicle drive electrical system as a control device for controlling the drive of a vehicle drive motor, and a DC power supplied from an onboard battery or an onboard power generator constituting an onboard power source is a predetermined AC power. Then, the AC power obtained is supplied to the vehicle drive motor to control the drive of the vehicle drive motor. Further, since the vehicle drive motor also has a function as a generator, the vehicle drive inverter device also has a function of converting AC power generated by the vehicle drive motor into DC power according to the operation mode. ing. The converted DC power is supplied to the on-vehicle battery.

  Note that the configuration of the present embodiment is optimal as a power converter for driving a vehicle such as an automobile or a truck, but can be applied to other power converters. For example, power converters for trains, ships, airplanes, etc., industrial power converters used as control devices for motors that drive factory equipment, or motors that drive household solar power generation systems and household appliances The present invention can also be applied to a household power conversion device that is used in other control devices.

  FIG. 1 is a diagram showing a control block of a hybrid vehicle. In FIG. 1, a hybrid electric vehicle (hereinafter referred to as “HEV”) 110 is one electric vehicle and includes two vehicle drive systems. One of them is an engine system that uses an engine 120 that is an internal combustion engine as a power source. The engine system is mainly used as a drive source for HEV 110. The other is an in-vehicle electric system using motor generators 192 and 194 as a power source. The in-vehicle electric system is mainly used as a drive source for HEV 110 and a power generation source for HEV 110. The motor generators 192 and 194 are, for example, synchronous machines or induction machines, and operate as both a motor and a generator depending on the operation method.

  A front wheel axle 114 is rotatably supported at the front portion of the vehicle body. A pair of front wheels 112 are provided at both ends of the front wheel axle 114. A rear wheel axle (not shown) is rotatably supported on the rear portion of the vehicle body. A pair of rear wheels are provided at both ends of the rear wheel axle. The HEV 110 of the present embodiment employs a so-called front wheel drive system in which the main wheel driven by power is the front wheel 112 and the driven wheel to be driven is the rear wheel. You may adopt.

  A front wheel side differential gear (hereinafter referred to as “front wheel side DEF”) 116 is provided at the center of the front wheel axle 114. The front wheel axle 114 is mechanically connected to the output side of the front wheel side DEF 116. The output shaft of the transmission 118 is mechanically connected to the input side of the front wheel side DEF 116. The front wheel side DEF 116 is a differential power distribution mechanism that distributes the rotational driving force that is shifted and transmitted by the transmission 118 to the left and right front wheel axles 114. The output side of the motor generator 192 is mechanically connected to the input side of the transmission 118. The output side of the engine 120 and the output side of the motor generator 194 are mechanically connected to the input side of the motor generator 192 via the power distribution mechanism 122. Motor generators 192 and 194 and power distribution mechanism 122 are housed inside the casing of transmission 118.

  The motor generators 192 and 194 are synchronous machines having permanent magnets on the rotor, and the AC power supplied to the armature windings of the stator is controlled by the inverter devices 140 and 142, whereby the motor generators 192 and 194 are used. Is controlled. A battery 136 is connected to the inverter devices 140 and 142, and power can be exchanged between the battery 136 and the inverter devices 140 and 142.

  In the present embodiment, the HEV 110 includes two parts, a first motor generator unit composed of a motor generator 192 and an inverter device 140, and a second motor generator unit composed of a motor generator 194 and an inverter device 142, depending on the operating state. I use them properly. That is, in the situation where the vehicle is driven by the power from the engine 120, when assisting the driving torque of the vehicle, the second motor generator unit is operated by the power of the engine 120 as a power generation unit to generate power, and the power generation The first motor generator unit is operated as an electric unit by the electric power obtained by the above. Further, when assisting the vehicle speed in the same situation, the first motor generator unit is operated by the power of the engine 120 as a power generation unit to generate power, and the second motor generator unit is generated by the electric power obtained by the power generation. Operate as an electric unit.

  In the present embodiment, the vehicle can be driven only by the power of the motor generator 192 by operating the first motor generator unit as an electric unit by the electric power of the battery 136. Furthermore, in this embodiment, the battery 136 can be charged by operating the first motor generator unit or the second motor generator unit as a power generation unit by the power of the engine 120 or the power from the wheels to generate power.

  The battery 136 is also used as a power source for driving an auxiliary motor 195. As an auxiliary machine, for example, there is a motor that drives a compressor of an air conditioner or a motor that drives a hydraulic pump for control. The DC power supplied from the battery 136 to the inverter device 43 is converted into AC power by the inverter device 43. And supplied to the motor 195. The inverter device 43 has the same function as the inverter devices 140 and 142 and controls the phase, frequency, and power of alternating current supplied to the motor 195. For example, the motor 195 generates torque by supplying AC power having a leading phase with respect to the rotation of the rotor of the motor 195. On the other hand, by generating the delayed phase AC power, the motor 195 acts as a generator, and the motor 195 is operated in a regenerative braking state. The control function of the inverter device 43 is the same as the control function of the inverter devices 140 and 142. Since the capacity of the motor 195 is smaller than the capacity of the motor generators 192 and 194, the maximum conversion power of the inverter device 43 is smaller than the inverter devices 140 and 142, but the circuit configuration of the inverter device 43 is basically the circuit of the inverter devices 140 and 142. Same as the configuration.

  Inverter devices 140, 142, and 43 and capacitor module 500 are in an electrical close relationship. Furthermore, there is a common point that measures against heat generation are necessary. It is also desired to make the volume of the device as small as possible. From these points, the power conversion device 200 described in detail below includes the inverter devices 140, 142, and 43 and the capacitor module 500 in the casing of the power conversion device 200. With this configuration, a small and highly reliable device can be realized.

  Next, the electric circuit configuration of the inverter devices 140 and 142 or the inverter device 43 will be described with reference to FIG. In the embodiment illustrated in FIGS. 1 to 2, the case where the inverter devices 140 and 142 or the inverter device 43 are individually configured will be described as an example. The inverter devices 140, 142, and 43 have the same configuration, operation, and function. Here, the inverter device 140 will be described as a representative example.

  The inverter device 140 includes an inverter circuit 144 and a control unit 170. The inverter circuit 144 includes three upper and lower arm series circuits 150 corresponding to the U phase, the V phase, and the W phase. Each upper and lower arm series circuit 150 has an IGBT 328 (insulated gate bipolar transistor) and a diode 156 that operate as an upper arm, and an IGBT 330 and a diode 166 that operate as a lower arm. An AC power line (AC bus bar) 186 to the motor generator 192 is connected to the AC terminal 159 of the middle point (intermediate electrode 169) of each upper and lower arm series circuit 150. AC power line 186 is electrically connected to a corresponding phase winding of the armature winding of motor generator 192 via AC connector 188. The control unit 170 includes a driver circuit 174 that drives and controls the inverter circuit 144 and a control circuit 172 that supplies a control signal to the driver circuit 174 via the signal line 176.

  The upper arm and the lower arm IGBTs 328 and 330 are switching power semiconductor elements. The IGBTs 328 and 330 operate in response to the drive signal output from the control unit 170, and convert DC power supplied from the battery 136 into three-phase AC power. The converted electric power is supplied to the armature winding of the motor generator 192.

  The inverter circuit 144 is configured by a three-phase bridge circuit, and the upper and lower arm series circuit 150 for three phases is electrically connected to the DC positive electrode terminal 314 that is electrically connected to the positive electrode side of the battery 136 and the negative electrode side. The DC negative electrode terminal 316 is electrically connected in parallel.

  In this embodiment, IGBTs 328 and 330 are used as switching power semiconductor elements. The IGBTs 328 and 330 include collector electrodes 153 and 163, emitter electrodes (signal emitter electrode terminals 155 and 165), and gate electrodes (gate electrode terminals 154 and 164). Diodes 156 and 166 are electrically connected between the collector electrodes 153 and 163 of the IGBTs 328 and 330 and the emitter electrode as shown. The diodes 156 and 166 are electrically connected to the collector electrode of the IGBTs 328 and 330 and the anode electrode are electrically connected to the emitter electrodes of the IGBTs 328 and 330 so that the direction from the emitter electrode to the collector electrode of the IGBTs 328 and 330 is the forward direction. It is connected to the. A MOSFET (metal oxide semiconductor field effect transistor) may be used as the switching power semiconductor element. In this case, the diode 156 and the diode 166 are not necessary.

  As described above, the upper and lower arm series circuit 150 is provided for three phases corresponding to each phase winding of the armature winding of the motor generator 192, and each is electrically connected in parallel. The collector electrode 153 of the upper arm IGBT 328 is connected to the positive capacitor electrode of the capacitor module 500 via the positive terminal (P terminal) 157, and the emitter electrode of the lower arm IGBT 330 is connected to the capacitor module 500 via the negative terminal (N terminal) 158. Are respectively electrically connected (connected by a DC bus bar).

  Capacitor module 500 constitutes a smoothing circuit for suppressing fluctuations in DC voltage caused by the switching operation of IGBTs 328 and 330. The positive electrode side of the battery 136 is electrically connected to the positive electrode side capacitor electrode of the capacitor module 500, and the negative electrode side of the battery 136 is electrically connected to the negative electrode side capacitor electrode of the capacitor module 500 via the DC connector 138. Thus, the capacitor module 500 is connected between the collector electrode 153 of the upper arm IGBT 328 and the positive electrode side of the battery 136, and between the emitter electrode of the lower arm IGBT 330 and the negative electrode side of the battery 136. The upper and lower arm series circuit 150 is electrically connected in parallel.

  The control unit 170 is for operating the IGBTs 328 and 330 and includes a control circuit 172 and a drive circuit 174. The control circuit 172 generates a timing signal for controlling the switching timing of the IGBTs 328 and 330 based on input information from other control devices and sensors. The drive circuit 174 generates a drive signal for switching the IGBTs 328 and 330 based on the timing signal output from the control circuit 172.

  The control circuit 172 includes a microcomputer (hereinafter referred to as “microcomputer”) for calculating the switching timing of the IGBTs 328 and 330. The microcomputer inputs the target torque value required for the motor generator 192, the current value supplied from the upper and lower arm series circuit to the armature winding of the motor generator 192, and the magnetic pole position of the rotor of the motor generator 192. Input as information. The target torque value is based on a command signal output from a host controller (not shown). The current value is detected based on the detection signal output from the current sensor 180. The magnetic pole position is detected based on a detection signal output from a rotating magnetic pole sensor (not shown) provided in the motor generator 192. In the present embodiment, the case where the current values of three phases are detected will be described as an example, but the current values for two phases may be detected.

  The microcomputer in the control circuit 172 calculates the d and q axis current command values of the motor generator 192 based on the target torque value, and the calculated d and q axis current command values and the detected d and q Based on the difference from the current value of the axis, the voltage command values for the d and q axes are calculated. Further, the microcomputer converts the calculated voltage command values for the d and q axes into U-phase, V-phase, and W-phase voltage command values based on the detected magnetic pole positions. Then, the microcomputer generates a pulse-like modulated wave based on a comparison between the fundamental wave (sine wave) and the carrier wave (triangular wave) based on the voltage command values of the U phase, V phase, and W phase, and the generated modulation wave The wave is output to the driver circuit 174 as a PWM (pulse width modulation) signal.

  When driving the lower arm, the driver circuit 174 amplifies the PWM signal and outputs the amplified PWM signal as a drive signal to the gate electrode of the corresponding IGBT 330 of the lower arm. On the other hand, when driving the upper arm, the driver circuit 174 amplifies the PWM signal after shifting the level of the reference potential of the PWM signal to the level of the reference potential of the upper arm, and uses this as a drive signal. Output to the gate electrode of the IGBT 328 of the upper arm. As a result, each IGBT 328, 330 performs a switching operation based on the input drive signal.

  In addition, the control unit 170 performs abnormality detection (overcurrent, overvoltage, overtemperature, etc.) to protect the upper and lower arm series circuit 150. For this reason, sensing information is input to the control unit 170. For example, information on the current flowing through the emitter electrodes of the IGBTs 328 and 330 is input to the corresponding drive units (ICs) from the signal emitter electrode terminals 155 and 165 of each arm. Thereby, each drive part (IC) detects overcurrent, and when overcurrent is detected, the switching operation of corresponding IGBT328,330 is stopped, and corresponding IGBT328,330 is protected from overcurrent. Information on the temperature of the upper and lower arm series circuit 150 is input to the microcomputer from a temperature sensor (not shown) provided in the upper and lower arm series circuit 150. In addition, voltage information on the DC positive side of the upper and lower arm series circuit 150 is input to the microcomputer. The microcomputer performs over-temperature detection and over-voltage detection based on the information, and when over-temperature or over-voltage is detected, stops the switching operation of all the IGBTs 328 and 330, and sets the upper and lower arm series circuit 150 to over-temperature or Protect from overvoltage.

  The conduction and cut-off operations of the IGBTs 328 and 330 of the upper and lower arms of the inverter device 140 are switched in a certain order, and the current generated in the stator winding of the motor generator 192 at this switching flows through a circuit including the diodes 156 and 166. In the power conversion device 200 of the present embodiment, one upper and lower arm series circuit 150 is provided for each phase of the inverter device 140. However, as a circuit that generates an output of each phase of the three-phase AC output to the motor generator 192. The power converter may have a circuit configuration in which two upper and lower arm series circuits 150 are connected in parallel to each phase.

  FIG. 3 is a perspective view showing an overview of the power conversion device 200, and FIG. 4 is an exploded perspective view showing the internal configuration of the power conversion device 200. As external parts of the power conversion device 200, a casing 12 having a substantially rectangular top or bottom surface, a cooling water inlet pipe 13 and a cooling water outlet pipe 14 provided on one of the outer circumferences on the short side of the casing 12, An upper case 10 for closing the upper opening of the housing 12 and a lower case 16 for closing the lower opening of the housing 12 are provided. The upper case 10 and the lower case 16 are fixed to the housing 12 by fastening parts such as screws and bolts, for example. Since the shape of the bottom surface side or the top surface side of the housing 12 is substantially rectangular, it is easy to attach to the vehicle and to produce easily.

  Two sets of AC terminal cases 17 used for connection to the motor generators 192 and 194 are provided on the outer periphery of the long side of the power conversion device 200. AC terminal 18 is used to electrically connect power module 300 and motor generators 192 and 194 shown in FIG. The power conversion device 200 is provided with two power modules 300. One power module 300 includes an inverter circuit 144 and the other power module 300 includes an inverter circuit 145. The AC current output from the power module 300 is transmitted to the motor generators 192 and 194 via the AC terminal 18.

  The connector 21 is connected to a control circuit board 20 built in the housing 12. The control circuit board 20 is provided with the control circuit 172 described above. Various signals from the outside are transmitted to the control circuit board 20 via the connector 21. In the present embodiment, the connector 21 is provided on one side of the outer peripheral surface on the short side of the housing 12.

  The direct current (battery) negative electrode side connection terminal portion 510 and the direct current (battery) positive electrode side connection terminal portion 512 electrically connect the battery 136 and the capacitor module 500. On the other hand, the direct current (battery) negative electrode side connection terminal portion 510 and the direct current (battery) positive electrode side connection terminal portion 512 are provided on the outer peripheral surface on the short side opposite to the surface on which the connector 21 is provided. That is, the connector 21 and the direct current (battery) negative electrode side connection terminal portion 510 are arranged apart from each other. As a result, noise that enters the housing 12 from the direct current (battery) negative electrode side connection terminal portion 510 and propagates to the connector 21 can be reduced, and the controllability of the motor by the control circuit board 20 can be improved.

  As shown in FIG. 4, a cooling jacket 19 </ b> A having a cooling water flow path 19 formed therein is provided at approximately the center in the height direction of the housing 12. Openings 400 and 402 are formed in the upper part of the cooling jacket 19A along the flow direction. The openings 400 and 402 are respectively formed on the forward path and the return path of the cooling water flow path 19, and the power module 300 disposed so as to close the pair of openings 400 and the power module disposed so as to close the pair of openings 402. 300 are fixed to the upper surface of the cooling jacket 19A. Each power module 300 is provided with cooling fins 305 (see FIG. 7) for heat dissipation, and the cooling fins 305 of each power module 300 protrude into the cooling water channel 19 from the openings 400 and 402 of the cooling jacket 19A, respectively. ing.

  In addition, an auxiliary inverter device 43 is attached to the lower surface of the cooling jacket 19A. As shown in FIG. 2, the auxiliary inverter device 43 has a power module in which a power semiconductor element constituting the inverter circuit 146 is incorporated. The auxiliary inverter device 43 is fixed to the lower surface of the cooling jacket 19A so that the heat dissipating metal surface of the built-in power module faces the lower surface of the cooling jacket 19A.

  In the present embodiment, the housing 12 is formed by aluminum casting. An opening 404 for facilitating aluminum casting is formed on the lower surface of the cooling jacket 19 </ b> A, and the opening 404 is closed by the lower cover 420. An O-ring 800 for sealing is provided between the power module 300 and the housing 12, and an O-ring 802 is also provided between the lower cover 420 and the housing 12. In this embodiment, the sealing material is an O-ring, but a resin material, a liquid seal, packing, or the like may be used instead of the O-ring. In particular, when a liquid seal is used, the assemblability of the power conversion device 200 can be improved.

  As described above, the cooling water channel 19 is formed inside the cooling jacket 19A by covering the upper surface opening of the cooling jacket 19A with the power module 300 and covering the lower surface opening with the lower cover 420. The water leakage test is performed during the assembly, and after passing the water leakage test, an operation of attaching the substrate and the capacitor module 500 from the upper and lower openings of the housing 12 is performed. In this way, the cooling jacket 19A is disposed in the center of the housing 12, and after the water leak test, a structure is employed in which necessary work can be fixed from the upper and lower openings of the housing 12, so that productivity is improved. improves. In addition, other parts can be attached after the water leak test, which improves both productivity and reliability.

  3 and 4, a lower case 16 is provided below the cooling jacket 19A, and a capacitor module 500 is provided in the lower case 16. Capacitor module 500 is fixed to the inner surface of the bottom plate of lower case 16 such that the heat dissipation surface of the metal case is in contact with the inner surface of the bottom plate of lower case 16. With this structure, the power module 300 and the inverter device 43 can be efficiently cooled using the upper surface and the lower surface of the cooling jacket 19A, which leads to a reduction in the size of the entire power conversion device.

  When the cooling water from the cooling water inlet / outlet pipes 13 and 14 flows through the cooling water channel 19, the heat radiation surface of the power module 300 fixed so as to close the openings 400 and 402, that is, the surface provided with the cooling fins is the cooling water. The two power modules 300 are cooled as a result of the direct cooling. Similarly, the auxiliary inverter device 43 provided on the lower surface of the cooling jacket 19A is also directly cooled by the cooling water.

  Further, the casing 12 provided with the cooling jacket 19A is cooled, whereby the lower case 16 provided at the lower portion of the casing 12 is cooled. As a result, the heat of the capacitor module 500 is thermally conducted to the cooling water through the lower case 16 and the housing 12, and the capacitor module 500 is cooled.

  A laminated conductor plate 700 for electrically connecting the power module 300 and the capacitor module 500 is disposed above the power module 300. The laminated conductor plate 700 is configured to be wide in the parallel arrangement direction of the two power modules 300 across the two power modules 300. The laminated conductor plate 700 is composed of a positive electrode conductor plate and a negative electrode conductor plate connected to the positive electrode conductor plate 507 and the negative electrode conductor plate 50 of the capacitor module 500, and an insulating sheet disposed between these conductor plates. With such a configuration, the laminated area of the laminated conductor plate 700 can be increased, and the parasitic inductance from the power module 300 to the capacitor module 500 can be reduced. In addition, since one laminated conductor plate 700 is placed on the two power modules 300, the laminated conductor plate 700, the power module 300, and the capacitor module 500 can be electrically connected. Even if it is a power converter provided, the assembly man-hour can be suppressed.

  A control circuit board 20 and a drive circuit board 22 are disposed above the laminated conductor plate 700. A metal base plate 11 is disposed between the drive circuit board 22 and the control circuit board 20. The metal base plate 11 functions as an electromagnetic shield for a circuit group mounted on both the boards 22 and 20 and also has an action of releasing and cooling the heat generated in the drive circuit board 22 and the control circuit board 20. Yes. As described above, the cooling jacket 19A is provided in the central portion of the housing 12, the power module 300 for driving the motor generators 192 and 194 is disposed on one side thereof, and the inverter device (power module for auxiliary equipment) is disposed on the other side. ) 43 can be efficiently cooled in a small space, and the entire power conversion device can be downsized.

  Further, by integrally forming the cooling jacket 19A and the housing 12 by aluminum casting, in addition to the cooling effect of the cooling jacket 19A, an effect of increasing the mechanical strength can be obtained. Further, since the casing 12 and the cooling jacket 19A are integrally formed by casting aluminum, the heat conduction is improved, and the cooling efficiency for the drive circuit board 22, the control circuit board 20 and the capacitor module 500 located far from the cooling jacket 19A is improved. improves.

  The drive circuit board 22 is provided with an inter-board connector 23 that passes through the metal base plate 11 and is connected to a circuit group of the control circuit board 20. The control circuit board 20 is provided with a connector 21 for electrical connection with the outside. The connector 21 is used to transmit a signal to and from the in-vehicle battery 136 provided outside the power converter, that is, a lithium battery module. A signal representing the state of the battery and a signal such as the state of charge of the lithium battery are sent from the lithium battery module to the control circuit board 20. A signal line 176 (not shown in FIG. 4) shown in FIG. 2 is connected to the board-to-board connector 23, and a switching timing signal of the inverter circuit is transmitted from the control circuit board 20 to the drive circuit board 22. The drive circuit board 22 is gate-driven. A signal is generated and applied to each gate electrode of the power module.

  5A and 5B are diagrams showing the structure of the housing 12, where FIG. 5A is a perspective view, FIG. 5B is a top view, and FIG. 5C is a diagram showing the lower surface side of the housing 12. As shown in FIG. 5 (a), a cooling water inlet pipe 13 and a cooling water inlet pipe 14 for taking in cooling water are provided on one side surface of the short side of the casing 12 having a substantially rectangular shape in plan view. Is provided. The cooling water that has flowed into the cooling water channel 19 from the cooling water inlet pipe 13 flows along the long side of the rectangle in the direction of the arrow 418, and in the vicinity of the near side of the other side of the short side of the rectangle, the arrows 421a and 421b. Then, it flows again in the direction of the arrow 422 along the long side of the rectangle, and flows out from the outlet hole (not shown) to the cooling water inlet pipe 14.

  As described above, on the upper surface of the cooling jacket 19A, the openings 400 and 402 are provided in the forward path and the return path of the cooling water flow path 19, respectively. As shown in FIG. 5B, a sealing material (O-ring 800) is provided on the power module mounting surface 410S of the cooling jacket 19A so as to surround the opening 400. When the power module 300 is fixed to the mounting surface 410S, the periphery of the opening is sealed watertight by the O-ring 800. The O-ring 800 is similarly provided for the opening 402.

  A portion located between the opening 400 and the opening 402 of the attachment surface 410S will be referred to as a support portion 410. One of the two power modules 300 is disposed across the forward path and the return path so as to block a pair of openings 400 provided on the inlet / outlet side of the cooling water with respect to the support portion 410. The other power module 300 is disposed across the forward path and the backward path so as to block a pair of openings 402 provided on the cooling water return side with respect to the support portion 410. The heat radiation fins of each power module 300 protrude into the cooling water of the cooling water passage 19 from the respective openings. The plurality of screw holes 412 formed in the attachment surface 410S are used to fix the power module 300 on the entrance / exit side. On the other hand, the screw hole 414 is used for fixing the power module 300 on the folded side.

  Thus, by arranging each power module 300 so as to straddle both the forward path and the return path of the cooling water flow path 19, the inverter circuits 144 and 145 can be integrated on the metal base 304 (see FIG. 7) with high density, The power module 300 can be downsized, which greatly contributes to downsizing of the power conversion device 200.

  The power module 300 on the inlet / outlet side is cooled by the cold cooling water from the cooling water inlet pipe 13 and the cooling water heated near the outlet side by the heat from the heat generating components. On the other hand, the folded-back power module 300 is cooled by a slightly warmed cooling water and a cooling water that is slightly cooler than the cooling water near the outlet hole 403. As a result, the arrangement relationship between the folded cooling passage and the two power modules 300 has an advantage that the cooling efficiency of the two power modules 300 is balanced.

  The above-described support portion 410 not only uses the O-ring 800 for the arrangement surface, but also has a great effect on strengthening the strength of the housing 12. The cooling water channel 19 is provided with a partition wall 408 that separates the outward path and the return path, and the partition wall 408 is formed integrally with the support portion 410. The partition 408 also has a function of increasing the mechanical strength of the housing 12. Heat is transmitted from the cooling water in the return path to the cooling water in the forward path through the partition wall 408, and the temperature of the cooling water is made uniform. If the temperature difference between the inlet side and the outlet side of the cooling water is large, uneven cooling efficiency increases. However, the partition wall 408 is formed integrally with the support portion 410, so that there is an effect of suppressing the temperature difference of the cooling water. .

  FIG. 5C shows the back surface of the cooling jacket 19 </ b> A, and an opening 404 is formed on the back surface side of the portion where the support portion 410 is provided. By forming the opening 404, a double structure of the support portion 410 and the bottom portion of the cooling water channel 19 is avoided, and casting is easy and productivity is improved.

  A through hole 406 is formed on the outer side of the cooling water passage 19. Electrical components (the power module 300 and the capacitor module 500) installed on both sides of the cooling water channel 19 are connected via the through hole 406.

  Since the housing 12 can be manufactured as an integral structure with the cooling jacket 19A, it is suitable for casting production, particularly aluminum die casting production.

  FIG. 6 is a diagram showing the inverter device 43 fixed to the lower surface of the cooling jacket 19A. On one long side of the rectangle of the housing 12, an AC power line 186 and an AC connector 188 protrude from the housing 12. In FIG. 6, a part of the laminated conductor plate 700 connected to the power module 300 can be seen through the through hole 406 formed in the housing 12.

  The auxiliary inverter device 43 is disposed in the vicinity of the side surface of the housing 12 to which the DC positive electrode side connection terminal portion 512 is connected. Further, as shown in FIG. 4, the capacitor module 500 is arranged below the auxiliary inverter device 43 (on the side opposite to the side where the cooling water passage 19 is present). The auxiliary machine positive terminal 44 and the auxiliary machine negative terminal 45 protrude downward (in the direction in which the capacitor module 500 is disposed), and are respectively connected to the auxiliary machine positive terminal 532 and the auxiliary machine negative terminal 534 on the capacitor module 500 side. Connected. As a result, the wiring distance from the capacitor module 500 to the auxiliary device inverter 43 is shortened, so that the auxiliary device positive terminal 532 and the auxiliary device negative terminal 534 on the capacitor module 500 side through the metal casing 12. Noise that enters the control circuit board 20 can be reduced.

  In addition, the auxiliary inverter device 43 is disposed in the gap between the coolant channel 19 and the capacitor module 500, and the auxiliary inverter device 43 is approximately as high as the lower cover 420. Therefore, the auxiliary inverter device 43 can be cooled and an increase in the height of the power conversion device 200 can be suppressed.

  FIG. 7 is a cross-sectional view taken along the line AA in FIG. 6 and shows a cross section of a portion of the power module 300 provided on the opening 402. A cooling jacket 19 </ b> A is integrally formed at substantially the center in the vertical direction of the housing 12 so as to partition the interior space of the housing vertically. A cooling water channel 19 is formed in the cooling jacket 19A, and the water channel on the left side in the figure is the forward channel, and the water channel on the right side is the return channel. One end of a plate-like AC power line 186 is connected to the AC terminal 159 of the power module 300. The other end of the AC power line 186 protrudes from the power conversion device 200 to form an AC connector.

  The power module 300 is fixed to the cooling jacket 19A so as to straddle the forward path and the return path. As will be described in detail later, the power module 300 is provided with a metal base 304 for heat dissipation. The IGBTs 328 and 330 and the diodes 156 and 166 of the power module 300 are connected to the metal base 304 via an insulating substrate (not shown). It is provided on the upper surface. A large number of cooling fins 305 are formed on the lower surface of the metal base 304. The cooling fins 305 of the present embodiment are configured with pin fins, but are not limited to pin fins and may be straight fins or the like.

  On the metal base 304, the upper arm IGBT 328 and the diode 156 are provided in a region corresponding to the forward-side opening 400 (see FIG. 5) of the cooling water channel 19. On the other hand, the IGBT 330 and the diode 166 for the lower arm are provided in a region corresponding to the return-side opening 402 (see FIG. 5) of the cooling water channel 19. The cooling fin 305 is formed by being divided into two regions, a lower surface of the region where the upper arm IGBT 328 and the diode 156 are provided, and a lower surface of the region where the lower arm IGBT 330 and the diode 166 are provided. ing. The cooling fins 305 formed in each region protrude into the cooling water channel 19 from the openings 400 and 402 (see FIG. 5), respectively, and are directly cooled by the cooling water in the channel. Further, an auxiliary inverter device 43 is fixed to the lower surface of the cooling jacket 19A.

  The substrate thickness of the metal base 304 is set to be thin in a region where the cooling fin 305 is formed (hereinafter referred to as a fin region) and thick in other regions (hereinafter referred to as thick regions) 304a and 304b. Yes. The thick regions 304a and 304b face the support portion 410, the power module mounting surface 410S, and the partition 408 of the cooling jacket 19A. An O-ring 800 is disposed on these opposing surfaces. That is, the surfaces of the thick regions 304a and 304b function as seal surfaces.

  Above the power module 300, a drive circuit board 22 on which a driver circuit 174 (not shown) is mounted is disposed. A metal base plate 11 is provided above the drive circuit board 22 to enhance the effects of heat dissipation and electromagnetic shielding, and a control circuit board 20 is further arranged above the metal base board 11. The control circuit board 20 is mounted with the control circuit 172 (not shown) shown in FIG. In addition, a capacitor module 500 is provided below the auxiliary inverter device 43 fixed to the lower surface of the cooling jacket 19A so as to be fixed to the lower case 16.

  As described above, the power module 300 is fixed to one surface of the cooling water passage 19 and the auxiliary inverter device 43 is fixed to the other surface, so that the power module 300 and the auxiliary inverter device are connected to the cooling water passage 19. 43 is cooled at the same time. In the case of the power module 300, since the lower surface of the metal base 304 and the cooling fin 305 are in direct contact with the cooling water, the cooling effect can be further enhanced.

  Further, in the present embodiment, the power module 300 having a large calorific value has a structure in which the cooling fins 305 are directly cooled with cooling water to efficiently cool the power module 300, and then the auxiliary inverter device 43 having the next largest heat radiation amount is connected to the cooling water flow path. The capacitor module 500 is cooled on the other surface 19 and then the capacitor module 500 having the next largest heating value is cooled via the housing 12 and the lower case 16. Thus, since it is set as the cooling structure match | combined with much heat dissipation, while cooling efficiency and reliability improve, the power converter device 200 can be reduced more in size.

  Further, the casing 12 is also cooled by cooling the cooling jacket 19A with the cooling water. By fixing the lower case 16 and the metal base plate 11 to the housing 12, the lower case 16 and the metal base plate 11 are cooled. Since the metal case of the capacitor module 500 is fixed to the lower case 16, the capacitor module 500 is cooled via the housing 12 and the lower case 16. Furthermore, by fixing the control circuit board 20 and the drive circuit board 22 to the metal base plate 11, these are cooled.

  FIG. 8 is a view showing the power module 300 of the present embodiment, where (a) is an upper perspective view and (b) is a top view. The power module 300 mainly includes a power module case 302, a semiconductor module portion provided in the power module case 302, a metal base 304, and a connection terminal for connecting to the outside. The power module case 302 is formed of an electrically insulating material such as a resin material, and the metal base 304 is made of a metal material such as Cu, Al, AlSiC, for example. As the connection terminals, for example, a control terminal 320U for connection with the control circuit, a DC positive terminal and a DC negative terminal for connection with the capacitor module 500, an AC terminal 159 for connection with the motor generator, and the like are provided. Yes. Reference numerals 314 a and 316 a denote terminal portions of a DC positive terminal and a DC negative terminal, which are provided on the upper surface of the power module case 302. The DC positive terminal 314a and the DC negative terminal 316a are partially overlapped, and 318 is an insulating paper provided between them. An AC terminal 159 is also provided on the upper surface of the power module case 302.

  In the semiconductor module unit, an insulating substrate is fixed on the metal base 304, and the upper and lower arms IGBTs 328 and 330, the diodes 156/166, and the like are provided on the insulating substrate. The semiconductor module portion surrounded by the power module case 302 is filled with a resin or silicon gel (not shown) to protect the semiconductor elements and wiring provided in the semiconductor module portion. The insulating substrate may be a ceramic substrate or a thinner insulating sheet.

  8B, three rectangular areas 151 indicated by dotted lines indicate the upper arm circuit in which the IGBT 328 and the diode 156 in the upper and lower arm series circuit 150 are disposed. From the left side are the U phase, V phase, and W phase. On the other hand, a lower rectangular area 152 indicates a lower arm circuit in which the IGBT 330 and the diode 166 in the upper and lower arm series circuit 150 are disposed. This is also the U phase, V phase, and W phase from the left. In the example shown in FIG. 8, two IGBTs 328 and 330 and two diodes 327 and 332 are connected in parallel to form an upper arm and a lower arm, and the current capacity that can be supplied to the upper and lower arms is increased.

  FIG. 9 is a perspective view showing the lower surface side of the power module 300, that is, the lower surface side of the metal base 304. FIG. 10 is a cross-sectional view of the power module 300. Two recesses 304 f are formed on the lower surface of the metal base 304. The formation region of these recesses 304f is set corresponding to the region where the upper and lower arm semiconductor elements (IGBT and diode) are disposed. A cooling fin 305 is formed in each recess 304f. As shown in the cross-sectional view of FIG. 10, the thick portions 304a and 304b provided around the recess 304f are larger by the dimension L than the recess 304f with respect to the thickness M of the metal base 304 of the recess 304f. Is set to Fastening through holes 301 for fixing the metal base 304 to the power module attachment surface 410S of the cooling jacket 19A are formed at the four corners of the rectangular metal base 304. The metal base 304 is fixed to the power module mounting surface 410S by four bolts 303.

  In a power conversion device used for an electric vehicle such as a hybrid vehicle, the power module 300 is enlarged, and the dimension of one side of the metal base 304 is 100 mm or more (for example, 145 × 120). In addition, a power module of an electric vehicle generates a large amount of heat from a power element (IBGT or the like), and it is necessary to improve the heat dissipation performance of the metal base 304 in order to prevent a decrease in element life due to temperature rise.

  On the other hand, the power module 300 is attached so as to close the openings 400 and 402 of the cooling water passage 19 through which the cooling water flows, and water pressure by the cooling water is applied to the lower surface of the metal base 304. Therefore, it is necessary to suppress the deformation due to the water pressure of the seal portion (the portion where the O-ring 800 is opposed) of the metal base 304 to such an extent that the sealing performance by the O-ring 800 is ensured and water leakage can be prevented. Of course, the metal base 304 can be made smaller by increasing the number of bolts 303 for fixing the metal base 304 and reducing the interval (pitch) between the through holes 301. However, since it is necessary to secure a space necessary for fastening the bolts while securing a place for arranging the terminals 159 and the like, there is a disadvantage that the entire power module 300 is necessarily enlarged.

  Therefore, in the present embodiment, as shown in FIG. 9, sufficient heat dissipation performance can be ensured in the region where the semiconductor elements (IGBT and diode) of the upper and lower arms are disposed (corresponding to the concave portion 304f). The substrate thickness is set to M (for example, M = 3 mm), and in other regions (thick portions 304a and 304b), the thickness is set to L (= M + N) so as to ensure sealing performance.

  The substrate thickness M of the metal base 304 is determined in consideration of heat dissipation performance, solder life, and the like. Moreover, as a material of the metal base 304, a material having as high a thermal conductivity as possible is desirable. In order to improve the cooling capacity, it is preferable to use, for example, oxygen-free copper or tough pitch copper. As described above, the IGBTs 328 and 330 and the diodes 156 and 166 are provided on the upper surface of the metal base 304 via the insulating substrate. The IGBTs 328 and 330 and the diodes 156 and 166 are soldered on an insulating substrate formed of a ceramic substrate or the like, and the insulating substrate is soldered on the metal base 304.

  Since the thermal expansion coefficient of the metal base 304 is larger than the thermal expansion coefficient of the insulating substrate, the elongation of the metal base 304 is larger than the elongation of the insulating substrate at a high temperature. Therefore, when a high temperature-low temperature thermal cycle is repeated, a phenomenon of ratchet deformation occurs. At a high temperature, the joining solder connecting the insulating substrate and the metal base 304 becomes soft, so that the difference in elongation is absorbed by the shear deformation of the joining solder. As a result, the metal base 304 is unlikely to warp. On the other hand, at a low temperature, the shrinkage amount of the metal base 304 becomes larger than the shrinkage amount of the insulating substrate, and the shear deformation amount of the joining solder becomes small. Therefore, the difference in the amount of shrinkage between the metal base 304 and the insulating substrate cannot be completely absorbed by the bonding solder, and the metal base 304 is bent into a shape that is convex toward the insulating substrate.

  At this time, since a tensile force acts simultaneously with the bending moment on the metal base 304, the maximum stress is generated at the joint surface with the insulating substrate. If the yield stress of the metal base 304 is larger than the maximum stress, the deformation amount of the metal base 304 is within a range in which it can be elastically deformed, and can return to its original shape each time the temperature cycle is repeated. However, when the maximum stress exceeds the yield stress of the metal base 304, the metal base 304 is plastically deformed. When plastic deformation occurs, even if the metal base 304 becomes high temperature again, a bending force that returns to the original shape does not work, and the insulating substrate is fixed by solder along the surface of the metal base 304 that is bent due to shear deformation. Will be.

  As described above, the metal base 304 undergoes plastic deformation such that the insulating substrate side is curved in a convex shape at low temperatures. The plastic deformation of the metal base 304 is accumulated when the temperature cycle is repeated, and the amount of deformation gradually increases. A phenomenon generated by such a mechanism is called ratchet deformation. When the ratchet phenomenon occurs due to the thermal load cycle (temperature cycle) of the metal base 304, the insulating substrate may be damaged and the power module 300 may be damaged. Therefore, in the power module, it is necessary to prevent such ratchet deformation.

  As a method of preventing ratchet deformation, there is a method of reducing the stress generated by the temperature cycle by making the metal base 304 thick. However, in the ratchet deformation prevention measure depending on the thickness of the material, the thermal fatigue life of the solder joining the insulating substrate and the metal base 304 is shortened, as can be seen from FIG. 20 showing the metal base thickness and the temperature cycle life of the solder joint. End up. This is because the shear stress generated by the temperature cycle increases as the metal base 304 becomes thicker. In the HEV 110 of this embodiment, the temperature cycle life of −40 to 125 ° C. is set to 1000 times or more. Therefore, according to the correlation characteristics shown in FIG. 20, the plate thickness needs to be thinner than 4 mm, but is too thin. Since the ratchet deformation described above becomes a problem, it can be understood that 3 mm to 4 mm is suitable. Therefore, in this embodiment, the thickness of the metal base 304 is 3 mm.

  A ratchet deformation is considered when the metal base 304 of the power module 300 is made of copper and the thickness is 3 mm. Since HEV110 is normally used in the environment of -40-125 degreeC, the temperature cycle assumed in this embodiment assumes low temperature side minimum temperature -40 degreeC and high temperature side upper limit temperature +125 degreeC. The maximum stress when a thermal load is applied to the metal base 304 under such conditions can be calculated as follows.

  When the elastic stress in the state where the insulating substrate was bonded to the 3 mm metal base 304 was analyzed, the maximum stress of the metal base 304 was 150 MPa along with the temperature change from 125 ° C. to −40 ° C. Assuming that the deformation of the metal base 304 becomes a neutral state at the intermediate temperature of the above temperature cycle, the maximum applied to the metal base 304 at a low temperature is provided by compressing to the high temperature side and evenly distributing the tensile stress to the low temperature side. The stress is 75 MPa.

  FIG. 21 is a graph with the horizontal axis representing yield stress and the vertical axis representing Vickers hardness. As can be seen from FIG. 21, there is a correlation between the Vickers hardness of the metal material and the yield stress. As described above, the maximum stress generated in the metal base 304 with the temperature cycle is 75 MPa. Accordingly, it can be seen from the graph of FIG. 16 that if a material having a Vickers hardness of 60 or more after forging is selected, ratchet deformation can be prevented. Even when the above-described oxygen-free copper or tough pitch copper is used as the material of the metal base 304, the metal base 304 is manufactured by forging, and therefore has a high hardness due to its work hardening. Therefore, if the metal base 304 is forged with oxygen-free copper or tough pitch copper having a thickness M = 3 mm, the Vickers hardness becomes 60 or more and ratchet deformation can be prevented.

  On the other hand, the thickness L varies depending on the size of the metal base 304 and the bolt pitch. For example, in this embodiment, the long side dimension of the metal base 304 × the short side dimension = 145 mm × 120 mm, the pitch of the through holes 301 is 111.5 mm on the short side, 130.5 mm on the long side, and the substrate thickness M = 3 mm. However, when the thickness of the metal base is uniformly set to 3 mm as in the prior art, the sealing performance becomes insufficient due to deformation due to water pressure. However, by providing thick parts 304a and 304b with a thickness L = 7mm (= 3mm + 4mm), the rigidity of the seal part of the metal base 304 is improved, and sealing performance is ensured by simply fixing the four corners of the metal base 304 with bolts. can do.

  Thus, by making the heat generating element arrangement area of the metal base 304 thin (here 3 mm) and the other area thick (here 7 mm), the bolt pitch is secured while ensuring the heat radiation performance and the sealing performance. It is possible to increase the size, and the power module 300 can be reduced in size. Here, the heating element mounting area (area corresponding to the fin area) on which the semiconductor element (IGBT or diode) is mounted is thin and all other areas are thick, but the rigidity of the seal portion of the metal base 304 is increased. If a sufficient sealing property is obtained by securing the heat generating element, a larger area including the heating element arrangement area may be a thin area.

  For example, in the first modification shown in FIGS. 11 and 12, the recessed region 304d is not on the lower surface where the cooling fin 305 of the metal base 304 is formed, but on the upper surface side where the IGBT and diode of the upper and lower arm series circuit 150 are fixed. Formed. Therefore, the shape of the lower surface of the metal base 304 is the same as that of the conventional power module as shown in FIG. The power module case 302 is mounted on the thick portion 304e around the recessed region 304d. The through hole 301 for the bolt 303 is formed in a thick part 304e having a frame shape.

  FIG. 13 is a diagram for explaining the deformation amount of the seal portion of the metal base 304 due to water pressure when the frame-shaped thick portion 304e is formed and fixed with four bolts 303 as shown in FIG. Here, when the surface pressure applied to the lower surface of the metal base 304, that is, the water pressure by the cooling water is 200 kPa, the amount of displacement in the vertical direction of the frame portion (thick portion 304e) constituting the seal portion is calculated (finite element) Method). In FIG. 13, the vertical axis represents the displacement (mm) of the thick portion 304e in FIG. The horizontal axis represents the position in the direction along the straight line L in FIG. 11, and represents the position x when the center of the bolt pitch is x = 0. Here, in order to simplify the calculation, the calculation was performed for the case where the cooling fin was not formed.

  In FIG. 13, the plate thickness M of the metal base 304 is M = 3 (mm), and the displacement is obtained using the thickness increment N in the thick portion 304e as a parameter. L11 is a case where N = 4 mm, L12 is a case where N = 5 mm, L13 is a case where N = 6 mm, and L14 is a case where N = 7 mm. It can be seen that the displacement decreases as the thickness increment N of the thick portion 304e increases, and the rigidity of the seal portion of the metal base 304 increases as the thickness of the thick portion 304e increases.

  FIG. 14 shows the displacement (deflection amount) of the center position when the dimension N is changed. The vertical axis represents the deflection amount (mm), and the horizontal axis represents the dimension N (mm). . The upper two types of data indicate the amount of deflection when the metal base 304 is fixed with four bolts 303 when the width dimension d of the thick portion 304e is 7 mm and 10 mm. On the other hand, the two types of data on the lower side show the amount of deflection when the metal base 304 is fixed with six bolts 303 when the width dimension d of the thick portion 304e is 7 mm and 10 mm. Regardless of whether the number of bolts is 4 or 6, the difference in deflection amount due to the difference in width dimension does not change, and the difference in deflection amount when d = 7 and d = 10 is small. On the other hand, when the number of bolts is increased from 4 to 6, it can be seen that the amount of deflection greatly decreases. From the calculation results as shown in FIGS. 13 and 14, it can be seen that the displacement of the seal portion of the metal base 304 can be effectively suppressed by providing the thick portion 304e.

  In the example shown in FIGS. 9 to 12, the rigidity is improved by forming the thick portions 304a, 304b, and 304e on the metal base 304. However, the structure shown in the second modification of FIGS. Thus, the rigidity may be improved. FIG. 15 is a view showing the metal base 304 and the power module case 302 as in the case of FIG. 11. In the second modification, the thickness of the substrate is constant at dimension M, but by providing a bent stepped portion 304m on the metal base 304, the rigidity of the seal portion is made higher than that of the flat plate. .

  FIGS. 16A and 16B are views showing a cross section of the power module 300, where FIG. 16A is a CC cross sectional view and FIG. 16B is a DD cross sectional view. The metal base 304 has a step structure, and the heating element disposition region 304g to which the IGBT and the diode of the upper and lower arm series circuit 150 are fixed protrudes upward in the figure with respect to the peripheral region 304h. Therefore, on the lower surface of the metal base 304, a heating element disposition region 304g is recessed, and cooling fins 305 are formed in the recessed region. The lower surface of the peripheral region 304h functions as a seal surface when fixed to the power module mounting surface 410S of the cooling jacket 19A. As an example, the substrate thickness M is M = 3 mm, and the step of the heating element arrangement region 304g is 4 mm.

  In the second modification shown in FIGS. 15 and 16, the step portion 304 m is formed for each of the upper arm and the lower arm and the two heating element arrangement regions 304 g are provided, but the third modification shown in FIGS. As an example, the peripheral portion of the metal base 304 may be a fixed portion, and a stepped portion 304m may be provided between the heat generating element disposition region 304j inside. 18 is a perspective view showing the lower surface side of the power module 300. FIG. 9A is a cross-sectional view taken along line EE in FIG. 17, and FIG. 19B is a cross-sectional view taken along line FF.

  FIG. 17 is a view similar to FIG. 15, showing the metal base 304 and the power module case 302. The metal base 304 is formed with a heating element disposition region 304j formed so as to protrude upward, and a rectangular frame-shaped peripheral region 304k provided so as to surround the periphery, and a step between the regions is formed. A portion 304m is formed. As shown in FIG. 18, the lower surface side of the heating element arrangement region 304j is recessed, and cooling fins 305 for the upper arm and the lower arm are respectively formed in the recess (fin formation region).

  Comparing the cross-sectional view of FIG. 16B and the cross-sectional view of FIG. 19B, in the third modification, the substrate portion between the fin groups constituting the upper and lower arm cooling fins 305 is the cooling fin. Similarly to the partial degree where 305 is provided, it protrudes upward. Therefore, the lower surface of the peripheral region 304k in the peripheral portion of the metal base 304 is used as a seal surface.

  In addition, as a manufacturing method of the metal base 304, there are a method of forging a plate material to integrally form the thick portion and the cooling fin, and a method of integrally forming the substrate portion, the thick portion and the cooling fin by casting. . Alternatively, the plate material may be pressed to form a recess as shown in FIGS. 15 and 16, and the cooling fin 305 may be brazed into the recess. In the case of casting, metal injection molding is suitable. In the metal powder injection molding method, a metal powder and a resin binder are mixed and injection molded, followed by firing to obtain a molded product.

The embodiment described above can provide the following operational effects.
(1) The metal base 304 provided in the power module 300 has a semiconductor element (IGBT and a diode) mounted on one surface and an opening 400 formed in the cooling water channel 19 of the cooling jacket 19A on the other surface. , 402 is closed. In the metal base 304, the substrate thickness M in the mounting region of the semiconductor element is determined according to the heat dissipation amount for radiating the heat generated from the semiconductor element to the refrigerant. In the case of a vehicle power converter, the amount of heat generated is large, and M is about 3 mm in consideration of heat resistance of the semiconductor element. By making the fixing region (thick portions 304a and 304b) including the seal portion of the metal base 304 thick, the rigidity of the fixing region is increased compared to the mounting region, so that the seal portion of the metal base 304 is deformed by the cooling water pressure. It is suppressed and the sealing performance by the O-ring 800 is ensured. Thereby, the pitch of the bolts 303 for fixing the metal base 304 can be made larger than before, and the number of the bolts 303 can be reduced. As a result, it is possible to reduce the size of the power module 300 while maintaining the heat dissipation performance as in the conventional case.
(2) For example, by setting the substrate thickness L of the fixed region of the metal base 304 (the region of the thick portions 304a and 304b) to be larger than the substrate thickness M of the recess 304f that is the mounting region, the rigidity of the seal portion To prevent water leakage.
(3) Also, as shown in FIG. 16, the mounting area thickness and the fixed area thickness are set to the same value M,
A step may be provided at the boundary between the two regions so that the rigidity of the fixed region 304h is greater than the rigidity of the mounting region 304g. A stepped portion 304m that is bent in such a manner is formed. By forming such a stepped portion 304, it is possible to improve the rigidity of the peripheral region 304h, which is a fixed portion, and to prevent water leakage from the seal portion.
(4) As shown in FIG. 10, a cooling fin 305 is formed on the lower surface side of a portion set to a thickness M as a mounting region for semiconductor elements (IGBT and diode), that is, a recess 304f is used as a fin forming region. I did it. By directly cooling the cooling fins 305 formed in the recesses 304f by projecting into the cooling water flow, it is possible to improve the heat radiation performance for radiating the heat generated in the semiconductor element to the cooling water.
(5) When the metal base 304 has a plurality of semiconductor arrangement regions, a plurality of regions where the cooling fins 305 are formed may be formed corresponding to each. For example, as shown in FIG. 9, when semiconductor elements are provided separately for the upper arm and the lower arm, a fin forming region is provided corresponding to each. Thus, when the fin formation region is divided into two regions, the press pressure during forging can be kept small by forming it by forging separately in two stages, and the processing apparatus is increased in size. Can be avoided.
(6) Thick parts 304a and 304b and cooling fins 305 in the recesses 304f as shown in FIG. 9 may be integrally formed by forging a metal plate (for example, a copper plate). By forming the thick portions 304a and 304b, the rigidity of the seal portion of the metal base 304 is improved. In addition, the hardness of the metal plate itself increases due to work hardening during forging.
(7) Further, the metal base plate 304 may be integrally formed by a metal powder injection molding method (Metal Injection Molding). Even if the cooling fin 305 has an elongated shape like a pin fin, it can be easily and uniformly formed.
(8) The substrate shape of the metal base 304 is rectangular, and the rectangular frame region at the periphery of the rectangular region is used as a seal portion, and the four corners of the rectangular frame region are fastened to the cooling jacket with fastening parts such as bolts. good. By making the seal part thick or providing the step part 304m, the rigidity of the seal part is improved. Therefore, it is possible to ensure sufficient sealing performance by fixing only the four corners by bolt fastening. As a result, it is possible to reduce the size of the apparatus and reduce the number of assembly steps.

  It is also possible to combine one or a plurality of embodiments and modifications. Any combination of the modified examples is possible.

  The above description is merely an example, and the present invention is not limited to the configuration of the above embodiment. For example, although the cooling fins 305 are formed on the metal base 304 in the above-described embodiment to improve the heat dissipation performance, the heat generation of the semiconductor element is not so great and sufficient heat dissipation is possible even without forming the cooling fins 305. If the performance can be secured, the cooling fins 305 are not necessarily formed. In that case, by omitting the cooling fins 305, the processing of the metal base 304 is reduced, and the cost can be reduced.

  10: Upper case, 11: Metal base plate, 12: Housing, 13: Cooling water inlet piping, 14: Cooling water outlet piping, 16: Lower case, 19: Cooling water flow path, 19A: Cooling jacket, 43, 140, 142: inverter device, 136: battery, 144, 145: inverter circuit, 150: upper and lower arm series circuit, 156, 166: diode, 192, 194: motor generator, 200: power converter, 300: power module, 302: power Module case, 303: Bolt, 304: Metal base, 304a, 304b, 304e: Thick portion, 304d, 304f: Recess, 304g, 304j: Heating element placement region, 304h, 304k: Peripheral region, 304m: Stepped portion, 305: Cooling fin, 328, 330: IGBT, 400, 402: Opening 800,802: O-ring,

Claims (5)

A cooling jacket in which a flow path through which the refrigerant flows and an opening in which a part of the flow path is exposed;
A semiconductor element for converting the DC power and the AC power to each other, comprising an upper arm semiconductor element and a lower arm semiconductor element constituting an inverter circuit ;
The semiconductor element is mounted on one surface of a plate-like member, and a metal base plate that is fixed to the cooling jacket so that the other surface closes the opening and contacts the refrigerant;
A sealing member sandwiched between the metal base plate and the cooling jacket and sealing leakage of the refrigerant from the opening,
The metal base plate is mounted with the semiconductor element, and includes a first mounting area for the upper arm semiconductor element, and a second mounting area for the lower arm semiconductor element , A fixing region that presses and seals the seal member to the cooling jacket, and includes a first fin forming region and a second fin forming region corresponding to each of the first mounting region and the second mounting region,
The metal base plate is made of a material having a Vickers hardness in which a stress generated in the metal base plate due to a temperature cycle does not reach a yield stress,
The thickness of the mounting region is determined according to the amount of heat released to dissipate heat generated from the semiconductor element to the refrigerant, and a fin formation region is provided on the other surface of the mounting region, and the fin formation region Forming a plurality of cooling fins protruding into the flow path;
The power converter according to claim 1, wherein a thickness of the fixed area is set larger than a thickness of the mounting area, and a rigidity of the fixed area is set larger than a rigidity of the mounting area. The power conversion device according to claim 1,
A thickness of the mounting area is 3 to 4 mm. In the power converter device according to claim 1 or 2 ,
The power conversion device, wherein the mounting region, the fixed region, and the cooling fin are integrally formed by forging a metal plate material. In the power converter device according to claim 1 or 2 ,
The power conversion device, wherein the mounting region, the fixed region, and the cooling fin are integrally formed by a metal powder injection molding method. In the power converter device as described in any one of Claims 1-4 ,
The substrate shape of the metal base is a rectangle, and a rectangular frame region at the periphery of the rectangular region is the fixed region,
The power conversion device, wherein four corners of the rectangular frame region are fastened to the cooling jacket by fastening parts.

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