Power conversion device

Abstract

The present application obtains a small and light electric power conversion device, which can sufficiently dissipate heat generated from a capacitor module to suppress temperature rise of the capacitor module. The electric power conversion device is characterized by comprising: a first cooler on which the capacitor module is placed and which cools heat generated from the capacitor module; a second cooler on which a semiconductor module is placed and which cools heat generated from the semiconductor module; and a heat sink thermally connected to the capacitor module and the second cooler and which dissipates a part of the heat generated from the capacitor module via the second cooler, the first cooler and the second cooler being configured to form a refrigerant flow path and sharing the refrigerant.

Description

Technical Field

[0001] This application relates to an electric power conversion device. Background Technology

[0002] Traditionally, power conversion devices such as inverters, DC / DC converters, and on-board chargers have been installed in electric or hybrid vehicles. These power conversion devices, such as inverters, which act as switching devices, incorporate capacitor modules to smooth the power supplied from the power source. Generally, these modules include conductive materials that electrically connect the capacitor module and a semiconductor module, as well as a control device that controls the switching of the semiconductor module. For example, the capacitor module has the function of storing or releasing electricity and is generally composed of capacitive elements such as capacitors. In addition to being installed in inverters that convert power between the power source and the rotating motor, capacitor modules are also installed in power conversion devices such as converters that convert power to other voltages. The power conversion device is configured to control the current driving the rotating motor by controlling the switching elements of the installed semiconductor modules to switch the supply path of the current supplied from the power source.

[0003] In high-output power conversion devices, high current flows through the semiconductor and capacitor modules, causing them to heat up. In particular, when the capacitor module heats up, the capacitors within it may melt and short-circuit, leading to malfunctions and, in the worst case, damage to the power conversion device. Therefore, a power conversion device is proposed to connect the housing surface of a capacitor module (capacitor module) to a semiconductor cooler for cooling a power semiconductor module (semiconductor module) via a heat-conducting plate, and to dissipate heat generated from the capacitor module from the semiconductor cooler via the heat-conducting plate (for example, see Patent Document 1). [Existing technical documents] [Patent Literature]

[0004] [Patent Document 1]: Japanese Patent Application Publication No. 2017-108524 Summary of the Invention

[0005] However, in the conventional power conversion device disclosed in Patent Document 1, the heat dissipation from the capacitor module is limited to heat dissipation from the semiconductor cooler via a heat-conducting plate. When a high current is applied to the capacitor module, the capacitor module heats up and becomes high-temperature. The conventional cooling method using only the heat-conducting plate is insufficient. It is necessary to install a cooler in the capacitor module and increase the path for dissipating the heat generated from the capacitor module to achieve cooling, etc., in order to improve the cooling effect. When using the conventional power conversion device disclosed in Patent Document 1, several cooling methods can be conceived. For example, as a countermeasure, a structure is adopted in which the semiconductor cooler is extended and a capacitor module is also mounted on the semiconductor cooler. However, when the connection point between the heat-conducting plate and the semiconductor cooler is close to the capacitor module, the heat dissipated from the heat-conducting plate by the capacitor module will cause thermal interference between the capacitor module and the semiconductor cooler, thus the capacitor module is not sufficiently cooled. Therefore, the connection point between the heat-conducting plate and the semiconductor cooler only needs to be connected at a position that can sufficiently cool the capacitor module without being affected by thermal interference with the capacitor module. However, in the above case, there is a problem of increasing the size of the semiconductor cooler.

[0006] Furthermore, as another countermeasure to suppress thermal interference, the cooling system can be configured as a dual system, that is, in addition to the cooler for the semiconductor module, a cooler for the capacitor module is also provided to cool the capacitor module, and the coolers are configured to be separated so that the heat generated from the capacitor module does not cause thermal interference to the cooler for the capacitor module via the heat-conducting plate and the semiconductor cooler. However, in the above case, the cooling system becomes a dual system, which complicates the cooling structure and increases the weight. In particular, from the point of view of fuel efficiency, the inverter installed in hybrid electric vehicles as a power conversion device requires small size and light weight for high efficiency, but in the case of the conventional power conversion device disclosed in Patent Document 1, as seen from the aforementioned problems, it is difficult to achieve miniaturization and light weight while improving the cooling effect, resulting in a worse fuel efficiency.

[0007] This application discloses a technology for solving the aforementioned technical problems, with the aim of providing a small and lightweight power conversion device that can adequately dissipate heat generated from the capacitor module to suppress the temperature rise of the capacitor module.

[0008] The power conversion device disclosed in this application is characterized by comprising: a first cooler, which houses a capacitor module and cools the heat generated from the capacitor module; a second cooler, which houses a semiconductor module and cools the heat generated from the semiconductor module; and a heat sink, which is thermally connected to the capacitor module and the second cooler and dissipates a portion of the heat generated from the capacitor module via the second cooler, wherein the first cooler and the second cooler are configured to form a refrigerant flow path and share the refrigerant.

[0009] According to the power conversion device disclosed in this application, a small and lightweight power conversion device can be obtained, which can effectively dissipate the heat generated from the capacitor module to suppress the temperature rise of the capacitor module. Attached Figure Description

[0010] Figure 1 This is a side view showing the power conversion device of Embodiment 1. Figure 2 This is an exploded perspective view of the power conversion device according to Embodiment 1. Figure 3 This is a diagram schematically illustrating the heat dissipation path of the power conversion device in Embodiment 1. Figure 4 This is a side view showing a modified example of the power conversion device according to Embodiment 1. Figure 5 This is a side view showing the power conversion device of Embodiment 2. Figure 6 This is a side view showing a modified example of the power conversion device according to Embodiment 2. (Symbol Explanation) 1 Capacitor module; 2 First cooler; 3 Semiconductor module; 4 Second cooler; 5 Heat sink; 6 Fixing component; 7 Sealing component; 8 Refrigerant flow path; 9 Fins; 10 Housing; 11 Third cooler; 12 Heat source; 50 Power conversion device; a First cooling path; b Second cooling path; c Third cooling path. Detailed Implementation

[0011] Implementation Method 1 Hereinafter, Embodiment 1 will be described based on the accompanying drawings. Furthermore, in each drawing, the same symbol represents the same or equivalent part.

[0012] Figure 1 This is a side view showing the power conversion device of Embodiment 1. (e.g.) Figure 1 As shown, the power conversion device 50 of Embodiment 1 includes: a first cooler 2, which houses a capacitor module 1 and cools the heat generated from the capacitor module 1; a second cooler 4, which houses a semiconductor module 3 and cools the heat generated from the semiconductor module 3; and a heat sink 5, which is thermally connected to the capacitor module 1 and the second cooler 4 and dissipates a portion of the heat generated from the capacitor module 1 via the second cooler 4. The power conversion device 50 is housed in a housing 10. Furthermore, in the power conversion device 50 of Embodiment 1, the first cooler 2 and the second cooler 4 are configured to form a refrigerant flow path 8 (cooling path) and share a refrigerant. Additionally, the power conversion device 50 of Embodiment 1 includes: a conductive material such as a busbar, wherein a capacitor module 1 is mounted on the conductive material to smooth the current supplied from the power source, and the capacitor module 1 is electrically connected to the semiconductor module 3; and a control device that controls the switching of the semiconductor module 3. Figure 1The diagram omits conductive materials such as busbars that connect semiconductor module 3 to capacitor module 1, as well as the control device (control board) that controls the switching on or off of semiconductor module 3.

[0013] The semiconductor module 3 is configured to contact the surface of the second cooler 4 to cool the heat generated from the semiconductor module 3. Furthermore, the projected area of ​​the second cooler 4 is larger than that of the semiconductor module 3. This reduces the thermal interference of the heat generated from the semiconductor module 3 on the heat sink 5 and allows for easy connection of the heat sink 5 to the second cooler 4. The capacitor module 1 is configured to contact the surface of the first cooler 2 to cool the heat generated from the capacitor module 1. The capacitor module 1 is cooled by the first cooler 2. On the other hand, a portion of the heat generated from the capacitor module 1 is also cooled by the second cooler 4 via the heat sink 5. That is, the heat generated from the capacitor module 1 is cooled through two main paths: one is the path of heat dissipation from the first cooler 2 to the refrigerant, and the other is the path of heat dissipation from the second cooler 4 via the heat sink 5.

[0014] Furthermore, in the power conversion device 50 of Embodiment 1, the heat sink 5 is a copper plate and is connected to the second cooler 4 without passing through the first cooler 2. Additionally, the heat sink 5 is connected to the connection portion between the first cooler 2 and the second cooler 4. The second cooler 4 and the heat sink 5 are together fixed to the first cooler 2 by the fixing member 6. Furthermore, in the power conversion device 50 of Embodiment 1, the first cooler 2 is a housing containing refrigerant, and the second cooler 4 is, for example, a radiator having fins 9 and serving as a metal plate. Moreover, the first cooler 2 of the power conversion device 50 of Embodiment 1 is formed of a metal alloy containing aluminum, specifically an aluminum die-casting. Furthermore, the radiator serving as the second cooler 4 is formed of aluminum.

[0015] Furthermore, as described above, in the power conversion device 50, the first cooler 2 and the second cooler 4 are configured to form a refrigerant flow path 8 and share a refrigerant. In the power conversion device 50 of Embodiment 1, the first cooler 2 and the second cooler 4 are configured to constitute the entire refrigerant flow path 8 (cooling path). In the power conversion device 50 of Embodiment 1, the refrigerant flow path 8 (cooling path) is formed as a single line so that the same refrigerant flows to the first cooler 2 and the second cooler 4. According to the power conversion device 50 of Embodiment 1, a structure can be formed that cools the first cooler 2 and the second cooler 4 with the same refrigerant, thereby achieving miniaturization and weight reduction. Furthermore, if the projected area of ​​the second cooler 4 is smaller than the projected area of ​​the refrigerant flow path 8 (cooling path) formed by the first cooler 2 and the second cooler 4, the projected area for sealing the first cooler 2 and the second cooler 4 can be reduced.

[0016] Figure 2 This is an exploded perspective view of the power conversion device according to Embodiment 1. Figure 2 Specifically, this means that basket 10 will be moved from... Figure 1 An exploded perspective view of the structure removed from the power conversion device 50 shown. like Figure 2 As shown, in the power conversion device 50 of Embodiment 1, a sealing member 7 is disposed between the first cooler 2 and the second cooler 4. The second cooler 4 is disposed above the first cooler 2 via the sealing member 7. The sealing member 7 is configured to improve sealing performance so that the refrigerant flowing in the refrigerant flow path 8 (cooling path) formed by the first cooler 2 and the second cooler 4 does not leak. The heat dissipation plate 5 is fastened to the bolts used as fixing members 6 in the seal of the first cooler 2 and the second cooler 4. As a result, screws and the like used for mounting the heat dissipation plate 5 to the second cooler 4 can be omitted.

[0017] Here, the sealing performance of the first cooler 2 and the second cooler 4 of the power conversion device 50 in Embodiment 1 will be explained. If the first cooler 2 and the second cooler 4 are fixed only by the fixing member 6, the sealing performance may sometimes be insufficient. When the refrigerant is a gas, such as air, leakage from the refrigerant flow path 8 may not always cause significant problems. In this case, the first cooler 2 and the second cooler 4 can be fixed solely by the fixing member 6. However, when the refrigerant is a liquid, such as water, leakage from the gap between the first cooler 2 and the second cooler 4 constituting the refrigerant flow path 8 can cause short circuits and other malfunctions; therefore, it is necessary to prevent refrigerant leakage.

[0018] In this case, to prevent the liquid refrigerant from leaking from the gap at the connection between the first cooler 2 and the second cooler 4, an O-ring or liquid gasket, serving as a sealing member 7, is inserted between the first cooler 2 and the second cooler 4. For example, when using an O-ring, the second cooler 4 is fixed towards the first cooler 2 by using bolts in the fixing member 6 and tightening the bolts to flatten the O-ring. This improves the sealing performance by filling the gap where liquid leakage is possible. However, if foreign objects are trapped between the sealing member 7 and the second cooler 4 or between the sealing member 7 and the first cooler 2, gaps can form, reducing the sealing performance and increasing the possibility of poor manufacturing. If the sealing area of ​​the sealing member 7 becomes larger, the risk of liquid leakage due to trapped foreign objects or poor manufacturing increases. Therefore, it is preferable that the sealing area of ​​the sealing member 7 is small.

[0019] In the power conversion device 50 of Embodiment 1, if the heat sink 5 is fixed together with the fixing point where the fixing member 6 is fixed, the position where the heat sink 5 is connected to the second cooler 4 and the fixing point where the second cooler 4 is fixed to the first cooler 2 can be made common without being separate. As a result, there is no need to provide other components such as screws at the position where the heat sink 5 is connected to the second cooler 4, which reduces the number of parts and thus achieves a lightweight effect. Thus, according to the power conversion device 50 of embodiment 1, since the heat generated from the capacitor module 1 is dissipated from the second cooler 4 connected to the heat sink 5, thermal interference can be suppressed compared to directly connecting the heat sink 5 to only the first cooler 2.

[0020] As mentioned earlier, the heat generated from the capacitor module 1 is cooled via two main paths: one from the first cooler 2 to the refrigerant, and the other from the second cooler 4 via the heat sink 5. Here, in the path of heat dissipation from the second cooler 4 via the heat sink 5, countermeasures to prevent thermal interference between the heat generated from the capacitor module 1 and the first cooler 2 via the heat sink 5 will be explained. First, such as Figure 1 As shown, the structure in which the heat sink 5 is connected to the second cooler 4 without passing through the first cooler 2 is adopted. For example, such as Figure 1 As shown, if the second cooler 4 is positioned above the first cooler 2, and then the heat sink 5 is positioned above the second cooler 4 at the connection between the second cooler 4 and the first cooler 2 and connected thereto, the heat sink 5 can be connected to the second cooler 4 without passing through the first cooler 2.

[0021] In this way, if the heat sink 5 is connected to the second cooler 4 without passing through the first cooler 2, the heat generated from the capacitor module 1, after being dissipated to the heat sink 5, will be dissipated to the refrigerant from the first cooler 2 once it passes through the path of dissipation from the second cooler 4. If the heat sink 5 is connected to the second cooler 4 without passing through the first cooler 2, the heat dissipated from the heat sink 5 to the first cooler 2 is only the residual heat after partial dissipation from the heat sink 5 through the second cooler 4, which can suppress thermal interference to the capacitor module 1 caused by the heat generated from the capacitor module 1 being dissipated through the heat sink 5.

[0022] Figure 3 This is a diagram schematically illustrating the heat dissipation path of the power conversion device in Embodiment 1. Second, such as Figure 3As shown, the first thermal resistance of the first cooling path a, which uses heat generated from the heat source 12 (which is the capacitor module 1) to dissipate heat from the heat sink 5 to the refrigerant from the second cooler 4, is smaller than the second thermal resistance of the second cooling path b, which uses heat generated from the capacitor module 1 to dissipate heat from the heat sink 5 and the second cooler 4 to the refrigerant from the first cooler 2.

[0023] If the thermal resistance is low, the heat conduction from the heat generated by the capacitor module 1 to the second cooler 4 increases, and the heat dissipation from the second cooler 4 increases. As a result, of the heat generated by the capacitor module 1 that dissipates heat via the heat sink 5, the amount of heat dissipated from the second cooler 4 to the refrigerant (heat dissipation) is greater than the amount of heat dissipated from the first cooler 2 to the refrigerant (heat dissipation). That is, the amount of heat dissipated from the first cooler 2 to the refrigerant from the heat generated by the capacitor module 1 is reduced, thus suppressing thermal interference to the first cooler 2. The higher the cooling performance, the lower the thermal resistance. That is to say, if the cooling performance of the first cooler 2 is higher than that of the second cooler 4, then because the thermal resistance of the first cooling path a from the second cooler 4 is small, the thermal interference of the capacitor module 1 on the first cooler 2 can be suppressed, as mentioned above.

[0024] At this point, even if the cooling performance of the second cooler 4 is higher than that of the first cooler 2, the heat generated from the capacitor module 1 is difficult to dissipate to the second cooler 4 due to the high thermal resistance of the heat sink 5. The heat generated from the capacitor module 1 can be roughly divided into two paths: one through the heat sink 5 and the other through the first cooler 2 connected to the capacitor module 1. However, as mentioned earlier, when the thermal resistance of the heat sink 5 is high, the heat generated from the capacitor module 1 through the first cooler 2 will be relatively larger. If the heat dissipation performance of the second cooler 4 is to be improved to the required heat dissipation in order to suppress the relative ratio of heat generated from the capacitor module 1 to the heat dissipated to the first cooler 2, then the second cooler 4 needs to be enlarged.

[0025] Therefore, in order to keep the size of the second cooler 4 below the permissible size, the heat sink 5 needs to be made of a material with low thermal resistance, and its width or thickness needs to be increased to reduce thermal resistance. As mentioned earlier, the heat sink 5 is, for example, a copper plate, and the first cooler 2 is formed of an aluminum-containing metal alloy, specifically an aluminum die-casting. Furthermore, the heat sink of the second cooler 4 is formed of aluminum. In comparison by materials, generally speaking, the heat dissipation performance (cooling performance) of the heat sink 5 made of copper is higher than that of the second cooler 4 made of aluminum. Furthermore, generally speaking, the heat dissipation performance (cooling performance) of the second cooler 4 made of aluminum is higher than that of the first cooler 2 made of an aluminum-containing metal alloy. However, thermal resistance is not only adjusted based on the material, but also based on the width, thickness, surface area, etc., as mentioned above.

[0026] If, in addition to the aforementioned heat sink 5 which reduces thermal resistance, the heat dissipation performance (cooling performance) of the second cooler 4 is also improved, then thermal interference of heat generated from the capacitor module 1 to the first cooler 2 via the heat sink 5 can be suppressed. Methods for improving the heat dissipation performance (cooling performance) of the second cooler 4 include using a material with low thermal resistance, such as a metal, in the material of the second cooler 4 to efficiently move heat from the heat sink 5 to the second cooler 4, thereby improving the heat dissipation performance (cooling performance); and providing fins 9 along the cooling path of the second cooler 4 to increase the surface area and thus improve the heat dissipation performance (cooling performance). In particular, according to the power conversion device 50 of embodiment 1, when the fins 9 are provided in the second cooler 4, the processing method of the second cooler 4 can be made easier.

[0027] Here, the processing methods for the cooler will be explained. For example, the processing methods for a cooler with fins 9, such as the second cooler 4, include extrusion processing or machining. Extrusion processing is characterized by its ability to reduce processing costs, while machining is characterized by its ability to manufacture complex cooling fins with high precision. On the other hand, when manufacturing large finned coolers, the regulation and management of temperature, friction, extrusion speed, and pressure are more difficult during extrusion compared to smaller extrusions. Furthermore, machining time increases with the size of the extruded part. Therefore, finned coolers are preferably small. Typically, the semiconductor module 3 generates more heat than the capacitor module 1. Therefore, it is preferable to configure the second cooler 4, which cools the semiconductor module 3, as a finned cooler 9. On the other hand, fins are not required in the first cooler 2, which cools the capacitor module 1, which generates less heat.

[0028] In the power conversion device 50 of Embodiment 1, the first cooler 2 and the second cooler 4 can be separated before assembly, and can be processed in a state where the projected area of ​​the second cooler 4 is reduced. Therefore, the second cooler 4 can be processed separately from the first cooler 2. At this time, since the second cooler 4 can be processed into a cooler with fins 9 and can be processed into the size required for heat dissipation, it has the effect of being easy to process. On the other hand, if a finless cooler is used in the first cooler 2, it can be processed by sheet metal processing or easy die casting without complicated methods. The entire cooler, which combines the first cooler 2 and the second cooler 4, does not require difficult processing.

[0029] In this way, in the semiconductor module 3, which requires more cooling, by adding fins 9 to the second cooler 4, the cooling performance can be improved while ensuring the required cooling performance for the capacitor module 1 by dissipating heat from the second cooler 4 via the heat sink 5 and from the first cooler 2. Furthermore, by utilizing easy processing methods to fabricate most of the cooling path, processing costs can be kept low.

[0030] Figure 4 This is a side view showing a modified example of the power conversion device according to Embodiment 1. Where the heat generated from the capacitor module 1 has sufficient capacity to allow thermal interference to the first cooler 2 via the heat sink 5, as... Figure 4 As shown, a structure can be formed in which a heat sink 5 is sandwiched between the first cooler 2 and the second cooler 4, and the heat sink 5 is connected to both the first cooler 2 and the second cooler 4. In this case, a portion of the heat dissipated from the heat sink 5 is dissipated to the first cooler 2 without passing through the second cooler 4. Although the heat dissipation performance of this structure is lower than that of the structure where the heat sink 5 is connected to the second cooler 4 without passing through the first cooler 2 to dissipate heat from the capacitor module 1, the heat sink 5 can be fixed by being sandwiched between the first cooler 2 and the second cooler 4, thus reducing the steps required to fix the heat sink 5.

[0031] According to a variation of the power conversion device of Embodiment 1, such as Figure 4 As shown, the first thermal resistance of the first cooling path a, which dissipates heat from the capacitor module 1 to the refrigerant via the heat sink 5 from the second cooler 4, is smaller than the third thermal resistance of the third cooling path c, which dissipates heat from the capacitor module 1 to the refrigerant via the heat sink 5 from the first cooler 2.

[0032] As described above, the power conversion device 50 according to Embodiment 1 includes: a first cooler 2, which houses a capacitor module 1 and cools the heat generated from the capacitor module 1; a second cooler 4, which houses a semiconductor module 3 and cools the heat generated from the semiconductor module 3; and a heat sink 5, which is thermally connected to the capacitor module 1 and the second cooler 4 and dissipates a portion of the heat generated from the capacitor module 1 via the second cooler 4. The power conversion device 50 is housed in a housing 10. Furthermore, in the power conversion device 50 of Embodiment 1, the first cooler 2 and the second cooler 4 are configured to form a refrigerant flow path 8 and share a refrigerant. That is, in the power conversion device 50 of Embodiment 1, the structure is such that the first cooler 2 and the second cooler 4 constitute the entire refrigerant flow path 8 (cooling path), and the same refrigerant that cools the second cooler 4 and the first cooler 2 flows through the cooling path.

[0033] Therefore, according to the power conversion device 50 of embodiment 1, even when the capacitor module 1 generates a large amount of heat, the temperature rise of the capacitor module 1 can be suppressed by dissipating the heat generated from the capacitor module 1, thereby achieving sufficient cooling. As a result, a small and lightweight power conversion device 50 can be obtained. Therefore, even under high current conditions, the capacitor module 1 will not melt due to heat. Moreover, since the refrigerant flow path 8 (cooling path) is treated as a system, there is no need to install additional coolers relative to the capacitor module 1. As a result, the coolers in the power conversion device 50 will not be large or heavy. Consequently, the power conversion device 50 can be miniaturized and made lighter.

[0034] In the power conversion device 50 of Embodiment 1, the heat sink 5 is preferably made of a material with high insulation and thermal conductivity, but materials with these properties are generally expensive. For cost-effectiveness, a metallic material is usually chosen for the heat sink 5. In this case, the capacitor module 1 and the second cooler 4 need to be electrically insulated. By electrically insulating the heat sink 5 from either the capacitor module 1 or the second cooler 4, the capacitor module 1 can be electrically insulated from the second cooler 4. That is, the heat sink 5 is thermally connected to either or both of the capacitor module 1 and the second cooler 4 via an insulating member.

[0035] Implementation Method 2 Figure 5 This is a side view showing the power conversion device of Embodiment 2. (e.g.) Figure 5 As shown, in the power conversion device 50 of Embodiment 2, the first cooler 2 is a heat sink that serves as a metal plate, and another housing is provided as a third cooler 11. According to the power conversion device 50 of Embodiment 2, the first cooler 2 and the second cooler 4 are configured to form part of the refrigerant flow path 8 (cooling path). The third cooler 11 is configured to form the refrigerant flow path 8 together with the first cooler 2 and the second cooler 4.

[0036] Figure 6 This is a side view showing a modified example of the power conversion device according to Embodiment 2. For example... Figure 6 As shown, in a modified example of the power conversion device 50 of Embodiment 2, the first cooler 2 is a heat sink that is a metal plate, and the refrigerant flow path 8 (cooling path) formed by the first cooler 2 and the second cooler 4 is opened, and the refrigerant is, for example, air flowing through a fan (not shown). As described above, according to Embodiment 2, the power conversion device 50 can suppress the temperature rise of the capacitor module 1 even when the capacitor module 1 generates a large amount of heat, thereby achieving sufficient cooling. As a result, a small and lightweight power conversion device 50 can be obtained.

[0037] This application describes various exemplary implementation methods and embodiments, but the various features, methods and functions described in one or more implementation methods are not limited to specific implementation methods, and can be applied to implementation methods alone or in various combinations. Therefore, numerous variations not illustrated are contemplated within the scope of the technology disclosed in this application. These include variations, additions, or omissions of at least one constituent element, as well as the extraction of at least one constituent element and its combination with constituent elements of other embodiments.

Claims

1. A power conversion device, characterized in that, include: A first cooler is provided, which houses a capacitor module and cools the heat generated from the capacitor module. A second cooler is provided, which houses a semiconductor module and cools the heat generated from the semiconductor module. as well as A heat sink is thermally connected to the capacitor module and the second cooler, and dissipates a portion of the heat generated from the capacitor module via the second cooler. The first cooler and the second cooler are configured to form a refrigerant flow path and share the refrigerant. The first thermal resistance of the first cooling path from the capacitor module to the refrigerant via the heat sink and the heat dissipation from the second cooler is... The second thermal resistance of the second cooling path from the capacitor module to the refrigerant via the heat sink and the second cooler, or The third thermal resistance is smaller compared to the third cooling path through which heat generated from the capacitor module is dissipated from the first cooler to the refrigerant via the heat sink.

2. A power conversion device, characterized in that, include: A first cooler is provided, which houses a capacitor module and cools the heat generated from the capacitor module. A second cooler is provided, which houses a semiconductor module and cools the heat generated from the semiconductor module. as well as A heat sink is thermally connected to the capacitor module and the second cooler, and dissipates a portion of the heat generated from the capacitor module via the second cooler. The first cooler and the second cooler are configured to form a refrigerant flow path and share the refrigerant. The second cooler and the heat dissipation plate are fixed to the first cooler together by a fixing member.

3. A power conversion device, characterized in that, include: A first cooler is provided, which houses a capacitor module and cools the heat generated from the capacitor module. A second cooler is provided, which houses a semiconductor module and cools the heat generated from the semiconductor module. as well as A heat sink is thermally connected to the capacitor module and the second cooler, and dissipates a portion of the heat generated from the capacitor module via the second cooler. The first cooler and the second cooler are configured to form a refrigerant flow path and share the refrigerant. The first cooler is a first heat sink made of metal. The second cooler is a second radiator with fins. In the case where the first cooler is the first radiator, a third cooler is also provided, which together with the first cooler and the second cooler constitutes the refrigerant flow path.

4. The power conversion device as described in any one of claims 1 to 3, characterized in that, The heat sink is a copper plate and is connected to the second cooler without passing through the first cooler.

5. The power conversion device as described in any one of claims 1 to 3, characterized in that, The heat sink is connected to the connection between the first cooler and the second cooler.

6. The power conversion device as described in claim 4, characterized in that, The heat sink is connected to the connection between the first cooler and the second cooler.

7. The power conversion device as described in any one of claims 1 to 3, characterized in that, The heat sink is thermally connected to either or both of the capacitor module and the second cooler via an insulating component.

8. The power conversion device as described in claim 4, characterized in that, The heat sink is thermally connected to either or both of the capacitor module and the second cooler via an insulating component.

9. The power conversion device as described in claim 1 or 3, characterized in that, The second cooler and the heat dissipation plate are fixed to the first cooler together by a fixing member.

10. The power conversion device according to any one of claims 1 to 3, characterized in that, The second cooler is disposed above the first cooler via a sealing member.

11. The power conversion device as claimed in claim 4, characterized in that, The second cooler is disposed above the first cooler via a sealing member.

12. The power conversion device as described in claim 1 or 2, characterized in that, The first cooler is either a first housing containing the refrigerant or a first heat sink made of metal. The second cooler is a second radiator with fins.

13. The power conversion device as described in claim 12, characterized in that, When the first cooler is the first housing, the first housing is formed of an aluminum-containing metal alloy. The second heat sink is made of aluminum.

14. The power conversion device as claimed in claim 12, characterized in that, In the case where the first cooler is the first radiator, a third cooler is also provided, which together with the first cooler and the second cooler constitutes the refrigerant flow path.

15. The power conversion device as claimed in claim 12, characterized in that, When the first cooler is the first radiator, the refrigerant flow path formed by the first cooler and the second cooler becomes open, and the refrigerant is circulating air.

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