Electric circuit body and power conversion device

Abstract

To solve the problem that there have been problems associated with insulation reliability conventionally when raising of a voltage is taken into consideration.SOLUTION: There is provided an electric circuit body that comprises: a conductor plate to which a semiconductor element is joined; a cooling member arranged opposite the conductor plate, and cooling heat generated by the semiconductor element; and an insulation sheet arranged between the conductor plate and the cooling member. Therein: the insulation sheet includes an intermediate conductor built in opposite the conductor plate; and 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 electrically parallel with the conductor plate.SELECTED DRAWING: Figure 2

Description

[Technical field]

[0001] The present invention relates to an electric circuit and a power conversion device. [Background technology]

[0002] Power conversion devices that convert between DC and AC power by the switching operation of semiconductor elements have high conversion efficiency and are therefore widely used in consumer, automotive, railway, substation equipment, etc. Power conversion devices are configured by incorporating an electric circuit body that includes a cooling member that cools heat generated by the semiconductor elements and an insulating sheet disposed between the semiconductor elements and the cooling member so as to operate as an inverter. The electric circuit body used as an inverter is required to be compact and lightweight, and is also required to have improved insulation reliability to meet the demand for higher voltages.

[0003] Patent Document 1 discloses a power module comprising a first power semiconductor element on an upper arm side and a second power semiconductor element on a lower arm side, a first conductor portion for transmitting AC current, a second conductor portion for transmitting DC current, a conductive heat dissipation portion, a first intermediate conductor layer arranged between the first conductor portion and the heat dissipation portion with an insulating layer interposed therebetween, and a second intermediate conductor layer arranged between the second conductor portion and the heat dissipation portion with an insulating layer interposed therebetween, wherein the second intermediate conductor layer is configured separately from the first intermediate conductor layer, and the first intermediate conductor layer forms a capacitive circuit for sharing the voltage between the first conductor portion and the heat dissipation portion. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] JP 2016-059147 A Summary of the Invention [Problem to be solved by the invention]

[0005] The device described in Patent Document 1 has a problem with insulation reliability when considering high voltages. [Means for solving the problem]

[0006] The electrical circuit body according to the present invention comprises a conductor plate to which a semiconductor element is joined, a cooling member arranged opposite the conductor plate for cooling heat generated by the semiconductor element, and an insulating sheet arranged between the conductor plate and the cooling member, wherein the insulating sheet incorporates an intermediate conductor facing the conductor plate, the intermediate conductor being divided into multiple pieces and arranged on the conductor plate corresponding to one of the semiconductor elements, forming an electrical capacitance that is electrically parallel to the conductor plate. Effect of the Invention

[0007] According to the present invention, the insulation reliability of the electric circuit body is improved. [Brief description of the drawings]

[0008] [Figure 1] FIG. [Diagram 2] FIG. 2 is a cross-sectional view of the electric circuit body taken along line XX. [Diagram 3] 4 is a cross-sectional view of the electric circuit body taken along line YY. FIG. [Figure 4] FIG. [Diagram 5] FIG. 2 is a semi-transparent plan view of a semiconductor module. [Figure 6] FIG. 2 is a circuit diagram of a semiconductor module. [Figure 7] 10 is an enlarged cross-sectional view of an electric circuit body according to Modification 1. FIG. [Figure 8] FIG. 11 is a plan view of an insulating sheet in Modification 2. [Figure 9] FIG. 13 is a plan view of an insulating sheet in Modification 3. [Figure 10] FIG. 13 is a plan view of an insulating sheet in Modification 4. [Figure 11] FIG. 13 is an enlarged cross-sectional view of an electric circuit body according to a fifth modified example. [Figure 12] 1 is a circuit diagram of a power conversion device using a semiconductor module. [Figure 13]FIG. 2 is an external perspective view of the power conversion device. [Figure 14] FIG. 2 is a cross-sectional perspective view of the power conversion device taken along line XV-XV. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0009] Hereinafter, 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 appropriate omissions and simplifications have been made for clarity of explanation. The present invention can be implemented in various other forms. Unless otherwise specified, each component may be singular or plural.

[0010] In order to facilitate understanding of the invention, the position, size, shape, range, etc. of each component shown in the drawings may not represent the actual position, size, shape, range, etc. Therefore, the present invention is not necessarily limited to the position, size, shape, range, etc. disclosed in the drawings.

[0011] 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 module 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.

[0012] 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 of the semiconductor module 300 connected to the semiconductor elements 155 and 157 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 a positive terminal 325P and a negative terminal 325M connected to a capacitor module 500 (see FIG. 12) of a DC circuit, and an AC terminal 325A connected to motor generators 192 and 194 (see FIG. 12) of an AC circuit. The semiconductor elements 155 and 157 may be switching elements such as IGBTs (insulated gate bipolar transistors) and MOSFETs (metal oxide semiconductor field effect transistors).

[0013] The terminals extending from the sealing material 360 on the side surface 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 the like. These terminals extending from the semiconductor module 300 are connected to wiring such as a wiring pattern of 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 switching operations 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 may be arbitrarily set according to various forms of the electric circuit body 400.

[0014] 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 coolant flows, and the coolant flowing through the flow path cools the heat generated from the semiconductor elements 155, 157. The coolant used is water or an antifreeze solution made by mixing ethylene glycol into water. The cooling member 340 is desirably made of aluminum, which has high thermal conductivity and is lightweight.

[0015] Figures 2 and 3 are cross-sectional views of the electric circuit body 400. Figure 2 is a cross-sectional view of the electric circuit body 400 taken along line XX in Figure 1. Figure 3 is a cross-sectional view of one semiconductor module 300 taken along line YY in Figure 1.

[0016] As shown in FIG. 2, the power conversion device 200 includes an active element 155 and a diode 156 as first semiconductor elements forming an upper arm circuit (see FIGS. 5 and 6 described later). As the active element, Si, SiC, GaN, GaO, C, etc. can be used. When a body diode of the active element 155 is used, 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. For this bonding, solder or sintered metal may be used. The first conductor plate 430 is bonded to the emitter side of the first semiconductor element 155.

[0017] 2 and 3, the second semiconductor element forming the lower arm circuit includes an active element 157 and a diode 158 (see FIGS. 5 and 6 described below). The collector side of the second semiconductor element 157 is joined to a fourth conductor plate 433. The third conductor plate 432 is joined to the emitter side of the second semiconductor element 157.

[0018] The conductive plates 430, 431, 432, and 433 are not particularly limited as long as they are made of a material having high electrical conductivity and thermal conductivity, but it is preferable to use a metal material such as a copper-based or aluminum-based material, or a composite material of a metal material and a high thermal conductivity diamond, carbon, ceramic, etc. These may be used alone, or may be plated with Ni, Ag, etc. to improve the bondability with solder or sintered metal.

[0019] The conductor plates 430, 431, 432, and 433, in addition to carrying electric current, 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 become 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 electric potentials, an insulating sheet 443 is disposed between the heat dissipation surfaces. That is, the insulating sheet 443 is intended to prevent electric current from being conducted 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 a part that forms the main insulation of the semiconductor module 300 in the power conversion device 200.

[0020] The insulating sheet 443 covers the conductive plates 430, 431, 432, and 433 on one side and is bonded to the heat dissipation surfaces of the conductive plates 430, 431, 432, and 433. The insulating sheet 443 can be made of either an organic or inorganic material as long as it can ensure a certain level of insulation. Generally, the insulating sheet 443 is called a resin insulating layer and is often made of epoxy resin, but ceramic may also be used. The insulating sheet 443 using ceramic is manufactured by, for example, firing a green sheet in the same manner as a ceramic capacitor, and inserting a sheet-shaped electrode as the intermediate conductor 440. By using ceramic, thermal deterioration is less likely to occur even if partial discharge occurs. Filler particles may be added to the insulating sheet 443 to improve thermal conductivity.

[0021] Details of insulating sheet 443 will be described later, but insulating sheet 443 incorporates an intermediate conductor 440 that faces conductor plates 430, 431, 432, and 433, and intermediate conductor 440 is divided into multiple conductor plates 430, 431, 432, and 433 that correspond to one of semiconductor elements 155, 157, and forms an electrical capacitance that is electrically parallel to 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.

[0022] The semiconductor elements 155, 156, 157, 158, the conductor plates 430, 431, 432, 433, together with the insulating sheet 443 and the surface conductor layer 444, are sealed with the 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.

[0023] The cooling members 340 are disposed 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 disposed on both sides of the semiconductor module 300 will be described, but the electric circuit body 400 in which the cooling members 340 are disposed on one side of the semiconductor module 300 may also be used. In this case, a housing or mounting member is disposed on the other side of the semiconductor module 300, and the other side of the semiconductor module 300 is fixed to the housing or mounting member by fixing members.

[0024] The heat conductive member 453 is disposed between the semiconductor module 300 and the cooling member 340 in order to reduce contact thermal resistance. The heat conductive member 453 uses grease, gel grease, a phase change sheet, or the like.

[0025] FIG. 4 is an enlarged cross-sectional view of the electric circuit body 400, showing part A of FIG. As shown in FIG. 4, insulating sheet 443 incorporates intermediate conductor 440 facing conductive plate 433. Conductive plate 433 corresponds to semiconductor element 157 (see FIG. 3). Intermediate conductor 440 is divided into a plurality of pieces and arranged relative to conductive plate 433. As a result, intermediate conductor 440 divided into a plurality of pieces forms an electric capacitance that is electrically parallel with conductive plate 433. Note that the thickness of insulating sheet 443 is set so that the distance between intermediate conductor 440 and conductive plates 430, 432 or cooling member 340 sandwiching insulating sheet 443 does not cause partial discharge during normal operation.

[0026] A portion P where the insulating sheet 443, the sealing material 360, and the conductive plate 433 contact each other is generally called a triple point from an electrical viewpoint. This triple point is a boundary between members with different relative dielectric constants, so potential concentration and the like are likely to occur at the triple point, and it is therefore required to improve the insulation reliability. In addition, the triple point is also likely to generate voids such as voids, cracks, and peeling due to the application of mechanical force, and it is therefore required to improve the insulation reliability. In addition, not only the triple point but also the region of the insulating sheet 443 facing the end of the conductive plate 433 is likely to cause peeling and the like due to thermal stress during operation of the power conversion device 200, and it is therefore required to improve the insulation reliability.

[0027] Insulating sheet 443 has conductive intermediate conductor 440 built in, so even if potential concentrates in voids due to the low dielectric constant of insulating sheet 443 when voids occur therein, intermediate conductor 2 can share the potential concentration in the voids, etc. It is desirable that the area ratio of intermediate conductor 440 to the cross section of insulating sheet 443 be 20% or more.

[0028] 4, intermediate conductor 440 is divided into a plurality of pieces of the same width and arranged at equal intervals within insulating sheet 443. Note that the width and intervals at which intermediate conductor 440 is divided and arranged are merely examples, and can be appropriately determined depending on the structure, configuration, and electrical characteristics of semiconductor module 300. For example, intermediate conductor 440 may be configured to be divided into a plurality of pieces and arranged at least in a region facing an end of conductor plate 433.

[0029] Since the intermediate conductor 440 of the insulating sheet 443 is divided into multiple pieces, even if the intermediate conductor 440 divided by a void or the like is partially short-circuited, the entire intermediate conductor 440 will not be at the same potential, and concentration of potential on the intermediate conductor 440 other than the short-circuited portion can be suppressed.

[0030] 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 according to the voltage value of the driving voltage. This in turn improves the insulation performance of the power conversion device 200, which can contribute to improving the output density of the power conversion device 200.

[0031] Furthermore, even if peeling or the like due to thermal stress or the like occurs not only at the triple junction but also in the region of insulating sheet 443 opposite the end of conductor plate 433, insulation reliability can be improved by dividing intermediate conductor 440 into multiple pieces and arranging them in this region.

[0032] Fig. 5 is a semi-transparent plan view of the semiconductor module 300. Fig. 6 is a circuit diagram of the semiconductor module 300.

[0033] 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 a capacitor instead of GND.

[0034] The upper arm emitter sense terminal 325E is output from the emitter of active element 155 of the upper arm circuit, and the lower arm emitter sense terminal 325E is output from the emitter of active element 157 of the lower arm circuit. The upper arm collector sense terminal 325C is output from the collector of active element 155 of the upper arm circuit, and the lower arm collector sense terminal 325C is output from the collector of active element 157 of the lower arm circuit.

[0035] Additionally, 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).

[0036] 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 a plurality of 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 possible to reduce the size.

[0037] Fig. 7 is an enlarged cross-sectional view of an electric circuit body 400 in the first modification, and corresponds to part A in Fig. 3, similar to Fig. 4. The same reference numerals are used to designate the same parts as in Fig. 4, and their description will be simplified.

[0038] 4 shows an example in which intermediate conductor 440 is divided into a plurality of pieces of the same width and arranged at equal intervals within insulating sheet 443. In modification 1, as shown in FIG. 7, the number of divisions of intermediate conductor 440 in the region facing the end portion of conductive plate 433 is greater than the number of divisions in the region facing the center portion of conductive plate 433.

[0039] The area of ​​insulating sheet 443 facing the end of conductor plate 433 is prone to peeling due to thermal stress and other factors when power conversion device 200 is in operation, but by increasing the number of divisions of intermediate conductor 440 in this area, the insulation reliability can be improved.

[0040] Fig. 8 is a plan view of insulating sheet 443 in modification 2. Intermediate conductor 440 in insulating sheet 443 is indicated by diagonal hatching, and peripheries of ends of conductor plates 430 and 432 are indicated by dashed lines. Note that although the shapes of insulating sheet 443 and conductor plates 430 and 432 are not the same as those shown in the semi-transparent plan view of Fig. 5, they are illustrated diagrammatically in Fig. 8 and Figs. 9 and 10 shown below for ease of understanding.

[0041] 8, the divided intermediate conductors 440 having smaller areas are arranged in the portions of the insulating sheet 443 located around the ends of the conductor plates 430 and 432. Furthermore, the divided intermediate conductors 440 having smaller areas are arranged in the portions of the insulating sheet 443 located around the ends of the conductor plates 430 and 432.

[0042] 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 concentration of potential on the intermediate conductor 440 other than the short-circuited portion can be suppressed.

[0043] 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. 9, intermediate conductor 440 of insulating sheet 443 is divided into a spherical grid. The area of ​​the sphere 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 semiconductor module 300. Divided intermediate conductor 440 is appropriately arranged in the portion located around the end of conductive plates 430 and 432. Note that the shape is not limited to a sphere, and may be an ellipse, a semicircle, or another shape, or these shapes may be mixed. Furthermore, the areas of divided intermediate conductors 440 may be the same or different, regardless of whether they are the same shape or different shapes.

[0044] According to the third modification, it is possible to eliminate the need to design the division positions and area of ​​the intermediate conductor 440 according to the positions of the conductive plates 430 and 432. Furthermore, it is possible to improve the insulation reliability.

[0045] 10 is a plan view of an insulating sheet 443 in Modification 4. 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. 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 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 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.

[0046] According to the fourth modification, it is possible to eliminate the need to design the division positions and area of ​​the intermediate conductor 440 according to the positions of the conductive plates 430 and 432. Furthermore, it is possible to improve the insulation reliability.

[0047] Fig. 11 is an enlarged cross-sectional view of an electric circuit body 400 in the fifth modification, and corresponds to the portion A in Fig. 3, similar to Fig. 7. The same reference numerals are used to designate the same parts as in Fig. 7, and their description will be simplified.

[0048] 7 shows an example in which insulating sheet 443 has one intermediate conductor 440 embedded in the thickness direction of insulating sheet 443. In modification 5, as shown in FIG. 11, insulating sheet 443 has two intermediate conductors 440 embedded in the thickness direction of insulating sheet 443. The number of intermediate conductors is not limited to two, and multiple intermediate conductors may be provided. The distance between intermediate conductor 440 and conductive plates 430, 432 or cooling member 340 sandwiching insulating sheet 443 is set to be larger than the diameter of filler particles mixed in insulating sheet 443.

[0049] Increasing the number of intermediate conductors 440 makes it possible to more effectively share the potential between the intermediate conductors 440 and either the conductive plates 430 and 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.

[0050] 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 making it possible to handle an increase in the current capacity. 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 handle an increase in the current capacity.

[0051] The inverter circuit unit 140 and the inverter circuit unit 142 have the same basic circuit configuration, and the control method and operation are also basically the same. Since the outline of the circuit operation of the inverter circuit unit 140 and the like is well known, a detailed description will be omitted here.

[0052] The upper arm circuit includes an upper arm active element 155 and an upper arm diode 156 as switching semiconductor elements, and the lower arm circuit includes a lower arm active element 157 and a lower arm diode 158 as switching semiconductor elements. The active elements 155 and 157 perform switching operation upon receiving a drive signal output from one or the other of two driver circuits constituting the driver circuit 174, and convert the DC power supplied from the battery 136 into three-phase AC power.

[0053] 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. As a result, the current flows from the emitter electrodes of the upper arm active element 155 and the lower arm active element 157 to the collector electrodes in the forward direction. The active elements 155 and 157 are, for example, IGBTs.

[0054] It should be noted 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.

[0055] Positive terminal 325P and negative terminal 325M of each upper and lower arm series circuit are respectively connected to DC terminals for connecting capacitors of capacitor module 500. AC power is generated at the connection portion between the upper arm circuit and the lower arm circuit, and the connection portion between the upper arm circuit and the lower arm circuit of each upper and lower arm series circuit is connected to AC side terminal 325A of each semiconductor module 300. AC side terminal 320B of each semiconductor module 300 of each phase is respectively connected to an AC output terminal of power conversion device 200, and the generated AC power is supplied to the stator winding of motor generator 192 or 194.

[0056] 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 a vehicle-side control device and a sensor (e.g., a current sensor 180). The driver circuit 174 generates a drive signal for performing a switching operation on 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.

[0057] 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 detection 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, thereby protecting the upper and lower arm series circuits from over-temperature or over-voltage.

[0058] 13 is an external perspective view of the power converter 200 shown in FIG. 12, and FIG. 14 is a cross-sectional perspective view of the power converter 200 shown in FIG. 13 taken along line XV-XV.

[0059] The power converter 200 includes a housing 12 formed of a lower case 11 and an upper case 10 and having a substantially rectangular parallelepiped shape. An electric circuit body 400, a capacitor module 500, and the like are housed inside the housing 12. The electric circuit body 400 has a cooling flow path that flows to a 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 opened, 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 a sealed manner from the outside. The upper case 10 and the lower case 11 may be integrally configured. The housing 12 is formed into a simple rectangular parallelepiped shape, which makes it easy to attach to a vehicle or the like and also easy to produce.

[0060] A connector 17 is attached to one side surface in the longitudinal direction 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.

[0061] As shown in FIG. 14, an electric circuit body 400 is accommodated 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 accommodated 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 a vehicle. An AC side terminal 325A of the electric circuit body 400 is connected to a connector 188 through a current sensor 180. In addition, a positive side terminal 325P and a negative side terminal 325M, which are DC terminals of the semiconductor module 300, are joined to positive and negative terminals 362A and 362B of the capacitor module 500, respectively.

[0062] According to the embodiment described above, the following advantageous effects can be obtained. (1) Electric circuit body 400 includes conductive plates 430, 431, 432, 433 to which semiconductor elements 155, 156, 157, 158 are joined, cooling member 340 that is disposed opposite conductive plates 430, 431, 432, 433 and cools heat generated by semiconductor elements 155, 156, 157, 158, and insulating sheets that are disposed between conductive plates 430, 431, 432, 433 and cooling member 340. and 443, the insulating sheet 443 incorporates an intermediate conductor 440 facing the conductive plates 430, 431, 432, 433, and the intermediate conductor 440 is divided into a plurality of pieces and arranged with respect to the conductive 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 conductive plates 430, 431, 432, 433. This improves the insulation reliability of the electric circuit body.

[0063] The present invention is not limited to the above-described embodiment, and other embodiments that are conceivable within the scope of the technical concept of the present invention are also included within the scope of the present invention as long as they do not impair the characteristics of the present invention. In addition, the above-described embodiment may be combined with a number of modified examples. [Explanation of symbols]

[0064] 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 electrode side terminal, 325M···Negative electrode side terminal, 325A···AC side 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···Conductor plate, 440···Intermediate conductor, 443···Insulating sheet, 444···Surface conductor layer, 453···Heat conductive member, 500···Capacitor module.

Claims

1. 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. 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.

3. 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.

4. 2. The electric circuit body according to claim 1, The intermediate conductor is an electric circuit divided into a lattice shape.

5. 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.

6. 2. The electric circuit body according to claim 1, The insulating sheet is an electric circuit body using ceramic.

7. 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. 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.

9. 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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