JP2013110856A - Electric power conversion apparatus and electric vehicle - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an electric power conversion apparatus which suppresses temperature rise of a circuit board controlling a switching element.SOLUTION: An electric power conversion apparatus 10 includes: a reactor 8; a heat sink 6b; a power module 22 housing a switching element SW; a cooler 25; a circuit board 3 where a circuit controlling the switching element is mounted; and a heat insulation material 31. The cooler 25 is integrated with the power module 22 to form a PE unit 20. The heat sink 6 connects with the cooler 25 at one end and is positioned above the reactor 8. The heat insulation material 31 is disposed between the heat sink 6b and the circuit board 3. The heat insulation material 31 disposed between the heat sink 6b and the circuit board 3 reduces influences on the circuit board which are caused by heat of the reactor.

Description

  The present invention relates to a power conversion device.

  In recent years, electric vehicles have become widespread, and power conversion devices such as DC converters and inverters have been installed in electric vehicles. Since a vehicle drive motor for an electric vehicle outputs a large torque, a large amount of current is required. For this reason, the power conversion device that converts the power of the main battery into power suitable for driving the motor also handles a large current and generates a large amount of heat. On the other hand, vehicle devices are also required to be compact. Electric power converters for electric vehicles are required to be both heat-resistant and compact. Note that the power conversion device is typically an inverter that converts direct current to alternating current, or a combination of an inverter and a voltage converter that converts the voltage of direct current power to a different voltage. The “electric vehicle” in this specification includes a hybrid vehicle and a fuel cell vehicle.

  Among the power conversion devices, the heat source is particularly a switching element (a so-called power transistor such as an IGBT or a power element such as a free wheel diode connected in parallel thereto) and a reactor. As is well known, the reactor is a passive element mainly composed of a coil. In a power converter, the reactor mainly smoothes the current input to the power transistor or the output current of the power transistor. Used for. Since it is preferable that the transmission path for the large current is short, the reactor is disposed in the vicinity of an electronic component such as a power transistor.

  Compared to components such as power transistors, the reactor is large in size, and requires some effort to achieve both compactness and heat dissipation. For example, Patent Document 1 proposes a technique in which a power transistor and a reactor are compactly housed in one case, and the core of the reactor is brought into contact with the case to efficiently transfer the heat of the reactor to the case and dissipate heat. Patent Document 2 proposes a technique for improving the cooling efficiency of the entire device configured by the reactor and the switching element by arranging the reactor on the downstream side of the flow of the refrigerant with respect to the switching element. Furthermore, Patent Document 3 discloses a technique for increasing the cooling efficiency by housing a power transistor and a reactor in separate cases and disposing a metal plate for heat dissipation in each case. Patent Document 4 proposes a power conversion device in which a switching element, a reactor, and a cooler for cooling them are housed in a compact manner. The cooler of the power converter has a plurality of flat refrigerant passages, and has a structure in which a plurality of flat power modules containing switching elements and refrigerant passages are alternately stacked. The reactor is sandwiched between two outermost adjacent refrigerant passages. That is, in the power converter, a reactor and a plurality of power modules are sandwiched between flat refrigerant passages. The reason why the switching element is separated from other circuits (such as a circuit for controlling the switching element) as a power module is to cool the switching element intensively.

JP 2008-113540 A JP 2010-277747 A JP 2011-078217 A JP 2010-225723 A

  In recent years, the performance of electric vehicles, in particular, hybrid vehicles has been improved, and the motors mounted on them have also become high output. The power conversion apparatus is further increased in current, and accordingly, a higher cooling capacity is required than ever. On the other hand, further compactness is also required for in-vehicle devices. On the other hand, the power conversion device includes a circuit board on which a circuit for controlling the switching elements in the power module is mounted, in addition to a power module in which switching elements such as power transistors are packaged. The circuit board is disposed in the vicinity of the power module in order to minimize the power loss between the power module and the circuit board and the switching element on the circuit board are preferably mounted on a single board. Is mounted on a separate board to cool a switching element having a large heating value). In order to make the entire power conversion device compact, the circuit board is naturally close to the reactor. According to the inventors' investigation, it has been found that the circuit board is not a large heat source, but if the ambient temperature rises due to the heat generated by the power module or the reactor, the heat damage to the circuit board cannot be ignored. The present specification solves the above problems. The technology disclosed in this specification provides a technology for suppressing a temperature rise of a circuit board that controls a switching element in a power conversion device.

  In the technology disclosed in this specification, the cooler cools not only the power module but also the reactor and the circuit board, but separates the heat transfer path from the reactor to the cooler and the heat transfer path from the circuit board to the cooler, Makes it difficult for heat to accumulate around the circuit board. A power conversion device according to an embodiment of the technology disclosed in the present specification includes a reactor, a power module containing a switching element, a cooler integrated with the power module, a heat sink, a circuit board, and a heat insulating material. Is provided. One end of the heat radiating plate is connected to the cooler and is located at the upper part of the reactor. Although a heat sink receives the radiation of a reactor, the heat is discharge | released outside through a cooler. A circuit board on which a circuit for controlling the switching element is mounted is disposed above the reactor and the heat sink. Furthermore, a heat insulating material is disposed between the heat sink and the circuit board. The heat insulating material arranged between the heat sink and the circuit board reduces the influence on the circuit board of the heat of the heat sink that receives the heat radiation from the reactor. The heat insulating material is preferably provided on the surface of the heat sink on the circuit board side. Such an arrangement makes it difficult for the heat of the reactor to reach the circuit board. In addition, regarding the heat transfer path, a member that mainly supports a component can serve as the heat transfer path. Therefore, the bracket that supports the reactor may also have the function of the heat radiating plate.

  The power conversion device disclosed in the present specification is advantageous in that it is mounted on an electric vehicle in combination with a drive train having an inclined upper surface. That is, the power converter is preferably fixed to the inclined upper surface so that the PE unit is located on the lower side and the reactor is located on the higher side. When the reactor is positioned on the higher side, the warm air inside the case of the power conversion device collects above the reactor. However, in the above power converter, the heat of the reactor is efficiently radiated from the lower side of the reactor, so that the heat remaining inside the case is reduced, and it is difficult for the heat to be accumulated above the reactor. And since a 2nd cooler is located in the bottom part of a power converter device, the thermal interference with a reactor or PE unit, and a drive train can be interrupted | blocked.

It is a side view of the power converter device of an Example. It is a top view of the power converter device of an Example. It is a typical perspective view of a PE unit. It is a side view of the power converter device of the 1st modification. It is a side view of the power converter device of the 2nd modification. It is a side view of the power converter device of the 3rd modification. It is a side view of the power converter device of the 4th modification. It is a perspective view which shows the device layout in an engine compartment. It is a typical side view of a drive train carrying a power converter.

  A power conversion device 10 according to an embodiment will be described with reference to the drawings. Although FIG. 1 is a side view, in order to help understanding, FIG. 1 depicts the case 4 and its cover 2 in cross section (hatched), and the parts inside the case are depicted as side views. FIG. 2 is a plan view, but shows a state where the cover 2 and the circuit board 3 located above the power converter 10 are removed.

  The electric power converter 10 includes a voltage converter that converts battery voltage and an inverter that converts direct current to alternating current in terms of electrical circuits. Specifically, the electric circuit of the voltage converter and the inverter is a circuit board that controls the reactor 8, the smoothing capacitor 9, the switching elements SW in the plurality of power modules 22, and the switching elements SW in the power modules 22. It is composed of three. As is well known, a reactor is in a power conversion device and forms a voltage conversion circuit together with a switching element. Both the voltage converter and the inverter have a plurality of switching circuits in which a power transistor and a free-wheeling diode are connected in parallel. A power transistor and a free wheel diode constituting the switching circuit correspond to the switching element SW. One or two switching circuits are mounted on one independent substrate, which is referred to as one power module 22. In FIGS. 1 to 3, only six power modules are illustrated for easy understanding of the drawings, but the power conversion apparatus 10 may include more power modules. As other members constituting the power conversion device 10, there are a cooler 25 that cools the power module 22, a first bracket 5, and a second bracket 6. The cooler 25 also cools the reactor 8 and the circuit board 3. The first bracket 5 is a member that supports the unit (PE unit) of the circuit board 3, the cooler 25, and the power module 22 with respect to the case 4. The second bracket 6 is a member that connects the cooler 25 and the reactor 8. The second bracket 6 supports the reactor 8 with respect to the cooler 25.

  The cooler 25 and the power module 22 are integrated, and this is referred to as a PE unit 20. The PE unit 20 will be described. FIG. 3 shows a schematic perspective view of the PE unit 20. In the cooler 25, two pipes 29a and 29b pass through the plurality of flat refrigerant passages 21, and support the plurality of refrigerant passages 21 (cooling plates) so that they are arranged in parallel. The two pipes 29a and 29b and the respective refrigerant passages 21 communicate with each other, and the refrigerant supplied from one pipe 29a passes through each refrigerant passage 21 and is discharged from the other pipe 29b. The refrigerant may typically be water or LLC (Long Life Coolant). The power module 22 containing the switching element SW is sandwiched between two adjacent refrigerant passages 21. That is, the PE unit 20 is configured by alternately laminating a plurality of flat power modules 22 and a plurality of flat refrigerant passages 21 of the cooler 25. In the PE unit 20, since the refrigerant passes through both surfaces of the flat power module 22, the switching element SW can be efficiently cooled. A lead wire 22a extends from each power module 22 (switching element SW). The lead wire 22a is connected to the circuit board 3 as shown in FIG. Further, a flat refrigerant passage corresponding to the rear end of the PE unit 20 is particularly denoted by reference numeral 21e.

  Returning to FIG. 1 and FIG. The smoothing capacitor 9, the PE unit 20, and the circuit board 3 are supported by the first bracket 5. The reactor 8 is supported by the second bracket 6. The smoothing capacitor 9, the PE unit 20, the circuit board 3, and the reactor 8 are supported by any bracket and accommodated in the case 4. The first bracket 5 is fixed above the case 4 and is pressed and fixed by the cover 2 from above. As shown in FIG. 2, the first bracket 5 surrounds the PE unit 20 and the reactor 8 when viewed in plan.

  As shown in FIG. 1, the PE unit 20 is fixed by being sandwiched between two stays 5 b extending downward from the first bracket 5. That is, the PE unit 20 is supported by the first bracket 5 from above. In FIG. 1, a spring 13 is inserted between the left stay 2b and the end of the PE unit 20, and this spring 13 urges the PE unit 20 between the two stays 5b to fix it. doing. The spring 13 presses the refrigerant passage 21 and the power module 22 in the stacking direction, whereby the refrigerant passage 21 and the power module 22 are firmly adhered, and the heat of the power module 22 is well transmitted to the refrigerant passage 21. Is done.

  A circuit for controlling elements in the power module 22 is mounted on the circuit board 3. The circuit board 3 is supported above the PE unit 20 and the reactor 8 by a stay 5 a extending upward from the first bracket 5. As shown in FIG. 1, lead wires 22 a extending from the power module 22 are connected to the circuit board 3.

  The reactor 8 is supported by the second bracket 6 (heat radiating plate). The second bracket 6 includes a stay 6a and a cover 6b, and the end of the stay 6a corresponding to the end of the second bracket 6 is located on the end surface of the end refrigerant passage 21e of the laminate of the PE unit 20. Fixed. A cover 6b is connected to the tip of the stay 6a. The covering portion 6b covers substantially the upper half of the reactor 8. A stay 6c extends from the ceiling of the cover 6b, and the reactor 8 is supported by the stay 6c. The reactor 8 includes two coils arranged in parallel (one winding) and one core passing through them.

  The first bracket 5 is manufactured by pressing from a single metal plate including the stays 5a and 5b. The second bracket 6 is manufactured by press working from a single metal plate including the stay 6a, the cover 6b, and the stay 6c.

  A heat insulating sheet 31 (heat insulating material) is attached to the upper surface of the cover portion 6 b of the second bracket 6. In other words, the heat insulating sheet 31 is disposed between the circuit board 3 and the cover portion 6 b of the second bracket 6. The heat insulating material is made of, for example, phenol foam. Among the phenolic foams, a specific species (for example, a material called a type A phenolic foam) has a thermal thermal conductivity of 0.022 [W / mK] or less. This value is smaller than the thermal conductivity of dry air (0.0241 [W / mK]), and the heat insulation performance is very high.

  The PE unit 20 and the reactor 8 are supported by the second bracket 6 so as to be adjacent to each other with a gap. Further, the circuit board 3 is supported above the PE unit 20 by the first bracket 5. As well shown in FIG. 1, the circuit board 3 is disposed above the reactor 8 (above the cover 6 b) with a gap and a heat insulating sheet 31 therebetween. As well shown in FIG. 1, the second bracket 6 is in contact with the end refrigerant passage 21 e of the cooler 25 and the reactor 8 and is not in contact with other members. Moreover, the reactor 8 is only in contact with the cover portion 6b (stay 6c) of the second bracket 6 and a bus bar 7 (described later), and is not in contact with other members.

  As shown well in FIG. 2, four smoothing capacitors 9 are arranged on the side of the PE unit 20 and the reactor 8. The smoothing capacitor 9 is for smoothing the current flowing through the reactor 8. Voltage conversion (step-up or step-down) is achieved by chopping the current flowing through the reactor 8. Each time chopping, the current flowing through the reactor 8 pulsates, but the smoothing capacitor 9 suppresses the pulsation. The capacitor 9 is also supported by the first bracket 5. Reactor 8 and capacitor 9 are electrically connected by bus bar 7. The bus bar 7 exits from below the reactor 8, passes through the side of the reactor 8, and reaches the capacitor 9.

  The advantages of the structure of the power conversion device 10 will be described. The cooler 25 of the power conversion apparatus 10 mainly cools the power module 22, but also cools the circuit board 3 and the reactor 8. The heat of the circuit board 3 is transmitted to the cooler 25 through the first bracket 5. Further, the heat of the reactor 8 is transmitted to the cooler 25 through the second bracket 6. In particular, the second bracket 6 serves as a heat radiating plate that releases the heat of the reactor 8. One end of the second bracket 6 is connected to the cooler 25, and a part of the second bracket 6 is located above the reactor 8. The first bracket 5 and the second bracket 6 are both made of metal plates and have good thermal conductivity. Since the second bracket 5 and the second bracket 6 are not in contact with each other, the heat transfer paths do not cross each other. In particular, the heat of the reactor 8 is not transmitted to the circuit board 3. Although the reactor 8 is adjacent to the circuit board 3 above the reactor 8, the upper part of the reactor 8 is covered with the covering portion 6 b of the second bracket 6, so that the ambient air heated by the reactor 8 is There is no flow around. Furthermore, the gap between the reactor 8 and the PE unit 20 also contributes to separating the heat transfer path from the reactor 8 and the heat transfer path from the circuit board 3.

  Furthermore, the heat insulation sheet 31 is affixed on the upper surface of the cover part 6b. A heat insulating sheet 31 (heat insulating material) is disposed between the second bracket 6 (heat radiating plate) and the circuit board 3. More specifically, the heat insulating sheet 31 is attached to the surface of the second bracket 6 on the circuit board 3 side. The heat insulating sheet 31 thermally blocks between the cover portion 6b (second bracket 6) and the circuit board 3. In particular, the cover 6b (second bracket 6) takes the heat of the reactor 8 and its temperature rises, but the heat insulating sheet 31 blocks the radiant heat of the cover 6b and prevents the circuit board 3 from being radiated. To do. Thus, in the power converter 10, the heat transfer path between the reactor 8 and the circuit board 3 is separated, and a structure in which the heat of the reactor 8 is not easily transmitted to the circuit board 3 is realized. That is, the circuit board 3 is thermally protected by the above-described structure.

  Next, a modified example of the power conversion device will be described. FIG. 4 is a side view of the power converter 110 of the first modification. In addition to the configuration of the power conversion device 10 in FIG. 1, the power conversion device 110 includes an insulating sheet 112 disposed between the reactor 8 and the inside of the cover 6b. By disposing the insulating sheet 112, the gap between the cover 6b and the reactor 8 can be narrowed. Thereby, the whole power converter device can be made compact. Or the thickness of the cover part 6b can be thickened by the part which narrowed the clearance gap between the cover part 6b and the reactor 8, and the thermal conductivity of the cover part 6b can be raised. The insulating sheet 112 is preferably made of a material having a high thermal conductivity.

  FIG. 5 is a side view of the power conversion apparatus 210 of the second modified example. In the power conversion device 210, the entire cover portion 6 b of the second bracket 6 is covered with a heat insulating sheet 213. Other configurations are the same as those of the power conversion device 10 of FIG. The power conversion device 20 supports the reactor 8 and further covers the entire covering portion 6b covered with the heat insulating sheet 231, thereby preventing the heat of the reactor 8 from leaking outside the covering portion 6b as much as possible. . In addition, since air with high temperature tends to move upward, the lower part of the reactor 8 does not need to be covered with the cover part 6b and the heat insulation sheet 231. Furthermore, in this modification, it is also preferable to fill a heat transfer material between the lower surface of the reactor 8 and the bottom surface of the case 4. The heat of the reactor 8 can be dissipated using not only the second bracket 6 but also the heat transfer material and the case 4.

  FIG. 6 is a side view of a power conversion device 310 according to a third modification. In the power conversion device 310, the heat insulating sheet 331 is attached to the lower surface of a part of the first bracket 5 located between the circuit board 3 and the reactor 8, not the upper surface of the cover 6b. Other configurations are the same as those of the power conversion device 10 of FIG. Even if it is the structure which affixes the heat insulation sheet 331 on the lower surface of the 1st bracket 5 between the circuit board 3 and the cover part 6b, the radiant heat of the cover part 6b can be interrupted | blocked. Thereby, the circuit board 3 can be thermally protected.

  FIG. 7 is a side view of a power conversion device 410 according to a fourth modification. In this power conversion device 410, the cover 406b of the second bracket 6 (heat radiating plate) that supports the reactor 8 with respect to the cooler does not cover the reactor 8 in a container shape. This is an example of covering the shape. Other configurations are the same as those of the power conversion device 10 of FIG. The heat insulating sheet 31 is attached to the upper surface of the U-shaped covering portion 406b, that is, the surface on the circuit board 3 side. Also according to the embodiment of FIG. 7, the effect of thermally protecting the circuit board 3 can be expected.

  An automobile 90 equipped with the power conversion device 10 (or the power conversion devices 110, 210, 310) will be described with reference to FIGS. The automobile 90 is a hybrid car equipped with an engine EG and a motor. The automobile 90 is equipped with a power converter 10 (inverter) for driving a motor. The power conversion device 10 is mounted in the engine compartment EC together with the engine EG and the drive train 50. The engine EG and the drive train 50 are arranged behind the radiator RT. The engine EG and the drive train 50 are arranged side by side in the horizontal direction. A battery BT is disposed on the side of the drive train 50. The drive train 50 incorporates two motors MG1 and MG2 and a transmission TM that transmits the output of the power source (engine and motor) to the axle. The output shaft of the engine EG is also engaged with the transmission TM. As shown in FIG. 9, in the drive train 50, a total of three main shafts of two motors MG1 and MG2 output shafts 51 and 52 and a transmission TM main shaft 53 (corresponding to an engine output shaft) are provided. It is parallel. As shown in FIG. 9, the motor MG1 is located slightly above. The two motors MG1, MG2 and the transmission TM are arranged in such a direction that three shafts extend in the lateral direction of the vehicle (Y-axis direction in the figure). With such an arrangement of the two motors MG1, MG2 and the transmission TM, the drive train 50 is low on the front side of the vehicle (in the figure, the positive direction of the X axis) and on the rear side of the vehicle (in the figure, in the negative direction of the X axis). Has an inclined upper surface 50a. The power converter 10 is fixed to the inclined upper surface 50a. The power conversion device 10 is fixed to the inclined upper surface 50a so that the PE unit 20 is located on the lower side (vehicle front side) and the reactor 8 is located on the higher side (vehicle rear side). Therefore, the pipe 29 that passes the refrigerant to the cooler 25 protrudes from the side surface of the power conversion device 10 on the vehicle front side. A refrigerant pipe 55 is connected to the pipe 29. The refrigerant is supplied to the cooler 25 through the refrigerant pipe 55 and discharged from the cooler 25.

  The power converter 10 is located on the side where the reactor 8 is high, and the circuit board 3 is located thereon. Hot air moves upward in the power converter 10. Here, as described above, the upper portion of the reactor 8 is covered with the cover portion 6b of the second bracket 6, and the heat insulating sheet 31 (231, 331) is disposed on the upper surface of the cover portion 6b. The heat generated by the reactor 8 stays inside the cover 6b and does not reach around the circuit board 3 located above the cover 6b. Therefore, the circuit board 3 is thermally protected.

  Points to be noted regarding the power conversion device of the embodiment will be described. The PE unit 20 is supported from above by the first bracket 5, and the reactor 8 is supported from above by the second bracket 6. The PE unit 20 and the reactor 8 may be supported from the side thereof. The PE unit 20 and the circuit board 3 are supported by the case 4 via the first bracket 5 and are thermally separated from the case 4. The reactor 8 is supported by the second bracket 6 with respect to the PE unit 20 and is also thermally separated from the case 4.

  With regard to the heat transfer path, a member that mainly supports the component can be the heat transfer path. Therefore, in one aspect of the power conversion device of the embodiment, the bracket that supports the cooler and the circuit board and the bracket that supports the reactor are completely separated, and the heat transfer path is separated. Furthermore, a heat insulating material is arranged between the bracket that transmits the heat of the reactor to the cooler and the circuit component so that the heat of the reactor is hardly transmitted to the circuit component. The technology of the embodiment employs two brackets and a heat insulating material to separate the heat transfer path between the reactor and the circuit board and suppress the temperature rise of the circuit board. The “bracket” is a term generally indicating a member for fixing a component (in this case, a reactor or the like). It should be noted that there are no particular restrictions on the shape other than the shape described in the specification.

  One aspect of the power conversion device disclosed in this specification includes a circuit board on which a reactor, a power module containing a switching element, and a circuit for controlling the switching element are mounted. Here, the “power module” means a substrate in which elements (IGBTs and freewheeling diodes) to be intensively cooled from among the circuits of the voltage converter and the inverter are made independent of other control circuits. One aspect of the power conversion device of the embodiment includes a cooler and first and second brackets. The cooler is integrated with the power module. This is because the most important element to be cooled is the switching element. Hereinafter, a unit in which a power module containing a switching element and a first cooler that cools the power module are integrated is referred to as a power element unit, abbreviated as a PE unit. The first bracket supports the circuit board and supports the PE unit so as to be positioned below the circuit board. One end of the second bracket is fixed to the cooler, supports the reactor so as to be positioned below the circuit board, and covers the top of the reactor. Here, the first bracket and the second bracket are not in direct contact with each other. In the following, the portion of the second bracket that covers the top of the reactor is referred to as a “covering portion”. And in the power converter device of one Embodiment, a heat insulating material is arrange | positioned between a cover part and the circuit board located above it.

  In one embodiment, the heat of the circuit board is transferred to the cooler through the first bracket. The heat of the reactor is transferred to the cooler through the second bracket. Since the first bracket and the second bracket are not in direct contact with each other, the heat of the reactor is hardly transmitted to the circuit board. In addition, the ambient air is also heated by the heat of the reactor, but the covered portion of the second bracket covers the upper portion of the reactor, so that the heated air is difficult to move above the covering portion. Although the circuit board is disposed above the cover portion, the air heated by the heat of the reactor is difficult to reach the circuit board. Furthermore, since the heat insulating material is disposed between the circuit board and the cover portion of the second bracket, the circuit board is prevented from being heated by the radiation of the cover portion. With the above configuration, the temperature rise of the circuit board is suppressed.

  The heat insulating material preferably has a thermal conductivity smaller than that of air (in the case of dry air, 0.0241 [W / mK]). An example of such a heat insulating material is phenol foam.

  In still another embodiment of the power conversion device disclosed in the present specification, an insulating sheet may be disposed between the inside of the cover portion and the reactor. By arrange | positioning an insulating sheet, the clearance gap between a cover part and a reactor can be narrowed. Thereby, the whole power converter device can be made compact. Or the thickness of a cover part can be thickened by the part which narrowed the clearance gap between a cover part and a reactor, and the thermal conductivity of a cover part can be raised.

  One aspect of the cooler has a structure in which a plurality of flat refrigerant passages are arranged in parallel. Each of the plurality of flat power modules is sandwiched between adjacent flat refrigerant passages to form a laminate. At this time, the first bracket may support the laminated body sandwiched from both sides. Moreover, it is good for the end of a 2nd bracket to be fixed to the flat refrigerant path located in the end of a laminated body. That is, the flat refrigerant passage located at the end of the laminated body mainly contributes to the cooling of the reactor and the cooling of the circuit board. The other flat refrigerant passage can be dedicated to cooling the power element module (switching element). Separating the flat refrigerant passage responsible for cooling the power element module and the flat refrigerant passage responsible for cooling the reactor / circuit board facilitates heat transfer simulation and facilitates thermal design. The ease of thermal design means that precise thermal design is possible, and improvement in cooling efficiency can be expected.

  Although phenol foam was mentioned as an example of the material of a heat insulation sheet, a heat insulation sheet is not restricted to this. Although it is desirable that the thermal insulation sheet has a thermal conductivity smaller than that of air, the technology disclosed in this specification excludes the use of a thermal insulation sheet whose thermal conductivity is larger than that of air. It is not a thing.

  Specific examples of the present invention have been described in detail above, but these are merely examples and do not limit the scope of the claims. The technology described in the claims includes various modifications and changes of the specific examples illustrated above. The technical elements described in this specification or the drawings exhibit technical usefulness alone or in various combinations, and are not limited to the combinations described in the claims at the time of filing. In addition, the technology exemplified in this specification or the drawings can achieve a plurality of objects at the same time, and has technical usefulness by achieving one of the objects.

2: Cover 3: Circuit board 4: Case 5: First bracket 6: Second bracket 6a, 6c: Stay 6b: Cover (heat sink)
7: Bus bar 8: Reactor 9: Smoothing capacitor 10: Power converter 13: Spring 20: Power element unit (PE unit)
21: Refrigerant passage 22: Power module 25: Coolers 31, 231, 331: Heat insulation sheet (heat insulation material)
50: Drive train 50a: Inclined upper surface 90: Automotive 110, 210, 310: Power conversion device 112: Insulating sheet 406: Heat sink EC: Engine compartment EG: Engine MG1, MG2: Motor TM: Transmission

Claims (3)

A power converter,
Reactor,
A power module containing a switching element;
A cooler integrated with the power module;
One end is connected to the cooler, and the heat sink located at the top of the reactor,
A circuit board mounted on the reactor and the heat sink, and mounted with a circuit for controlling the switching element;
A heat insulating material disposed between the heat sink and the circuit board;
A power conversion device comprising:   The power converter according to claim 1, wherein the heat insulating material is provided on a surface of the heat sink on the circuit board side. The power conversion device according to claim 1 or 2, wherein the power conversion device converts the power of the battery into power suitable for a traveling motor;
A drive train having an inclined top surface;
With
An electric vehicle characterized in that a power conversion device is fixed to the inclined upper surface so that a unit of a power module and a cooler is located on a low side and a reactor is located on a high side.

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