JP2007202309A - Cooling structure of power semiconductor element and invertor - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a cooling structure of a power semiconductor element which can control the temperature of the element easily and properly while attaining a size reduction, and to provide an invertor. <P>SOLUTION: The cooling structure of the power semiconductor element is equipped with a plurality of chips 31 loaded on a loading surface, a cooling water channel 26 formed facing the loading surface, and fins 41 provided projecting from the inner wall of the cooling water channel 26 into the cooling water channel 26. The cooling water channel 26 has a straight portion 15 extending linearly and a connector 16 extending while bending. The fin 41 has a straight fin 42 and a wavy fin 43. The wavy fin 43 is arranged in a division of a portion of the straight portion 15. A chip 31 includes a chip 31D arranged facing the connector 16. The cooling structure of the power semiconductor element is furthermore equipped with a controller which controls the current flowing in the chip 31 based on the temperature information of the chip 31D. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention generally relates to a cooling structure for a power semiconductor element and an inverter, and more particularly to a cooling structure for a power semiconductor element including a coolant passage extending in a meandering manner and an inverter to which the cooling structure is applied.

  Regarding the conventional cooling structure for power semiconductor elements, for example, Japanese Patent Laid-Open No. 11-262241 aims to increase the output current without reducing the safety of the elements and without complicating the device. A power electronic circuit device is disclosed (Patent Document 1). In Patent Document 1, cooling fins are formed on a base plate manufactured by aluminum die casting. On the base plate, an IGBT chip constituting a three-phase inverter circuit and a temperature sensor are arranged side by side.

  Japanese Patent Laid-Open No. 2003-18861 discloses that when a single temperature sensor is provided for a plurality of inverters, the temperature of the junction portion of the power semiconductor element constituting each inverter is accurately calculated. An inverter cooling control device for the purpose is disclosed (Patent Document 2).

Japanese Patent Application Laid-Open No. 11-215838 discloses an inverter device for the purpose of appropriately protecting a subsequent drive target even when the power supply is reset (Patent Document 3). . Japanese Patent Application Laid-Open No. 2004-327124 includes a thermistor for accurately detecting the temperature of a semiconductor switching element, eliminating the need for high insulation, enabling quick mounting by an automatic machine, and manufacturing at low cost. A printed circuit board is disclosed (Patent Document 4).
JP-A-11-262241 JP 2003-18861 A Japanese Patent Application Laid-Open No. 11-215838 JP 2004-327124 A

  In Patent Document 1 described above, it is determined whether or not to limit the output current of the three-phase inverter circuit based on the temperature near the element detected by the temperature sensor. However, if a plurality of chips are arranged more densely in order to reduce the size of the inverter, the chips may be positioned at a plurality of places where the cooling efficiency is inferior. In such a case, if it is attempted to accurately determine the timing for limiting the output current of the three-phase inverter circuit, it is necessary to detect and monitor the chip temperature at a plurality of locations where the temperature rise is considered to be greatest. For this reason, the temperature control of the chip may be complicated or difficult.

  SUMMARY OF THE INVENTION Accordingly, an object of the present invention is to solve the above-described problems, and to provide a power semiconductor element cooling structure and an inverter in which the element temperature can be controlled easily and appropriately while downsizing.

  A cooling structure for a power semiconductor element according to the present invention includes a plurality of power semiconductor elements mounted on a mounting surface, a refrigerant passage formed to face the mounting surface, and through which a refrigerant for cooling the plurality of power semiconductor elements flows. And fins provided so as to protrude from the inner wall of the refrigerant passage into the refrigerant passage. The refrigerant passage has a straight portion that extends in a straight line and a connection portion that is connected to the straight portion and extends while bending. The fin has a first portion and a second portion that are disposed in different sections on the path of the refrigerant passage. The first portion is formed from a surface extending along the flow direction of the refrigerant along the path of the refrigerant passage. The second part is disposed in a partial section of the straight part, and is provided in a form in which the heat transfer coefficient with the refrigerant is larger than that of the first part. The plurality of power semiconductor elements includes a power semiconductor element disposed to face the connection portion. The cooling structure of the power semiconductor element further includes a control unit that controls currents flowing through the plurality of power semiconductor elements based on temperature information of the power semiconductor elements arranged to face the connection part.

  According to the cooling structure of the power semiconductor element configured as described above, the power semiconductor element is arranged at a position facing the connecting portion, so that the power semiconductor element is arranged only at a position facing the straight portion. Thus, more power semiconductor elements can be provided on a narrower mounting surface. Thereby, size reduction of the apparatus provided with a some power semiconductor element can be achieved. In this case, by providing the second portion in a partial section of the straight portion, it is possible to preferentially improve the cooling efficiency of the power semiconductor element disposed facing the section. Therefore, easy and appropriate control can be realized by controlling the current flowing through the plurality of power semiconductor elements based on the temperature information of the power semiconductor elements arranged to face the connecting portion.

  Preferably, a region where a plurality of power semiconductor elements are relatively densely arranged is formed on the mounting surface so as to face the straight portion. The second part is provided to face the region.

  According to the power semiconductor element cooling structure configured as described above, by providing the second portion having excellent cooling efficiency so as to face the region with larger heat generation, the performance of the plurality of power semiconductor elements with respect to heat can be improved. It can be improved well.

  Also preferably, the second portion is formed of a wave fin extending while undulating along the path of the refrigerant passage. According to the cooling structure of the power semiconductor element configured as described above, the contact area between the refrigerant and the second portion can be increased, and turbulent flow can be positively generated in the refrigerant flow. For this reason, the heat transfer coefficient between the second part and the refrigerant can be made larger than the heat transfer coefficient between the first part and the refrigerant.

  Preferably, the second portion is formed of a plurality of pin fins standing upright apart from each other. According to the cooling structure of the power semiconductor element configured as described above, a turbulent flow can be positively generated in the refrigerant flow. For this reason, the heat transfer coefficient between the second part and the refrigerant can be made larger than the heat transfer coefficient between the first part and the refrigerant.

  The inverter according to the present invention uses the power semiconductor element cooling structure described above and is mounted on a vehicle. According to the inverter configured as described above, easy and appropriate control of the inverter can be realized while downsizing the inverter.

  As described above, according to the present invention, it is possible to provide a power semiconductor element cooling structure and an inverter in which the element temperature is easily and appropriately controlled while downsizing.

  Embodiments of the present invention will be described with reference to the drawings. In the drawings referred to below, the same or corresponding members are denoted by the same reference numerals.

  FIG. 1 is a perspective view showing a cooling system of an HV (Hybrid Vehicle) system. The cooling system of the HV system shown in the figure is mounted on a hybrid vehicle that is driven by a motor and an internal combustion engine such as a gasoline engine or a diesel engine.

  Referring to FIG. 1, a hybrid vehicle includes an engine 310, a trunk axle 330 incorporating a drive motor and a generator for power generation (hereinafter referred to as a motor generator), a DC voltage of a battery, and an AC voltage of a motor generator. Are mutually converted, and a radiator 350 is provided.

  The radiator 350 is provided with two independent cooling water channels, one of which constitutes the cooling system of the engine 310 and the other of which constitutes the cooling system of the HV system. The cooling system of the HV system is formed by a cooling water path that follows the radiator 350 → the inverter 130 → the reservoir tank 320 → the water pump 340 → the trunk axle 330 → the radiator 350. Cooling water (for example, ethylene glycol-based coolant) in the water channel is forcibly circulated by the water pump 340 to sequentially cool the inverter 130 and the motor generator provided in the trunk axle 330. The cooling water whose temperature has risen due to cooling passes through the radiator 350, so that the temperature is lowered. In addition, the refrigerant | coolant used is not limited to a liquid, Gas may be used.

  FIG. 2 is an electric circuit diagram showing a main part of the HV system. 2, in addition to motor generator 110 and inverter 130, HV system 200 includes converter 120, control device 140, capacitors C1, C2, power supply lines PL1-PL3, output lines 220, 240, 260. The motor generator 110 is actually composed of a motor generator MG1 mainly functioning as a generator and a motor generator MG2 mainly functioning as a motor. However, in order to simplify the following explanation, Is shown as one motor generator.

  Converter 120 is connected to battery B via power supply lines PL1 and PL3. Inverter 130 is connected to converter 120 via power supply lines PL2 and PL3. Inverter 130 is connected to motor generator 110 via output lines 220, 240, and 260. Battery B is a DC power source, and is formed of a secondary battery such as a nickel metal hydride battery or a lithium ion battery. Battery B is charged with the DC power supplied to converter 120 or received from converter 120.

  Motor generator 110 is, for example, a three-phase AC synchronous motor generator, and generates a driving force by AC power received from inverter 130. Motor generator 110 is also used as a generator, generates AC power by power generation action (regenerative power generation) during deceleration, and supplies the generated AC power to inverter 130.

  Converter 120 includes an upper arm and a lower arm formed of a semiconductor module, and a reactor L. The upper arm and the lower arm are connected in series between the power supply lines PL2 and PL3. The upper arm connected to the power supply line PL2 includes a power transistor (IGBT: Insulated Gate Bipolar Transistor) Q1 and a diode D1 connected in antiparallel to the power transistor Q1. The lower arm connected to the power supply line PL3 includes a power transistor Q2 and a diode D2 connected in antiparallel to the power transistor Q2. Reactor L is connected between power supply line PL1 and a connection point between the upper arm and the lower arm.

  Converter 120 boosts the DC voltage received from battery B using reactor L, and supplies the boosted voltage to power supply line PL2. Converter 120 steps down the DC voltage received from inverter 130 and charges battery B. Converter 120 is not necessarily provided.

  Inverter 130 includes a U-phase arm 152, a V-phase arm 154, and a W-phase arm 156. U-phase arm 152, V-phase arm 154 and W-phase arm 156 are connected in parallel between power supply lines PL2 and PL3. Each of the U-phase arm 152, the V-phase arm 154, and the W-phase arm 156 is composed of an upper arm and a lower arm made of semiconductor modules. The upper arm and lower arm of each phase arm are connected in series between power supply lines PL2 and PL3.

  The upper arm of the U-phase arm 152 includes a power transistor (IGBT) Q3 and a diode D3 connected in antiparallel to the power transistor Q3. The lower arm of U-phase arm 152 includes power transistor Q4 and diode D4 connected in antiparallel to power transistor Q4. The upper arm of V-phase arm 154 includes power transistor Q5 and diode D5 connected in antiparallel to power transistor Q5. The lower arm of V-phase arm 154 includes power transistor Q6 and diode D6 connected in antiparallel to power transistor Q6. The upper arm of W-phase arm 156 includes power transistor Q7 and a diode D7 connected in antiparallel to power transistor Q7. The lower arm of W-phase arm 56 includes power transistor Q8 and diode D8 connected in antiparallel to power transistor Q8. The connection point of the power transistor of each phase arm is connected to the anti-neutral point side of the coil of the corresponding phase of motor generator 110 via the corresponding output line.

  In the figure, a case where the upper arm and the lower arm of the U-phase arm 152 to the W-phase arm 156 are each composed of one semiconductor module composed of a power transistor and a diode is shown. The semiconductor module may be configured.

  Inverter 130 converts a DC voltage received from power supply line PL <b> 2 into an AC voltage based on a control signal from control device 140, and outputs the AC voltage to motor generator 110. Inverter 130 rectifies the AC voltage generated by motor generator 110 into a DC voltage and supplies it to power supply line PL2.

  Capacitor C1 is connected between power supply lines PL1 and PL3, and smoothes the voltage level of power supply line PL1. Capacitor C2 is connected between power supply lines PL2 and PL3, and smoothes the voltage level of power supply line PL2.

  Control device 140 calculates each phase coil voltage of motor generator 110 based on the torque command value of motor generator 110, each phase current value, and the input voltage of inverter 130. Based on the calculation result, control device 140 generates a PWM signal for turning on / off power transistors Q <b> 3 to Q <b> 8 and outputs the PWM signal to inverter 130. Each phase current value of motor generator 110 is detected by a current sensor incorporated in a semiconductor module constituting each arm of inverter 130. This current sensor is disposed in the semiconductor module so as to improve the S / N ratio. Control device 140 calculates the duty ratio of power transistors Q1 and Q2 for optimizing the input voltage of inverter 130 based on the torque command value and the motor speed described above. Based on the result, control device 140 generates a PWM signal for turning on / off power transistors Q1, Q2, and outputs the PWM signal to converter 120.

  Further, control device 140 controls the switching operation of power transistors Q1 to Q8 in converter 120 and inverter 130 in order to convert AC voltage generated by motor generator 110 into DC voltage and charge battery B.

  Subsequently, the cooling structure of the inverter 130 will be described. In the present embodiment, the power semiconductor element cooling structure according to the present invention is applied to inverter 130. FIG. 3 is a plan view showing a cooling structure of the inverter in FIG. FIG. 4 is a cross-sectional view of the inverter taken along line IV-IV in FIG.

  3 and 4, inverter 130 includes a case body 21 having a mounting surface 21a and an installation surface 21b facing the opposite side of mounting surface 21a. The case body 21 is manufactured by a casting process such as aluminum die casting. As a material for forming the case body 21, for example, iron or magnesium may be used.

  A heat radiating plate 33 is fixed to the mounting surface 21 a via silicon grease 34. On the heat radiating plate 33, a plurality of chips 31 are further fixed via an insulating substrate 32. The plurality of chips 31 are provided at positions separated from each other on the mounting surface 21a. Chip 31 is provided corresponding to an upper arm and a lower arm that form U-phase arm 152 to W-phase arm 156, and includes a semiconductor module including a power transistor and a diode. In FIG. 3, twelve chips 31 are shown, and each arm is constituted by two chips 31.

  A cooling water passage 26 is formed on the installation surface 21b. Cooling water for cooling the chips 31 flows through the cooling water passage 26. The cooling water passage 26 is formed to face the mounting surface 21a on which the chip 31 is mounted. The cooling water passage 26 has a supply port 23 through which cooling water is supplied and a discharge port 24 through which cooling water is discharged, and extends between the supply port 23 and the discharge port 24. The cooling water passage 26 extends parallel to the mounting surface 21a. The cooling water passage 26 extends so as to overlap with the mounting position of the chip 31 when the mounting surface 21a is viewed in plan.

  The cooling water passage 26 includes a straight portion 15 that extends linearly on the installation surface 21b, and a connection portion 16 that is connected to the straight portion 15 and extends while curving on the installation surface 21b. On the path of the cooling water passage 26 from the supply port 23 toward the discharge port 24, the straight portions 15 and the connection portions 16 are alternately provided. A plurality of straight portions 15 are provided side by side in one direction. The plurality of straight portions 15 extend in parallel to each other. The plurality of straight portions 15 may extend in different directions. The connection part 16 connects between a plurality of adjacent straight parts 15. The connecting portion 16 extends while changing the extending direction by 180 °.

  The cooling water supplied to the cooling water passage 26 through the supply port 23 flows along the path of the cooling water passage 26. During this time, the cooling water exchanges heat with the chip 31 via the case body 21 to cool the chip 31. The cooling water whose temperature has been increased by heat exchange with the chip 31 is discharged from the cooling water passage 26 through the discharge port 24.

  FIG. 5 is a perspective view showing a cooling water passage in FIG. 3. 3 to 5, the mounting surface 21a is formed with regions 11 and 12 in which the chips 31 are arranged relatively sparsely and regions 13 in which the chips 31 are arranged relatively densely. ing. A chip 31A and a chip 31C are disposed in the areas 11 and 12, respectively, and a chip 31B is disposed in the area 13. The chips 31A and 31C have a relatively large distance to the adjacent chip 31, and the chip 31B has a relatively small distance to the adjacent chip 31. The chip 31B is positioned between the chip 31A and the chip 31C.

  On the mounting surface 21 a, the regions 11 and 12 that face the straight portion 15, the region 13 that faces the straight portion 15, and in which the chips 31 are densely arranged as compared to the regions 11 and 12, and the connection portion 16. Region 14 to be formed.

  In each of the regions 11 and 12, a plurality of chips 31A and a plurality of chips 31C are provided. In the region 13, a plurality of chips 31B are arranged. When the average value of the distance between adjacent chips in each region is obtained (for example, the average value of the distance between chips in region 11 is (L1 + L2) / 2), the average of the distance between chips in region 13 The value is smaller than the average value of the distance between the chips in the regions 11 and 12. That is, the chips 31A and 31C are arranged so that the distance between adjacent chips is relatively large, and the chip 31B is arranged so that the distance between adjacent chips is relatively small. In the region 14, a chip 31D is disposed.

  Fins 41 are provided in the cooling water passage 26. The fin 41 promotes heat exchange between the chip 31 and the cooling water flowing in the cooling water passage 26 performed through the case body 21. The fin 41 protrudes from the installation surface 21 b that forms a part of the inner wall of the cooling water passage 26. The fins 41 are formed integrally with the case body 21. The cross-sectional shape of the fin 41 when cut by a plane orthogonal to the flow direction of the cooling water is not limited to the rectangle shown in FIG. 4 and may be, for example, a mountain shape.

  A plurality of fins 41 are formed at intervals in the direction orthogonal to the direction in which the cooling water passage 26 extends. The fin 41 extends along the direction in which the cooling water passage 26 extends. The fins 41 are provided so as to protrude from the inner wall of the cooling water passage 26 toward the space in the cooling water passage 26. In the present embodiment, the fin 41 plays a role as a guide member for guiding the cooling water flowing through the cooling water passage 26. The plurality of fins 41 are arranged at equal intervals. The plurality of fins 41 may be arranged at different intervals.

  The fin 41 has a straight fin portion 42 and a wave fin portion 43. The straight fin portion 42 and the wave fin portion 43 are disposed in different sections of the section in which the fin 41 extends along the cooling water passage 26. The fin 41 includes a straight fin portion 42 and a wave fin portion 43.

  The straight fin portion 42 is formed from a straight fin. That is, the straight fin portion 42 is formed from a surface 42 a extending along the flow direction of the cooling water along the path of the cooling water passage 26. The surface 42a is formed by a smooth surface. The straight fin portion 42 extends parallel to the path of the cooling water passage 26. The straight fin part 42 is formed by the surface 42a from the lower end connected to the installation surface 21b to the upper end located on the opposite side.

  The wave fin portion 43 is formed from a wave fin. That is, the wave fin portion 43 has a surface 43 a that extends in a direction that intersects the flow direction of the cooling water along the path of the cooling water passage 26. The surface 43 a is formed by an uneven surface that repeats unevenness along the path of the cooling water passage 26. The surface 43a is formed by a curved surface. The wave fin portion 43 extends while undulating along the path of the cooling water passage 26. The wave fin portion 43 is formed by a surface 43a from the lower end to the upper end. The area of the surface 43a per unit length of the path of the cooling water passage 26 is larger than the area of the surface 42a.

  The straight fin portion 42 is provided so as to face the regions 11, 12 and 14. The wave fin portion 43 is provided so as to face the region 13. That is, when the mounting surface 21a is viewed in a plan view, the straight fin portion 42 is provided so as to overlap the chips 31A, 31C, and 31D. The wave fin portion 43 is provided so as to overlap the chip 31B.

  In the region 13 where the chips 31 are relatively densely arranged, if the straight fin portions 42 are provided in the entire section of the cooling water passage 26, the temperature of the chip 31B arranged in the region 13 is This is a region that is equal to or higher than the temperature of the chip 31D disposed in the region 14.

  FIG. 6 is a diagram illustrating a method of comparing the heat transfer coefficient between the cooling water and the fin between the wave fin portion and the straight fin portion. 6A and 6B show a wave fin portion 43 and a straight fin portion 42, respectively.

  Referring to FIG. 6, the wave fin portion 43 is provided so that the heat transfer coefficient with the cooling water flowing through the cooling water passage 26 is larger than that of the straight fin portion 42. On the surface 43 a of the wave fin portion 43, a turbulent flow is positively formed by the flow of the cooling water, and heat exchange between the cooling water and the wave fin portion 43 is promoted.

  The magnitude relationship of the heat transfer coefficient between the wave fin part 43 and the straight fin part 42 is measured by the method demonstrated below, for example.

  In the vicinity of the chip 31, a heat chip 45 including a resistor and generating heat by supplying a current is disposed. The heat chip 45 is caused to generate heat, and a heat quantity Q is given to the chip 31. After a certain time has elapsed, the temperature Ta of the chip 31 and the temperature Tb of the cooling water are measured. A temperature difference ΔT (= Ta−Tb) between the temperature Ta of the chip 31 and the temperature Tb of the cooling water is calculated. The above measurement is performed in each of the case where the straight fin portion 42 is used and the case where the wave fin portion 43 is used. At this time, each measurement is performed under the same conditions such as the amount of heat Q applied to the chip 31, the flow condition of cooling water such as a flow rate and temperature, and the boundary condition between the chip 31 and the fin 41.

  The temperature difference ΔT is compared between when the straight fin portion 42 is used and when the wave fin portion 43 is used. When the temperature difference ΔT is larger when the wave fin portion 43 is used than when the straight fin portion 42 is used, the heat transfer coefficient between the cooling water and the wave fin portion 43 is less than the cooling water and the straight fin portion. It is judged that it is larger than the heat transfer coefficient with 42.

  2 and 3, control device 140 detects the temperature of chip 31 </ b> D based on a signal from a temperature detection unit built in chip 31 </ b> D. The control device 140 determines whether or not the detected temperature of the chip 31D is higher than a predetermined upper limit value. When it is determined that the temperature of the chip 31D is higher than a predetermined upper limit value, the control device 140 outputs a control signal for suppressing the output current to the inverter 130. Note that the control device 140 may control the output current of the inverter 130 based on the temperature information of the chip 31 provided facing the connection unit 16 other than the chip 31D.

  FIG. 7 is a graph showing the temperature of the chip in FIG. Referring to FIG. 7, in the graph, the temperatures of chips 31A to 31D in FIG. 3 are shown. A line segment 101 indicates the temperature of the chip 31 when the fins 41 are not provided. A line segment 102 indicates the temperature of the chip 31 when the fin 41 using both the straight fin portion 42 and the wave fin portion 43 is provided.

  In the connection part 16 extended while curving, the cooling efficiency by the cooling water tends to be lower than that of the straight part 15. For this reason, the temperature of the chip 31D arranged in the region 14 is higher than the temperature of the chips 31A and 31C arranged in the regions 11 and 12, respectively.

  Further, when the fins 41 are not provided, the temperature of the chip 31B arranged in the region 13 is greatly affected by the temperature of the chip 31 arranged around, and thus becomes relatively high. The temperatures of the chips 31A and 31C respectively disposed are relatively low because they are not significantly affected by the temperature of the chips 31 disposed around them. As a result, the temperature of the chip 31B is equal to or higher than the temperature of the chip 31D even though the chip 31B is disposed to face the straight portion 15.

  In this embodiment, the cooling efficiency of the chip 31B is preferentially improved by providing the wave fin portion 43 so as to overlap the chip 31B. Thereby, the temperature of the chip 31B can be significantly reduced as compared with the chips 31A, 31C, and 31D. As a result, in the present embodiment, the chip 31D provided in the region 14 facing the connection portion 16 is set to the highest temperature.

  In addition, although the cooling fin flow is prevented by providing the wave fin portion 43, in the present embodiment, the straight fin portion 42 and the wave fin portion 43 are used in combination with the straight portion 15. For this reason, compared with the case where only the wave fin part 43 is provided, the increase in the pressure loss of a cooling water flow can be suppressed to the minimum.

  The cooling structure of the power semiconductor element in the embodiment of the present invention includes a chip 31 as a plurality of power semiconductor elements mounted on the mounting surface 21a and a coolant that is formed facing the mounting surface 21a and cools the chip 31. The cooling water passage 26 is provided as a refrigerant passage through which the cooling water flows, and the fins 41 are provided so as to protrude from the inner wall of the cooling water passage 26 into the cooling water passage 26. The cooling water passage 26 includes a straight portion 15 that extends in a straight line, and a connection portion 16 that is connected to the straight portion 15 and extends while bending. The fin 41 includes a straight fin portion 42 as a first portion and a wave fin portion 43 as a second portion, which are disposed in different sections on the cooling water passage 26. The straight fin portion 42 is formed from a surface 42 a extending along the flow direction of the cooling water along the path of the cooling water passage 26. The wave fin portion 43 is disposed in a part of the straight portion 15 and is provided in a form in which the heat transfer coefficient with the cooling water is larger than that of the straight fin portion 42. The chip 31 includes a chip 31 </ b> D arranged to face the connection unit 16. The cooling structure of the power semiconductor element further includes a control device 140 as a control unit that controls the current flowing through the chip 31 based on the temperature information of the chip 31 </ b> D arranged to face the connection unit 16.

  According to the power semiconductor element cooling structure in the embodiment of the present invention configured as described above, the chip 31 has not only the regions 11, 12 and 13 facing the straight portion 15 but also the connection portion 16 inferior in cooling efficiency. It is also arranged in the region 14 facing the. For this reason, a predetermined number of chips 31 can be mounted on the narrower mounting surface 21a. Thereby, size reduction of the inverter 130 can be achieved. Further, by providing the wave fin portion 43 at a position with relatively large heat generation in the straight portion 15, the performance of the inverter 130 with respect to heat can be effectively improved.

  When the wave fin portion 43 is not provided in the straight portion 15, it is necessary to control the output current of the inverter 130 by managing the temperatures of both the chip 31B and the chip 31D. In this case, it becomes difficult to perform control easily and appropriately. On the other hand, in the present embodiment, as a result of the wave fin portion 43 being provided in the straight portion 15, the chip 31D provided to face the connection portion 16 is set to the highest temperature. For this reason, the temperature control of the chip 31 can be performed easily and appropriately by controlling the output current of the inverter 130 based on the temperature of the chip 31D.

  FIG. 8 is a perspective view of a cooling water passage showing a modification of the fin in FIG. Referring to FIG. 8, wave fin portion 43 in FIG. 5 has a constant thickness, whereas in this modification, wave fin portion 43 repeatedly increases or decreases the thickness along the path of cooling water passage 26. It extends while letting.

  As another modification, the fin 41 may include a straight fin portion 42 and a bent fin portion extending in a zigzag manner along the path of the cooling water passage 26 instead of the wave fin portion 43.

  FIG. 9 is a perspective view of a cooling water passage showing still another modification of the fin in FIG. Referring to FIG. 9, in the present modification, fin 41 includes straight fin portion 42 and pin fin portion 51 provided in place of wave fin portion 43 in FIG. 5. The pin fin portion 51 is formed of a plurality of pin fins that protrude from the installation surface 21 b toward the cooling water passage 26. The plurality of pin fins are arranged at intervals. The plurality of pin fins are arranged at equal intervals. The plurality of pin fins are arranged in a staggered manner in the flow direction of the cooling water. The plurality of pin fins may be arranged in a matrix.

  When the cooling water flowing through the cooling water passage 26 collides with the pin fin portion 51, a turbulent flow is positively formed by the flow of the cooling water, and heat exchange between the cooling water and the pin fin portion 51 is promoted.

  Also in these modified examples, by controlling the output current of the inverter 130 based on the temperature of the chip 31D set to the highest temperature, the above-described effects can be obtained similarly.

  The embodiment disclosed this time should be considered as illustrative in all points and not restrictive. The scope of the present invention is defined by the terms of the claims, rather than the description above, and is intended to include any modifications within the scope and meaning equivalent to the terms of the claims.

It is a perspective view which shows the cooling system of an HV system. It is an electric circuit diagram which shows the principal part of an HV system. It is a top view which shows the cooling structure of the inverter in FIG. It is sectional drawing of the inverter along the IV-IV line in FIG. FIG. 4 is a perspective view showing a cooling water passage in FIG. 3. It is a figure which shows the method of comparing the heat transfer coefficient of a cooling water and a fin between a wave fin part and a straight fin part. It is a graph which shows the temperature of the chip | tip in FIG. FIG. 6 is a perspective view of a cooling water passage showing a modification of the fin in FIG. 5. It is a perspective view of the cooling water channel which shows another modification of the fin in FIG.

Explanation of symbols

  11, 12, 13, 14 region, 15 straight part, 16 connection part, 21a mounting surface, 26 cooling water passage, 31, 31A to 31D chip, 41 fin, 42 straight fin part, 42a surface, 43 wave fin part, 51 Pin fin section, 140 control device.

Claims (5)

A plurality of power semiconductor elements mounted on the mounting surface;
A refrigerant passage having a straight portion extending in a straight line and a connecting portion connected to the straight portion and extending while being bent, and is formed facing the mounting surface, and through which a refrigerant for cooling the plurality of power semiconductor elements flows. When,
A fin having a first portion and a second portion, which are provided so as to protrude from the inner wall of the refrigerant passage into the refrigerant passage and are disposed in different sections on the path of the refrigerant passage;
The first portion is formed from a surface extending along a refrigerant flow direction along the path of the refrigerant passage, and the second portion is disposed in a partial section of the straight portion. And the heat transfer coefficient with the refrigerant is larger than that of the first portion.
The plurality of power semiconductor elements include a power semiconductor element disposed to face the connection portion, and
A cooling structure for a power semiconductor element, comprising: a control unit that controls a current flowing through the plurality of power semiconductor elements based on temperature information of the power semiconductor element arranged to face the connection part. On the mounting surface, an area is formed in which the plurality of power semiconductor elements are disposed relatively densely facing the straight portion.
The power semiconductor element cooling structure according to claim 1, wherein the second portion is provided to face the region.   3. The power semiconductor element cooling structure according to claim 1, wherein the second portion is formed of a wave fin extending while undulating along a path of the refrigerant passage. 4.   3. The power semiconductor element cooling structure according to claim 1, wherein the second portion is formed of a plurality of pin fins standing upright apart from each other.   An inverter mounted with a vehicle, wherein the power semiconductor element cooling structure according to claim 1 is used.

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