Power conversion device

Abstract

To provide a power conversion device that is compact in size and secures freedom in layout while suppressing transmission to a capacitor of an influence of heat generation of a rapid discharge resistor..SOLUTION: A power conversion device comprises: a capacitor; a semiconductor module that is electrically connected to the capacitor and includes a semiconductor element; a substrate with a control circuit that controls the semiconductor module; and a rapid discharge resistor that discharges an electric charge accumulated in the capacitor. The capacitor and the semiconductor module are provided on one surface side of the substrate, and the rapid discharge resistor is provided on the other surface side of the substrate.SELECTED DRAWING: Figure 2

Description

Technical Field

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

Background Art

[0002] In electric vehicles such as hybrid vehicles, plug-in hybrid vehicles, electric vehicles, and fuel cell vehicles, in which a motor is used as a drive source, a power conversion device such as an inverter for driving a drive motor and a converter for boosting and lowering the power supply voltage of a battery is mounted. In order to secure a trunk and a passenger living space inside the electric vehicle, the power conversion device is required to be mounted in a limited space, so the power conversion device is required to be a small component.

[0003] A power conversion device mounted on an electric vehicle generally includes a capacitor, a substrate having a control circuit, a semiconductor module having a semiconductor element for power conversion, a housing having a cooler for cooling the semiconductor module, and a cover for covering an opening of the housing. In such a power conversion device, a discharge resistor having a relatively low resistance value (hereinafter referred to as a rapid discharge resistor) is connected in parallel to the capacitor. The rapid discharge resistor is a resistor for rapidly discharging the electric charge accumulated in the capacitor when the electric vehicle stops or the like. By providing the rapid discharge resistor, the electric charge of the capacitor can be rapidly discharged. With the increase in the high voltage of the battery mounted on the electric vehicle, the necessity of active discharge (hereinafter referred to as active discharge) using the rapid discharge resistor is increasing. For example, in the People's Republic of China, in national standards and the like, when there is a requirement for active discharge, it is stipulated that the discharge of the capacitor be completed within 3 seconds.

[0004] The rapid discharge resistor is a resistor that discharges the charge stored in a capacitor by converting electrical energy into thermal energy. Therefore, when active discharge is required, the charge of a capacitor with a large capacitance is instantly converted into thermal energy within a short time of 3 seconds, so the heat generation of the rapid discharge resistor itself becomes very large. The heat generation time itself due to active discharge is not over a long period because it is within 3 seconds. However, since the amount of heat generated per unit time is very large, the heat capacity of the rapid discharge resistor is ensured by increasing the size of the rapid discharge resistor so as not to exceed the heat-resistant temperature of the rapid discharge resistor itself. Therefore, the rapid discharge resistor is a large-sized component.

[0005] The configuration of a power conversion device capable of active discharge is disclosed (see, for example, Patent Document 1). In the configuration disclosed in Patent Document 1, the power conversion device includes a semiconductor module, a cooler, a substrate, a capacitor, and a rapid discharge resistor, and the semiconductor module, the cooler, the capacitor, and the rapid discharge resistor are arranged on one side of the substrate. Further, the rapid discharge resistor is arranged in the vicinity of a multi-stage waterway forming member which is a cooler in which a waterway is formed. By configuring in this way, the semiconductor module, the cooler, the capacitor, and the rapid discharge resistor can be assembled from the same surface side of the substrate, so the assembly man-hours of the power conversion device can be reduced.

Prior Art Documents

Patent Documents

[0006]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0007] Since a large current flows through the bus bar connected to the capacitor and the semiconductor module, the heat generation of the bus bar and the semiconductor module becomes very large. Therefore, although the capacitor receives heat from these components, the capacitors used in power conversion devices generally have lower heat resistance compared to other components provided in the power conversion device. Thus, even in normal use conditions, the temperature of the capacitor may rise close to the heat-resistant temperature of the capacitor. There has been a problem that when the heat from the steep heat generation of the rapid discharge resistor is applied to the capacitor, the temperature of the capacitor may exceed the heat-resistant temperature of the capacitor.

[0008] In Patent Document 1 mentioned above, by assembling each component on the same surface side of the substrate, the assembly man-hours of the power conversion device can be reduced. However, since all components are assembled on the same surface side of the substrate, there has been a problem that the layout property deteriorates. In addition, since all components including large components are concentrated and arranged only on one surface side of the substrate, there has been a problem that the power conversion device becomes large-sized. Further, when the rapid discharge resistor is provided away from the vicinity of the capacitor in order to suppress the temperature rise of the capacitor, there have been problems that the layout property further deteriorates and the power conversion device further increases in size.

[0009] Therefore, an object of the present disclosure is to obtain a power conversion device that is downsized while ensuring layout property while suppressing the influence of heat generation of the rapid discharge resistor from being transmitted to the capacitor.

Means for Solving the Problem

[0010] The power conversion device of the present disclosure includes a capacitor, a semiconductor module that is electrically connected to the capacitor and has semiconductor elements, a substrate having a control circuit that controls the semiconductor module, and a rapid discharge resistor that discharges the charge accumulated in the capacitor. The capacitor and the semiconductor module are provided on one surface side of the substrate, and the rapid discharge resistor is provided on the other surface side of the substrate.

Effect of the Invention

[0011] According to the power conversion device of the present disclosure, a capacitor, a semiconductor module electrically connected to the capacitor and having semiconductor elements, a substrate having a control circuit for controlling the semiconductor module, and a rapid discharge resistor for discharging the charge accumulated in the capacitor are provided. The capacitor and the semiconductor module are provided on one side of the substrate, and the rapid discharge resistor is provided on the other side of the substrate. Therefore, for a capacitor with low heat resistance, the heat of the rapid discharge resistor that rapidly generates heat during active discharge can be blocked by the substrate, so that the influence of the heat generation of the rapid discharge resistor can be suppressed from being transmitted to the capacitor. Also, since not all components are assembled on the same side of the substrate, layout performance can be ensured. Further, although the rapid discharge resistor, the capacitor, and the semiconductor module are relatively large components, by mounting the rapid discharge resistor on the other side of the substrate and mounting the capacitor and the semiconductor module on one side of the substrate, the installation area on one side of the substrate can be reduced, so that the power conversion device can be miniaturized.

Brief Description of the Drawings

[0012]

Figure 1

Figure 2

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Figure 12

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Figure 18

Mode for Carrying Out the Invention

[0013] Hereinafter, a power conversion device according to an embodiment of the present disclosure will be described with reference to the drawings. In each figure, the same or corresponding members and parts will be described with the same reference numerals.

[0014] Embodiment 1. FIG. 1 is a plan view showing an outline of the power conversion device 1 according to Embodiment 1, in which the cover 6 is removed and only the outer shape of the substrate 4 is shown; FIG. 2 is a cross-sectional view of the power conversion device 1 cut at the A-A cross-sectional position in FIG. 1; FIGS. 3, 4, and 5 are cross-sectional views of another power conversion device 1 cut at the A-A cross-sectional position in FIG. 1; FIG. 6 is a plan view of the capacitor 3 of another power conversion device 1 shown in FIG. 5; FIG. 7 is a plan view showing an outline of the rapid discharge resistor 2 of the power conversion device 1; FIG. 8 is a cross-sectional view of the rapid discharge resistor 2 cut at the B-B cross-sectional position in FIG. 7; FIG. 9 is a plan view showing a main part of the substrate 4 of another power conversion device 1, showing only the part where the notch 4b is provided; FIGS. 10 and 11 are cross-sectional views showing a main part of the rapid discharge resistor mounting portion 3a of the power conversion device 1, showing an enlarged view of the portion where the rapid discharge resistor 2 is fixed. The power conversion device 1 is, for example, a device that converts an input current from direct current to alternating current, from alternating current to direct current, or converts an input voltage to a different voltage.

[0015] As shown in FIG. 2, the power conversion device 1 includes a capacitor 3, a semiconductor module 8 having a semiconductor element 8a and electrically connected to the capacitor 3, a substrate 4 having a control circuit (not shown) for controlling the semiconductor module 8, and a rapid discharge resistor 2 for discharging the charge accumulated in the capacitor 3. In the present embodiment, the power conversion device 1 further includes a housing 5 having an opening 5a for accommodating the capacitor 3, the semiconductor module 8, the substrate 4, and the rapid discharge resistor 2, and a cover 6 for covering the opening 5a. The housing 5 has a cooler 9 for cooling the semiconductor module 8. The cooler 9 may further cool the capacitor 3 in addition to the semiconductor module 8. The rapid discharge resistor 2, the capacitor 3, the substrate 4, and the semiconductor module 8 are surrounded by the housing 5 and the cover 6. In the configuration of the power conversion device 1 shown in FIG. 2, the rapid discharge resistor 2 is attached to the rapid discharge resistor mounting portion 3a, and the substrate 4 is provided between the rapid discharge resistor 2 and the capacitor 3.

[0016] The power conversion device 1 in this embodiment is a device that converts DC power smoothed by a capacitor 3 connected to a DC power source (not shown) into AC power using a semiconductor module 8 and outputs it. This embodiment shows a power conversion device 1 that outputs three-phase AC. As shown in FIG. 1, the semiconductor module is composed of three semiconductor modules 8 corresponding to each phase. The configuration of the power conversion device 1 is not limited to this, and it may be a device that converts the input current from AC to DC.

[0017] <Rapid discharge resistor 2> The configuration of each part of the power conversion device 1 will be described. First, the rapid discharge resistor 2 will be described with reference to FIGS. 7 and 8. The rapid discharge resistor 2 is provided to discharge the charge stored in the capacitor 3 when an abnormality is detected in the power conversion device 1 or the like. As shown in FIG. 8, the rapid discharge resistor 2 includes a resistor 2c that discharges the charge of the capacitor 3, a rapid discharge resistor case 2a that houses the resistor 2c and has a part opened, and a sealing material 2b that seals the resistor 2c inside the rapid discharge resistor case 2a. The resistor 2c and the capacitor 3 are connected in parallel by a connecting member (not shown). In this embodiment, as shown in FIG. 7, the rapid discharge resistor 2 has two resistors 2c, but the number of resistors 2c included in the rapid discharge resistor 2 is not limited to this. The two resistors 2c may be connected in series or in parallel.

[0018] The resistor 2c is surrounded by the rapid discharge resistor case 2a, but at least a part of the rapid discharge resistor case 2a is open in the manufacturing process of pouring the sealing material 2b into the rapid discharge resistor case 2a. The opened part of the rapid discharge resistor case 2a is the case opening 2d. In this embodiment, the rapid discharge resistor case 2a has one case opening 2d, but the case opening 2d is not limited to one. The rapid discharge resistor case 2a has case through holes 2e on both sides. The rapid discharge resistor 2 is fixed to the rapid discharge resistor mounting part by, for example, a screw passing through the case through hole 2e.

[0019] The connecting member is taken out to the outside of the rapid discharge resistor case 2a through the case opening 2d of the rapid discharge resistor case 2a or a through hole (not shown) provided in the rapid discharge resistor case 2a. When taking out the connecting member from the through hole, a member for preventing leakage of the sealing material 2b is provided at the portion of the through hole. The connecting member extends toward the substrate 4 side and is connected to the capacitor 3. The rapid discharge resistor 2 is energized when discharging the charge, and the resistor 2c generates heat at that time. However, since the amount of heat generated by the connecting member is small, it may be configured such that the terminal or connector of the connecting member penetrates the capacitor 3 side of the substrate 4, or the terminal or connector of the connecting member may be routed to the capacitor 3 side of the substrate 4.

[0020] Due to its characteristics, the rapid discharge resistor 2 is not constantly energized. The rapid discharge resistor 2 is energized as needed, and active discharge is performed to discharge the charge accumulated in the capacitor 3. A control circuit for controlling the necessity of the energization may be integrally incorporated inside the rapid discharge resistor 2. The arrangement of the control circuit is not limited to inside the rapid discharge resistor 2, and the control circuit may be provided on the substrate 4.

[0021] <Capacitor 3> As shown in FIG. 1, the capacitor 3 includes a main body portion 3e composed of a capacitor element, a capacitor bus bar 3f connected to the main body portion 3e, and a capacitor case 3d that houses the main body portion 3e. The capacitor case 3d is filled with a sealing material 3b, and the capacitor bus bar 3f protrudes from the sealing material 3b as shown in FIG. 2. In FIG. 1, the main body portion 3e is shown by a broken line through the sealing material 3b, but in FIG. 2, the main body portion 3e is omitted. The sealing material 3b is a member having insulation properties made of an epoxy resin or the like. The capacitor bus bar 3f is made of, for example, copper or an aluminum alloy having a low electrical resistivity and excellent conductivity. The capacitor 3 shown in FIG. 2 further has a rapid discharge resistor mounting portion 3a. Details of the rapid discharge resistor mounting portion 3a will be described later.

[0022] The main body 3e smooths the DC power. The main body 3e has electrodes (not shown) at both ends. Each of the electrodes is a positive electrode or a negative electrode. The capacitor bus bar 3f has a P bus bar and an N bus bar. The P bus bar is connected to the positive electrode, and the N bus bar is connected to the negative electrode. The power conversion device 1 shown in FIG. 2 includes a bus bar 3c that electrically connects the capacitor 3 and the semiconductor module 8. The bus bar 3c is made of, for example, copper or an aluminum alloy with low electrical resistivity and excellent conductivity. The end of the bus bar 3c on the side of the capacitor 3 is connected to the capacitor bus bar 3f, for example, by TIG welding. The end of the bus bar 3c on the side of the semiconductor module 8 is connected to the module bus bar 8b of the semiconductor module 8, for example, by TIG welding. The configuration is not limited to connecting the capacitor 3 and the semiconductor module 8 via the bus bar 3c. As shown in FIG. 3, the capacitor 3 and the semiconductor module 8 may be directly connected without passing through the bus bar 3c.

[0023] Since the capacitor 3 is connected to the semiconductor module 8, the heat of the semiconductor module 8 is transferred to the capacitor 3. Generally, the capacitor 3 has lower heat resistance than surrounding components such as the semiconductor module 8, the bus bar 3c, and the substrate 4. Therefore, the capacitor 3 needs to pay careful attention to self-heating due to energization and thermal effects from surrounding components.

[0024] The main body 3e is, for example, a film capacitor having a laminated structure in which a metal foil serving as an internal electrode and a resin film are wound in a roll shape. Generally, since a film capacitor has a higher withstand voltage than other types of capacitors, by using a film capacitor for the main body 3e, the power conversion device 1 can be used for in-vehicle applications that require a high withstand voltage. In the present embodiment, as shown in FIG. 1, one capacitor element is shown as the main body 3e, but the number of capacitor elements is not limited to this. Three capacitor elements may be provided and each of the three capacitor elements may be connected to each of the three semiconductor modules 8.

[0025] The capacitor case 3d is manufactured, for example, by resin molding. In the present embodiment, as shown in FIG. 2, the capacitor case 3d is formed in a bottomed cylindrical shape. The bottom wall of the capacitor case 3d is formed, for example, in a rectangular shape. The capacitor case 3d has an opening 3d1 which is an open portion on the side opposite to the side of the bottom wall of the capacitor case 3d. The opening 3d1 faces the substrate 4. The capacitor bus bar 3f protrudes from the opening 3d1. The arrangement of the capacitor case 3d is not limited to this, and the capacitor case 3d may be arranged such that the opening 3d1 faces the semiconductor module 8 side so that the capacitor bus bar 3f protrudes from the sealing material 3b toward the semiconductor module 8 side. When the capacitor case 3d is arranged such that the opening 3d1 faces the semiconductor module 8 side, it is desirable to provide the rapid discharge resistor mounting portion on the housing 5 or the cover 6. The configuration in which the rapid discharge resistor mounting portion is provided on the housing 5 or the cover 6 will be described later.

[0026] <semiconductor module 8> The semiconductor module 8 includes a semiconductor element 8a for power conversion, a module main body portion 8c that houses the semiconductor element 8a, a module bus bar 8b connected to the capacitor 3, an output terminal (not shown), and a plurality of control terminals (not shown). The module bus bar 8b, the output terminal, and the control terminals are provided to protrude outward from the module main body portion 8c. The portion of the module main body portion 8c shown in FIG. 1 is a sealing resin that surrounds the semiconductor element 8a. In FIG. 1, the module bus bar 8b is omitted. The module bus bar 8b, the output terminal, and the control terminals are made of, for example, copper or aluminum alloy with low electrical resistivity and excellent conductivity. The module bus bar 8b has a positive bus bar and a negative bus bar. The positive bus bar is electrically connected to the P bus bar of the capacitor bus bar 3f via the bus bar 3c. The negative bus bar is electrically connected to the N bus bar of the capacitor bus bar 3f via the bus bar 3c. The number of semiconductor elements 8a may be single or plural.

[0027] The semiconductor element 8a is a semiconductor element for power control such as a MOSFET (Metal Oxide Semiconductor Field Effect Transistor) or an IGBT (Insulated Gate Bipolar Transistor), or a freewheeling diode may be used. The semiconductor element 8a is not limited to these, and other semiconductor elements such as bipolar transistors may also be used. Also, an RC-IGBT (Reverse Conducting IGBT) in which a switching element and a freewheeling diode are integrated may be used.

[0028] The semiconductor element 8a is formed on a semiconductor substrate made of a material such as silicon, silicon carbide, or gallium nitride, and a wide bandgap semiconductor element having a bandgap wider than that of silicon can be used for the semiconductor element 8a. When using, for example, a MOSFET formed of silicon carbide, which is a wide bandgap semiconductor element, the amount of time change of current di / dt generated during switching can be made larger than that of a MOSFET formed of silicon. Also, since the wide bandgap semiconductor element has a small on-resistance, less loss, and less heat generation, the chip area can be reduced. Since the chip area is reduced, the semiconductor module 8 can be miniaturized.

[0029] <Substrate 4> The power conversion device 1 includes a substrate 4 on which a control circuit for controlling the semiconductor module 8 is mounted. The substrate 4 and the semiconductor module 8 are connected by a plurality of control terminals (not shown) that the semiconductor module 8 has. The substrate 4 is installed, for example, in the vicinity of the opening 5a. A control circuit for controlling the rapid discharge resistor 2 may be further mounted on the substrate 4. When the control circuit of the rapid discharge resistor 2 is incorporated inside the rapid discharge resistor 2, effects such as thermal shock from the resistor 2c on the control circuit are conceivable. Therefore, it is desirable to also integrate and mount the control circuit for controlling the rapid discharge resistor on the substrate 4.

[0030] <Housing 5, Cover 6> The housing 5 is formed, for example, in a bottomed cylindrical shape. In the present embodiment, the cover 6 is also formed in a bottomed cylindrical shape, and a box-like state is formed by connecting the opening side of the housing 5 and the opening side of the cover 6. The shapes of the housing 5 and the cover 6 are not limited to this. It is also possible to configure the housing 5 with a higher side wall height and form the cover 6 in a plate shape to cover the opening 5a. The housing 5 and the cover 6 are generally made of metal, more specifically, an aluminum alloy. The materials of the housing 5 and the cover 6 are not limited to metal, and a configuration in which resin is used for the main body portions of the housing 5 and the cover 6 and metal coating is applied to the surface, or a configuration in which they remain resin, may be acceptable.

[0031] In the present embodiment, a cooler 9 having a flow path 9a for cooling the semiconductor module 8 and the capacitor 3 is provided in the outer portion of the bottom wall 5b of the housing 5. The semiconductor module 8 and the capacitor 3 are thermally connected to the inner portion of the bottom wall 5b of the housing 5. The thermal connection is not limited to a configuration in which the bottom wall 5b, the semiconductor module 8, and the capacitor 3 are directly in contact and connected. The bottom wall 5b and the semiconductor module 8 and the capacitor 3 may be thermally connected via a heat conduction member such as grease or a heat dissipation sheet. A refrigerant flows through the flow path 9a. As the refrigerant, for example, a liquid such as water or ethylene glycol solution, or a gas such as air is used. The cooler 9 is also generally made of metal, more specifically, an aluminum alloy. The cooler 9 has refrigerant inlets and outlets (not shown) through which the refrigerant flows in and out. A plurality of cooling fins may be provided on the portion of the flow path 9a on the side of the bottom wall 5b.

[0032] In the present embodiment, the housing 5 has the cooler 9 and the cooler 9 is integrated with the housing 5, but it is not limited to this. A configuration in which a separately formed cooler 9 is attached to the housing 5 may also be acceptable. When the housing 5 has the cooler 9, the portion for attaching a separate cooler 9 to the housing 5 becomes unnecessary, so the power conversion device 1 can be miniaturized. Also, a configuration in which the cooler 9 is not provided may be acceptable, but by providing the cooler 9, the semiconductor module 8 can be efficiently cooled, so the heat of the semiconductor module 8 can be suppressed from being transmitted to the capacitor 3.

[0033] In this embodiment, the cover 6 is formed in a bottomed cylindrical shape, and the bottom wall portion is formed in a flat plate shape, but it is not limited to this. In another power conversion device 1 shown in FIG. 4, the cover 6 has a protruding portion 6a that protrudes in a direction away from the housing 5. Inside the protruding portion 6a, a protruding portion of the rapid discharge resistor 2 is provided. By configuring in this way, the volume of the power conversion device 1 can be reduced. The portion of the power conversion device 1 provided inside the protruding portion 6a is not limited to the rapid discharge resistor 2, and other components may be used.

[0034] <Arrangement of each part of the power conversion device 1> The configuration of the arrangement of each part of the power conversion device 1, which is a main part of the present disclosure, will be described. As shown in FIG. 2, the capacitor 3 and the semiconductor module 8 are provided on one surface side of the substrate 4, and the rapid discharge resistor 2 is provided on the other surface side of the substrate 4. In the figure, one surface of the substrate 4 is defined as surface 41, and the other surface of the substrate 4 is defined as surface 42. By configuring in this way, with respect to the capacitor 3 having low heat resistance, the heat of the rapid discharge resistor 2 that rapidly generates heat during active discharge can be blocked by the substrate 4, so that the influence of the heat generation of the rapid discharge resistor 2 can be suppressed from being transmitted to the capacitor 3. Since not all components are assembled on the same surface side of the substrate, layout properties can be ensured.

[0035] As described in the prior art, when a rapid discharge resistor is installed near a multi-stage waterway forming member which is a cooler, the layout of the waterways and the method of forming the waterways are restricted, so there is a problem that the layout property of the waterways and the periphery of the waterways deteriorates. In order to suppress the temperature rise of the capacitor, even when the rapid discharge resistor is arranged near the cooler, there is a problem that the layout property further deteriorates. However, in the above-described configuration, since there is no need to arrange the rapid discharge resistor 2 near the cooler, the layout property of the power conversion device 1 can be improved. Further, although the rapid discharge resistor 2, the capacitor 3, and the semiconductor module 8 are relatively large components, by mounting the rapid discharge resistor 2 on the surface 42 side of the substrate 4 and mounting the capacitor 3 and the semiconductor module 8 on the surface 41 side of the substrate 4, the installation area on the surface 41 side of the substrate 4 can be reduced, so that the power conversion device 1 can be miniaturized.

[0036] In the present embodiment, the power conversion device 1 includes a bus bar 3c that electrically connects the capacitor 3 and the semiconductor module 8, and the bus bar 3c is provided on one surface side of the substrate 4. By providing the bus bar 3c separately from the capacitor 3 and the semiconductor module 8 in this way, since it is easier to make the structure of the bus bar 3c more complicated, the structures of the bus bar on the capacitor 3 side and the bus bar on the semiconductor module 8 side can be simplified, so that the layout property of the capacitor 3 and the semiconductor module 8 can be improved.

[0037] Since the bus bar 3c is made of a metal such as copper or an aluminum alloy, it has excellent thermal conductivity. Therefore, when the heat of the rapid discharge resistor 2 is transmitted to the bus bar 3c, the heat is also transmitted to the capacitor 3. By providing the bus bar 3c on one surface side of the substrate 4, it is possible to suppress the heat of the rapid discharge resistor 2 from being transmitted to the bus bar 3c. Since the heat of the rapid discharge resistor 2 being transmitted to the bus bar 3c is suppressed, the heat transfer of the rapid discharge resistor 2 to the capacitor 3 via the bus bar 3c can be suppressed.

[0038] In this embodiment, a substrate 4 is provided between the capacitor 3 and the rapid discharge resistor 2. In the configuration of the power conversion device 1 shown in FIGS. 1 and 2, the substrate 4 is provided in substantially all portions between the capacitor 3 and the rapid discharge resistor 2. By not only arranging the capacitor 3 and the rapid discharge resistor 2 on both sides of the substrate 4 but also providing the substrate 4 in the portion between the capacitor 3 and the rapid discharge resistor 2, it is possible to surely suppress the heat of the rapid discharge resistor 2 from being transmitted to the capacitor 3.

[0039] <Rapid discharge resistor mounting portion> The rapid discharge resistor mounting portion will be described. In this embodiment, as shown in FIG. 2, the capacitor 3 has a rapid discharge resistor mounting portion 3a. The rapid discharge resistor 2 is attached to the rapid discharge resistor mounting portion 3a. The rapid discharge resistor 2 is fixed to the capacitor 3 by the rapid discharge resistor mounting portion 3a. A part of the rapid discharge resistor mounting portion 3a is embedded in the sealing material 3b, and the portion for attaching the rapid discharge resistor 2 is exposed from the sealing material 3b. In this embodiment, the rapid discharge resistor mounting portion 3a has an extending portion 3a1 extending from one side of the substrate 4 to the other side of the substrate, and the rapid discharge resistor 2 is attached to the end of the extending portion 3a1 on the other side of the substrate 4, and the substrate 4 has a through hole 4a or a notch 4b through which the extending portion 3a1 passes. In the configuration shown in FIG. 2, the substrate 4 has a through hole 4a, and the extending portion 3a1 passes through the through hole 4a from the side of the surface 41 to the side of the surface 42. The portion of the substrate 4 through which the extending portion 3a1 passes is not limited to the through hole 4a, and a notch 4b shown in FIG. 9 may also be used. The rapid discharge resistor 2 is fixed to the extending portion 3a1 of the rapid discharge resistor mounting portion 3a by, for example, a screw (not shown).

[0040] Since the capacitor 3 has the rapid discharge resistor mounting portion 3a, while suppressing the heat of the rapid discharge resistor 2 from being transmitted to the capacitor 3 by the substrate 4, it is not necessary to provide additional components for attaching the rapid discharge resistor 2, so the number of components of the power conversion device 1 can be reduced. Since the number of components of the power conversion device 1 is reduced, the power conversion device 1 can be made less costly.

[0041] Further, by providing the rapid discharge resistor mounting portion 3a penetrating the substrate 4, the rapid discharge resistor 2 and the capacitor 3 are arranged overlappingly when viewed perpendicularly to the substrate surface of the substrate 4, so that the mounting area of the components of the power conversion device 1 can be reduced. Since the mounting area of the components of the power conversion device 1 is reduced, the power conversion device 1 can be miniaturized. Also, since the assembling direction of the power conversion device 1 is unified in one direction, the assembling man-hours of the power conversion device 1 can be reduced.

[0042] At least a part of the rapid discharge resistor mounting portion 3a is made of a material having a higher thermal resistance than metal. The material having a higher thermal resistance than metal is, for example, a resin material. By using a material having a higher thermal resistance than metal for the whole or at least a part of the rapid discharge resistor mounting portion 3a, the heat conduction from the rapid discharge resistor 2 to the capacitor 3 through the rapid discharge resistor mounting portion 3a can be suppressed.

[0043] When the rapid discharge resistor mounting portion 3a is composed only of resin, it becomes very difficult to ensure the strength of the rapid discharge resistor mounting portion 3a from the viewpoints of fatigue of the rapid discharge resistor mounting portion 3a during vibration and stress during screw fastening. Therefore, a configuration in which a metal fastening member or a metal reinforcing member is provided in a portion contributing to the fastening of the rapid discharge resistor 2 is desirable. As shown in FIGS. 10 and 11, the rapid discharge resistor mounting portion 3a has a reinforcing member made of metal or a fastening portion made of metal to which the rapid discharge resistor 2 is fixed. By configuring in this way, the strength of the rapid discharge resistor mounting portion 3a can be ensured.

[0044] In the configuration shown in Fig. 10, the extension part 3a1 of the rapid discharge resistor mounting part 3a has a metal screw insert 3a2 inside as a reinforcing material. The rapid discharge resistor 2 is fixed to the screw insert 3a2 by a screw 10 passing through the case through-hole 2e. The reinforcing material is not limited to a configuration having a fastening part of the screw, and a configuration in which a reinforcing material without a fastening part is provided in the extension part 3a1 may be used. In the configuration shown in Fig. 11, the extension part 3a1 of the rapid discharge resistor mounting part 3a has a metal insert nut 3a3 inside as a fastening part. The rapid discharge resistor 2 is fixed to the insert nut 3a3 by a screw 10 passing through the case through-hole 2e. Since the screw insert 3a2 and the insert nut 3a3 can be provided in the rapid discharge resistor mounting part 3a by insert molding, the configuration of the rapid discharge resistor mounting part 3a provided with a reinforcing material or a fastening part can be easily manufactured.

[0045] The configuration in which the capacitor 3 has the rapid discharge resistor mounting part 3a is not limited to a configuration in which a part of the rapid discharge resistor mounting part 3a is embedded in the sealing material 3b. Another configuration in which the capacitor 3 has the rapid discharge resistor mounting part 3a will be described with reference to Figs. 5 and 6. As shown in Fig. 6, the rapid discharge resistor mounting part 3a is integrated with the capacitor case 3d. As shown in Fig. 5, the extension part 3a1 integrated with the capacitor case 3d penetrates the substrate 4, and the rapid discharge resistor 2 is fixed to the extension part 3a1 by, for example, a screw (not shown). By configuring in this way, when manufacturing the capacitor case 3d, the rapid discharge resistor mounting part 3a can also be manufactured, so that the productivity of the power conversion device 1 can be improved.

[0046] <Modification Example of Rapid Discharge Resistor Mounting Part> In the above-described configuration, the capacitor 3 had the rapid discharge resistor mounting portion 3a. However, the arrangement of the rapid discharge resistor mounting portion is not limited to the configuration in which the capacitor 3 has the rapid discharge resistor mounting portion. Two configurations in which the capacitor 3 does not have the rapid discharge resistor mounting portion will be described. The first configuration will be described with reference to FIGS. 12 and 13, and the second configuration will be described with reference to FIGS. 14 and 15. FIG. 12 is a plan view showing an outline of another power conversion device 1 according to Embodiment 1, in which the cover 6 is removed and only the outer shape of the substrate 4 is shown. FIG. 13 is a cross-sectional view of another power conversion device 1 cut at the C-C cross-sectional position of FIG. 12. FIG. 14 is a plan view showing an outline of another power conversion device 1 according to Embodiment 1, in which the cover 6 is removed and only the outer shape of the substrate 4 is shown. FIG. 15 is a cross-sectional view of another power conversion device 1 cut at the D-D cross-sectional position of FIG. 14.

[0047] The first configuration will be described. In the first configuration, as shown in FIG. 13, the housing 5 has a rapid discharge resistor mounting portion 5c. The substrate 4 has a notch portion 4c. The rapid discharge resistor mounting portion 5c is provided on the bottom wall 5b of the housing 5 and extends through the notch portion 4c in the direction of the cover 6. The rapid discharge resistor 2 is attached to the side of the rapid discharge resistor mounting portion 5c on the cover 6 side.

[0048] As shown in FIG. 12, when viewed perpendicular to the substrate surface of the substrate 4, the substrate 4 surrounds the rapid discharge resistor 2, but the rapid discharge resistor 2 and the substrate 4 do not overlap due to the notch portion 4c. Also, due to the notch portion 4c, a part of the capacitor 3 does not overlap with the substrate 4 either. As indicated by the dashed arrow in FIG. 13, there is a portion where the substrate 4 is not provided between the rapid discharge resistor 2 and the capacitor 3.

[0049] In the first configuration, as shown in FIG. 12, since most of the capacitor 3 is covered by the substrate 4, heat transfer from the rapid discharge resistor 2 to the capacitor 3 can be reduced. However, as shown in FIG. 13, since there is a portion between the rapid discharge resistor 2 and the capacitor 3 indicated by the dashed arrow where the substrate 4 is not provided, heat radiation from the rapid discharge resistor 2 to the capacitor 3 and the like cannot be inhibited, so the degree of reduction in heat transfer from the rapid discharge resistor 2 to the capacitor 3 is relatively small.

[0050] The second configuration will be described. In the second configuration, as shown in FIG. 15, the rapid discharge resistor 2 is provided between the cover 6 and the substrate 4. The cover 6 has a rapid discharge resistor attachment portion 6b, and the rapid discharge resistor 2 is attached to the rapid discharge resistor attachment portion 6b. In the present embodiment, the rapid discharge resistor attachment portion 6b extends inside the cover 6 in the direction of the substrate 4. The rapid discharge resistor attachment portion 6b of the present embodiment is a boss. The rapid discharge resistor 2 is attached to the side of the rapid discharge resistor attachment portion 6b on the substrate 4 side by a screw 10. By configuring in this way, the substrate 4 can be provided in all portions between the capacitor 3 and the rapid discharge resistor 2. Since the substrate 4 is provided in all portions between the capacitor 3 and the rapid discharge resistor 2, the heat shielding effect by the substrate 4 can be maximized. However, since the portion for accommodating on the other surface side of the substrate 4 including the screw 10 for attaching the rapid discharge resistor expands, the power conversion device 1 becomes slightly larger.

[0051] The power conversion device 1 may be configured as the first configuration or the second configuration. However, from the viewpoints of suppressing heat transfer from the rapid discharge resistor 2 to the capacitor 3 and miniaturizing the power conversion device 1, a configuration in which the capacitor 3 has a rapid discharge resistor attachment portion 3a is desirable.

[0052] In this embodiment, the housing 5 is shown to have the cooler 9, but the present invention is not limited thereto, and the housing 5 may not have the cooler 9. Further, the power conversion device 1 may not include one or both of the housing 5 and the cover 6. The components of the power conversion device 1 such as the capacitor 3 may be directly attached to other devices. Further, the power conversion device 1 may not include the housing 5 and the cover 6, and a cooler may be directly attached to the components of the power conversion device 1 such as the capacitor 3. Further, it may be a form in which the components and functions of another device are integrated.

[0053] As described above, in the power conversion device 1 according to Embodiment 1, the capacitor 3, the semiconductor module 8 electrically connected to the capacitor 3 and having the semiconductor element 8a, the substrate 4 having a control circuit for controlling the semiconductor module 8, and the capacitor 3 are provided. The rapid discharge resistor 2 for discharging the electric charge accumulated in the capacitor 3 is provided. Since the capacitor 3 and the semiconductor module 8 are provided on one surface side of the substrate 4 and the rapid discharge resistor 2 is provided on the other surface side of the substrate 4, the heat of the rapid discharge resistor 2 that rapidly generates heat during active discharge can be blocked by the substrate 4 from the capacitor 3 having low heat resistance. Therefore, it is possible to suppress the influence of the heat generation of the rapid discharge resistor 2 from being transmitted to the capacitor 3. Further, since not all components are assembled on the same surface side of the substrate, layout properties can be ensured. Further, although the rapid discharge resistor 2, the capacitor 3, and the semiconductor module 8 are relatively large components, by mounting the rapid discharge resistor 2 on the surface 42 side of the substrate 4 and mounting the capacitor 3 and the semiconductor module 8 on the surface 41 side of the substrate 4, the installation area on the surface 41 side of the substrate 4 can be reduced, so that the power conversion device 1 can be miniaturized.

[0054] When the power conversion device 1 includes a bus bar 3c that electrically connects the capacitor 3 and the semiconductor module 8, and the bus bar 3c is provided on one side of the substrate 4, providing the bus bar 3c separately from the capacitor 3 and the semiconductor module 8 makes it easier to complicate the structure of the bus bar 3c. Therefore, the structures of the bus bar on the capacitor 3 side and the bus bar on the semiconductor module 8 side can be simplified, and the layout property of the capacitor 3 and the semiconductor module 8 can be improved.

[0055] When a substrate 4 is provided between the capacitor 3 and the rapid discharge resistor 2, not only are the capacitor 3 and the rapid discharge resistor 2 arranged separately on both sides of the substrate 4, but also by providing the substrate 4 in the portion between the capacitor 3 and the rapid discharge resistor 2, it is possible to reliably suppress the heat of the rapid discharge resistor 2 from being transmitted to the capacitor 3.

[0056] When the capacitor 3 has a rapid discharge resistor mounting portion 3a and the rapid discharge resistor 2 is attached to the rapid discharge resistor mounting portion 3a, there is no need to provide additional parts for attaching the rapid discharge resistor 2, so the number of parts of the power conversion device 1 can be reduced. Since the number of parts of the power conversion device 1 is reduced, the power conversion device 1 can be made less costly.

[0057] When at least a part of the rapid discharge resistor mounting portion 3a is made of a material having a higher thermal resistance than metal, heat conduction from the rapid discharge resistor 2 to the capacitor 3 through the rapid discharge resistor mounting portion 3a can be suppressed.

[0058] When the rapid discharge resistor mounting portion 3a has a reinforcing member made of metal or a fastening portion made of metal to which the rapid discharge resistor 2 is fixed, the strength of the rapid discharge resistor mounting portion 3a can be ensured as compared with the case where the rapid discharge resistor mounting portion 3a is composed only of resin.

[0059] The rapid discharge resistor mounting portion 3a has an extending portion 3a1 that extends from one side of the substrate 4 to the other side of the substrate. The rapid discharge resistor 2 is attached to the end of the extending portion 3a1 on the other side of the substrate 4. When the substrate 4 has a through hole 4a or a notch 4b through which the extending portion 3a1 passes, when viewed perpendicular to the substrate surface of the substrate 4, the rapid discharge resistor 2 and the capacitor 3 are arranged overlappingly, so that the mounting area of the components of the power conversion device 1 can be reduced. Since the mounting area of the components of the power conversion device 1 is reduced, the power conversion device 1 can be miniaturized. Also, since the assembly direction of the power conversion device 1 is unified in one direction, the assembly man-hours of the power conversion device 1 can be reduced.

[0060] When the rapid discharge resistor 2 is provided between the cover 6 and the substrate 4, the cover 6 has a rapid discharge resistor mounting portion 6b, and the rapid discharge resistor 2 is attached to the rapid discharge resistor mounting portion 6b, the substrate 4 can be provided in all portions between the capacitor 3 and the rapid discharge resistor 2. Since the substrate 4 is provided in all portions between the capacitor 3 and the rapid discharge resistor 2, the heat shielding effect by the substrate 4 can be maximized.

[0061] When the housing 5 has a cooler 9 for cooling the semiconductor module 8, the portion for attaching a separate cooler 9 to the housing 5 becomes unnecessary, so that the power conversion device 1 can be miniaturized. Also, since the semiconductor module 8 can be cooled efficiently, the heat of the semiconductor module 8 can be suppressed from being transmitted to the capacitor 3.

[0062] Embodiment 2. The power conversion device 1 according to Embodiment 2 will be described. FIG. 16 is a cross-sectional view showing the outline of the power conversion device 1 according to Embodiment 2, and is a cross-sectional view of the power conversion device 1 cut at a position equivalent to the A-A cross-sectional position in FIG. 1. The power conversion device 1 according to Embodiment 2 has a configuration in which a heat conduction member 7 is provided in addition to the configuration of Embodiment 1.

[0063] In this embodiment, the power conversion device 1 includes a housing 5 and a cover 6. The rapid discharge resistor 2 is provided between the cover 6 and the substrate 4, and the rapid discharge resistor 2 is thermally connected to the cover 6 via a heat conduction member 7. The heat conduction member 7 is, for example, a heat dissipation gap filler, a heat conduction grease, or a heat dissipation sheet. The heat conduction member 7 may be in the form of a sheet or may be in a liquid state having a large viscosity during manufacturing. The large viscosity means a viscosity such that no liquid dripping occurs during manufacturing. When the sheet-shaped heat conduction member 7 is selected, the installation of the heat conduction member 7 in the manufacturing process of the power conversion device 1 becomes manual work by a person because it is difficult to handle by the device. Therefore, since the installation of the sheet-shaped heat conduction member 7 cannot be automated, when considering assembling the power conversion device 1 automatically, the heat conduction member 7 is preferably in a liquid state.

[0064] The outline of the process of providing the liquid heat conduction member 7 will be described. First, immediately before the step of attaching the cover 6, the heat conduction member 7 is applied to the upper part of the rapid discharge resistor 2 with an automatic applicator. A recess may be provided at the part where the heat conduction member 7 is applied, and the heat conduction member 7 may be applied so that the heat conduction member 7 bulges from the recess. Next, the cover 6 is attached to the housing 5 so that the inside of the cover 6 and the heat conduction member 7 are in contact with each other. When a material that cures with the passage of time is selected for the heat conduction member 7, the heat conduction member 7 cures with the passage of time, and the cover 6 and the rapid discharge resistor 2 are thermally connected. Note that, as described above, the process is not limited to the step of applying the heat conduction member 7 as a separate body after assembling the rapid discharge resistor 2. The rapid discharge resistor 2 with the heat conduction member 7 applied in advance may be assembled into the power conversion device 1. In this case, the step of applying the heat conduction member 7 to the upper part of the rapid discharge resistor 2 assembled in the power conversion device 1 can be omitted.

[0065] By providing the heat conduction member 7, the heat generated when the rapid discharge resistor 2 generates heat can be transferred to the cover 6, so that the apparent heat capacity of the rapid discharge resistor 2 can be increased. In addition, since the rapid discharge resistor 2 can be radiated from the side of the cover 6, the heat radiation performance of the rapid discharge resistor 2 can be improved. Since the heat radiation performance of the rapid discharge resistor 2 is improved, the influence of the heat generation of the rapid discharge resistor 2 on the capacitor 3 can be further suppressed from being transmitted.

[0066] In the configuration provided with the heat conduction member 7, the cover 6 is preferably made of a metal having excellent heat conductivity, and a structure for thermally conducting to the housing 5 through the cover 6 is desirable. However, even when heat is not conducted to the housing 5, the heat capacity with respect to the rapid discharge resistor 2 can be increased. Therefore, in consideration of the balance between the heat establishment of the capacitor 3 and the rapid discharge resistor 2 and the cost of the structure, the material of the cover 6 should be considered.

[0067] Embodiment 3. The power conversion device 1 according to Embodiment 3 will be described. FIGS. 17 and 18 are cross-sectional views showing the outline of the power conversion device 1 according to Embodiment 3, and are cross-sectional views of the power conversion device 1 cut at a position equivalent to the A-A cross-sectional position in FIG. 1. The power conversion device 1 according to Embodiment 3 has a configuration in which the arrangement of the open portion of the rapid discharge resistor case 2a is determined.

[0068] In the present embodiment, as shown in FIG. 17, a cover 6 is provided to face the opening side of a case opening 2d which is an open portion of a rapid discharge resistor case 2a. When the rapid discharge resistor 2 abnormally generates heat due to a trouble in the control circuit of the power conversion device 1 or the like, thermal expansion occurs inside the rapid discharge resistor 2, and there is a possibility that the sealing material 2b scatters vigorously from the case opening 2d of the rapid discharge resistor 2. Even when the sealing material 2b scatters vigorously when such a trouble occurs, by opposing the cover 6 to the opening side of the case opening 2d, it is possible to prevent the scattered objects from directly colliding with the substrate 4, the capacitor 3, etc. Since the scattered objects do not directly collide with the substrate 4, the capacitor 3, etc., it is possible to protect the substrate 4 and the capacitor 3 which are difficult to replace. Further, since the rapid discharge resistor 2 is attached to the side of the cover 6, when the rapid discharge resistor 2 is damaged, the rapid discharge resistor 2 can be easily replaced.

[0069] The configuration in which the cover 6 is opposed to the opening side of the case opening 2d is not limited to the configuration shown in FIG. 17, and the configuration shown in FIG. 18 may also be used. In the embodiment shown in FIG. 18, the cover 6 has a protruding portion 6a protruding in a direction away from the housing 5, and the case opening 2d is provided inside the protruding portion 6a. By configuring in this way, the scattering of the sealing material 2b is further suppressed, so that the effect of preventing damage to surrounding components due to the scattering of the sealing material 2b can be further improved. For suppressing the scattering of the sealing material 2b, a configuration in which the case opening 2d is provided inside the protruding portion 6a is desirable.

[0070] Although various exemplary embodiments and examples are described in the present disclosure, the various features, aspects, and functions described in one or more embodiments are not limited to the application of a specific embodiment, but can be applied to the embodiments alone or in various combinations. Therefore, countless variations not illustrated are envisioned within the scope of the technology disclosed in this specification. For example, it includes the case where at least one component is deformed, added, or omitted, and further, the case where at least one component is extracted and combined with the components of other embodiments.

[0071] Hereinafter, aspects of the present disclosure will be collectively described as appendices. (Appendix 1) A power conversion device comprising a capacitor, a semiconductor module electrically connected to the capacitor and having a semiconductor element, a substrate having a control circuit for controlling the semiconductor module, and a rapid discharge resistor for discharging the charge stored in the capacitor. The capacitor and the semiconductor module are provided on one side of the substrate, and the rapid discharge resistor is provided on the other side of the substrate. (Appendix 2) A bus bar electrically connecting the capacitor and the semiconductor module. The bus bar is provided on one side of the substrate in the power conversion device according to Appendix 1. (Appendix 3) The power conversion device according to Appendix 1 or 2, wherein the substrate is provided between the capacitor and the rapid discharge resistor. (Appendix 4) A housing that houses the capacitor, the semiconductor module, the substrate, and the rapid discharge resistor and has an opening, and a cover that covers the opening. The rapid discharge resistor includes a resistor, a rapid discharge resistor case that houses the resistor and has a partially open portion, and a sealing material that seals the resistor inside the rapid discharge resistor case. The cover is provided to face the opening side of the case opening, which is the open portion of the rapid discharge resistor case, in the power conversion device according to any one of Appendices 1 to 3. The cover has a protruding portion protruding in a direction away from the housing. (Appendix 5) The case opening is provided inside the protruding portion in the power conversion device according to Appendix 4. The power conversion device according to Appendix 4, wherein the capacitor, the semiconductor module, the substrate, and the rapid discharge resistor are housed in a housing having an opening, and a cover that covers the opening. (Appendix 6) A housing that houses the capacitor, the semiconductor module, the substrate, and the rapid discharge resistor and has an opening, and a cover that covers the opening. The power conversion device according to Appendix 4, further comprising a cover that covers the opening. The rapid discharge resistor is provided between the cover and the substrate, The rapid discharge resistor is thermally connected to the cover via a heat conducting member. The power conversion device according to any one of Appendices 1 to 5. (Appendix 7) The capacitor has a rapid discharge resistor mounting portion, The rapid discharge resistor is attached to the rapid discharge resistor mounting portion. The power conversion device according to any one of Appendices 1 to 6. (Appendix 8) At least a part of the rapid discharge resistor mounting portion is made of a material having a higher thermal resistance than metal. The power conversion device according to Appendix 7. (Appendix 9) The rapid discharge resistor mounting portion has a reinforcing member made of metal or a fastening portion made of metal to which the rapid discharge resistor is fixed. The power conversion device according to Appendix 7 or 8. (Appendix 10) The rapid discharge resistor mounting portion has an extending portion extending from one side of the substrate to the other side of the substrate, The rapid discharge resistor is attached to an end of the extending portion on the other side of the substrate, The substrate has a through hole or a notch through which the extending portion passes. The power conversion device according to any one of Appendices 7 to 9. (Appendix 11) A housing that houses the capacitor, the semiconductor module, the substrate, and the rapid discharge resistor and has an opening, A cover that covers the opening, The rapid discharge resistor is provided between the cover and the substrate, The cover has a rapid discharge resistor mounting portion, The rapid discharge resistor is attached to the rapid discharge resistor mounting portion. The power conversion device according to any one of Appendices 1 to 6. (Appendix 12) The housing has a cooler for cooling the semiconductor module. The power conversion device according to any one of Appendices 4 to 6.

Explanation of Signs

[0072] 1 Power conversion device, 2 Rapid discharge resistor, 2a Rapid discharge resistor case, 2b Sealing material, 2c Resistor, 2d Case opening, 2e Case through-hole, 3 Capacitor, 3a Rapid discharge resistor mounting part, 3a1 Extension part, 3a2 Thread insert, 3a3 Insert nut, 3b Sealing material, 3c Bus bar, 3d Capacitor case, 3d1 Opening, 3e Body part, 3f Capacitor bus bar, 4 Substrate, 4a Through-hole, 4b, 4c Notch, 41, 42 Surfaces, 5 Housing, 5a Opening, 5b Bottom wall, 5c Rapid discharge resistor mounting part, 6 Cover, 6a Protrusion, 6b Rapid discharge resistor mounting part, 7 Heat conduction member, 8 Semiconductor module, 8a Semiconductor element, 8b Module bus bar, 8c Module body part, 9 Cooler, 9a Flow path, 10 Screw

Claims

1. A power conversion device comprising: a capacitor; a semiconductor module electrically connected to the capacitor and having a semiconductor element; a substrate having a control circuit for controlling the semiconductor module; and a rapid discharge resistor for discharging the charge stored in the capacitor, wherein the capacitor and the semiconductor module are provided on one side of the substrate, and the rapid discharge resistor is provided on the other side of the substrate.

2. The power conversion device according to claim 1, further comprising a bus bar electrically connecting the capacitor and the semiconductor module, wherein the bus bar is provided on one side of the substrate.

3. The power conversion device according to claim 1 or 2, wherein the substrate is provided between the capacitor and the rapid discharge resistor.

4. A power conversion device comprising: a housing that houses the capacitor, the semiconductor module, the substrate, and the rapid discharge resistor and has an opening; and a cover that covers the opening, wherein the rapid discharge resistor includes a resistor, a rapid discharge resistor case that houses the resistor and has a partially open portion, and a sealing material that seals the resistor inside the rapid discharge resistor case, and the cover is provided to face the opening side of a case opening portion that is an open portion of the rapid discharge resistor case.

5. The power conversion device according to claim 4, wherein the cover has a protruding portion that protrudes in a direction away from the housing, and the case opening portion is provided inside the protruding portion.

6. A power conversion device comprising: a housing that houses the capacitor, the semiconductor module, the substrate, and the rapid discharge resistor and has an opening; and a cover that covers the opening, wherein the rapid discharge resistor is provided between the cover and the substrate, and the rapid discharge resistor is thermally connected to the cover via a heat conduction member.

7. The power conversion device according to claim 1, wherein the capacitor has a rapid discharge resistor mounting portion, and the rapid discharge resistor is mounted on the rapid discharge resistor mounting portion.

8. The power conversion device according to claim 7, wherein at least a part of the rapid discharge resistor mounting portion is made of a material having a higher thermal resistance than metal.

9. The power conversion device according to claim 7 or 8, wherein the rapid discharge resistor mounting portion is made of a reinforcing material made of metal or has a fastening portion made of metal to which the rapid discharge resistor is fixed. ​ ​

10. The rapid discharge resistor mounting portion has an extending portion that extends from one side of the substrate to the other side of the substrate, The rapid discharge resistor is attached to an end of the extending portion on the other side of the substrate, The power conversion device according to claim 7 or 8, wherein the substrate has a through hole or a notch through which the extending portion passes.

11. A housing that houses the capacitor, the semiconductor module, the substrate, and the rapid discharge resistor and has an opening, A cover that covers the opening, The rapid discharge resistor is provided between the cover and the substrate, The cover has a rapid discharge resistor mounting portion, The power conversion device according to claim 1, wherein the rapid discharge resistor is attached to the rapid discharge resistor mounting portion.

12. The power conversion device according to any one of claims 4 to 6, wherein the housing has a cooler for cooling the semiconductor module.

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