Power converter

Abstract

To provide a power conversion device that improves the cooling performance of heat-generating components while also being easy to assemble. [Solution] In a power conversion device comprising a housing 15 and a heat-generating component (e.g., a capacitor) 10 provided in contact with one side surface of the housing 15, the housing 15 is provided with a refrigerant passage 18 through which a refrigerant flows and a boss portion 16 extending from the one side surface. The heat-generating component 10 is provided with a cooling plate 13 on the side opposite to the side in contact with the housing 15. The cooling plate 13 is joined to the housing via the boss portion 16. The refrigerant passage 18 is provided with an opening 18a that opens on the one side surface of the housing 15. The heat-generating component 10 is fixed to the one side surface of the housing 15 so as to close the opening 18a.

Description

Technical Field

[0001] The present invention relates to a cooling technology for heat-generating components mounted on a power conversion device (such as an inverter unit).

Background Art

[0002] FIG. 12 shows an electrical circuit diagram of a general inverter unit. As shown in FIG. 12, a capacitor (for example, a film capacitor) C is connected between a P terminal and an N terminal. Also, switching elements Su, Sx, switching elements Sv, Sy, switching elements Sw, Sz are respectively connected in series between the P terminal and the N terminal. The switching elements are, for example, IGBTs, and the switching elements Su to Sz constitute an inverter (IGBT package) 1.

[0003] A motor M is connected to the AC side of the inverter 1 (the connection points of the switching elements Su and Sx, the connection points of the switching elements Sv and Sy, the connection points of the switching elements Sw and Sz). Also, a current sensor 2 is provided between the inverter 1 and the motor M.

[0004] The capacitor C serves to smooth the DC link voltage. Also, a discharge resistor R is connected in parallel to the capacitor C. The discharge resistor R discharges the charge of the capacitor C when the input power supply of the inverter unit is turned off. Thereby, an electric shock accident is prevented.

[0005] Note that, for the wiring in the inverter unit as shown in FIG. 12, a bus bar with low impedance and low inductance is often used. Also, a reactor may be incorporated in the inverter unit.

[0006] FIG. 13 shows a configuration of a conventional capacitor C. As shown in FIG. 13, the capacitor C includes a rectangular parallelepiped capacitor case 3 that houses capacitor elements.

Prior Art Documents

Patent Documents

[0007] [Patent Document 1] Japanese Patent Publication No. 2013-169070 [Patent Document 2] Japanese Patent Publication No. 2021-197838 [Overview of the project] [Problems that the invention aims to solve]

[0008] Capacitor C is a heat-generating component through which current constantly flows. In conventional designs, cooling of capacitor C is achieved by placing thermal conductive sheets 4 on the top and bottom surfaces of capacitor C and further connecting it to the inverter unit housing 5 via the thermal conductive sheets 4. Patent document 1 discloses prior art relating to this technology.

[0009] However, since the heat source is inside the molded capacitor (capacitor elements and internal conductors), and the generated heat is dissipated through the resin mold → capacitor case 3 → thermal conductive sheet 4 → inverter unit housing 5, there is a risk that sufficient cooling performance may not be obtained.

[0010] Furthermore, capacitor C is a large component within the inverter unit, and its heat generation becomes a bottleneck when attempting to miniaturize it. In recent years, miniaturization of individual components and the units themselves has progressed from the perspective of increasing power density through miniaturization. Consequently, thermal management within the unit has become an increasingly important issue. In conventional cooling methods, as shown in Figure 13, a thermal conductive sheet was placed on the top or bottom surface of the heat-generating component, and cooling was performed by bringing the heat-generating component into contact with the unit housing via the thermal conductive sheet. In the future, it is expected that components will be arranged more densely than before, and there is a risk that conventional cooling methods will not be able to provide sufficient cooling performance.

[0011] Based on the above, the challenge is to provide a power conversion device that improves the cooling performance of heat-generating components such as capacitors while also being easy to assemble. [Means for solving the problem]

[0012] The present invention was devised in view of the above-mentioned prior art problems, and one embodiment thereof is a power conversion device comprising a housing and a heat-generating component provided in contact with one side surface of the housing, wherein the housing comprises a refrigerant passage through which a refrigerant flows and a boss portion extending from the one side surface, the heat-generating component comprises a cooling plate on the side opposite to the side in contact with the housing, the cooling plate is joined to the housing via the boss portion, the refrigerant passage comprises an opening that opens in the one side surface of the housing, and the heat-generating component is fixed to the one side surface of the housing so as to close the opening.

[0013] According to a preferred embodiment of the present invention, the heat-generating component is a capacitor, or a reactor, or a busbar unit housing a busbar.

[0014] According to a preferred embodiment of the present invention, the heat-generating component is a reactor having two windings, and the cooling plate has a T-shaped portion having a T-shaped cross-section, the T-shaped portion having an extension that extends toward one side of the housing and is inserted into the gap between the two windings.

[0015] Another preferred embodiment of the present invention is a power conversion device comprising a heat-generating component and a liquid-cooled heat sink through which a coolant flows, wherein the liquid-cooled heat sink has a boss portion extending from the side in contact with the heat-generating component, the heat-generating component has a cooling plate on the side opposite to the side in contact with the liquid-cooled heat sink, and the cooling plate is joined to the liquid-cooled heat sink via the boss portion. [Effects of the Invention]

[0016] According to the present invention, it is possible to provide a power conversion device that improves the cooling performance of heat-generating components while also being easy to assemble. [Brief explanation of the drawing]

[0017] [Figure 1] A diagram showing the configuration of the power conversion device in Example 1. [Figure 2] Comparison diagram showing the configurations of a capacitor according to the prior art and the capacitor of Example 1. [Figure 3] Diagram showing the manner of assembling the cooling plate in the capacitor of Example 1. [Figure 4] Diagram showing the configuration of the housing of Example 1. [Figure 5] Cross-sectional view of the power conversion device along the dashed line A-A shown in FIG. 1, and diagram showing the heat dissipation path of the capacitor in Example 1. [Figure 6] Exploded view showing the configuration of the power conversion device in a modification of Example 1. [Figure 7] Diagram showing the configuration of the power conversion device in Example 2. [Figure 8] Exploded view showing the internal configuration of the power conversion device in Example 2. [Figure 9] Cross-sectional view of the power conversion device along the dashed line B-B shown in FIG. 7, and diagram showing the heat dissipation path of the reactor in Example 2. [Figure 10] Diagram showing the configuration of the power conversion device in Example 3. [Figure 11] Exploded view showing the internal configuration of the power conversion device in Example 3. [Figure 12] Electrical circuit diagram of a general inverter unit. [Figure 13] Diagram showing the configuration of a capacitor according to the prior art. [Embodiments for Carrying Out the Invention]

[0018] Hereinafter, Examples 1 to 3 of the power conversion device in the present invention will be described in detail based on FIGS. 1 to 11.

[0019] [Example 1] Example 1 relates to the cooling of a capacitor mounted on a power converter. Figure 1 shows the configuration of the power converter in Example 1. Figure 2 shows the configuration of the capacitor 10 in Example 1 in comparison with a conventional capacitor C. Figure 3 shows the method of assembling the cooling plate 13 on the capacitor 10. Figure 4 shows the configuration of the housing 15 in Example 1. Figure 5 is a cross-sectional view of the power converter along the dashed line AA shown in Figure 1, showing the heat dissipation path from the capacitor 10 in Example 1.

[0020] As shown in Figure 1, the power conversion device in Embodiment 1 comprises a housing 15 and a capacitor 10 installed on one side of the housing 15. The configurations of the capacitor 10 and the housing 15 will be described below.

[0021] <Capacitor Configuration> Figure 2 shows an existing capacitor C in (a) and a capacitor 10 of Example 1 in (b). The existing capacitor C comprises a rectangular parallelepiped capacitor case 3 housing a capacitor element which is a heat-generating element, and electrode terminals 6 exposed from the capacitor case 3. The capacitor 10 of Example 1 comprises a rectangular parallelepiped capacitor case 11 housing a capacitor element 10a (see Figure 3) which is a heat-generating element, electrode terminals 12 exposed from the capacitor case 11, and a cooling plate 13.

[0022] The cooling plate 13 is a substantially flat member made of a material with high thermal conductivity, and comprises a main body portion 13a housed inside the capacitor case 11 together with the capacitor element 10a, and a terminal portion 13b exposed from the capacitor case 11.

[0023] The side of the capacitor case 11 opposite to the side in contact with the housing 15 (the top surface in Figures 1-3) has a rectangular opening. Of the four sides of the opening, the terminal portion 13b of the cooling plate 13 is exposed from a pair of opposing sides, and the electrode terminals 12 of the capacitor element 10a are exposed from the other two sides.

[0024] When assembling the cooling plate 13 in the capacitor 10, as shown in Figure 3, resin is filled into the capacitor case 11 where the capacitor element 10a, electrode terminals 12, and cooling plate 13 are placed, and the electrode terminals 12 (P terminal, N terminal) of the capacitor element 10a and the cooling plate 13 are fixed in an electrically insulated state.

[0025] <Housing Configuration> The housing 15 of the power converter is configured to cool the liquid-cooled surface of the condenser 10 that is in contact with the housing 15 (the lower surface of the condenser 10 in Figures 1-3) by passing a refrigerant such as cooling water through its interior. As shown in Figure 4, the housing 15 includes a pair of refrigerant inlets 17a and 17b that serve as a supply port and a discharge port for the refrigerant, a refrigerant passage 18 that connects the refrigerant inlets 17a and 17b and serves as a refrigerant flow path, and four cylindrical parts (bosses) 16 that stand vertically from the surface of the housing 15 that is in contact with the condenser 10 (the upper surface in Figures 1 and 4).

[0026] The air passages 17a and 17b are located opposite each other in the direction of refrigerant flow and are through-holes that connect the inside and outside of the housing 15.

[0027] The refrigerant passage 18 has a rectangular opening 18a on the surface of the housing 15 that is in contact with the condenser 10. When assembling the condenser 10 to the housing 15, this opening 18a is closed off by the liquid-cooled surface of the condenser 10. As a result, the refrigerant flowing through the refrigerant passage 18 comes into direct contact with the liquid-cooled surface of the condenser 10 and cools it. In other words, the housing 15 in the power converter of Embodiment 1 is configured to cool the condenser 10 by direct liquid cooling.

[0028] The opening 18a of the refrigerant passage 18 is located on the surface of the housing 15 that contacts the condenser 10, closer to the center than the four cylindrical portions 16, and has approximately the same area as the liquid-cooled surface of the condenser 10.

[0029] The bottom surface of the refrigerant passage 18 (the surface opposite to the opening 18a) may have a shape that is partially raised toward the opening 18a, for example, as shown in Figures 4 and 5, in order to more reliably bring the refrigerant into contact with the liquid-cooled surface of the condenser 10.

[0030] The four cylindrical sections 16 are used to fix the capacitor 10 to the housing 15. Specifically, each of the four cylindrical sections 16 has a screw hole, and the terminal section 13b of the cooling plate 13 is fixed to the cylindrical section 16 by screws 14. In addition, as will be described later, the four cylindrical sections 16 also function as part of the heat dissipation path through the cooling plate 13.

[0031] <Cooling Method> Based on Figure 5, the cooling method of the capacitor 10 in Example 1 will be described.

[0032] The dashed arrows in Figure 5 indicate the flow of heat conduction discharged through the cooling plate 13. In other words, the heat generated inside the capacitor 10 (capacitor element 10a, etc.) is discharged to the housing 15 via the resin mold (short distance) → cooling plate 13 → cylindrical section 16.

[0033] In a conventional capacitor C configuration, the heat generated internally is discharged to the housing 5 via the resin mold (at a distance) → capacitor case 3 → thermal conductive sheet 4.

[0034] Therefore, in the configuration of Example 1, the heat dissipation path is shorter than in the conventional configuration (due to the reduction in the distance of the resin mold and the omission of the capacitor case 3), and heat can be efficiently discharged to the housing 15 via the cooling plate 13, which has high thermal conductivity.

[0035] The dotted arrows in Figure 5 indicate the flow of refrigerant inside the housing 15. In this way, the refrigerant flows through the refrigerant passage 18 and cools the condenser 10 by directly contacting the liquid-cooled surface of the condenser 10 through the opening 18a of the refrigerant passage 18. In addition, the heat discharged to the housing 15 through the cooling plate 13 via the path of the dashed arrow is also discharged to the outside of the housing 15 by the refrigerant flowing through the refrigerant passage 18.

[0036] As described above, in Embodiment 1, the condenser 10 is provided with a cooling mechanism using direct liquid cooling via a refrigerant passage 18 on the liquid-cooled side and a cooling mechanism using a cooling plate 13 on the opposite side of the liquid-cooled side. These two cooling mechanisms work together to efficiently cool the condenser 10. In particular, the provision of a cooling mechanism using direct liquid cooling via a refrigerant passage 18 allows for more powerful cooling of the condenser 10.

[0037] The opening 18a of the refrigerant passage 18 is located on the housing 15 closer to the center than the four cylindrical portions 16, and has approximately the same area as the liquid-cooled surface of the condenser 10. This allows for a larger contact area between the condenser 10 and the refrigerant, thereby increasing cooling efficiency.

[0038] The terminal portion 13b of the cooling plate 13 and the electrode terminal 12 of the capacitor element 10a are exposed to the outside from different sides of the opening in the capacitor case 11. This facilitates the design and assembly of the assembly structure of the terminal portion 13b of the cooling plate 13 in the capacitor 10.

[0039] In Embodiment 1, the only task required when assembling the capacitor 10 into the housing 15 is to fix the terminal portion 13b of the cooling plate 13 to the cylindrical portion 16. In other words, there is no need to install a thermal conductive sheet or the like between the capacitor 10 and the housing 15, which simplifies the assembly process.

[0040] According to Embodiment 1 configured as described above, it is possible to provide a power conversion device that improves the cooling capacity of the heat-generating component, the capacitor, while also being easy to assemble.

[0041] <Modification> Figure 6 is an exploded view of a power conversion device showing a modification of Example 1. This modification is an example in which the cooling mechanism provided on the liquid-cooled side of the capacitor 10 in Example 1 is replaced from direct liquid cooling by the refrigerant passage 18 to indirect liquid cooling by the liquid-cooled heat sink 170, which will be described later.

[0042] In this modified example, some configurations of the power converter housing 150 differ from those in Embodiment 1. Specifically, the housing 150 does not have a refrigerant passage 18 and refrigerant outlets 17a and 17b, but instead has a liquid-cooled heat sink 170. The liquid-cooled heat sink 170 has a cylindrical portion (boss portion) 16 extending from the side in contact with the capacitor 10.

[0043] The liquid-cooled heatsink 170 is a cooling mechanism through which a refrigerant flows. However, unlike in Embodiment 1, the housing 150 does not have an opening on the surface that contacts the condenser 10. Therefore, in the liquid-cooled heatsink 170, the refrigerant does not directly contact the liquid-cooled surface of the condenser 10, but rather cools the liquid-cooled side of the condenser 10 via the wall surface of the liquid-cooled heatsink 170 that contacts the condenser 10.

[0044] In the example shown in Figure 6, a thermal conductive sheet 160 is provided between the capacitor 10 and the liquid-cooled heat sink 170, and the capacitor 10 is joined to the liquid-cooled heat sink 170 via the thermal conductive sheet 160. This further increases the cooling efficiency of the liquid-cooled side of the capacitor 10 by the liquid-cooled heat sink 170. This thermal conductive sheet 160 can be omitted depending on the configuration of the power conversion device. This modified example is useful when it is difficult to provide a refrigerant passage 18 in the housing 150.

[0045] In this modified example, as described above, a cooling mechanism using indirect liquid cooling with a liquid-cooled heat sink 170 is provided on the liquid-cooled side of the capacitor 10, and a cooling mechanism using a cooling plate 13 is provided on the side opposite to the liquid-cooled side. Therefore, similar to Example 1, the capacitor 10 can be efficiently cooled by the cooperation of the two cooling mechanisms. In particular, by providing a cooling mechanism using indirect liquid cooling with a liquid-cooled heat sink 170, the capacitor 10 can be cooled very effectively.

[0046] Furthermore, in this modified example, the configuration of the capacitor 10 is the same as in Example 1, and since the terminal portion 13b of the cooling plate 13 and the electrode terminal 12 of the capacitor element 10a are exposed to the outside from different sides of the opening of the capacitor case 11, the design and assembly work of the assembly structure of the terminal portion 13b of the cooling plate 13 in the capacitor 10 becomes easier.

[0047] [Example 2] Example 2 relates to the cooling of a reactor mounted on a power converter. Figure 7 shows the configuration of the power converter in Example 2. Figure 8 is an exploded view showing the internal configuration of the power converter in Example 2. Figure 9 is a cross-sectional view of the power converter along the dashed line BB shown in Figure 7, showing the heat dissipation path from the reactor 20 in Example 2. Hereafter, the same reference numerals are used for components similar to those in Example 1, and their descriptions are omitted.

[0048] As shown in Figures 7 and 8, the power conversion device in Embodiment 2 comprises a housing 15 and a reactor 20 installed on one side of the housing 15.

[0049] The housing 15 in Embodiment 2 is substantially the same as that in Embodiment 1, and includes refrigerant outlets 17a, 17b and a refrigerant passage 18 for direct liquid cooling of the liquid-cooled surface of the reactor 20 (the lower surface of the reactor 20 in Figures 7 and 8), and four cylindrical parts (bosses) 16 for fixing the reactor 20. In addition, the housing 15 of Embodiment 2 is provided with screw holes for receiving screws 14b for fixing the reactor case 23, which will be described later, to the housing 15.

[0050] The reactor 20 comprises two windings 21, one for the positive electrode and one for the negative electrode; an annular iron core 22 that penetrates the center of both windings 21; a substantially rectangular parallelepiped reactor case 23 that houses the two windings 21 and the iron core 22; two electrode terminals 24a and 24b that are connected to the two windings 21 respectively and exposed from the reactor case 23; and a cooling plate 25 provided on the side of the reactor 20 opposite to the liquid-cooled surface. The reactor case 23 is filled with resin to fix the windings 21 and the iron core 22 in place.

[0051] The reactor case 23 is fixed to the housing 15 by screws 14b at its four corners on the liquid-cooled side. The side of the reactor case 23 opposite the liquid-cooled side has a rectangular opening, through which the electrode terminals 24a and 24b are exposed to the outside of the reactor case 23.

[0052] The cooling plate 25 comprises a T-shaped portion 25a having a roughly T-shaped cross-section and a terminal portion 25b extending outward from the reactor case 23.

[0053] The T-shaped portion 25a consists of a horizontal portion 25aa that is horizontal to the liquid-cooled surface of the reactor 20, and an extension portion 25ab that extends perpendicularly from the horizontal portion 25aa toward the liquid-cooled surface and is inserted between the two windings 21 within the reactor case 23.

[0054] The terminal portion 25b is fixed to the four cylindrical portions 16 of the housing 15 by screws 14a. The terminal portion 25b extends outward from the reactor case 23 from a side of the reactor case 23 that is different from the side of the reactor case 23 from which the electrode terminals 24a and 24b are exposed.

[0055] Figure 9 shows the cooling method of the reactor 20 in the power conversion device of Example 2.

[0056] The dashed arrows in Figure 9 indicate the flow of heat conduction discharged through the cooling plate 25. The heat generated in the two windings 21 is discharged to the housing 15 via the T-shaped portion 25a of the cooling plate 25 → the terminal portion 25b of the cooling plate 25 → the cylindrical portion 16.

[0057] The dotted arrows in Figure 9 indicate the flow of refrigerant inside the housing 15. In this way, the refrigerant flows through the refrigerant passage 18 and cools the reactor 20 by directly contacting the liquid-cooled surface of the reactor 20 through the opening 18a of the refrigerant passage 18. In addition, the heat discharged to the housing 15 through the cooling plate 25 via the path of the dashed arrow is also discharged to the outside of the housing 15 by the refrigerant flowing through the refrigerant passage 18.

[0058] Thus, in Embodiment 2, a cooling mechanism using direct liquid cooling via a refrigerant passage 18 is provided on the liquid-cooled side of the reactor 20, and a cooling mechanism using a cooling plate 25 is provided on the side opposite to the liquid-cooled side. These two cooling mechanisms work together to efficiently cool the reactor 20.

[0059] In particular, by providing a cooling mechanism using direct liquid cooling via the refrigerant passage 18, the reactor 20 can be cooled more powerfully. Generally, a large current flows through the windings of a reactor, and the resulting copper and iron losses tend to cause high temperatures, so direct liquid cooling is effective.

[0060] The opening 18a of the refrigerant passage 18 is located on the surface of the housing 15 that contacts the reactor 20, closer to the center than the four cylindrical portions 16, as in Embodiment 1, and has approximately the same area as the liquid-cooled surface of the reactor 20. This allows for a larger contact area between the reactor 20 and the refrigerant, thereby increasing cooling efficiency. In particular, when two windings are provided as in Embodiment 2, the reactor case becomes larger, so a configuration that allows for a larger contact area with the refrigerant is effective.

[0061] In addition, in Embodiment 2, a T-shaped portion 25a is provided on the cooling plate 25. Generally, when a reactor is used in the DC section of a power converter, windings are often provided on both the electrode terminal 24a side and the 24b side, as in Embodiment 2. In Embodiment 2, since the extension portion 25ab of the T-shaped portion 25a is inserted into the gap between the two windings 21 on the positive and negative sides, heat is easily transferred from the windings 21 to the cooling plate 25, thereby increasing the cooling efficiency of the reactor 20.

[0062] The terminal portion 25b of the cooling plate 25 and the electrode terminals 24a and 24b of the winding 21 extend outward or are exposed from different sides of the opening of the reactor case 23. This facilitates the design and assembly of the assembly structure of the terminal portion 25b of the cooling plate 25 in the reactor 20.

[0063] In Example 2, the only work required when assembling the reactor 20 to the housing 15 is to fix the terminal portion 25b of the cooling plate 25 and the reactor case 23 to the housing 15. In other words, there is no need to install a thermal conductive sheet or the like between the reactor 20 and the housing 15, which simplifies the assembly process.

[0064] According to Embodiment 2 configured as described above, it is possible to provide a power conversion device that improves the cooling capacity of the reactor, which is a heat-generating element, while also being easy to assemble.

[0065] [Example 3] Example 3 relates to the cooling of busbars mounted on a power converter. Figure 10 shows the configuration of the power converter in Example 3. Figure 11 is an exploded view showing the internal configuration of the power converter in Example 3. Hereafter, components similar to those in Examples 1 and 2 will be given the same reference numerals and their descriptions will be omitted.

[0066] As shown in Figures 10 and 11, the power conversion device in Embodiment 3 comprises a housing 35 and a busbar unit 30 installed on one side of the housing 35.

[0067] The housing 35 in Embodiment 3 is similar to the housing 15 in Embodiment 1 and includes refrigerant outlets 17a, 17b and a refrigerant passage 18 for direct liquid cooling of the liquid-cooled surface of the busbar unit 30 (the lower surface of the busbar unit 30 in Figures 10 and 11), and two cylindrical parts (bosses) 16 for fixing the busbar unit 30.

[0068] The busbar unit 30 comprises three rectangular flat busbars 31, a rectangular flat cooling plate 32, and a rectangular parallelepiped busbar case 33 that partially houses the busbars 31 and the cooling plate 32. The busbar case 33 is filled with resin to fix the busbars 31 and the cooling plate 32 in place.

[0069] Each busbar 31 penetrates the busbar case 33 in a direction perpendicular to the longitudinal direction of the busbar case 33, and both ends of each busbar 31 in this penetrating direction are exposed to the outside of the busbar case 33.

[0070] The cooling plate 32 penetrates the busbar case 33 in the longitudinal direction of the busbar case 33, and both ends of the cooling plate 32 in this penetrating direction are exposed to the outside of the busbar case 33. The exposed ends of the cooling plate 32 are fixed to the two cylindrical parts 16 of the housing 35 by screws 14.

[0071] Inside the busbar case 33, the busbar 31 and the cooling plate 32 are in a torsional position relative to each other, with the busbar 31 positioned closer to the liquid-cooled surface of the busbar unit 30.

[0072] In the power converter of Example 3, the heat generated by the busbar 31 is transferred to the cooling plate 32 and discharged to the housing 35 via the cylindrical portion 16.

[0073] Furthermore, similar to Examples 1 and 2, the refrigerant flows through the refrigerant passage 18 of the housing 35 and cools the busbar unit 30 by directly contacting the liquid-cooled surface of the busbar unit 30 through the opening 18a of the refrigerant passage 18, thereby cooling the busbar unit 30 and the busbar 31. The heat discharged to the housing 35 through the cooling plate 32 is also discharged to the outside of the housing 35 by the refrigerant flowing through the refrigerant passage 18.

[0074] Thus, in Embodiment 3, a cooling mechanism using a refrigerant passage 18 is provided on the liquid-cooled side of the busbar unit 30, and a cooling mechanism using a cooling plate 32 is provided on the side opposite to the liquid-cooled side. These two cooling mechanisms work together to efficiently cool the busbar unit 30 and, consequently, the busbar 31.

[0075] In particular, the cooling mechanism provided by the refrigerant passage 18 allows for more powerful cooling of the busbar 31. Generally, large currents flow through busbars, and the associated losses tend to cause them to become hot, so direct liquid cooling of the busbar unit is effective.

[0076] The opening 18a of the refrigerant passage 18 of the housing 35 is located on the surface of the housing 35 that contacts the busbar unit 30, closer to the center than the two cylindrical portions 16, as in Embodiments 1 and 2, and has approximately the same area as the liquid-cooled surface of the busbar unit 30. This allows for a wider contact area between the busbar unit 30 and the refrigerant, thereby increasing cooling efficiency.

[0077] Both ends of the cooling plate 32 are exposed to the outside of the busbar case 33. Furthermore, the cooling plate 32 and the busbar 31 are exposed to the outside from different sides of the busbar case 33. This facilitates the design and assembly of the assembly structure of both ends of the cooling plate 32 in the busbar unit 30.

[0078] In Example 3, the only work required when assembling the busbar unit 30 to the housing 35 is to fix both ends of the cooling plate 32 to the cylindrical portion 16. In other words, there is no need to install a heat conductive sheet or the like between the busbar unit 30 and the housing 35, which simplifies the assembly process.

[0079] According to Embodiment 3 configured as described above, it is possible to provide a power conversion device that improves the cooling capacity of the busbar, which is a heat-generating element, while also being easy to assemble.

[0080] Although the present invention has been described in detail only with respect to the specific examples described above, it will be obvious to those skilled in the art that a wide variety of modifications and alterations are possible within the scope of the technical concept of the present invention, and it is natural that such modifications and alterations fall within the scope of the claims.

[0081] For example, in Examples 2 and 3, a housing equipped with a refrigerant passage for direct liquid cooling was used, similar to Example 1. However, this may be replaced with a housing equipped with a liquid cooling heat sink for indirect liquid cooling, similar to a modified example of Example 1.

[0082] Furthermore, for heat-generating components other than capacitors, reactors, and busbars, housings with direct or indirect liquid cooling functions, as shown in Examples 1 to 3, may be used. [Explanation of symbols]

[0083] 10…Capacitor 10a... Capacitor element 11... Capacitor case 12...Electrode terminal 13…Cooling plate 13a...Main body 13b...Terminal section 14... screw 15…Cabinet 16…Cylindrical section (boss section) 17a, 17b...refrigerant flow port 18…Refrigerant passage 18a...Opening 150... cabinet 160... Thermal conductive sheet 170... Refrigerant passage 20… Reactor 21...winding 22...Tetsushin 23… Reactor case 24a, 24b...electrode terminal 25…Cooling plate 25a…T-shaped part 25b…Terminal section 30... Busbar Unit 31... Bus bar 32…Cooling plate 33…Bus bar case 35... Cabinet

Claims

1. A power conversion device comprising a housing and a heat-generating component provided in contact with one side surface of the housing, The housing comprises a refrigerant passage through which the refrigerant flows, and a boss portion extending from one side surface. The heat-generating component is provided with a cooling plate on the side opposite to the side in contact with the housing. The cooling plate is joined to the housing via the boss portion, The refrigerant passage has an opening that is made on one side of the housing, The power conversion device is characterized in that the heat-generating component is fixed to one side of the housing so as to close the opening.

2. The power conversion device according to claim 1, characterized in that the heat-generating component is a capacitor, or a reactor, or a busbar unit housing a busbar.

3. The aforementioned heat-generating component is a reactor with two windings. The cooling plate has a T-shaped section with a T-shaped cross-section, The power conversion device according to claim 1, characterized in that the T-shaped portion extends toward one side of the housing and has an extension portion inserted into the gap between the two windings.

4. A power conversion device comprising a heat-generating component and a liquid-cooled heat sink through which a refrigerant flows, The liquid-cooled heat sink includes a boss portion extending from the side in contact with the heat-generating component, The heat-generating component is provided with a cooling plate on the side opposite to the side in contact with the liquid-cooled heat sink. The power conversion device is characterized in that the cooling plate is joined to the liquid-cooled heat sink via the boss portion.

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