Power converter

Abstract

To obtain a miniaturized power conversion device while ensuring vibration resistance. [Solution] The power converter comprises a main circuit component body, a main circuit busbar connected to the main circuit component body, and a main circuit component having a board connection terminal on one side connected to the main circuit busbar, and a board connected to the other side of the board connection terminal, wherein the board is positioned in the first direction of the main circuit component, and the Young's modulus of the board connection terminal is greater than the Young's modulus of the main circuit busbar.

Description

Technical Field

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

Background Art

[0002] Electrified vehicles such as hybrid vehicles (HV), plug-in hybrid vehicles (PHV, PHEV), electric vehicles (EV), and fuel cell vehicles (FCV) are equipped with a power conversion device, which is a component for electrification. Examples of the power conversion device include an inverter that converts DC power from a battery into AC power for a motor and supplies the AC power to the driving motor, and a converter that boosts the voltage of the battery. In recent years, there has been a demand for cost reduction of the power conversion device.

[0003] In addition, in HV, PHV, and PHEV, in addition to the engine, a power conversion device is mounted in the engine room. Therefore, there is a tendency to require a small-sized power conversion device. Also, in EV, a drive motor and an inverter may be mounted on the rear side, and there is a tendency to require a small-sized power conversion device in order to secure the trunk room and the passenger living space.

[0004] In recent years, for the purpose of shortening the connection harness of each power conversion device, the number of cases of each power conversion device is reduced, and for the purpose of cost reduction and miniaturization, direct rigid connection of a power conversion device such as an inverter to a case of a motor, an engine, or a transmission is increasing. Therefore, the internal components of the power conversion device are required to withstand severe vibration specifications.

[0005] For example, in a power converter that is a motor control unit, a circuit board equipped with a control circuit for controlling the motor and a smoothing capacitor are provided inside. If an X capacitor for EMC noise suppression is provided on the circuit board, a terminal for electrically connecting the smoothing capacitor near the DC input to the circuit board is provided on the smoothing capacitor. Also, for power module control, a terminal for electrically connecting the smoothing capacitor to the circuit board is provided on the smoothing capacitor.

[0006] Under demanding vibration conditions, terminals can be damaged. Therefore, it is necessary to implement vibration countermeasures on the terminals themselves to meet high vibration requirements. Generally, structures that can withstand demanding vibration specifications are disclosed that incorporate a low-rigidity structure on the terminal itself to alleviate stress (see, for example, Patent Document 1). In the structure disclosed in Patent Document 1, a low-rigidity structure is provided on the lead, which is the terminal connecting the capacitor cell and the conductor plate. As a result, the vibration resistance of the lead is improved. [Prior art documents] [Patent Documents]

[0007] [Patent Document 1] Japanese Patent Publication No. 2017-28747 [Overview of the project] [Problems that the invention aims to solve]

[0008] In the above-mentioned Patent Document 1, a low-rigidity structure is provided on the terminal itself that is connected to other components, thereby improving the vibration resistance of the terminal itself. However, although damage to the terminal with improved vibration resistance can be prevented, there was a problem in that the vibration resistance of other components, such as the circuit board connected to the terminal, deteriorated. Adding new components to improve the vibration resistance of other components resulted in the problem of increasing the size of the power conversion device.

[0009] Therefore, the purpose of this disclosure is to obtain a power conversion device that is miniaturized while ensuring vibration resistance. [Means for solving the problem]

[0010] The power conversion device of this disclosure comprises a main circuit component body, a main circuit busbar connected to the main circuit component body, and a main circuit component having a board connection terminal on one side connected to the main circuit busbar, and a board connected to the other side of the board connection terminal, wherein the board is arranged in the first direction of the main circuit component, and the Young's modulus of the board connection terminal is greater than the Young's modulus of the main circuit busbar. [Effects of the Invention]

[0011] The power converter of this disclosure comprises a main circuit component body, a main circuit busbar connected to the main circuit component body, and a main circuit component having a board connection terminal with one side connected to the main circuit busbar, and a board connected to the other side of the board connection terminal. The board is positioned in the first direction of the main circuit component, and the Young's modulus of the board connection terminal is greater than that of the main circuit busbar. As a result, the rigidity of the board connection terminal is greater than that of the main circuit busbar, and the board connection terminal can withstand stringent vibration specifications, thereby improving the vibration resistance of the board connection terminal. The vibration resistance of the board connection terminal is improved, and the board connection terminal also acts as a support member for the board, thus improving the vibration resistance of the board connected to the board connection terminal. As the vibration resistance of the board connection terminal and the board is improved, the vibration resistance of the power converter can be ensured. Furthermore, as the vibration resistance of the board is improved, the number of screws or bolts used to fix the board can be reduced, thus reducing the projected area of ​​the board and allowing the power converter to be miniaturized. [Brief explanation of the drawing]

[0012] [Figure 1] This is an exploded perspective view showing a schematic of the power conversion device according to Embodiment 1. [Figure 2] This is a perspective view showing an outline of the power conversion device according to Embodiment 1. [Figure 3] This is a cross-sectional view of the power converter taken at the AA section in Figure 2. [Figure 4]This is a cross-sectional view of another power converter taken at cross-sectional position AA in Figure 2. [Figure 5] This figure shows an example of the connection of a power converter according to Embodiment 1. [Figure 6] This is a side view showing another board connection terminal of the power converter according to Embodiment 1. [Figure 7] This is a perspective view showing another board connection terminal of the power converter according to Embodiment 1. [Figure 8] This figure shows an example of the installation state of the power converter according to Embodiment 1. [Modes for carrying out the invention]

[0013] The power conversion device according to the embodiment of this disclosure will be described below with reference to the figures. In each figure, the same or equivalent components and parts will be denoted by the same reference numerals.

[0014] Embodiment 1. Figure 1 is an exploded perspective view showing a schematic of the power converter 1 according to Embodiment 1, Figure 2 is a schematic perspective view showing the power converter 1, Figure 3 is a cross-sectional view of the power converter 1 cut at the AA cross-section position in Figure 2, Figure 4 is a cross-sectional view of another power converter 1 cut at the AA cross-section position in Figure 2, Figure 5 is a diagram showing an example of the connection of the power converter 1, Figure 6 is a side view showing another board connection terminal 2d of the power converter 1 according to Embodiment 1, Figure 7 is a perspective view showing another board connection terminal 2d of the power converter 1 according to Embodiment 1, and Figure 8 is a diagram showing an example of the installation state of the power converter 1. The power converter 1 is a device that converts input current from DC to AC, AC to DC, or input voltage to a different voltage. The power converter 1 is a device that is mounted on an electric vehicle. In this embodiment, as shown in Figure 5, the power converter 1 is connected to the power supply 10. The power module 3 of the power converter 1 converts the DC power of the power supply 10 into AC power, and outputs the converted three-phase AC power to the rotating electric machine 11. In this embodiment, the power converter 1 is an in-vehicle inverter. Note that the configuration of the power converter 1 is not limited to an inverter; it may also be a converter.

[0015] <Power conversion device 1> The power conversion device 1 includes a main circuit component body part, a main circuit bus bar connected to the main circuit component body part, and a main circuit component having a board connection terminal 2d with one side connected to the main circuit bus bar, and a board 4 connected to the other side of the board connection terminal 2d. In the present embodiment, the main circuit component is a capacitor 2 as shown in FIG. 1. Therefore, the main circuit component body part is a capacitor element 2b, and the main circuit bus bar is a capacitor bus bar 2a. The power conversion device 1 further includes a plurality of power modules 3. In the present embodiment, the power conversion device 1 includes three power modules 3, but the number of power modules 3 is not limited to three. The board 4 is arranged in the first direction of the capacitor 2. In the figure, the first direction of the capacitor 2 is the Z direction. In the present embodiment, the board 4 is also arranged in the first direction of the three power modules 3. By arranging the board 4 in the first direction of the capacitor 2, the board 4 can be arranged adjacent to the capacitor 2, so that the power conversion device 1 can be miniaturized.

[0016] The power conversion device 1 mounted on an electrified vehicle such as an HV or EV can have various layouts. For example, a capacitor 2, which is a smoothing capacitor for surge absorption, is arranged near the DC input part of the inverter, an X capacitor (not shown) for EMC noise countermeasure is provided near the DC input part on the board 4 in the first direction of the capacitor 2, and a board connection terminal 2d for connecting to the X capacitor is provided starting from near the DC input part. Or, a layout in which a board connection terminal 2d for connecting from the main circuit bus bar of the capacitor 2 to a surge countermeasure circuit provided on the board 4 may be used. The board connection terminal 2d is not limited to one, and two or more board connection terminals 2d may be provided.

[0017] As shown in Figure 3, the capacitor 2 has a capacitor element 2b which is the main circuit component body, a capacitor busbar 2a which is the main circuit busbar, a board connection terminal 2d connected to the capacitor busbar 2a, a bottom wall 2c1 and a side wall 2c2 surrounding the bottom wall 2c1, with the portion of the side wall 2c2 opposite to the bottom wall 2c1 being open, housing the capacitor element 2b, the capacitor busbar 2a and the board connection terminal 2d, and a potting resin 2f which seals the capacitor element 2b, the capacitor busbar 2a and the board connection terminal 2d inside the capacitor case 2c, with at least a portion of the capacitor busbar 2a and the board connection terminal 2d exposed. In this embodiment, as shown in Figure 1, the capacitor 2 has nine capacitor elements 2b, but the number of capacitor elements 2b is not limited to this. As shown in Figure 3, the power module 3 is arranged adjacent to the capacitor 2 in the Y direction, which is perpendicular to the Z direction. As shown in Figure 1, the capacitor busbar 2a is connected to the power terminal 3a of the power module 3, for example, by welding.

[0018] The power module 3 has semiconductor chips (not shown) and is arranged in the X direction, which is perpendicular to the Z and Y directions. The main body of each power module 3 is rectangular parallelepiped. As shown in Figure 3, the substrate 4 is arranged at intervals on the first faces 3c of the multiple power modules 3 and is electrically connected to the module terminals 3b of each of the multiple power modules 3. The module terminals 3b protrude from the second face 3d and the third face 3e opposite the second face 3d of the power module 3, and then extend in the direction of the substrate 4. In this embodiment, as shown in Figure 1, four module terminals 3b are provided on each of the second face 3d and the third face 3e of the power module 3 and are connected to the substrate 4 through through holes 4a provided in the substrate 4. The arrangement surface of the main body of the power module 3 on which the module terminals 3b are arranged, and the number of module terminals 3b are not limited to these.

[0019] The power module 3 converts DC power and outputs three-phase AC power. In the present embodiment, the power conversion device 1 includes three power modules 3 corresponding to each phase. The arrangement of the plurality of power modules 3 is an arrangement in which each of the power modules 3 is arranged in the same direction in the X direction, which is a direction parallel to the second surface 3d. By configuring in this way, since the plurality of power modules 3 are arranged in alignment in the same direction, the power conversion device 1 can be miniaturized. In addition, when further providing a plurality of power modules 3, the power modules 3 may be arranged in two rows in alignment.

[0020] The power terminal 3a and the module terminal 3b are made of, for example, copper having a low electrical resistivity and excellent conductivity. The power terminal 3a is a terminal related to the input / output of the power module 3. The module terminal 3b is a terminal related to the drive of the power module 3. In the present embodiment, the power module 3 has three power terminals 3a. Two power terminals 3a are connected to a DC power source, and one power terminal 3a is connected to the rotating electrical machine 11 which is a load. In the present embodiment, one of the two power terminals 3a is connected to the capacitor 2 via the capacitor bus bar 2a, and further connected to the power source 10 via the capacitor 2.

[0021] As described above, in the present embodiment, the capacitor 2 and the power module 3 are connected by the capacitor bus bar 2a. However, the shorter the distance between the capacitor 2 and the power module 3, that is, the capacitor bus bar 2a, the more the one-way Ls can be reduced and the surge voltage can be reduced. Since the reduction of the surge voltage leads to the reduction of the capacitance of the capacitor 2, as a result, the power conversion device 1 can be made less costly and miniaturized.

[0022] Power module 3 is molded using transfer molding. Therefore, the semiconductor chip is covered by the molding resin. This configuration allows for easy protection of the semiconductor chip from external elements. Note that power module 3 is not limited to a configuration molded using transfer molding; it may also be configured by housing the semiconductor chip in a case and filling the inside of the case with gel.

[0023] The circuit board 4 has a through-hole 4a to which the module terminal 3b is connected, a through-hole 4b to which the board connection terminal 2d is connected, and a circuit 4c for driving the power module 3. The circuit 4c is provided, for example, in the area shown by the dashed line in Figure 1. In this embodiment, the power converter 1 has one circuit board 4, but the number of circuit boards 4 is not limited to this. Two circuit boards 4 may be provided side by side or stacked on top of each other. The circuit board 4 is fixed, for example, to one or both of the capacitor 2 and the power module 3. If the power converter 1 has a housing that accommodates the capacitor 2 and the power module 3, the circuit board 4 may be fixed to the housing. The circuit board 4 is fixed, for example, using screws or bolts.

[0024] <Board connection terminal 2d> The key component of this disclosure, the board connection terminal 2d, will now be described. The Young's modulus of the board connection terminal 2d is greater than that of the capacitor busbar 2a, which is the main circuit busbar. With this configuration, the rigidity of the board connection terminal 2d is greater than that of the capacitor busbar 2a, so the board connection terminal 2d can withstand stringent vibration specifications, thereby improving the vibration resistance of the board connection terminal 2d. The vibration resistance of the board connection terminal 2d is improved, and since the board connection terminal 2d also acts as a support member for the board 4, the vibration resistance of the board 4 connected to the board connection terminal 2d can be improved. Because the vibration resistance of the board connection terminal 2d and the board 4 is improved, the vibration resistance of the power converter 1 can be ensured. In addition, because the vibration resistance of the board 4 is improved, the number of screws or bolts used to fix the board 4 can be reduced, so the projected area of ​​the board 4 can be reduced. Because the projected area of ​​the board 4 is reduced, the power converter 1 can be miniaturized. Furthermore, since the circuit board 4 is positioned in the first direction relative to the capacitor 2, the circuit board connection terminal 2d can be shortened, thus enabling miniaturization of the power converter 1. In addition, the number of screws or bolts used to fix the circuit board 4 is reduced, allowing for lower costs for the power converter 1.

[0025] In this embodiment, the material of the capacitor busbar 2a, which is the main circuit busbar, is a material with a copper content of 99.9% or more, and the material of the board connection terminal 2d is a material with a copper content of 80% or less. Materials with a lower copper content tend to have a higher Young's modulus. For the capacitor busbar 2a with a copper content of 99.9% or more, for example, oxygen-free copper (C1020), which has low volume resistivity and excellent solderability, is used. For the board connection terminal 2d with a copper content of 80% or less, for example, brass (C2680), which has a higher Young's modulus than oxygen-free copper, a relatively low volume resistivity, and excellent solderability, is used.

[0026] By using a highly rigid copper alloy with a copper content of 80% or less, such as brass, for the board connection terminal 2d, the vibration resistance of the board connection terminal 2d itself can be improved. Since the vibration resistance of the board connection terminal 2d is improved and it also acts as a support member for the board 4, the vibration resistance of the board 4 connected to the board connection terminal 2d can also be improved.

[0027] Since a large current flows through the capacitor busbar 2a to which the board connection terminal 2d is connected, using a copper alloy such as brass, which has a higher volume resistivity than oxygen-free copper, for the capacitor busbar 2a will cause it to overheat. Therefore, it is necessary to use a copper material with a high copper content, such as oxygen-free copper with a copper content of 99.9% or more, for the capacitor busbar 2a. By using a copper material with a high copper content of 99.9% or more for the capacitor busbar 2a, the volume resistivity of the capacitor busbar 2a is reduced, thereby suppressing the overheating of the capacitor busbar 2a. Thus, it is necessary to use materials of different materials for the board connection terminal 2d and the capacitor busbar 2a and connect them together.

[0028] The materials used for the board connection terminals 2d and capacitor busbars 2a are not limited to copper or copper alloys. The materials for the board connection terminals 2d and capacitor busbars 2a may be aluminum-based materials. Aluminum-based materials are aluminum or alloys containing aluminum. By using aluminum-based materials for the board connection terminals 2d and capacitor busbars 2a, the cost of the board connection terminals 2d and capacitor busbars 2a can be reduced. As the cost of the board connection terminals 2d and capacitor busbars 2a is reduced, the cost of the power converter 1 can be reduced.

[0029] Even when aluminum-based materials are used for the PCB connection terminals 2d and capacitor busbars 2a, the Young's modulus of the PCB connection terminals 2d is greater than that of the capacitor busbars 2a. Furthermore, the volume resistivity of the PCB connection terminals 2d and capacitor busbars 2a is different. Thus, even when using aluminum-based materials, the same effect as when using copper can be obtained by using materials with different Young's moduli and volume resistivity for the PCB connection terminals 2d and capacitor busbars 2a.

[0030] As described above, the board connection terminal 2d is connected to the board 4 via a through-hole 4b provided in the board 4. Positional accuracy of the board connection terminal 2d and the connection between the board connection terminal 2d and the capacitor busbar 2a are required so that the end of the board connection terminal 2d fits into the through-hole 4b. The connection between the board connection terminal 2d and the capacitor busbar 2a is made by, for example, bolts. When connecting them by bolts, there is a challenge in achieving positional accuracy. The connection between the board connection terminal 2d and the capacitor busbar 2a is made by, for example, welding. When connecting them by welding, there is a challenge in determining the welding conditions because they are made of dissimilar metals.

[0031] In this embodiment, the board connection terminal 2d and the capacitor busbar 2a are connected by solder 2e. By connecting the board connection terminal 2d and the capacitor busbar 2a with solder 2e, the positional accuracy of the placement of the board connection terminal 2d and the positional accuracy of the connection between the board connection terminal 2d and the capacitor busbar 2a can be improved.

[0032] When aluminum-based materials are used for the PCB connection terminal 2d and the capacitor busbar 2a, and the two are connected by solder 2e, in this embodiment, at least the surfaces of the PCB connection terminal 2d and the capacitor busbar 2a at the terminal connection portion 5, which is the connection part between the PCB connection terminal 2d and the capacitor busbar 2a, are covered with plating 2d1. The plating 2d1 is, for example, tin plating or nickel plating. Figure 6 shows an example of the configuration of a PCB connection terminal 2d in which the portion of the PCB connection terminal 2d that connects to the capacitor busbar 2a is covered with plating 2d1. The portion of the PCB connection terminal 2d to which plating 2d1 is provided is not limited to the terminal connection portion 5, and the entire PCB connection terminal 2d may be plated 2d1. By configuring it in this way, even when aluminum-based materials are used for the PCB connection terminal 2d and the capacitor busbar 2a, solderability when connecting the two can be ensured.

[0033] In this embodiment, the terminal connection portion 5, to which the board connection terminal 2d and the capacitor busbar 2a are connected, is covered with resin 2g or potting resin 2f. Figure 3 shows an example in which the terminal connection portion 5, to which the board connection terminal 2d and the capacitor busbar 2a are connected, is covered with potting resin 2f, and Figure 4 shows an example in which the terminal connection portion 5, to which the board connection terminal 2d and the capacitor busbar 2a are connected, is covered with resin 2g. In these examples, not only the terminal connection portion 5, but also the capacitor busbar 2a, a part of the board connection terminal 2d, and the capacitor element 2b are covered with resin 2g or potting resin 2f.

[0034] In the configuration shown in Figure 4, at least a portion of the capacitor busbar 2a and the board connection terminal 2d is exposed, and the capacitor element 2b, the capacitor busbar 2a, and the board connection terminal 2d are sealed with resin 2g, which is an injection-molded resin. The portion of resin 2g covering the capacitor element 2b becomes the capacitor case 2c. The configuration is not limited to covering the terminal connection part 5 with resin 2g or potting resin 2f; the terminal connection part 5 may also be covered with epoxy resin.

[0035] By covering the terminal connection part 5 with resin 2g or potting resin 2f, the vibration resistance and durability of the terminal connection part 5 can be improved. When the PCB connection terminal 2d and the capacitor busbar 2a are connected by solder, the positional accuracy of the PCB connection terminal 2d is improved, but the strength of the solder itself is weak, which poses a challenge in terms of reliability. By connecting the PCB connection terminal 2d and the capacitor busbar 2a with solder 2e, and then covering the terminal connection part 5 connected by solder 2e with resin 2g or potting resin 2f, the durability of the terminal connection part 5 connected by solder 2e can be ensured.

[0036] In this embodiment, as shown in Figure 3 or Figure 4, the portion of the substrate connection terminal 2d exposed from the resin 2g or potting resin 2f is not bent and extends in the direction of the substrate 4. With this configuration, the portion of the substrate connection terminal 2d exposed from the resin 2g or potting resin 2f has a straight shape, which improves the rigidity of the substrate connection terminal 2d, and thus further improves the vibration resistance of the substrate connection terminal 2d. As the vibration resistance of the substrate connection terminal 2d is further improved, the vibration resistance of the substrate 4 connected to the substrate connection terminal 2d can be further improved. As the vibration resistance of the substrate connection terminal 2d and the substrate 4 is further improved, the vibration resistance of the power converter 1 can be further ensured. Also in this embodiment, the portion of the substrate connection terminal 2d exposed from the resin 2g or potting resin 2f extends perpendicular to the substrate surface 4d of the substrate 4 and in the direction of the substrate 4. With this configuration, the length of the substrate connection terminal 2d is shortened, so the cost of the substrate connection terminal 2d can be reduced.

[0037] A modified example of the board connection terminal 2d will be described. As shown in Figure 7, the cross-sectional area of ​​the other side portion 2d2 of the board connection terminal 2d, which is connected to the board 4, is smaller than the cross-sectional area of ​​the portion of the board connection terminal 2d adjacent to the other side portion 2d2. The cross-sectional area of ​​the other side portion 2d2 of the board connection terminal 2d is determined by the connection method because it is the portion connected to the board 4. Therefore, it is difficult to increase the cross-sectional area of ​​the other side portion 2d2. When the connection method is soldering, the cross-sectional area of ​​the other side portion 2d2 of the board connection terminal 2d, which is the soldered portion to the board 4, is determined by the constraints of soldering. There are no constraints on the cross-sectional area of ​​the portion of the board connection terminal 2d excluding the other side portion 2d2. By making the cross-sectional area of ​​the portion of the board connection terminal 2d adjacent to the other side portion 2d2 larger than the other side portion 2d2, the rigidity of the board connection terminal 2d is improved, and thus the vibration resistance of the board connection terminal 2d can be further improved.

[0038] Furthermore, when the terminal connection portion 5, to which the board connection terminal 2d and the capacitor busbar 2a are connected, is covered with resin 2g or potting resin 2f, the cross-sectional area of ​​the portion of the board connection terminal 2d exposed from the resin 2g or potting resin 2f increases with this configuration, thereby improving the rigidity of the board connection terminal 2d and further enhancing its vibration resistance. As the vibration resistance of the board connection terminal 2d is further improved, the vibration resistance of the board 4 connected to the board connection terminal 2d can be further improved. As the vibration resistance of the board connection terminal 2d and the board 4 is further improved, the vibration resistance of the power converter 1 can be further ensured.

[0039] The configuration of the board connection terminal 2d shown in Figure 7 is such that not only the cross-sectional area of ​​the portion of the board connection terminal 2d adjacent to the other portion 2d2, but also the cross-sectional area of ​​all portions of the board connection terminal 2d excluding the other portion 2d2 is larger than the cross-sectional area of ​​the other portion 2d2. The configuration of the modified board connection terminal 2d is not limited to this. It is also acceptable for the cross-sectional area of ​​one portion of the board connection terminal 2d connected to the capacitor busbar 2a to be smaller than the cross-sectional area of ​​the portion of the board connection terminal 2d adjacent to that portion.

[0040] The arrangement of each connection point will now be described. In this embodiment, as shown in Figure 3, both the element connection point 6, which is the connection point between the capacitor element 2b, which is the main circuit component body, and the capacitor busbar 2a, which is the main circuit busbar, connected by solder 2e, and the terminal connection point 5, which is the connection point between the capacitor busbar 2a and the board connection terminal 2d, connected by solder 2e, are provided on the same side with respect to the capacitor element 2b.

[0041] This configuration allows both the element connection part 6 and the terminal connection part 5 to be soldered at the same time, thereby improving the productivity of the power converter 1. Because the productivity of the power converter 1 is improved, the cost of the power converter 1 can be reduced. In the manufacturing process of the capacitor 2, after the step of connecting both the element connection part 6 and the terminal connection part 5 with solder 2e, the inside of the capacitor case 2c, including both the element connection part 6 and the terminal connection part 5, is sealed with, for example, potting resin 2f.

[0042] The arrangement of each connection point will be explained further. The direction from the bottom wall 2c1 of the capacitor case 2c toward the opening is defined as the height direction. In Figure 3, the Z direction is the height direction. In this embodiment, the height positions of both the element connection point 6, which is the connection point between the capacitor element 2b and the capacitor busbar 2a connected by solder 2e, and the terminal connection point 5, which is the connection point between the capacitor busbar 2a and the board connection terminal 2d connected by solder 2e, are closer to the opening surface 2h of the open portion of the capacitor case 2c than to the center 2b1 of the capacitor element 2b. The opening surface 2h is a hypothetical surface that passes through the end of the capacitor case 2c on the opening side.

[0043] This configuration allows both the element connection section 6 and the terminal connection section 5 to be soldered at the same time and from the same direction, thereby improving the productivity of the power converter 1. Furthermore, since the height positions of both the element connection section 6 and the terminal connection section 5 are closer to the opening surface 2h of the open portion of the capacitor case 2c than to the center of the capacitor element 2b, the capacitor element 2b can be soldered while housed in the capacitor case 2c. Because the capacitor element 2b can be soldered while housed in the capacitor case 2c, the process of moving the capacitor element 2b to which the capacitor busbar 2a and the board connection terminal 2d are connected becomes unnecessary, thus improving the productivity of the power converter 1. As the productivity of the power converter 1 is improved, the cost of the power converter 1 can be reduced.

[0044] The arrangement of each connection point will be explained further. In this embodiment, as shown in Figure 3, the opening surface 2h of the opened portion of the capacitor case 2c and the substrate surface 4d of the substrate 4 face each other. With this configuration, the opening surface 2h and the substrate surface 4d are closer together, and therefore the capacitor 2 and the substrate 4 are closer together, so the substrate connection terminal 2d can be shortened. Because the substrate connection terminal 2d is shortened, the power converter 1 can be miniaturized. In addition, because the substrate connection terminal 2d can be provided in a straight line, the rigidity of the substrate connection terminal 2d is improved, so the vibration resistance of the substrate connection terminal 2d can be further improved. Because the vibration resistance of the substrate connection terminal 2d is further improved, the vibration resistance of the substrate 4 connected to the substrate connection terminal 2d can be further improved. Because the vibration resistance of the substrate connection terminal 2d and the substrate 4 is further improved, the vibration resistance of the power converter 1 can be further ensured.

[0045] In this embodiment, the main circuit component is a capacitor 2. In this disclosure, the number of screws or bolts used to fix the substrate 4 can be reduced, the projected area of ​​the substrate 4 is reduced, and the power converter 1 is miniaturized, so the capacitor busbar 2a can be shortened. Since the capacitor busbar 2a is shortened, the one-cycle Ls can be reduced, the surge voltage can be reduced, and therefore the capacitance of the capacitor 2 can be reduced. In other words, by using a capacitor 2 as the main circuit component, the capacitance of the capacitor 2 is reduced, so the power converter 1 can be made less expensive and more compact.

[0046] <Example of installation of power converter 1> An example of the installation of the power converter 1 will be described. The power converter 1 is, for example, a device mounted on a vehicle 12. The vehicle 12 has vibration sources 13 such as an engine, transmission, gearbox, and motor. As shown in Figure 8, the power converter 1 is rigidly connected to at least one of the vibration sources 13 in the vehicle 12, namely the engine, transmission, gearbox, and motor. In Figure 8, the capacitor 2 is the part indicated by the dashed line. In this embodiment, the capacitor case 2c of the capacitor 2 is rigidly connected to the vibration source 13.

[0047] With the power converter 1 configured as described above, even if the power converter 1 is rigidly connected to the vibration source 13 of a vehicle 12 that has strict vibration resistance requirements, the vibration resistance of the power converter 1 can be ensured. A rigid connection is a connection in which both connected members do not bend at the connection point. Furthermore, since the vibration resistance of the power converter 1 is ensured, no additional fixing members are required to ensure the vibration resistance of the power converter 1, so the power converter 1 can be miniaturized.

[0048] In this embodiment, the power converter 1 is, for example, an in-vehicle inverter. When the power converter 1 is an in-vehicle inverter, the main circuit components include a capacitor 2. In this disclosure, the number of screws or bolts used to fix the substrate 4 can be reduced, the projected area of ​​the substrate 4 is reduced, and the power converter 1 is miniaturized, so the capacitor busbar 2a can be shortened. Since the capacitor busbar 2a is shortened, the loop Ls can be reduced, the surge voltage can be reduced, and therefore the capacitance of the capacitor 2 can be reduced. In other words, since the main circuit components include a capacitor 2, the capacitance of the capacitor 2 is reduced, so the power converter 1 can be made less expensive and smaller.

[0049] As described above, the power converter 1 according to Embodiment 1 comprises a main circuit component body, a main circuit busbar connected to the main circuit component body, and a main circuit component having a substrate connection terminal 2d with one side connected to the main circuit busbar, and a substrate 4 connected to the other side of the substrate connection terminal 2d. The substrate 4 is positioned in the first direction of the main circuit component, and the Young's modulus of the substrate connection terminal 2d is greater than that of the main circuit busbar. As a result, the rigidity of the substrate connection terminal 2d is greater than that of the main circuit busbar, and the substrate connection terminal 2d can withstand stringent vibration specifications, thereby improving the vibration resistance of the substrate connection terminal 2d. With improved vibration resistance of the substrate connection terminal 2d, the substrate connection terminal 2d also acts as a support member for the substrate 4, thus improving the vibration resistance of the substrate 4 connected to the substrate connection terminal 2d. As the vibration resistance of the substrate connection terminal 2d and the substrate 4 are improved, the vibration resistance of the power converter 1 can be ensured. Furthermore, since the vibration resistance of the substrate 4 is improved, the number of screws or bolts used to fix the substrate 4 can be reduced, thereby reducing the projected area of ​​the substrate 4 and allowing the power converter 1 to be miniaturized.

[0050] If the terminal connection portion 5, which is the connection point between the board connection terminal 2d and the capacitor busbar 2a, which is the main circuit busbar, is covered with resin 2g or potting resin 2f, the vibration resistance and durability of the terminal connection portion 5 can be improved.

[0051] If the capacitor busbar 2a, which is the main circuit busbar, is made of a material with a copper content of 99.9% or more, and the board connection terminal 2d is made of a material with a copper content of 80% or less, then by using a highly rigid copper alloy with a copper content of 80% or less for the board connection terminal 2d, the vibration resistance of the board connection terminal 2d itself can be improved. Since the vibration resistance of the board connection terminal 2d is improved and the board connection terminal 2d also acts as a support member for the board 4, the vibration resistance of the board 4 connected to the board connection terminal 2d can also be improved. By using a copper material with a high copper content of 99.9% or more for the capacitor busbar 2a, the volume resistivity of the capacitor busbar 2a is reduced, thereby suppressing heat generation in the capacitor busbar 2a.

[0052] If the portion of the substrate connection terminal 2d exposed from the resin 2g or potting resin 2f is not bent and extends in the direction of the substrate 4, the portion of the substrate connection terminal 2d exposed from the resin 2g or potting resin 2f will have a straight shape, thereby improving the rigidity of the substrate connection terminal 2d and further improving its vibration resistance. As the vibration resistance of the substrate connection terminal 2d is further improved, the vibration resistance of the substrate 4 connected to the substrate connection terminal 2d can be further improved. As the vibration resistance of the substrate connection terminal 2d and the substrate 4 is further improved, the vibration resistance of the power converter 1 can be further ensured.

[0053] If the cross-sectional area of ​​the other side portion 2d2 of the board connection terminal 2d connected to the board 4 is smaller than the cross-sectional area of ​​the portion of the board connection terminal 2d adjacent to the other side portion 2d2, the rigidity of the board connection terminal 2d can be improved by making the cross-sectional area of ​​the portion of the board connection terminal 2d adjacent to the other side portion 2d2 larger than the other side portion 2d2, thereby further improving the vibration resistance of the board connection terminal 2d. Also, if the terminal connection portion 5 to which the board connection terminal 2d and the capacitor busbar 2a are connected is covered with resin 2g or potting resin 2f, the cross-sectional area of ​​the portion of the board connection terminal 2d exposed from the resin 2g or potting resin 2f becomes larger with this configuration, thus improving the rigidity of the board connection terminal 2d, and further improving the vibration resistance of the board connection terminal 2d.

[0054] When the board connection terminal 2d and the capacitor busbar 2a are connected by solder 2e, the positional accuracy of the board connection terminal 2d and the positional accuracy of the connection between the board connection terminal 2d and the capacitor busbar 2a can be improved.

[0055] If the materials for the board connection terminal 2d and the capacitor busbar 2a are aluminum-based, the cost of the board connection terminal 2d and the capacitor busbar 2a can be reduced. Since the cost of the board connection terminal 2d and the capacitor busbar 2a is reduced, the cost of the power conversion device 1 can be reduced.

[0056] At the very least, if the surfaces of the board connection terminal 2d and the capacitor busbar 2a at the terminal connection portion 5, which is the connection portion between the board connection terminal 2d and the capacitor busbar 2a, are covered with plating 2d1, then even if aluminum-based materials are used for the materials of the board connection terminal 2d and the capacitor busbar 2a, solderability when connecting them can be ensured.

[0057] In this disclosure, the number of screws or bolts used to fix the substrate 4 can be reduced, the projected area of ​​the substrate 4 is reduced, and the power converter 1 can be miniaturized, thus allowing the capacitor busbar 2a to be shortened. Since the capacitor busbar 2a is shortened, the one-cycle Ls can be reduced, the surge voltage can be reduced, and therefore the capacitance of the capacitor 2 can be reduced. If the main circuit component is the capacitor 2, the capacitance of the capacitor 2 is reduced, so the power converter 1 can be made less expensive and smaller.

[0058] If both the element connection portion 6, which is the connection between the capacitor element 2b (the main circuit component body) and the capacitor busbar 2a (the main circuit busbar) connected by solder 2e, and the terminal connection portion 5, which is the connection between the capacitor busbar 2a and the board connection terminal 2d (also connected by solder 2e), are located on the same side relative to the capacitor element 2b, then both the element connection portion 6 and the terminal connection portion 5 can be soldered at the same time, thereby improving the productivity of the power converter 1. As the productivity of the power converter 1 is improved, the cost of the power converter 1 can be reduced.

[0059] When the opening surface 2h of the capacitor case 2c and the substrate surface 4d of the substrate 4 are facing each other, the opening surface 2h and the substrate surface 4d come closer together, and therefore the capacitor 2 and the substrate 4 come closer together, allowing the substrate connection terminal 2d to be shortened. Because the substrate connection terminal 2d is shortened, the power conversion device 1 can be miniaturized. In addition, because the substrate connection terminal 2d can be provided in a straight line, the rigidity of the substrate connection terminal 2d is improved, and the vibration resistance of the substrate connection terminal 2d can be further improved.

[0060] If the height positions of both the element connection portion 6, which is the connection between the capacitor element 2b and the capacitor busbar 2a connected by solder 2e, and the terminal connection portion 5, which is the connection between the capacitor busbar 2a and the board connection terminal 2d connected by solder 2e, are closer to the opening surface 2h of the open portion of the capacitor case 2c than to the center 2b1 of the capacitor element 2b, then both the element connection portion 6 and the terminal connection portion 5 can be soldered at the same time and from the same direction, thereby improving the productivity of the power converter 1. Furthermore, because the height positions of both the element connection portion 6 and the terminal connection portion 5 are closer to the opening surface 2h of the open portion of the capacitor case 2c than to the center of the capacitor element 2b, the capacitor element 2b can be soldered while housed in the capacitor case 2c. Since the capacitor element 2b can be soldered while housed in the capacitor case 2c, the process of moving the capacitor element 2b to which the capacitor busbar 2a and the board connection terminal 2d are connected becomes unnecessary, thus improving the productivity of the power converter 1.

[0061] If the power converter 1 of this disclosure is rigidly connected to at least one of the vibration sources 13 in the vehicle 12, namely the engine, transmission, gearbox, and motor, then the power converter 1 of this disclosure can ensure vibration resistance even when rigidly connected to the vibration sources 13 of the vehicle 12, which have strict vibration resistance requirements. Furthermore, because the vibration resistance of the power converter 1 is ensured, no additional fixing members are required to ensure the vibration resistance of the power converter 1, thus allowing the power converter 1 to be miniaturized.

[0062] If the power converter 1 of this disclosure is an in-vehicle inverter, the main circuit components include a capacitor 2, and since the capacitance of the capacitor 2 is reduced, the power converter 1 can be made less expensive and smaller.

[0063] Furthermore, while this disclosure describes various exemplary embodiments and examples, the various features, aspects, and functions described in one or more embodiments are not limited to the application of a particular embodiment, but can be applied individually or in various combinations to the embodiments. Accordingly, countless variations not illustrated are conceivable within the scope of the art disclosed in this specification. These include, for example, modifying, adding or omitting at least one component, or even extracting at least one component and combining it with components of other embodiments.

[0064] The various aspects of this disclosure are summarized below as an appendix. (Note 1) A main circuit component having a main circuit component body, a main circuit busbar connected to the main circuit component body, and a board connection terminal with one side connected to the main circuit busbar, The board comprises a board connected to the other side of the aforementioned board connection terminal, The substrate is arranged in the first direction of the main circuit components, A power conversion device in which the Young's modulus of the board connection terminal is greater than the Young's modulus of the main circuit busbar. (Note 2) The power conversion device as described in Appendix 1, wherein the connection between the board connection terminal and the main circuit busbar is covered with resin or potting resin. (Note 3) The power conversion device according to Appendix 1 or 2, wherein the material of the main circuit busbar is a material with a copper content of 99.9% or more, and the material of the board connection terminal is a material with a copper content of 80% or less. (Note 4) The power conversion device according to Appendix 2, wherein the portion of the substrate connection terminal exposed from the resin or potting resin is not bent and extends in the direction of the substrate. (Note 5) A power conversion device according to any one of the appendices 1 to 4, wherein the cross-sectional area of ​​the other side portion of the board connection terminal connected to the board is smaller than the cross-sectional area of ​​the portion of the board connection terminal adjacent to the other side portion. (Note 6) The power conversion device described in any one of the appendices 1 to 5, wherein the board connection terminal and the main circuit busbar are connected by solder. (Note 7) The power conversion device according to any one of Appendix 1, Appendix 2, or Appendix 4 to 6, wherein the material of the board connection terminal and the main circuit busbar is an aluminum-based material. (Note 8) The power conversion device according to Appendix 7, wherein at least the surface of the board connection terminal and the surface of the main circuit busbar at the terminal connection portion, which is the connection portion between the board connection terminal and the main circuit busbar, are covered with plating. (Note 9) The power conversion device described in any one of the appendices 1 to 8, wherein the main circuit component is a capacitor. (Note 10) The power conversion device as described in Appendix 9, wherein both the element connection portion, which is the connection portion between the capacitor element, which is the main body of the main circuit component, and the capacitor busbar, which is the main circuit busbar, and which is connected by solder, and the terminal connection portion, which is the connection portion between the capacitor busbar and the board connection terminal, are provided on the same side with respect to the capacitor element. (Note 11) The capacitor comprises a capacitor element which is the main body of the main circuit component, a capacitor busbar which is the main circuit busbar, a circuit board connection terminal connected to the capacitor busbar, a capacitor case which has a bottom wall and side walls surrounding the bottom wall, with the portion of the side wall opposite to the bottom wall being open, housing the capacitor element, the capacitor busbar and the circuit board connection terminal, and a potting resin which seals the capacitor element, the capacitor busbar and the circuit board connection terminal inside the capacitor case, with at least a portion of the capacitor busbar and the circuit board connection terminal exposed. The power conversion device according to Appendix 9 or 10, wherein the opening surface of the opened portion of the capacitor case and the substrate surface of the substrate face each other. (Note 12) The capacitor comprises a capacitor element which is the main body of the main circuit component, a capacitor busbar which is the main circuit busbar, a circuit board connection terminal connected to the capacitor busbar, a bottom wall and a side wall surrounding the bottom wall, the portion of the side wall opposite to the bottom wall being open, a capacitor case housing the capacitor element, the capacitor busbar and the circuit board connection terminal, and a potting resin that seals the capacitor element, the capacitor busbar and the circuit board connection terminal inside the capacitor case, with at least a portion of the capacitor busbar and the circuit board connection terminal exposed. The direction from the bottom wall of the capacitor case toward the opening side is defined as the height direction. The power conversion device according to Appendix 9, wherein the height position of both the element connection portion, which is the connection portion between the capacitor element and the capacitor busbar connected by solder, and the terminal connection portion, which is the connection portion between the capacitor busbar and the board connection terminal connected by solder, is closer to the opening surface of the open portion of the capacitor case than to the center of the capacitor element. (Note 13) A power conversion device according to any one of the appendices 1 to 12, mounted on a vehicle and rigidly connected to at least one of the engine, transmission, gearbox, and motor, which are sources of vibration in the vehicle. (Note 14) The power conversion device described in Appendix 13 is an in-vehicle inverter. [Explanation of symbols]

[0065] 1 Power converter, 2 Capacitor, 2a Capacitor busbar, 2b Capacitor element, 2b1 Center, 2c Capacitor case, 2c1 Bottom wall, 2c2 Side wall, 2d PCB connection terminal, 2d1 Plating, 2d2 Other side, 2e Solder, 2f Potting resin, 2g Resin, 2h Opening surface, 3 Power module, 3a Power terminal, 3b Module terminal, 3c First surface, 3d Second surface, 3e Third surface, 4 PCB, 4a, 4b Through-hole, 4c Circuit, 4d PCB surface, 5 Terminal connection section, 6 Element connection section, 10 Power supply, 11 Rotating electric machine, 12 Vehicle, 13 Vibration source

Claims

1. A main circuit component having a main circuit component body, a main circuit busbar connected to the main circuit component body, and a board connection terminal with one side connected to the main circuit busbar, The board comprises a board connected to the other side of the aforementioned board connection terminal, The substrate is arranged in the first direction of the main circuit components, A power conversion device in which the Young's modulus of the board connection terminal is greater than the Young's modulus of the main circuit busbar.

2. The power conversion device according to claim 1, wherein the connection portion between the board connection terminal and the main circuit busbar is covered with resin or potting resin.

3. The power conversion device according to claim 1, wherein the material of the main circuit busbar is a material with a copper content of 99.9% or more, and the material of the board connection terminal is a material with a copper content of 80% or less.

4. The power conversion device according to claim 2, wherein the portion of the substrate connection terminal exposed from the resin or potting resin is not bent and extends in the direction of the substrate.

5. The power conversion device according to claim 1, wherein the cross-sectional area of ​​the other side portion of the board connection terminal connected to the board is smaller than the cross-sectional area of ​​the portion of the board connection terminal adjacent to the other side portion.

6. The power conversion device according to claim 1, wherein the board connection terminal and the main circuit busbar are connected by solder.

7. The power conversion device according to claim 1, wherein the material of the board connection terminal and the main circuit busbar is an aluminum-based material.

8. The power conversion device according to claim 7, wherein at least the surface of the board connection terminal and the surface of the main circuit busbar at the terminal connection portion which is the connection portion between the board connection terminal and the main circuit busbar are covered with plating.

9. The power conversion device according to claim 1, wherein the main circuit component is a capacitor.

10. The power conversion device according to claim 9, wherein both the element connection portion, which is the connection portion between the capacitor element, which is the main circuit component body, and the capacitor busbar, which is the main circuit busbar, connected by solder, and the terminal connection portion, which is the connection portion between the capacitor busbar and the board connection terminal, connected by solder, are provided on the same side with respect to the capacitor element.

11. The capacitor comprises a capacitor element which is the main body of the main circuit component, a capacitor busbar which is the main circuit busbar, a circuit board connection terminal connected to the capacitor busbar, a capacitor case which has a bottom wall and side walls surrounding the bottom wall, with the portion of the side wall opposite to the bottom wall being open, housing the capacitor element, the capacitor busbar and the circuit board connection terminal, and a potting resin which seals the capacitor element, the capacitor busbar and the circuit board connection terminal inside the capacitor case, with at least a portion of the capacitor busbar and the circuit board connection terminal exposed. The power conversion device according to claim 9, wherein the opening surface of the opened portion of the capacitor case and the substrate surface of the substrate face each other.

12. The capacitor comprises a capacitor element which is the main body of the main circuit component, a capacitor busbar which is the main circuit busbar, a circuit board connection terminal connected to the capacitor busbar, a bottom wall and a side wall surrounding the bottom wall, the portion of the side wall opposite to the bottom wall being open, a capacitor case housing the capacitor element, the capacitor busbar and the circuit board connection terminal, and a potting resin that seals the capacitor element, the capacitor busbar and the circuit board connection terminal inside the capacitor case, with at least a portion of the capacitor busbar and the circuit board connection terminal exposed. The direction from the bottom wall of the capacitor case toward the opening side is defined as the height direction. The power conversion device according to claim 9, wherein the height position of both the element connection portion, which is the connection portion between the capacitor element and the capacitor busbar connected by solder, and the terminal connection portion, which is the connection portion between the capacitor busbar and the board connection terminal connected by solder, is closer to the opening surface of the open portion of the capacitor case than to the center of the capacitor element.

13. A power conversion device according to any one of claims 1 to 12, which is mounted on a vehicle and rigidly connected to at least one of the engine, transmission, gearbox, and motor, which are sources of vibration in the vehicle.

14. The power conversion device according to claim 13, which is an in-vehicle inverter.

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