Power converter

Abstract

To provide a power conversion device that can improve the cooling effect of capacitors. [Solution] The power conversion device comprises a capacitor having first and second terminal electrodes facing each other, a power module having a power semiconductor element, a terminal block for electrically connecting the capacitor and the power module to each other, first and second busbars connecting the first and second terminal electrodes to the terminal block, respectively, and a plate member on which the capacitor, power module, and terminal block are placed and which has a flow path for a cooling medium that cools the capacitor and the terminal block. The capacitor has the first terminal electrode facing the flow path side and the second terminal electrode facing the opposite side of the flow path. The terminal block has a first connection part connected to the first busbar and a second connection part connected to the second busbar, the thermal conductivity between the capacitor and the flow path is higher than that of the first connection part.

Description

Technical Field

[0001] The present invention relates to a power conversion device.

Background Art

[0002] Regarding a power conversion device, for example, Patent Document 1 describes placing a capacitor having a pair of end face electrodes facing each other and a semiconductor module connected to the capacitor by a bus bar on a cooler. The capacitor is placed on the cooler with one end face electrode facing the cooler side and the other end face electrode facing the side opposite to the cooler.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] In the capacitor, in the region near the end face electrode on the side opposite to the cooler, there is a possibility that a sufficient cooling effect cannot be obtained because it is far from the cooler compared to the region near the end face electrode on the cooler side.

[0005] Therefore, the present invention has been made in view of the above problems, and an object thereof is to provide a power conversion device capable of improving the cooling effect of a capacitor.

Means for Solving the Problems

[0006] The power conversion device of the present invention comprises a capacitor having a first terminal electrode and a second terminal electrode facing each other, a power module having one or more power semiconductor elements, a terminal block for electrically connecting the capacitor and the power module, a first busbar connecting the first terminal electrode and the terminal block, a second busbar connecting the second terminal electrode and the terminal block, and a plate member on which the capacitor, the power module, and the terminal block are placed and which has a flow path for a cooling medium that cools the capacitor and the terminal block, wherein the capacitor has its first terminal electrode facing the flow path side, and the terminal block has a first connection part connected to the first busbar and a second connection part connected to the second busbar, the thermal conductivity between the capacitor and the flow path is higher than that of the first connection part.

[0007] In the power conversion device described above, the connection position between the second connection part and the second busbar may be closer to the flow path than the connection position between the first connection part and the first busbar.

[0008] In the power conversion device described above, the first connection portion has a first nut on which the first busbar is fastened by a bolt, with the axial end face of the first nut facing the flow path, and the second connection portion has a second nut on which the second busbar is fastened by a bolt, with the axial end face of the second nut facing the flow path, and the area of ​​the end face of the second nut may be larger than the area of ​​the end face of the first nut.

[0009] In the power conversion device described above, the first connection portion has a first nut into which the first busbar is fastened with a bolt, with the axial end face of the first nut facing the flow path. The second connection portion has a second nut into which the second busbar is fastened by a bolt, with the axial end face of the second nut facing the flow path, and the thermal conductivity of the second nut may be higher than that of the first nut.

[0010] In the power conversion device described above, the first connection portion is provided with a first nut on which the first busbar is fastened by bolts, the axial end face of the first nut being embedded toward the flow path, and a first sheet member sandwiched between the end face of the first nut and the plate surface of the plate member; the second connection portion is provided with a second nut on which the second busbar is fastened by bolts, the axial end face of the second nut being embedded toward the flow path, and a second sheet member sandwiched between the end face of the second nut and the plate surface of the plate member; the thermal conductivity of the second sheet member may be higher than that of the first sheet member. [Effects of the Invention]

[0011] According to the present invention, the cooling effect of a capacitor in a power conversion device can be improved. [Brief explanation of the drawing]

[0012] [Figure 1] Figure 1 is a plan view showing an example of a power conversion device from above. [Figure 2] Figure 2 is a schematic diagram showing the circuit configuration of the power converter. [Figure 3] Figure 3 is a partial cross-sectional view along line AA in Figure 1. [Figure 4] Figure 4 is a plan view showing an example of a cooling water flow path from above. [Figure 5] Figure 5 is a partial cross-sectional view along line BB in Figure 1. [Figure 6] Figure 6(A) is a partial cross-sectional view along the CC line in Figure 1. Figure 6(B) is a plan view showing an example of the underside of a terminal block in a front view. [Modes for carrying out the invention]

[0013] (Configuration of power converter) Figure 1 is a plan view showing an example of a power converter 1 from above. Note that the X, Y, and Z directions, which are orthogonal to each other, are shown in each of the subsequent figures.

[0014] The power converter 1 includes a frame 10, a film capacitor 11, terminal blocks 12 and 16, a negative-side busbar 13, a positive-side busbar 14, a power module 15, and a terminal holding part 17. The power converter 1 is used, for example, as a power control unit for electric vehicles or hybrid vehicles. Note that the upper cover, control board, noise filter, and harness of the power converter 1 are not shown in the illustration.

[0015] The frame 10 is a roughly rectangular plate member. A film capacitor 11, terminal blocks 12 and 16, a power module 15, and a terminal holder 17 are mounted on the plate surface 10a of the frame 10. Inside the frame 10, there is a flow path for cooling water, which will be described later. This allows the frame 10 to cool the film capacitor 11, terminal blocks 12 and 16, power module 15, and terminal holder 17. The frame 10 is made of a metal with high rigidity and thermal conductivity.

[0016] The film capacitor 11 is an example of a capacitor. The film capacitor 11 has a positive terminal electrode and a negative terminal electrode connected to a positive busbar 14 and a negative busbar 13, respectively. The ends 14a and 13a of the positive busbar 14 and the negative busbar 13 are located outside the positive end in the Y direction of the frame 10 and are electrically connected to the positive and negative terminals of an external battery (not shown), respectively. The positive busbar 14 and the negative busbar 13 are made of a highly conductive metal such as copper.

[0017] An insulating member 18 for preventing short circuits is held between the positive-side busbar 14 and the negative-side busbar 13. The positive-side busbar 14 is positioned on the positive side (upper part) in the Z direction of the negative-side busbar 13, with the insulating member 18 in between. The positive-side busbar 14 and the negative-side busbar 13 bend from their respective ends 14a and 13a in the positive direction in the X direction, extend between the power module 15 and the film capacitor 11 in the negative direction in the Y direction, and branch out toward the terminal electrodes of the film capacitor 11 on the positive side in the X direction and the terminal block 12 on the negative side in the X direction.

[0018] The power module 15 incorporates one or more power semiconductor devices 150. The power semiconductor device 150 is, for example, an IPM (Intelligent Power Module). The IPM includes a switching device such as an IGBT (Insulated Gate Bipolar Transistor), and a freewheeling diode connected in parallel with the switching device. In this example, six power semiconductor devices 150 function as an inverter for performing power conversion. The power module 15 is electrically connected to the positive bus bar 14 and the negative bus bar 13 at one terminal block 12, and is electrically connected to the connection terminals 171u, 171v, 171w at the other terminal block 16.

[0019] The terminal holder 17 holds two sets of rectangular flat connection terminals 171u, 171v, 171w at the upper part of the frame 10. The connection terminals 171u, 171v, 171w are connected to an external motor (not shown), and extend parallel from the negative-side end in the X direction of the frame 10 to the terminal block 16. On the other hand, the power module 15 has six terminals 153 extending to the terminal block 16. Each terminal 153 is connected to the connection terminals 171u, 171v, 171w by bolts 80 on the terminal block 16, respectively.

[0020] Also, the power module 15 has three sets of positive terminals 152 and negative terminals 151 extending to the terminal block 12 on the opposite side of the terminal block 16 in the X direction. The positive terminals 152 and the negative terminals 151 are alternately arranged in the Y direction. The terminal block 12 has three sets of positive connection parts 122 and negative connection parts 121. The positive connection parts 122 and the negative connection parts 121 are alternately arranged in the Y direction. The positive connection part 122 is connected to the positive bus bar 14, and the negative connection part 121 is connected to the negative bus bar 13. The positive connection part 122 is an example of the first connection part, and the negative connection part 121 is an example of the second connection part.

[0021] The positive-side busbar 14 and the negative-side busbar 13 each branch in two directions: towards the terminal block 12 and towards the film capacitor 11. The positive-side busbar 14 and the negative-side busbar 13 each have three connection terminals 140 and 130, respectively, that extend to the terminal block 12. Connection terminal 140 and the positive terminal 152 are fastened to the positive-side connection part 122 by bolts 90, and connection terminal 130 and the negative terminal 151 are fastened to the negative-side connection part 121 by bolts 90. In this way, the terminal block 12 is used to electrically connect the film capacitor 11 and the power module 15 to each other.

[0022] Figure 2 is a schematic diagram showing the circuit configuration S of the power converter 1. The power converter 1 is connected between a battery E, such as a lithium-ion battery, and a motor MG. The motor MG is used, for example, as a power source for a vehicle. The end 14a of the positive-side busbar 14 is connected to the positive terminal of the battery E, and the end 14a of the negative-side busbar 13 is connected to the negative terminal of the battery E. In addition, the connection terminals 171u, 171v, and 171w are connected to the three-phase coils Lu, Lv, and Lw of the motor MG, respectively.

[0023] The power module 15 has an inverter INV. The inverter INV is connected in parallel with the film capacitor 11 and the battery E via the positive terminal connection 122 and the negative terminal connection 121 of the terminal block 12. The inverter INV has switch elements SW1u, SW1v, SW1w on the upper arm side and switch elements SW2u, SW2v, SW2w on the lower arm side, corresponding to the three phases. The switch elements SW1u, SW1v, SW1w on the upper arm side and the switch elements SW2u, SW2v, SW2w on the arm side are connected in series. A rectifier diode Di is connected to each of the switch elements SW1u, SW1v, SW1w, SW2u, SW2v, SW2w. The switch elements SW1u, SW1v, SW1w, SW2u, SW2v, SW2w and the rectifier diode Di are included in the power semiconductor element 150.

[0024] Each switch element SW1u, SW1v, SW1w, SW2u, SW2v, and SW2w is controlled on / off by a PWM (Pulse Width Modulation) signal from a control board (not shown). This converts the DC current input from battery E to inverter INV into a three-phase AC current, which is then output to motor MG.

[0025] The film capacitor 11 is connected in parallel to the battery E and the inverter INV, respectively. The positive busbar 14 connects the positive terminal of the battery E, the positive terminal electrode of the film capacitor 11, and the positive connection part 122 of the terminal block 12. The negative busbar 13 connects the negative terminal of the battery E, the negative terminal electrode of the film capacitor 11, and the negative connection part 121 of the terminal block 12. In the positive busbar 14 and the negative busbar 13, the DC component Id of the current flows between the battery E and the inverter INV, and the ripple component Ia of the current flows across both terminal electrodes of the film capacitor 11. The film capacitor 11 smooths the voltage across the inverter INV.

[0026] Figure 3 is a partial cross-sectional view along line AA in Figure 1. In Figure 3, components common to Figure 1 are denoted by the same reference numerals, and their descriptions are omitted. Inside the frame 10, a cooling water flow path 100 is provided along the plate surface 10a. The film capacitor 11 has a capacitor element 110, a positive terminal electrode 112, a negative terminal electrode 111, and a case 113. The plate surface 10a of the frame 10 has a step so that the mounting position of the film capacitor 11 in the Z direction is lower than the mounting positions of the terminal block 12 and the power module 15.

[0027] The capacitor element 110 is formed by winding a resin film coated with aluminum. The positive terminal electrode 112 and the negative terminal electrode 111 are end-face electrodes, sometimes called metallicons. In the Z direction, the negative terminal electrode 111 is located on the upper surface of the capacitor element 110, and the positive terminal electrode 112 is located on the lower surface of the capacitor element 110. The positive terminal electrode 112 and the negative terminal electrode 111 face each other in the Z direction, with the capacitor element 110 in between.

[0028] As described above, the film capacitor 11 is mounted on the frame 10 with the positive terminal electrode 112 facing the cooling water flow path 100 and the negative terminal electrode 111 facing away from the flow path 100. The positive terminal electrode 112 is an example of a first terminal electrode, and the negative terminal electrode 111 is an example of a second terminal electrode. Alternatively, the film capacitor 11 may be mounted on the frame 10 with the negative terminal electrode 111 facing the flow path 100 and the positive terminal electrode 112 facing away from it. In this case, the positive terminal electrode 112 corresponds to the second terminal electrode, the negative terminal electrode 111 corresponds to the first terminal electrode, the positive terminal connection part 122 corresponds to the second connection part, and the negative terminal connection part 121 corresponds to the first connection part.

[0029] The case 113 has a roughly rectangular box shape with one side open on the terminal block 12 side. A resin 114 called potting material is filled between the case 113 and the capacitor element 110. The case 113 is formed from, for example, resin, a metal such as aluminum, or a resin coated with aluminum.

[0030] A thermal cooling sheet 20 is provided between the lower part of the case 113 and the plate surface 10a of the frame 10. The thermal cooling sheet 20 diffuses the heat from the capacitor element 110 to the plate surface 10a of the frame 10. As a result, the film capacitor 11 is cooled by the cooling water via the thermal cooling sheet 20.

[0031] Furthermore, a thermal cooling sheet 21 is provided between the negative electrode connection portion 121 of the terminal block 12 and the plate surface 10a of the frame 10. The thermal cooling sheet 21 diffuses the heat from the negative electrode connection portion 121 to the plate surface 10a of the frame 10. The terminal block 12's temperature rises not only due to the DC component of the current flowing through the positive electrode busbar 14 and the negative electrode busbar 13, but also due to the heat conducted from the film capacitor 11 through the positive electrode busbar 14 and the negative electrode busbar 13. The heat from the negative electrode connection portion 121 of the terminal block 12 is cooled by the cooling water in the flow path 100 via the thermal cooling sheet 21. Note that cooling water is just one example of a cooling medium, and other fluids may be used as the cooling medium.

[0032] Figure 4 is a plan view showing an example of a cooling water flow path 100 from above. In Figure 4, components common to Figure 1 are denoted by the same reference numerals, and their explanations are omitted.

[0033] The flow path 100 has a roughly U-shape so as to pass under the film capacitor 11, terminal block 12, and power module 15. The symbol D indicates the direction in which the cooling water flows. The inlet 100a and outlet 100b of the flow path 100 are located side by side on the positive end face in the X direction of the frame 10. The inlet 100a and outlet 100b are connected to an external pump or the like.

[0034] Referring again to Figure 3, the negative-side busbar 13 includes a connection terminal 130, an extension portion 131, and an electrode connection portion 132. The connection terminal 130 extends from the lower end of the extension portion 131 in the Z direction to the negative side in the X direction and is fastened to the negative-side connection portion 121 of the terminal block 12 by a bolt 90 together with the negative-side terminal 151 on the power module 15 side. A nut 91 is embedded inside the negative-side connection portion 121 along the Z direction. By screwing the bolt 90 into the nut 91, the connection terminal 130 and the negative-side terminal 151 overlap and are fixed to the negative-side connection portion 121 of the terminal block 12.

[0035] The extension portion 131 is a plate-shaped member that extends in the positive direction in the Y direction, and is held in a position where its plate surface is approximately perpendicular to the plate surface 10a of the frame 10. The lower end of the extension portion 131 in the Z direction is connected to the connection terminal 130, and the upper end of the extension portion 131 in the Z direction is connected to the electrode connection portion 132. The electrode connection portion 132 extends from the upper end of the extension portion 131 in the Z direction to the positive direction in the X direction and is connected to the negative electrode terminal electrode 111 in the Z direction. In this way, the negative electrode busbar 13 connects the negative electrode terminal electrode 111 and the terminal block 12.

[0036] Some of the heat from the film capacitor 11 is cooled by the cooling water via the thermocon sheet 20, as indicated by the symbol Ro, while the other portion of the heat from the film capacitor 11 is cooled by the cooling water via a cooling path Ra through the negative-side busbar 13. The cooling path Ra extends from the negative-side terminal electrode 111 through the negative-side busbar 13 to the negative-side connection portion 121 of the terminal block 12. The heat from the film capacitor 11 conducts through the cooling path Ra and diffuses from the nut 91 in the negative-side connection portion 121 through the thermocon sheet 21 to the flow path 100 inside the frame 10.

[0037] Figure 5 is a partial cross-sectional view along line BB in Figure 1. In Figure 5, components common to Figure 1 are denoted by the same reference numerals, and their descriptions are omitted.

[0038] A thermal sheet 22 is provided between the positive terminal connection portion 122 of the terminal block 12 and the plate surface 10a of the frame 10. The thermal sheet 22 dissipates the heat from the positive terminal connection portion 122 to the plate surface 10a of the frame 10.

[0039] The positive-side busbar 14 includes a connection terminal 140, an extension portion 141, and an electrode connection portion 142. The connection terminal 140 extends from the upper end in the Z direction of the extension portion 141 to the negative side in the X direction and is fastened to the positive-side connection portion 122 of the terminal block 12 by a bolt 90 together with the positive-side terminal 152 on the power module 15 side. A nut 92 is embedded inside the positive-side connection portion 122 along the Z direction. By screwing the bolt 90 into the nut 92, the connection terminal 140 and the positive-side terminal 152 overlap and are fixed to the positive-side connection portion 122 of the terminal block 12.

[0040] The extension portion 141 is a plate-shaped member extending in the Y direction, and is held in a position where its plate surface is approximately perpendicular to the plate surface 10a of the frame 10. The upper end of the extension portion 141 in the Z direction is connected to the connection terminal 140, and the lower end of the extension portion 141 in the Z direction is connected to the electrode connection portion 142. The electrode connection portion 142 extends from the lower end of the extension portion 141 in the Z direction to the positive side in the X direction and is connected to the positive electrode side terminal electrode 112 in the Z direction. In this way, the positive electrode side busbar 14 connects the positive electrode side terminal electrode 112 and the terminal block 12.

[0041] A portion of the heat from the film capacitor 11 is cooled by the cooling water via a cooling path Rb that passes through the positive-side busbar 14. The cooling path Rb extends from the positive-side terminal electrode 112 through the positive-side busbar 14 to the positive-side connection portion 122 of the terminal block 12. The heat from the film capacitor 11 is conducted through the cooling path Rb and diffused from the nut 92 in the positive-side connection portion 122 through the thermocon sheet 22 to the flow path 100 inside the frame 10.

[0042] As described above, the positive terminal electrode 112 faces the cooling water flow path 100, and the negative terminal electrode 111 faces the opposite side of the flow path 100. Therefore, in the film capacitor 11, the negative terminal electrode 111 is further from the flow path 100 than the positive terminal electrode 112. Consequently, when cooling the film capacitor 11 via the thermocon sheet 20 at the bottom of the case 113, the area near the negative terminal electrode 111 of the capacitor element 110 does not provide the same cooling effect as the area near the positive terminal electrode 112.

[0043] In contrast, at the negative electrode connection 121, the thermal conductivity between the film capacitor 11 and the cooling water flow path 100 is higher than at the positive electrode connection 122. Therefore, the terminal block 12 is equipped with a cooling structure in which the cooling performance of the cooling path Ra is higher than that of the cooling path Rb when cooling the film capacitor 11. The vicinity of the negative electrode terminal electrode 111 of the capacitor element 110 is cooled better via the cooling path Ra than the vicinity of the positive electrode terminal electrode 112. Thus, the cooling effect of the film capacitor 11 is improved. An example of the cooling structure of the terminal block 12 is given below.

[0044] (Cooling structure of terminal block) Figure 6(A) is a partial cross-sectional view along the CC line in Figure 1. Figure 6(B) is a plan view showing an example of the lower surface 12a of the terminal block 12 in a front view. In Figures 6(A) and 6(B), components common to Figures 3 and 5 are denoted by the same reference numerals, and their descriptions are omitted. The terminal block 12 is equipped with the following first to fourth cooling structures.

[0045] [First cooling structure] In the Z direction, the height H2 of the negative electrode side connection portion 121 is lower than the height H1 of the positive electrode side connection portion 122. Therefore, the distance from the connection terminal 130 of the negative electrode side busbar 13 to the flow path 100 is shorter than the distance from the connection terminal 140 of the positive electrode side busbar 14 to the flow path 100. Thus, the first cooling structure is such that the connection position between the negative electrode side connection portion 121 and the negative electrode side busbar 13 is closer to the flow path 100 than the connection position between the positive electrode side connection portion 122 and the positive electrode side busbar 14. Therefore, the cooling performance of the cooling path Ra is higher than the cooling performance of the cooling path Rb, and the thermal conductivity of the negative electrode side connection portion 121 is higher than that of the positive electrode side connection portion 122.

[0046] [Second cooling structure] A nut 91 is embedded in the negative electrode connection part 121, and a nut 92 is embedded in the positive electrode connection part 122. Each nut 91 and 92 is embedded with its axial end faces 91a and 92a facing the flow path 100. The negative electrode busbar 13 is fastened to the nut 91 by a bolt 90, and the positive electrode busbar 14 is fastened to the nut 92 by a bolt 90. The second cooling structure is such that the area of ​​the end face 91a of the nut 91 is larger than the area of ​​the end face 92a of the nut 92. For example, the diameter R1 of the nut 91 is larger than the diameter R2 of the nut 92. As a result, the thermal conductivity from the nut 91 to the flow path 100 is higher than the thermal conductivity from the nut 92 to the flow path 100. Therefore, the cooling performance of the cooling path Ra is higher than the cooling performance of the cooling path Rb, and the thermal conductivity of the negative electrode connection part 121 is higher than that of the positive electrode connection part 122. Note that nut 92 is an example of a first nut, and nut 91 is an example of a second nut. Conversely, if the film capacitor 11 is mounted on the frame 10 with the negative terminal electrode 111 facing the flow path 100 and the positive terminal electrode 112 facing the opposite side, nut 92 corresponds to a second nut and nut 91 corresponds to a first nut.

[0047] [Third cooling structure] The third cooling structure is such that the thermal conductivity of nut 91 is higher than that of nut 92. For example, nut 91 is made of copper and nut 92 is made of iron. As a result, the thermal conductivity from nut 91 to the flow path 100 is higher than the thermal conductivity from nut 92 to the flow path 100. Therefore, the cooling performance of the cooling path Ra is higher than that of the cooling path Rb, and the thermal conductivity of the negative electrode side connection part 121 is higher than that of the positive electrode side connection part 122.

[0048] [Fourth cooling structure] The fourth cooling structure is one in which the thermal conductivity of the thermocon sheet 21 is higher than that of the thermocon sheet 22. The thermocon sheet 21 is sandwiched between the end face 91a of the nut 91 and the plate surface 10a of the frame 10, and the thermocon sheet 22 is sandwiched between the end face 92a of the nut 92 and the plate surface 10a of the frame 10. The thermocon sheets 21 and 22 are formed from resins such as silicon and olefin. One of the thermocon sheets 21 has inorganic fillers such as boron nitride and alumina added to it. As a result, the thermal conductivity of the thermocon sheet 21 is higher than that of the thermocon sheet 22.

[0049] As a result, the thermal conductivity from nut 91 to flow path 100 is higher than the thermal conductivity from nut 92 to flow path 100. Therefore, the cooling performance of cooling path Ra is higher than that of cooling path Rb, and the thermal conductivity of the negative electrode side connection part 121 is higher than that of the positive electrode side connection part 122. Note that the thermocon sheet 22 is an example of a first sheet member, and the thermocon sheet 21 is an example of a second nut. Conversely to this example, if the film capacitor 11 is mounted on the frame 10 with the negative electrode side terminal electrode 111 facing the flow path 100 side and the positive electrode side terminal electrode 112 facing the opposite side, the thermocon sheet 22 corresponds to a second nut, and the thermocon sheet 21 corresponds to a first nut.

[0050] Furthermore, the terminal block 12 does not necessarily need to have all of the first to fourth cooling structures; it is sufficient to have at least one of them. Also, in order to suppress heat generation due to the DC component of the current, the cross-sectional area of ​​the connection terminal 130 of the negative side busbar 13 may be larger than the cross-sectional area of ​​the connection terminal 140 of the positive side busbar 14.

[0051] The embodiments described above are preferred examples of the present invention. However, the invention is not limited thereto, and various modifications are possible without departing from the spirit of the invention. [Explanation of symbols]

[0052] 1 Power converter, 10 Frame (plate member), 10a Plate surface, 11 Film capacitor (capacitor), 12, 16 Terminal block, 13 Negative side busbar (second busbar), 14 Positive side busbar (first busbar), 15 Power module, 21 Thermocon sheet (second sheet member), 22 Thermocon sheet (first sheet member), 90 Bolt, 91 Nut (second nut), 92 Nut (first nut), 91a, 92a End face, 100 Flow path, 111 Negative side terminal electrode (second terminal electrode), 112 Positive side terminal electrode (first terminal electrode), Ra, Rb Cooling path, 121 Negative side connection (second connection), 122 Positive side connection (first connection)

Claims

1. A capacitor having a first terminal electrode and a second terminal electrode facing each other, A power module having one or more power semiconductor elements, A terminal block for electrically connecting the capacitor and the power module, A first busbar connecting the first terminal electrode and the terminal block, A second busbar connecting the second terminal electrode and the terminal block, The capacitor, the power module, and the terminal block are mounted on a plate member, which has a flow path for a cooling medium to cool the capacitor and the terminal block. The capacitor is mounted on the plate member with the first terminal electrode facing the flow path side and the second terminal electrode facing the opposite side of the flow path. The aforementioned terminal block is A first connection part connected to the first busbar, The second busbar is connected to the second connection portion, and the thermal conductivity between the capacitor and the flow path is higher than that of the first connection portion. Power converter.

2. The connection position between the second connection part and the second busbar is closer to the flow path than the connection position between the first connection part and the first busbar. The power conversion device according to claim 1.

3. The first connection portion has a first nut into which the first busbar is fastened by a bolt, with the axial end face of the first nut facing the flow path. The second connection portion has a second nut into which the second busbar is fastened by a bolt, with the axial end face of the second nut facing the flow path. The area of ​​the end face of the second nut is larger than the area of ​​the end face of the first nut. The power conversion device according to claim 1.

4. The first connection portion has a first nut into which the first busbar is fastened by a bolt, with the axial end face of the first nut facing the flow path. The second connection portion has a second nut into which the second busbar is fastened by a bolt, with the axial end face of the second nut facing the flow path. The thermal conductivity of the second nut is higher than that of the first nut. The power conversion device according to claim 1.

5. The first connection portion is provided with a first nut on which the first busbar is fastened by a bolt, the axial end face of the first nut is embedded facing the flow path, and a first sheet member is sandwiched between the end face of the first nut and the plate surface of the plate member. The second connecting portion is provided with a second nut on which the second busbar is fastened by a bolt, the axial end face of the second nut being embedded toward the flow path, and a second sheet member sandwiched between the end face of the second nut and the plate surface of the plate member. The thermal conductivity of the second sheet member is higher than that of the first sheet member. The power conversion device according to claim 1.

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