WO2024257636A1 - Electrical circuit body and power conversion device - Google Patents

Abstract

This electric circuit body is provided with: a conductor plate to which semiconductor elements are joined; a cooling member that is disposed to face the conductor plate and cools heat generated by the semiconductor elements; and an insulation sheet that is disposed between the conductor plate and the cooling member. The insulation sheet includes an intermediate conductor that faces the conductor plate. The intermediate conductor is disposed to be divided into a plurality of portions with respect to the conductor plate corresponding to one of the semiconductor elements, and forms an electric capacitance that is electrically parallel to the conductor plate.

Description

Electrical circuit and power conversion device

The present invention relates to an electric circuit and a power conversion device.

Power conversion devices, which convert between DC and AC power by the switching operation of semiconductor elements, have a high conversion efficiency and are therefore widely used in consumer, automotive, railway and substation equipment. Power conversion devices are configured by incorporating an electric circuit body that operates as an inverter and includes a cooling member that cools the heat generated by the semiconductor elements and an insulating sheet that is placed between the semiconductor elements and the cooling member. Electric circuits used as inverters are required to be compact and lightweight, and also to have improved insulation reliability in order to meet the demand for higher voltages.

Patent Document 1 discloses a power module that includes a first power semiconductor element on the upper arm side and a second power semiconductor element on the lower arm side, a first conductor portion that transmits AC current, a second conductor portion that transmits DC current, a conductive heat dissipation portion, a first intermediate conductor layer that is arranged between the first conductor portion and the heat dissipation portion via an insulating layer, and a second intermediate conductor layer that is arranged between the second conductor portion and the heat dissipation portion via an insulating layer, the second intermediate conductor layer being configured separately from the first intermediate conductor layer, and the first intermediate conductor layer forming a capacitive circuit that shares the voltage between the first conductor portion and the heat dissipation portion.

Japanese Patent Application Publication No. 2016-059147

The device described in Patent Document 1 had problems with insulation reliability when considering high voltages.

The electric circuit according to the present invention comprises a conductor plate to which a semiconductor element is bonded, a cooling member disposed opposite the conductor plate for cooling heat generated by the semiconductor element, and an insulating sheet disposed between the conductor plate and the cooling member, the insulating sheet incorporating an intermediate conductor facing the conductor plate, the intermediate conductor being divided into a plurality of pieces and disposed on the conductor plate corresponding to one of the semiconductor elements, and forming an electrical capacitance electrically parallel to the conductor plate.

The present invention improves the insulation reliability of the electrical circuit.

FIG. 2 is a cross-sectional view of the electric circuit body taken along line XX. 4 is a cross-sectional view of the electric circuit body taken along line YY. FIG. FIG. 2 is a semi-transparent plan view of a semiconductor module. FIG. 2 is a circuit diagram of a semiconductor module. FIG. 11 is an enlarged cross-sectional view of an electric circuit body according to a first modified example. FIG. 11 is a plan view of an insulating sheet in Modification 2. FIG. 13 is a plan view of an insulating sheet in Modification 3. FIG. 13 is a plan view of an insulating sheet in Modification 4. FIG. 13 is an enlarged cross-sectional view of an electric circuit body according to Modification 5. 1 is a circuit diagram of a power conversion device using a semiconductor module. FIG. 2 is an external perspective view of the power conversion device. 1 is a cross-sectional perspective view of the power conversion device taken along line XV-XV.

Below, an embodiment of the present invention will be described with reference to the drawings. The following description and drawings are examples for explaining the present invention, and some parts have been omitted or simplified as appropriate for clarity of explanation. The present invention can also be implemented in various other forms. Unless otherwise specified, each component may be singular or plural.

The position, size, shape, range, etc. of each component shown in the drawings may not represent the actual position, size, shape, range, etc., in order to facilitate understanding of the invention. Therefore, the present invention is not necessarily limited to the position, size, shape, range, etc. disclosed in the drawings.

FIG. 1 is a plan view of an electric circuit body 400 according to an embodiment of the present invention.
The electric circuit body 400 includes the semiconductor modules 300 and a cooling member 340. In the example shown in Fig. 1, the electric circuit body 400 includes three semiconductor modules 300 arranged in parallel.

The semiconductor module 300 incorporates the semiconductor elements 155 and 157, which are sealed with a sealing material 360. Both sides of the semiconductor module 300 dissipate heat generated by the switching operation of the semiconductor elements 155 and 157. Furthermore, the terminals connected to the semiconductor elements 155 and 157 of the semiconductor module 300 are led out from the sealing material 360 on the side of the semiconductor module 300. These terminals are power terminals through which a large current flows, such as the positive terminal 325P and the negative terminal 325M connected to the capacitor module 500 (see FIG. 12) of the DC circuit, and the AC terminal 325A connected to the motor generators 192 and 194 (see FIG. 12) of the AC circuit. The semiconductor elements 155 and 157 can be switching elements such as IGBTs (insulated gate bipolar transistors) and MOSFETs (metal oxide semiconductor field effect transistors).

The terminals extending from the sealing material 360 on the side of the semiconductor module 300 are the lower arm gate terminal 325L, the collector sense terminal 325C, the emitter sense terminal 325E, the upper arm gate terminal 325U, and other terminals. These terminals extending from the semiconductor module 300 are connected to wiring such as a wiring pattern on a substrate (not shown). An electric circuit body 400 having three semiconductor modules 300 arranged in parallel functions as a power conversion device 200 (see FIG. 12) that converts DC power and AC power mutually by the switching operation of the semiconductor elements 155, 157. The number of semiconductor modules 300 included in the electric circuit body 400 is not limited to three, and can be set arbitrarily according to various forms of the electric circuit body 400.

The cooling member 340 is disposed opposite the semiconductor module 300, and cools the heat generated by the switching operation of the semiconductor elements 155, 157. Specifically, the cooling member 340 has a flow path formed therein through which a refrigerant flows, and the refrigerant flowing through the flow path cools the heat generated by the semiconductor elements 155, 157. The refrigerant used may be water or an antifreeze solution made by mixing ethylene glycol into water. The cooling member 340 is preferably made of aluminum, which has high thermal conductivity and is lightweight.

FIGS. 2 and 3 are cross-sectional views of the electric circuit body 400. FIG. 2 is a cross-sectional view of the electric circuit body 400 shown in FIG. 1 taken along line X-X. FIG. 3 is a cross-sectional view of one semiconductor module 300 taken along line Y-Y of the electric circuit body 400 shown in FIG. 1.

As shown in FIG. 2, the power conversion device 200 includes an active element 155 and a diode 156 as first semiconductor elements forming the upper arm circuit (see FIGS. 5 and 6 described below). The active element may be made of Si, SiC, GaN, GaO, C, or the like. When using a body diode for the active element 155, a separate diode may be omitted. As shown in FIG. 3, the collector side of the first semiconductor element 155 is bonded to a second conductor plate 431. This bonding may be performed using solder or sintered metal. The first conductor plate 430 is bonded to the emitter side of the first semiconductor element 155.

As shown in Figures 2 and 3, the second semiconductor element forming the lower arm circuit includes an active element 157 and a diode 158 (see Figures 5 and 6 described below). The collector side of the second semiconductor element 157 is bonded to the fourth conductor plate 433. The third conductor plate 432 is bonded to the emitter side of the second semiconductor element 157.

The conductive plates 430, 431, 432, and 433 are not particularly limited as long as they are made of a material with high electrical conductivity and thermal conductivity, but it is preferable to use metallic materials such as copper-based or aluminum-based materials, or composite materials of metallic materials and diamond, carbon, ceramic, or other materials with high thermal conductivity. These may be used alone, or may be plated with Ni, Ag, or the like to improve adhesion to solder or sintered metal.

In addition to carrying current, the conductor plates 430, 431, 432, and 433 also serve as heat transfer members that transfer heat generated by the semiconductor elements 155, 156, 157, and 158 to the cooling member 340. The surfaces opposite to the surfaces joined to the semiconductor elements 155, 156, 157, and 158 are the heat dissipation surfaces of the conductor plates 430, 431, 432, and 433. Since the conductor plates 430, 431, 432, and 433 and the cooling member 340 have different potentials, an insulating sheet 443 is placed between the heat dissipation surfaces. In other words, the insulating sheet 443 is intended to prevent current from passing from the conductor plates 430, 431, 432, and 433 to the cooling member 340 and the like, and to provide electrical insulation. The insulating sheet 443 is the part that forms the main insulation of the semiconductor module 300 in the power conversion device 200.

Insulating sheet 443 covers conductor plates 430, 431, 432, and 433 on one side and is adhered to the heat dissipation surface of conductor plates 430, 431, 432, and 433. Insulating sheet 443 can be made of either organic or inorganic material as long as it can ensure the required insulation. Generally, insulating sheet 443 is called a resin insulating layer and is often made of epoxy resin, but ceramic may also be used. Insulating sheet 443 made of ceramic is manufactured by firing a green sheet in the same manner as ceramic capacitors, for example, and inserting a sheet-shaped electrode as intermediate conductor 440. By using ceramic, thermal degradation is less likely to occur even if partial discharge occurs. Insulating sheet 443 may contain filler particles to improve thermal conductivity.

Details of the insulating sheet 443 will be described later, but the insulating sheet 443 incorporates an intermediate conductor 440 that faces the conductor plates 430, 431, 432, and 433, and the intermediate conductor 440 is divided into multiple conductor plates 430, 431, 432, and 433 that correspond to one of the semiconductor elements 155, 157, and forms an electrical capacitance that is electrically parallel to the conductor plates 430, 431, 432, and 433.
A surface conductor layer 444 is attached to the other surface of the insulating sheet 443, is exposed on the surface of the semiconductor module 300, and is in contact with the heat conductive member 453. The surface conductor layer 444 is, for example, a metal foil.

The semiconductor elements 155, 156, 157, 158, conductor plates 430, 431, 432, 433, along with the insulating sheet 443 and the surface conductor layer 444, are sealed with sealing material 360 by transfer molding to form the semiconductor module 300. The sealing material 360 is often an epoxy resin, but any type of sealing material may be used as long as it has insulating properties.

The cooling members 340 are arranged on both sides of the semiconductor module 300 and are fixed to the semiconductor module 300 by fixing members not shown. Note that, in this embodiment, the electric circuit body 400 in which the cooling members 340 are arranged on both sides of the semiconductor module 300 is described, but the electric circuit body 400 in which the cooling members 340 are arranged on one side of the semiconductor module 300 may also be used. In this case, a housing or mounting member is arranged on the other side of the semiconductor module 300, and the other side of the semiconductor module 300 is fixed to this housing or mounting member by fixing members.

The thermal conductive member 453 is disposed between the semiconductor module 300 and the cooling member 340 to reduce contact thermal resistance. The thermal conductive member 453 may be made of grease, gel grease, a phase change sheet, or the like.

FIG. 4 is an enlarged cross-sectional view of the electrical circuit body 400, showing part A of FIG.
As shown in Fig. 4, the insulating sheet 443 incorporates an intermediate conductor 440 facing the conductive plate 433. The conductive plate 433 corresponds to the semiconductor element 157 (see Fig. 3). The intermediate conductor 440 is divided into a plurality of pieces and disposed relative to the conductive plate 433. As a result, the intermediate conductor 440 divided into a plurality of pieces forms an electric capacitance that is electrically parallel with the conductive plate 433. The thickness of the insulating sheet 443 is set so that the distance between the intermediate conductor 440 and the conductive plates 430, 432 or the cooling member 340 sandwiching the insulating sheet 443 does not cause partial discharge during normal operation.

The portion P where the insulating sheet 443, the sealing material 360, and the conductor plate 433 contact is generally called a triple point from an electrical standpoint. This triple point is the boundary between materials with different dielectric constants, so potential concentration is likely to occur at the triple point, and it is therefore necessary to improve the insulation reliability. Furthermore, the triple point is prone to voids, cracks, peeling, and other voids due to the application of mechanical force, so it is necessary to improve the insulation reliability. Furthermore, not only at the triple point, but also in the area of the insulating sheet 443 facing the end of the conductor plate 433, peeling is likely to occur due to thermal stress and other factors when the power conversion device 200 is in operation, so it is necessary to improve the insulation reliability.

The insulating sheet 443 incorporates a conductive intermediate conductor 440, so even if a void occurs in the insulating sheet 443 and potential concentrates due to its low dielectric constant, the intermediate conductor 2 can share the potential concentration in the voids, etc. It is desirable that the area of the intermediate conductor 440 in the cross section of the insulating sheet 443 is 20% or more.

As shown in FIG. 4, the intermediate conductor 440 is divided into multiple pieces of the same width and arranged at equal intervals within the insulating sheet 443. Note that the width and intervals at which the intermediate conductor 440 is divided and arranged are merely examples, and can be determined as appropriate depending on the structure, configuration, and electrical characteristics of the semiconductor module 300. For example, the intermediate conductor 440 may be configured to be divided into multiple pieces and arranged at least in the area facing the end of the conductor plate 433.

The intermediate conductor 440 of the insulating sheet 443 is divided into multiple pieces, so even if the intermediate conductor 440 divided by a void or the like is partially short-circuited, the entire intermediate conductor 440 does not become at the same potential, and the concentration of potential in the intermediate conductor 440 other than the short-circuited portion can be suppressed.

For example, even if voids, cracks, peeling, etc. occur at the triple junction indicated by part P due to potential concentration or mechanical force, the concentration of potential on the entire intermediate conductor 440 can be suppressed, and insulation reliability can be improved. As a result, the heat dissipation of the semiconductor module 300 can be improved and the size can be reduced by thinning the insulating sheet 443 depending on the voltage value of the drive voltage. This in turn improves the insulation performance of the power conversion device 200, contributing to an increase in the output density of the power conversion device 200.

In addition, even if peeling or the like due to thermal stress occurs in the region of the insulating sheet 443 opposite the end of the conductor plate 433, not limited to the triple junction, the insulation reliability can be improved by dividing the intermediate conductor 440 into multiple pieces and arranging them in this region.

FIG. 5 is a semi-transparent plan view of semiconductor module 300. FIG. 6 is a circuit diagram of semiconductor module 300.

As shown in Figures 5 and 6, the positive terminal 325P is output from the collector side of the upper arm circuit and is connected to the positive side of a battery or a capacitor. The upper arm gate terminal 325U is output from the gate of the active element 155 of the upper arm circuit. The negative terminal 325M is output from the emitter side of the lower arm circuit and is connected to the negative side of a battery or a capacitor, or GND. The lower arm gate terminal 325L is output from the gate of the active element 157 of the lower arm circuit. The AC terminal 325A is output from the collector side of the lower arm circuit and is connected to the motor. When the neutral point is grounded, the lower arm circuit is connected to the negative side of the capacitor instead of GND.

The emitter sense terminal 325E of the upper arm is output from the emitter of the active element 155 of the upper arm circuit, and the emitter sense terminal 325E of the lower arm is output from the emitter of the active element 157 of the lower arm circuit. The collector sense terminal 325C of the upper arm is output from the collector of the active element 155 of the upper arm circuit, and the collector sense terminal 325C of the lower arm is output from the collector of the active element 157 of the lower arm circuit.

Furthermore, conductor plates (upper arm circuit emitter side) 430 and conductor plates (upper arm circuit collector side) 431 are arranged above and below active element 155 and diode 156 of the semiconductor element (upper arm circuit). Conductor plates (lower arm circuit emitter side) 432 and conductor plates (lower arm circuit collector side) 433 are arranged above and below active element 157 and diode 158 of the semiconductor element (lower arm circuit).

The semiconductor module 300 of this embodiment has a 2-in-1 structure in which two arm circuits, an upper arm circuit and a lower arm circuit, are integrated into one module. Alternatively, a structure in which multiple upper arm circuits and lower arm circuits are integrated into one module may be used. In this case, the number of output terminals from the semiconductor module 300 can be reduced, making it smaller.

FIG. 7 is an enlarged cross-sectional view of the electric circuit body 400 in the first modification, and like FIG. 4, corresponds to part A in FIG. 3. The same parts as in FIG. 4 are given the same reference numerals and will be described briefly.

In FIG. 4, the intermediate conductor 440 is divided into multiple pieces of the same width within the insulating sheet 443 and arranged at equal intervals. In the first modification, as shown in FIG. 7, the number of divisions of the intermediate conductor 440 is greater in the area facing the end of the conductor plate 433 than in the area facing the center of the conductor plate 433.

The area of the insulating sheet 443 facing the end of the conductor plate 433 is prone to peeling due to thermal stress when the power conversion device 200 is in operation, but by increasing the number of divisions of the intermediate conductor 440 in this area, the insulation reliability can be improved.

FIG. 8 is a plan view of insulating sheet 443 in variant 2. Intermediate conductor 440 in insulating sheet 443 is shown with diagonal shading, and the periphery of the ends of conductor plates 430, 432 is shown with dashed lines. Note that although the shapes are not the same as those of insulating sheet 443 and conductor plates 430, 432 shown in the semi-transparent plan view of FIG. 5, they are illustrated diagrammatically in FIG. 8 and in FIG. 9 and FIG. 10 shown below for ease of understanding.

As shown in FIG. 8, the divided intermediate conductors 440 with smaller areas are arranged in the portions of the insulating sheet 443 that are located around the ends of the conductor plates 430 and 432. Furthermore, the divided intermediate conductors 440 with smaller areas are arranged in the portions of the insulating sheet 443 that are located around the ends.

According to the second modification, even if the divided intermediate conductor 440 is partially short-circuited with either the conductor plates 430, 432 sandwiching the insulating sheet 443 or the cooling member 340, the entire intermediate conductor 440 does not become at the same potential, and it is possible to suppress the concentration of potential on the intermediate conductor 440 other than the short-circuited portion.

9 is a plan view of an insulating sheet 443 in Modification 3. An intermediate conductor 440 in the insulating sheet 443 is indicated by hatching, and the periphery of the ends of the conductor plates 430 and 432 is indicated by dashed lines.
As shown in Fig. 9, the intermediate conductor 440 of the insulating sheet 443 is divided into a spherical lattice shape. The area of the spherical shape is smaller than the area of the regions of the conductor plates 430 and 432, and is appropriately determined according to the structure, configuration, and electrical characteristics of the semiconductor module 300. The divided intermediate conductors 440 are appropriately arranged in the portions located around the ends of the conductor plates 430 and 432. Note that the shape is not limited to a spherical shape, and may be an ellipse, a semicircle, or other shape, or these shapes may be mixed. Furthermore, regardless of whether the shapes are the same or different, the areas of the divided intermediate conductors 440 may be the same or different.

Variation 3 eliminates the need to design the division position and area of the intermediate conductor 440 according to the positions of the conductor plates 430 and 432. In addition, insulation reliability can be improved.

10 is a plan view of an insulating sheet 443 in Modification 4. The intermediate conductor 440 in the insulating sheet 443 is indicated by hatching, and the periphery of the ends of the conductor plates 430 and 432 is indicated by dashed lines.
As shown in Fig. 10, the intermediate conductor 440 of the insulating sheet 443 is divided into a diamond-shaped lattice. The area of the diamond shape is smaller than the area of the conductive plates 430 and 432, and is appropriately determined according to the structure, configuration, and electrical characteristics of the semiconductor module 300. The divided intermediate conductors 440 are appropriately arranged in the portions located around the ends of the conductive plates 430 and 432. The shape is not limited to a diamond shape, and may be a triangle, a rectangle, or another polygon, or these shapes may be mixed. Furthermore, the areas of the divided intermediate conductors 440 may be the same or different, regardless of whether they are the same shape or different shapes.

Variation 4 eliminates the need to design the division position and area of the intermediate conductor 440 according to the positions of the conductor plates 430 and 432. In addition, insulation reliability can be improved.

FIG. 11 is an enlarged cross-sectional view of the electric circuit body 400 in the fifth modified example, and like FIG. 7, corresponds to part A in FIG. 3. The same parts as in FIG. 7 are given the same reference numerals and will be described briefly.

In FIG. 7, an example is shown in which the insulating sheet 443 has one intermediate conductor 440 embedded in the thickness direction of the insulating sheet 443. In variant 5, as shown in FIG. 11, the insulating sheet 443 has two intermediate conductors 440 embedded in the thickness direction of the insulating sheet 443. The number of intermediate conductors is not limited to two, and multiple intermediate conductors may be provided. The distance between the intermediate conductor 440 and the conductive plates 430, 432 or cooling member 340 that sandwich the insulating sheet 443 is made larger than the diameter of the filler particles mixed in the insulating sheet 443.

By increasing the number of intermediate conductors 440, the potential can be shared more effectively between the intermediate conductors 440 and either the conductor plates 430, 432 sandwiching the insulating sheet 443 or the cooling member 340. This makes it possible to provide multiple protection in the event of a short circuit.

FIG. 12 is a circuit diagram of a power conversion device 200 using a semiconductor module 300.
The power conversion device 200 includes inverter circuit units 140 and 142, an inverter circuit unit 43 for auxiliary equipment, and a capacitor module 500. The inverter circuit units 140 and 142 include a plurality of semiconductor modules 300, which are connected to form a three-phase bridge circuit. When the current capacity is large, the semiconductor modules 300 are further connected in parallel, and these parallel connections are made corresponding to each phase of the three-phase inverter circuit, thereby enabling an increase in the current capacity to be accommodated. In addition, the active elements 155 and 157 and the diodes 156 and 158, which are semiconductor elements built into the semiconductor modules 300, can also be connected in parallel to enable an increase in the current capacity.

Inverter circuit unit 140 and inverter circuit unit 142 have the same basic circuit configuration, and their control methods and operations are also basically the same. The outline of the circuit operation of inverter circuit unit 140 and the like is well known, so a detailed explanation will be omitted here.

The upper arm circuit has an upper arm active element 155 and an upper arm diode 156 as switching semiconductor elements, and the lower arm circuit has a lower arm active element 157 and a lower arm diode 158 as switching semiconductor elements. The active elements 155 and 157 perform switching operations in response to drive signals output from one or the other of the two driver circuits that make up the driver circuit 174, and convert the DC power supplied from the battery 136 into three-phase AC power.

The upper arm active element 155 and the lower arm active element 157 each have a collector electrode, an emitter electrode, and a gate electrode. The upper arm diode 156 and the lower arm diode 158 each have two electrodes, a cathode electrode and an anode electrode. As shown in FIG. 6, the cathode electrodes of the diodes 156 and 158 are electrically connected to the collector electrodes of the active elements 155 and 157, and the anode electrodes are electrically connected to the emitter electrodes of the active elements 155 and 157, respectively. This causes the current flow from the emitter electrode of the upper arm active element 155 and the lower arm active element 157 to the collector electrode in the forward direction. The active elements 155 and 157 are, for example, IGBTs.

Note that a MOSFET may be used as the active element, in which case the upper arm diode 156 and the lower arm diode 158 are not necessary.

The positive terminal 325P and negative terminal 325M of each upper and lower arm series circuit are each connected to a DC terminal for connecting a capacitor to the capacitor module 500. AC power is generated at the connection between the upper arm circuit and the lower arm circuit, and the connection between the upper arm circuit and the lower arm circuit of each upper and lower arm series circuit is connected to the AC side terminal 325A of each semiconductor module 300. The AC side terminal 320B of each semiconductor module 300 of each phase is each connected to the AC output terminal of the power conversion device 200, and the generated AC power is supplied to the stator winding of the motor generator 192 or 194.

The control circuit 172 generates a timing signal for controlling the switching timing of the upper arm active element 155 and the lower arm active element 157 based on input information from the vehicle's control device and sensors (e.g., current sensor 180). The driver circuit 174 generates a drive signal for switching the upper arm active element 155 and the lower arm active element 157 based on the timing signal output from the control circuit 172. Note that 181 and 188 are connectors.

The upper and lower arm series circuits include a temperature sensor (not shown), and temperature information about the upper and lower arm series circuits is input to the microcomputer. In addition, voltage information about the DC positive pole side of the upper and lower arm series circuits is input to the microcomputer. The microcomputer performs over-temperature and over-voltage detection based on this information, and if over-temperature or over-voltage is detected, it stops the switching operation of all upper arm active elements 155 and lower arm active elements 157, protecting the upper and lower arm series circuits from over-temperature or over-voltage.

FIG. 13 is an external perspective view of the power conversion device 200 shown in FIG. 12, and FIG. 14 is a cross-sectional perspective view of the power conversion device 200 shown in FIG. 13 taken along line XV-XV.

The power conversion device 200 is provided with a housing 12 formed of a substantially rectangular parallelepiped shape and composed of a lower case 11 and an upper case 10. An electric circuit body 400, a capacitor module 500, etc. are housed inside the housing 12. The electric circuit body 400 has a cooling flow path that flows to the cooling member 340, and a refrigerant inlet pipe 13 and a refrigerant outlet pipe 14 that communicate with the cooling flow path protrude from one side of the housing 12. The upper side of the lower case 11 is open, and the upper case 10 is attached to the lower case 11 by closing the opening of the lower case 11. The upper case 10 and the lower case 11 are formed of an aluminum alloy or the like, and are fixed in place while being sealed from the outside. The upper case 10 and the lower case 11 may be integrally formed. By making the housing 12 a simple rectangular parallelepiped shape, it is easy to attach it to a vehicle, etc., and it is also easy to produce.

A connector 17 is attached to one longitudinal side of the housing 12, and an AC terminal 18 is connected to this connector 17. In addition, a connector 21 is provided on the surface from which the refrigerant inlet pipe 13 and the refrigerant outlet pipe 14 are led out.

As shown in FIG. 14, an electric circuit body 400 is housed in the housing 12. A control circuit 172 and a driver circuit 174 are arranged in the electric circuit body 400, and a capacitor module 500 is housed on the DC terminal side of the electric circuit body 400. By arranging the capacitor module at the same height as the electric circuit body 400, the power conversion device 200 can be made thinner, improving the degree of freedom of installation in the vehicle. The AC side terminal 325A of the electric circuit body 400 is connected to the connector 188 through the current sensor 180. In addition, the positive side terminal 325P and the negative side terminal 325M, which are the DC terminals of the semiconductor module 300, are joined to the positive and negative terminals 362A and 362B of the capacitor module 500, respectively.

According to the embodiment described above, the following advantageous effects can be obtained.
(1) The electric circuit body 400 includes conductive plates 430, 431, 432, 433 to which the semiconductor elements 155, 156, 157, 158 are joined, a cooling member 340 that is disposed opposite the conductive plates 430, 431, 432, 433 and cools the heat generated by the semiconductor elements 155, 156, 157, 158, and an insulating sheet 340 that is disposed between the conductive plates 430, 431, 432, 433 and the cooling member 340. The insulating sheet 443 incorporates an intermediate conductor 440 facing the conductor plates 430, 431, 432, 433, and the intermediate conductor 440 is divided into a plurality of pieces and arranged with respect to the conductor plates 430, 431, 432, 433 corresponding to one of the semiconductor elements 155, 156, 157, 158, and forms an electric capacitance electrically parallel to the conductor plates 430, 431, 432, 433. This improves the insulation reliability of the electric circuit body.

The present invention is not limited to the above-described embodiment, and other forms that are conceivable within the scope of the technical concept of the present invention are also included within the scope of the present invention, so long as they do not impair the characteristics of the present invention. In addition, a configuration that combines the above-described embodiment with multiple modified examples may also be used.

10: upper case, 11: lower case, 13: refrigerant inlet pipe, 14: refrigerant outlet pipe, 17, 21, 181, 182, 188: connector, 18: AC terminal, 43, 140, 142: inverter circuit, 155, 156, 157, 158: semiconductor element, 172: control circuit, 174: driver circuit, 180: current sensor, 192, 194: motor generator, 200: power conversion device, 300: semiconductor module, 310: circuit body, 32 5P: Positive terminal, 325M: Negative terminal, 325A: AC terminal, 325C: Collector sense terminal, 325L: Lower arm gate terminal, 325E: Emitter sense terminal, 325U: Upper arm gate terminal, 340: Cooling member, 360: Sealing material, 400: Electrical circuit body, 430, 431, 432, 433: Conductive plate, 440: Intermediate conductor, 443: Insulating sheet, 444: Surface conductor layer, 453: Heat conductive member, 500: Capacitor module.

Claims (9)

a conductive plate to which a semiconductor element is bonded, a cooling member disposed opposite the conductive plate for cooling heat generated by the semiconductor element, and an insulating sheet disposed between the conductive plate and the cooling member,
the insulating sheet includes an intermediate conductor that faces the conductor plate;
The intermediate conductor is an electric circuit body that is divided into a plurality of pieces and arranged on the conductor plate corresponding to one of the semiconductor elements, and forms an electric capacitance that is electrically parallel to the conductor plate. 2. The electric circuit body according to claim 1,
The intermediate conductor is an electric circuit body that is divided into a plurality of pieces and disposed in a region facing the end of the conductive plate. 2. The electric circuit body according to claim 1,
The intermediate conductor is an electric circuit body in which the number of divisions of the region facing the end portion of the conductor plate is greater than the number of divisions of the region facing the center portion of the conductor plate. 2. The electric circuit body according to claim 1,
The intermediate conductor is an electric circuit divided into a lattice pattern. 2. The electric circuit body according to claim 1,
The insulating sheet is an electric circuit body having a plurality of the intermediate conductors embedded therein in the thickness direction of the insulating sheet. 2. The electric circuit body according to claim 1,
The insulating sheet is an electric circuit body using ceramic. 2. The electric circuit body according to claim 1,
The insulating sheet is an electric circuit body, in which the area of the intermediate conductor occupies 20% or more of a cross section of the insulating sheet. 8. The electric circuit body according to claim 1,
the conductive plates are formed on both sides of the semiconductor element,
the cooling members are disposed on both sides of the conductive plates so as to face each other,
The insulating sheets are electric circuits disposed between the conductive plates and the cooling members. A power conversion device comprising the electric circuit body according to any one of claims 1 to 7, for converting DC power and AC power mutually.

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