JP7404652B2 - power converter - Google Patents

Description

The present invention relates to a power conversion device that converts AC power into DC power and supplies it to a load, or converts DC power into AC power and supplies it to a load.

A plurality of semiconductor modules constituting the main circuit of a power conversion device generate losses due to switching operations of built-in semiconductor switching elements and become hot. A heat radiator is used to cool semiconductor modules that become hot in this way. When a refrigerant such as liquid or air flows through the radiator, heat exchange is promoted between the radiator and the refrigerant, and heat generated in a semiconductor module thermally connected to the radiator is transferred via the radiator.

In the conventional technique disclosed in Patent Document 1, semiconductor switching elements are arranged in a staggered manner with respect to a plurality of passages formed in a cooler. The passage is a groove, a cavity, etc. formed in the cooler for passing the refrigerant. As a result, the plurality of semiconductor switching elements arranged on the upstream and downstream sides with respect to the direction in which the refrigerant flows are evenly cooled, and the temperature difference (temperature unevenness) between the plurality of semiconductor switching elements can be reduced. At the same time, constraints on the design of the heatsink are eliminated.

Japanese Patent Application Publication No. 2015-153766

However, in the conventional technique disclosed in Patent Document 1, in order to arrange a plurality of semiconductor switching elements in a staggered manner, it is necessary to use dedicated semiconductor modules in which semiconductor switching elements are placed in different positions. Therefore, the manufacturing cost of the main circuit may increase. Furthermore, when a dedicated semiconductor module is assembled onto a board, the distances from the terminals to be assembled onto the board to the switching elements are not uniform, resulting in variations in switching characteristics, resulting in adverse effects such as increased loss and failures due to surge voltage. Furthermore, if the placement of a general-purpose semiconductor module on a heatsink is devised, the same effect as the conventional technique disclosed in Patent Document 1 can be expected, but under conditions where there are restrictions on the shape of the heatsink, the conventional technique cannot be used. The problem is that it cannot be applied.

The present invention has been made in view of the above, and an object of the present invention is to obtain a power conversion device that can suppress an increase in temperature unevenness between a plurality of semiconductor elements with a simple configuration.

In order to solve the above-mentioned problems and achieve the objects, a power conversion device according to the present invention includes a plurality of fins that are provided apart from each other and in which air flow paths are formed in regions facing each other, and a plurality of the fins. and a fin base having a first end surface provided with a fin base and a second end surface opposite to the first end surface side. The power conversion device includes a first semiconductor module provided on the second end surface, and a second semiconductor module provided on the second end surface in a region upwind of the second end surface relative to the first semiconductor module. Equipped with The power conversion device includes: a first heat conductive member provided between the second end surface and the first semiconductor module and having a first thermal conductivity; and a first heat conductive member provided between the second end surface and the second semiconductor module. and a second thermal conductive member having a second thermal conductivity lower than the first thermal conductivity.

According to the present invention, it is possible to suppress an increase in temperature unevenness among a plurality of semiconductor elements with a simple configuration.

FIG. 1 shows a configuration example of a radiator 10 and the like included in a power conversion device 100 according to an embodiment of the present invention. FIG. 2 shows a configuration example of a radiator etc. included in the power conversion device 100 according to the embodiment of the present invention. Diagram representing an image of the internal structure of the semiconductor module 31 A diagram showing a first configuration example of a heat conductive member A diagram showing a second configuration example of a heat conductive member A diagram showing a third configuration example of a heat conductive member Diagram showing an example of the material of the thermally conductive member A diagram showing a state in which a temperature sensor 60 and the like are attached to a power conversion device 100. A cross-sectional view of the power conversion device 100 in the YZ plane including the line AA shown in FIG. A cross-sectional view of the power conversion device 100 in the YZ plane including the line BB shown in FIG. A cross-sectional view of the power conversion device 100 in the YZ plane including the line CC shown in FIG. 8 A diagram showing the results of measuring the temperature distribution of the fins when heat generated by the heater 80 is given to the radiator 10 and cooled with forced air by the fan 20 in an analytical model of the power conversion device 100. FIG. 1 shows a configuration example of a power conversion device 100A according to a modified example. FIG. 2 shows a configuration example of a power conversion device 100A according to a modified example. A diagram representing an image of the internal structure of the semiconductor module 31A shown in FIG.

EMBODIMENT OF THE INVENTION Below, the power converter apparatus based on embodiment of this invention is demonstrated in detail based on drawing. Note that the present invention is not limited to this embodiment. Note that in this embodiment, the X-axis direction, Y-axis direction, and Z-axis direction represent a direction parallel to the X-axis, a direction parallel to the Y-axis, and a direction parallel to the Z-axis, respectively. The X-axis direction, the Y-axis direction, and the Z-axis direction are orthogonal to each other. The XY plane, YZ plane, and ZX plane are, respectively, a virtual plane parallel to the X-axis direction and the Y-axis direction, a virtual plane parallel to the Y-axis direction and the Z-axis direction, and a virtual plane parallel to the Z-axis direction and the X-axis direction. represents. In FIG. 1 and subsequent figures, among the X-axis directions, the direction indicated by the arrow is the plus X-axis direction, and the opposite direction is the minus X-axis direction. Among the Y-axis directions, the direction indicated by the arrow is the positive Y-axis direction, and the direction opposite to this direction is the negative Y-axis direction. Among the Z-axis directions, the direction indicated by the arrow is the plus Z-axis direction, and the opposite direction is the minus Z-axis direction.

Embodiment FIG. 1 is a first diagram showing a configuration example of a radiator 10 and the like included in a power conversion device 100 according to an embodiment of the present invention. FIG. 1 shows a state in which a radiator 10 and the like included in a power conversion device 100 are viewed from above in an XY plane. FIG. 2 is a second diagram showing a configuration example of a heat radiator and the like included in the power conversion device 100 according to the embodiment of the present invention. FIG. 2 shows a plan view of the heat radiator 10 and the like of FIG. 1 on the YZ plane.

The power conversion device 100 is an inverter that drives a main motor installed in, for example, an electric vehicle (an electric vehicle, a hybrid vehicle, a plug-in hybrid vehicle, etc.). Note that the power conversion device 100 is not limited to an inverter for an electric vehicle as long as it is equipped with a main circuit (power conversion section) that includes two or more semiconductor modules in which switching elements are formed; for example, it can be installed in a train. It may be an inverter that drives a main motor, or a converter that converts a DC voltage of a predetermined value to a DC voltage of a different value.

The power conversion device 100 includes a radiator 10 that absorbs heat generated by the plurality of semiconductor modules 31 to 36 and radiates it to the atmosphere, and a fan 20 that is a blower for cooling the radiator 10 with forced air.

The heat radiator 10 includes a plurality of heat radiating fins 12 and a fin base 11 on which the plurality of fins 12 and the plurality of semiconductor modules 31 to 36 are provided. Examples of the material of the heat sink 10 include metals such as aluminum, austenitic stainless alloy, copper alloy, cast iron, steel, and iron alloy.

The fin base 11 is, for example, a square or rectangular plate member in which each of the four internal angles is equal to a right angle. The fin base 11 has a first end surface 11a on which a plurality of fins 12 are provided, and a second end surface 11b, which is an end surface on the opposite side to the first end surface 11a and on which a plurality of semiconductor modules 31 to 36 are provided. Note that the shape of the fin base 11 is not limited to these, and may be any shape that allows the plurality of semiconductor modules 31 to 36 to be provided on the second end surface 11b side, such as an ellipse shape.

Hereinafter, if the plurality of semiconductor modules 31 to 36 are not distinguished from each other, they may be simply referred to as "semiconductor modules." The semiconductor module is thermally and mechanically fixed to the fin base 11 of the heat sink 10 by soldering, adhesive, screwing, or the like. Note that the method of fixing the semiconductor module to the fin base 11 of the heat sink 10 is not limited to these methods. Further, each of the semiconductor modules 31 to 36 is thermally fixed to the fin base 11 via a plurality of heat conductive members 40 having different thermal conductivities.

The reason for using such a heat conductive member 40 is that when forced air cooling is performed using the fan 20 arranged as shown in FIG. This is to prevent temperature unevenness from occurring among a plurality of semiconductor switching elements (hereinafter referred to as switching elements).

That is, when the semiconductor modules 31 to 36 are arranged in three columns and two rows on the heatsink 10 as shown in FIG. Since the amount of heat exchange between the air and the surface of the radiator 10 differs depending on the position of the radiator 10, there are areas where the semiconductor module is easily cooled and areas where it is difficult to cool. In this case, rather than uniformly cooling all the semiconductor modules 31 to 36, a heat conductive member 40 with a relatively high thermal conductivity is installed in places where heat is difficult to escape so that heat can be quickly transferred to the radiator 10. It is preferable to adopt a heat conductive member 40 with a relatively low thermal conductivity in places where heat is likely to escape, giving priority to suppressing an increase in manufacturing costs rather than quickly transmitting heat to the radiator 10. . The areas where heat is difficult to escape are a region (downwind region) near the end face of the radiator 10 in the plus X-axis direction and a region near the center of the radiator 10 in the Y-axis direction. The areas where heat easily escapes are the area near the end face of the radiator 10 in the -X axis direction (windward side area), the area near the end face of the radiator 10 in the plus Y axis direction, and the area near the end face of the radiator 10 in the minus Y axis direction. This is the area near the end face of The windward side is a region (space) on the minus X-axis direction side of the radiator 10. The leeward side is a region on the plus X-axis direction side of the radiator 10.

In this way, by using heat conductive members 40 with different thermal conductivities in places where the heat transferred from the semiconductor module to the heat sink 10 can easily escape and places where it cannot easily escape, that is, by using the right material in the right place, all the heat conductive members can be 40, it is possible to reduce the manufacturing cost of the entire device while suppressing increases in temperature unevenness between multiple switching elements without using materials with high thermal conductivity and high material costs. Become.

The fin 12 is a plate-like member that extends from the end surface of the fin base 11 in the positive X-axis direction toward the end surface of the fin base 11 in the negative X-axis direction on the first end surface 11 a of the fin base 11 . The plurality of fins 12 are provided apart from each other in the Y-axis direction. As a result, a gap is formed between adjacent fins 12, and this gap functions as a flow path (air path 12a) for air generated by rotation of an impeller (not shown) included in the fan 20. The fins 12 may be fixed to the fin base 11 using screws, may be fixed to the fin base 11 by welding the contact portion to the fin base 11, or may be fixed to the fin base 11 by die-casting. When manufacturing the fin base 11, it may be manufactured integrally with the fin base 11.

The fan 20 is provided on the plus X-axis side of the radiator 10 such that the impeller faces the fin base 11 and the fins 12 on the XY plane including the radiator 10, for example. The fan 20 is positioned in the Z-axis direction so that air can flow through the plurality of semiconductor modules 31 to 36 and the air passage 12a of the fin 12. Note that the fan 20 may be provided on the windward side.

As the impeller of the fan 20 rotates, negative pressure is generated in the air passage 12a of the radiator 10, and this negative pressure generates air flows (wind) in the directions of the plurality of arrows shown in FIG. The direction in which the air flows is equal to the plus X-axis direction.

Next, the internal structure of the semiconductor module will be explained using FIG. 3. FIG. 3 is a diagram showing an image of the internal structure of the semiconductor module 31. As shown in FIG. The semiconductor module 31 is, for example, a 1-in-1 module or a discrete semiconductor element that includes one switching element 31a that constitutes one of the upper and lower arms of the main circuit. It is assumed that each of the semiconductor modules 32 to 36 other than the semiconductor module 31 is provided with a switching element similar to the switching element 31a shown in FIG.

Since switching loss occurs due to the switching operation of the switching element 31a, the junction temperature of the switching element 31a increases, and the surface temperature of the semiconductor module increases. Heat generated in the semiconductor module is transmitted to the fins 12 via the fin base 11, and the surface temperature of the fins 12 increases.

When the fan 20 rotates and a flow of air (wind) is generated in the air passage 12a, heat exchange occurs between the surface of the fin 12 whose temperature has increased and the air flowing in the air passage 12a. Thereby, the heat accumulated in the fins 12 is radiated around the fins 12, and the transfer of heat from the semiconductor module to the fins 12 is promoted, thereby suppressing the temperature rise of the semiconductor module.

Next, the heat conductive member 40 will be explained using FIG. 4 and the like. When the semiconductor modules 31 to 36 are arranged as shown in FIG. The temperature tends to be higher than the temperature of the windward side region of the fin 12 where heat is transferred. This is because the heat transferred to the windward side area of the fin 12 is radiated to the air existing in the air path 12a, and the air moves to the leeward side area of the fin 12. This is because the temperature of the air present in the fins 12 increases, the temperature difference between the temperature of the air and the temperature of the leeward side region of the fins 12 decreases, and the amount of heat exchange decreases.

In this case, the temperature of the semiconductor modules 31, 32, 33 placed on the leeward side rises higher than the temperature of the semiconductor modules 34, 35, 36 placed on the windward side. The temperature difference (temperature unevenness) between the switching element formed and the switching element formed in the upwind semiconductor module 34 increases. Temperature variation is equal to junction temperature variation. This increase in temperature unevenness between the switching elements may cause variations in switching characteristics between the switching elements, leading to deterioration in load drive characteristics such as output voltage distortion and torque ripple.

Further, temperature unevenness between switching elements may generate thermal stress on a control board (not shown) to which the semiconductor module is connected, which may cause solder cracks, cracks in pattern wiring, and the like.

In view of this, in the power conversion device 100 according to the present embodiment, multiple types of heat conductive members having different thermal conductivities are used, as shown in FIG. 4 and the like. FIG. 4 is a diagram showing a first configuration example of the heat conductive member. FIG. 5 is a diagram showing a second configuration example of the heat conductive member. FIG. 6 is a diagram showing a third configuration example of the heat conductive member. FIG. 7 is a diagram showing an example of the material of the heat conductive member.

A plurality of first heat conductive members 41 are provided in the leeward region of the fin base 11 in FIG. 4 . The semiconductor modules 31 to 33 are thermally connected to these first heat conductive members 41. The first thermally conductive member 41 is a plate-like member having a first thermal conductivity. Examples of the material of the first heat conductive member 41 will be described later.

A plurality of second heat conductive members 42 are provided in the windward side region of the fin base 11. The semiconductor modules 34 to 36 are thermally connected to these second heat conductive members 42. The second thermally conductive member 42 is a plate-like member having a second thermal conductivity lower than the first thermal conductivity. Examples of the material of the second heat conductive member 42 will be described later.

In this way, by arranging the second heat conductive member 42 on the windward side of the radiator 10, the heat generated in the semiconductor module 34 and the like is transferred to the heat radiator 10 by the second heat conductive member 42 having a low thermal conductivity. It becomes difficult to transmit to the windward side area. Thereby, the temperature rise in the windward side region of the radiator 10 becomes gradual, and heat is difficult to be transmitted to the leeward side region of the radiator 10.

By arranging the first heat conductive member 41 on the leeward side of the radiator 10, heat generated in the semiconductor module 31, etc. is transferred to the leeward side region of the radiator 10 by the first heat conductive member 41 having high thermal conductivity. It is transmitted quickly, and cooling of the semiconductor module 31 and the like is promoted.

Therefore, by using two types of first heat conductive member 41 and second heat conductive member 42, the switching element formed in the semiconductor module on the leeward side and the switching element formed in the semiconductor module on the windward side can be connected. temperature difference can be reduced, and stable load control is possible.

In addition, by applying a relatively inexpensive material to the second heat conductive member 42, the manufacturing cost of the main circuit is reduced compared to the case where the expensive first heat conductive member 41 is used for all heat conductive members. can do.

FIG. 5 shows a first modification of the configuration shown in FIG. 4. In FIG. 5, among the three heat conductive members provided on the windward side of the fin base 11, the heat conductive member provided closer to the center in the Y-axis direction is changed to the first heat conductive member 41.

As described above, the area near the center of the radiator 10 in the Y-axis direction is one of the areas where heat is difficult to escape. Therefore, by providing the first heat conductive member 41 having the first heat conductivity in the region, cooling of the semiconductor module 35 shown in FIG. Since the temperature difference between the switching element and the switching element formed in the module 34 can be reduced, even more stable control of the load is possible.

FIG. 6 shows a second modification of the configuration shown in FIG. 4. In FIG. In FIG. 6, among the three heat conductive members provided on the leeward side of the fin base 11, the heat conductive member provided closer to the center in the Y-axis direction is changed to the third heat conductive member 43. The third thermally conductive member 43 is a plate-like member having a third thermal conductivity higher than the first thermal conductivity of the first thermally conductive member 41 . Examples of the material of the third heat conductive member 43 will be described later.

Among the leeward side regions of the radiator 10, the region near the center of the radiator 10 in the Y-axis direction is a location where heat is most difficult to escape. Therefore, by providing the third heat conductive member 43 having the third heat conductivity in the region, cooling of the semiconductor module 32 shown in FIG. The temperature difference between the switching element and the switching element formed in the module 31 can be reduced, and the load can be controlled more stably.

Note that the configuration example of FIG. 6 may be combined with the configuration example of FIG. 5 . With this configuration, the temperature difference between the switching elements formed in the semiconductor module 32 and the switching elements formed in the semiconductor module 35 can also be reduced, making it possible to control the load more stably.

FIG. 7 shows an example of materials for the first heat conductive member 41, the second heat conductive member 42, the third heat conductive member 43, and the like.

An example of the material having a thermal conductivity of 6 w/mk is a highly thermally conductive resin compound in which a thermally conductive filler is added to a polymer component. Polymer components include polysiloxane (silicone polymer), polyacrylic, polyolefin, and the like. Note that the method for manufacturing the highly thermally conductive resin compound is well known, as disclosed in, for example, Japanese Patent No. 5089908 and Japanese Patent No. 5085050, and therefore the description thereof will be omitted. A highly thermally conductive resin compound is suitable for the second thermally conductive member 42 (a member having a second thermal conductivity lower than the first thermal conductivity) because, for example, it has a relatively low thermal conductivity but can be manufactured at low cost.

Examples of the material having a thermal conductivity of 30 w/mk include carbon fibers, carbon sheets formed from composite materials of carbon fibers and carbon, and the like. Carbon sheets are based on the fact that in recent years, there has been a trend in the production of many products that use carbon fiber. Since the technology for mass production in a short period of time is being established, it can be classified as a material with relatively low thermal conductivity and low cost. Furthermore, compared to solder, Ag-Cu sintering, etc., carbon sheet does not need to be melted when attaching the semiconductor module to the fin base 11, so even if the unit cost of the material is higher than that of solder, etc. There is no need to prepare a reflow oven, and the process from heating to cooling is no longer necessary, which has the effect of significantly shortening the time required to manufacture the main circuit. It can also increase thermal conductivity compared to compounds. Therefore, the carbon sheet may be applied, for example, to the first heat conductive member 41 (a member having a first heat conductivity), or to the second heat conductive member 42 (a member having a second heat conductivity lower than the first heat conductivity). The manufacturing cost of the main circuit can be reduced even when applied to a member having a

An example of the material having a thermal conductivity of 50 w/mk is solder (such as lead-free solder). As mentioned above, solder requires the use of a reflow oven, etc., but since the material cost is low, when mass producing main circuits, it is possible to use solder while suppressing the increase in the manufacturing cost of the main circuit alone, while using solder instead of carbon sheet. can also increase thermal conductivity. Therefore, solder is suitable for the first heat conductive member 41 or the third heat conductive member 43, for example.

An example of a material having a thermal conductivity of 200 w/mk is an Ag--Cu sintered body (Ag--Cu alloy containing Cu). Although the Ag-Cu sintered body is an expensive material because it contains Ag, it has high thermal conductivity and is suitable for heat dissipation in semiconductor modules, so it is suitable for the first heat conductive member 41 and the third heat conductive member 43. There is.

Note that the materials of the first heat conductive member 41 and the second heat conductive member 42 are not limited to these.

Next, the effects of using different types of heat conductive members will be explained using FIG. 8 and the like. FIG. 8 is a diagram showing a state in which the temperature sensor 60 and the like are attached to the power conversion device 100. 9A is a cross-sectional view of the power conversion device 100 in the YZ plane including the line AA shown in FIG. 8, FIG. 9B is a cross-sectional view of the power conversion device 100 in the YZ plane including the line BB shown in FIG. 8, FIG. 9C is a cross-sectional view of the power conversion device 100 in the YZ plane including the line CC shown in FIG.

The power conversion device 100 is provided with a fan 20, a radiator 10, semiconductor modules 31 to 36, etc. inside a housing 50, and further includes a plurality of temperature sensors 60 (thermocouples, etc.) for measuring the temperature of each part. provided. A plurality of temperature sensors 60 are provided on the fin base 11, the fins 12, etc., and are also provided on the heat insulating plate 70.

The heat insulating board 70 is a plate-shaped heat insulating material installed on the end face of the heater 80 in the plus Z-axis direction in order to suppress radiation of heat generated by the heater 80 . The heater 80 is a heat generation source for simulating the heat generated in the semiconductor module, and is provided in a number corresponding to each of the semiconductor modules 31 to 36, and in order to confirm the effect of the heat conduction member, each heater 80 is a heat generation source for simulating the heat generated in the semiconductor module. This was realized by controlling the current of the power supply device so that it occurs. A heat conductive member is provided between the heater 80 and the fin base 11. In FIGS. 8 and 9, two types of heat conductive members (first heat conductive member 41 and second heat conductive member 42) shown in FIG. 4 are used.

FIG. 10 is a diagram showing the results of measuring the temperature distribution of the fins when heat generated by the heater 80 is applied to the radiator 10 and forced air cooling is performed by the fan 20 in the analytical model of the power conversion device 100. In FIG. 10, temperatures measured by the temperature sensor 60 provided on the YZ plane including each of the AA line, BB line, and CC line are shown in order from the top. FIG. 10 shows the temperature of each part measured when the temperature of the heater 80 is set to about 90°C.

According to the measurement results in FIG. 10, it can be seen that on the upper surface of the fin base 11 of the radiator 10, there is a temperature difference of about 1° C. between the windward side region and the leeward side region. In this way, by using different types of heat conductive members, the temperature difference between the windward side and the leeward side can be reduced.

Note that the power conversion device 100 according to this embodiment may be configured as follows. FIG. 11 is a first diagram showing a configuration example of a power conversion device 100A according to a modification. FIG. 12 is a second diagram showing a configuration example of a power conversion device 100A according to a modification. FIG. 13 is a diagram showing an image of the internal structure of the semiconductor module 31A shown in FIG. 11.

In the power conversion device 100A, three semiconductor modules 31A to 33A are used, and the semiconductor module 31A is a 2-in-1 module including two switching elements 31a and 31b forming upper and lower arms, as shown in FIG. 13. The same applies to semiconductor modules 32A and 33A.

The semiconductor module 31A (second semiconductor module) is located at the periphery of the second end face 11b, in place of the above-mentioned windward region, compared to the semiconductor module 32A (first semiconductor module) in the direction perpendicular to the direction in which the wind flows. It is set up in an area closer to the department.

In addition, the semiconductor module 33A (second semiconductor module) has a second end face 11b which is located in the second end face 11b in the direction perpendicular to the direction in which the wind flows, instead of the above-mentioned windward region. It is provided in an area near the periphery.

Since heat tends to accumulate in the central region of the fin base 11, a first heat conductive member 41 having high thermal conductivity is provided. The semiconductor module 32A is connected to the first heat conductive member 41.

In addition, since heat is less likely to accumulate in the area closer to the periphery of the fin base 11 in the direction perpendicular to the direction in which the wind flows than in the central area, a second heat conductive member 42 is provided to reduce costs. It will be done. A semiconductor module 31A is connected to one second heat conductive member 42, and a semiconductor module 33A is connected to the other second heat conductive member 42.

As described above, in the power conversion device 100A according to the modification, the first heat conductive member 41 having the first thermal conductivity is provided in a location where heat is difficult to escape. Thereby, the heat generated in the semiconductor module 32A can be efficiently radiated, and the temperature difference between the switching elements formed in the semiconductor module 32A and the switching elements formed in each of the semiconductor modules 31A and 33A can be reduced. It can be made smaller and stable control of the load is possible.

In addition, in the power conversion device 100A according to the modification, the second heat conductive member 42 having a second heat conductivity lower than the first heat conductivity is provided in a location where heat is likely to escape in a direction perpendicular to the direction in which the wind flows. provided. As a result, compared to the case where materials with high thermal conductivity and high material costs are used for all thermal conductive members, the entire device can be This makes it possible to reduce manufacturing costs.

The configurations shown in the embodiments described above are examples of the contents of the present invention, and can be combined with other known techniques, and the configurations can be modified without departing from the gist of the present invention. It is also possible to omit or change parts.

10: Heat sink 11: Fin base 11a: First end surface 11b: Second end surface 12: Fin 12a: Air path 20: Fan 31: Semiconductor module 31A: Semiconductor module 31a: Switching element 31b: Switching element 32: Semiconductor module 32A: Semiconductor module 33: Semiconductor module 33A: Semiconductor module 34: Semiconductor module 35: Semiconductor module 36: Semiconductor module 40: Heat conduction member 41: First heat conduction member 42: Second heat conduction member 43: Third heat conduction member 50: Housing 60: Temperature sensor 70: Heat insulating board 80: Heater 100: Power converter 100A: Power converter

Claims (3)

a plurality of fins in which air flow paths are formed in areas that are spaced apart from each other and face each other;
a fin base having a first end surface on which a plurality of the fins are provided and a second end surface opposite to the first end surface;
a first semiconductor module provided on the second end surface;
a second semiconductor module provided on the second end surface and provided in a region closer to the peripheral edge of the second end surface than the first semiconductor module in a direction perpendicular to the direction in which the wind flows ;
a third semiconductor module provided on the second end surface and provided in a region on the leeward side of the second end surface than the first semiconductor module;
Provided on the second end face, and provided in a region closer to the peripheral edge of the second end face on the opposite side of the second semiconductor module than the first semiconductor module in a direction perpendicular to the direction in which the wind flows. a fourth semiconductor module;
a fifth semiconductor module provided on the second end surface and provided in a region closer to the peripheral edge of the second end surface than the third semiconductor module in a direction perpendicular to the direction in which the wind flows;
Provided on the second end face, and provided in a region closer to the peripheral edge of the second end face on the opposite side of the fifth semiconductor module than the third semiconductor module in a direction perpendicular to the direction in which the wind flows. a sixth semiconductor module;
a first thermally conductive member having a first thermal conductivity and provided between the second end surface and each of the first semiconductor module, the fifth semiconductor module, and the sixth semiconductor module ;
a second thermally conductive member provided between the second end surface and each of the second semiconductor module and the fourth semiconductor module and having a second thermal conductivity lower than the first thermal conductivity;
a third thermally conductive member provided between the second end surface and the third semiconductor module and having a third thermal conductivity higher than the first thermal conductivity;
A power conversion device comprising: The power conversion device according to claim 1, wherein the first semiconductor module and the second semiconductor module are 2-in-1 modules including two switching elements forming upper and lower arms. The power conversion device according to claim 1, wherein the first semiconductor module and the second semiconductor module are 1-in-1 modules or discrete semiconductor devices including one switching element constituting one of the upper and lower arms.

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