Circuit body and power conversion device

Abstract

A circuit body is provided with: a conductor plate bonded to a semiconductor element; a cooling member that is disposed facing the conductor plate and cools 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 disposed so as to be divided into a plurality of parts with respect to the conductor plate corresponding to one of the semiconductor elements, and forming a capacitance electrically connected in parallel with the conductor plate.

Description

Technical Field

[0001] The present invention relates to a circuit body and a power conversion device. Background Art

[0002] Power conversion devices, which convert direct current (DC) and alternating current (AC) through the switching action of semiconductor elements, are widely used in residential, automotive, railway, and substation applications due to their high conversion efficiency. These power conversion devices are assembled to operate as an inverter, using a circuit body equipped with a cooling element to cool the heat generated by the semiconductor elements and an insulating sheet positioned between the semiconductor elements and the cooling element. Circuit bodies used as inverters must be compact and lightweight, while also requiring improved insulation reliability to meet the demands of higher voltages.

[0003] Patent document 1 discloses a power module comprising: 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 for transmitting alternating current; a second conductor portion for transmitting direct current; an electrically conductive heat dissipation portion, a first intermediate conductor layer disposed between the first conductor portion and the heat dissipation portion via an insulating layer; and a second intermediate conductor layer disposed between the second conductor portion and the heat dissipation portion via an insulating layer, the second intermediate conductor layer being separate from the first intermediate conductor layer, and the first intermediate conductor layer forming a capacitive circuit for sharing the voltage between the first conductor portion and the heat dissipation portion. Prior art literature Patent Literature

[0004] Patent Document 1: Japanese Patent Application Laid-Open No. 2016-059147 Summary of the Invention Problems to be solved by the invention

[0005] The device described in Patent Document 1 has a problem in terms of insulation reliability when considering an increase in high voltage. Technical means to solve the problem

[0006] The circuit body of the present invention comprises: a conductor plate, which is joined to a semiconductor element; a cooling member, which is arranged opposite to the conductor plate and cools the heat generated by the semiconductor element; and an insulating sheet, which is arranged between the conductor plate and the cooling member, and the insulating sheet has an intermediate conductor opposite to the conductor plate. The intermediate conductor is divided into a plurality of parts relative to the conductor plate corresponding to one of the semiconductor elements, forming a capacitor electrically connected in parallel with the conductor plate. Effects of the Invention

[0007] According to the present invention, the insulation reliability of the circuit body is improved. BRIEF DESCRIPTION OF THE DRAWINGS

[0008] Figure 1 It is a top view of the circuit body. Figure 2 It is a cross-sectional view of the circuit body taken along line XX. Figure 3 It is a cross-sectional view of the circuit body taken along line YY. Figure 4 This is an enlarged cross-sectional view of the circuit body. Figure 5 Semi-transmissive top view of a semiconductor module. Figure 6 This is a circuit diagram of a semiconductor module. Figure 7 This is an enlarged cross-sectional view of the circuit body of Modification 1. Figure 8 This is a plan view of the insulating sheet in Modification 2. Figure 9 This is a plan view of the insulating sheet in Modification 3. Figure 10 This is a plan view of the insulating sheet in Modification 4. Figure 11 This is an enlarged cross-sectional view of the circuit body of Modification 5. Figure 12 This is a circuit diagram of a power conversion device using a semiconductor module. Figure 13 This is a perspective view of the power conversion device. Figure 14 It is a cross-sectional perspective view of the power conversion device taken along line XV-XV. DETAILED DESCRIPTION

[0009] The following describes embodiments of the present invention with reference to the accompanying drawings. The following description and drawings are examples for illustrating the present invention, and appropriate omissions and simplifications have been made for clarity of description. The present invention may also be implemented in various other forms. Unless otherwise specified, each component may be single or multiple.

[0010] To facilitate understanding of the invention, the positions, sizes, shapes, and ranges of the components shown in the drawings may not necessarily represent their actual positions, sizes, shapes, and ranges. Therefore, the present invention is not necessarily limited to the positions, sizes, shapes, and ranges disclosed in the drawings.

[0011] Figure 1 4 is a top view of the circuit body 400 in the embodiment of the present invention. The circuit body 400 is composed of the semiconductor module 300, the cooling member 340, etc. Figure 1 In the example shown, the circuit body 400 is composed of three semiconductor modules 300 connected in parallel.

[0012] The semiconductor module 300 is sealed with a sealing material 360 and built into the semiconductor elements 155 and 157. The heat generated by the switching operation of the semiconductor elements 155 and 157 is dissipated from both sides of the semiconductor module 300. 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 connected to the capacitor module 500 (see FIG. 5 ) of the DC circuit. Figure 12 ) connected to the positive terminal 325P and the negative terminal 325M, and the motor generator 192, 194 of the AC circuit (see Figure 12 ) is connected to the AC side terminal 325A or other power terminals through which a large current flows. In addition, the semiconductor elements 155 and 157 can use switching elements such as IGBT (insulated gate bipolar transistor) and MOSFET (metal oxide semiconductor field effect transistor).

[0013] In addition, 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 detection terminal 325C, the emitter detection terminal 325E, and the upper arm gate terminal 325U. These terminals extending from the semiconductor module 300 are connected to wiring patterns or the like of a substrate (not shown). The circuit body 400 in which three semiconductor modules 300 are arranged in parallel serves as a power conversion device 200 (see FIG. 1 ) that converts direct current and alternating current into each other by switching operations of the semiconductor elements 155 and 157. Figure 12 ) to function. In addition, the number of semiconductor modules 300 included in the circuit body 400 is not limited to three and can be arbitrarily set according to various aspects of the circuit body 400.

[0014] Cooling member 340 is positioned opposite semiconductor module 300 and cools heat generated by the switching operation of semiconductor elements 155 and 157. Specifically, cooling member 340 has a flow path formed therein for circulating a refrigerant, and the refrigerant flowing through the flow path cools the heat generated by semiconductor elements 155 and 157. Water or an antifreeze solution containing ethylene glycol mixed with water can be used as the refrigerant. Cooling member 340 is preferably made of aluminum, which has high thermal conductivity and is lightweight.

[0015] Figure 2 、 Figure 3 is a cross-sectional view of the circuit body 400 . Figure 2 yes Figure 1 A cross-sectional view of the circuit body 400 taken along line XX is shown. Figure 3 yes Figure 1 The circuit body 400 is a cross-sectional view of a semiconductor module 300 taken along line YY.

[0016] like Figure 2As shown, as the first semiconductor element forming the upper arm circuit of the power conversion device 200, an active element 155 and a diode 156 (see the following) are provided. Figure 5 、 Figure 6 As an active element, Si, SiC, GaN, GaO, C, etc. can be used. When the body diode of the active element 155 is used, the additional diode can be omitted. Figure 3 As shown, the collector side of the first semiconductor element 155 is bonded to the second conductor plate 431. This bonding can be done using solder or sintered metal. The emitter side of the first semiconductor element 155 is bonded to the first conductor plate 430.

[0017] like Figure 2 、 Figure 3 As shown, as the second semiconductor element forming the lower arm circuit, an active element 157 and a diode 158 (see later described) are provided. Figure 5 、 Figure 6 The fourth conductor plate 433 is bonded to the collector side of the second semiconductor element 157. The third conductor plate 432 is bonded to the emitter side of the second semiconductor element 157.

[0018] Conductor plates 430, 431, 432, and 433 are not particularly limited as long as they are made of a material with high electrical and thermal conductivity. However, preferably, metal materials such as copper or aluminum materials, or composite materials with high thermal conductivity such as diamond, carbon, or ceramics are used. These materials can be used alone, but may also be plated with Ni, Ag, or the like to improve bonding with solder or sintered metal.

[0019] In addition to conducting current, conductor plates 430, 431, 432, and 433 also function as heat transfer members, transferring heat generated by semiconductor elements 155, 156, 157, and 158 to cooling member 340. The surfaces opposite the surfaces bonded to semiconductor elements 155, 156, 157, and 158 serve as the heat dissipation surfaces of conductor plates 430, 431, 432, and 433. Furthermore, because the electrical potential of conductor plates 430, 431, 432, and 433 differs from that of cooling member 340, an insulating sheet 443 is positioned between the heat dissipation surfaces. Specifically, insulating sheet 443 prevents current from flowing from conductor plates 430, 431, 432, and 433 to cooling member 340 and other components, providing electrical insulation. Insulating sheet 443 primarily insulates semiconductor module 300 within power converter 200.

[0020] The insulating sheet 443 covers the conductor plates 430, 431, 432, 433 on one side and is bonded to the heat dissipation surface of the conductor plates 430, 431, 432, 433. As long as the specified insulation properties can be ensured, the insulating sheet 443 can be made of either an organic or an inorganic material. Usually, the insulating sheet 443 is called a resin insulating layer, and is mostly made of epoxy resin, but ceramic can also be used. The method of making the insulating sheet 443 using ceramic is, for example, to sinter a raw ceramic sheet in the same way as ceramic capacitors, and insert a sheet-shaped electrode as the intermediate conductor 440. By using ceramic, even if local discharge occurs, thermal degradation is less likely to occur. In order to improve thermal conductivity, filler particles are sometimes added to the insulating sheet 443.

[0021] The details of the insulating sheet 443 will be described later. The insulating sheet 443 has an intermediate conductor 440 built in that is opposite to the conductor plates 430, 431, 432, and 433. The intermediate conductor 440 is divided into multiple parts based on the conductor plates 430, 431, 432, and 433 corresponding to one of the semiconductor elements 155 and 157, forming a capacitor electrically connected in parallel with the conductor plates 430, 431, 432, and 433. A surface conductor layer 444 is bonded to the other surface of the insulating sheet 443, exposed on the surface of the semiconductor module 300, and in contact with the heat conducting member 453. The surface conductor layer 444 is, for example, a metal foil.

[0022] Semiconductor elements 155, 156, 157, 158, conductive plates 430, 431, 432, 433, insulating sheet 443, and surface conductive layer 444 are transfer molded together and sealed with sealing material 360 to form semiconductor module 300. Sealing material 360 is often epoxy resin, but any type of sealing material is not critical 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). In this embodiment, the circuit body 400 is described as having the cooling members 340 disposed on both sides of the semiconductor module 300. However, the circuit body 400 may also be configured such that the cooling member 340 is disposed on only one side of the semiconductor module 300. In this case, a frame and mounting members are disposed on the other side of the semiconductor module 300, and the other side of the semiconductor module 300 is fixed to the frame and mounting members by fixing members.

[0024] The heat conduction member 453 is provided between the semiconductor module 300 and the cooling member 340 to reduce contact thermal resistance. The heat conduction member 453 is made of heat conduction silicone grease, gel-like heat conduction paste, phase-change heat conduction sheet, or the like.

[0025] Figure 4This is an enlarged cross-sectional view of the circuit body 400, showing Figure 3 Part A of like Figure 4 As shown, the insulating sheet 443 has an intermediate conductor 440 built therein, which is opposite to the conductor plate 433. The conductor plate 433 and the semiconductor element 157 (see Figure 3 ). Intermediate conductor 440 is divided into multiple pieces and arranged relative to conductor plate 433. As a result, an electrically parallel capacitor is formed between the divided pieces of intermediate conductor 440 and conductor plate 433. Furthermore, the thickness of insulating sheet 443 is such that the distance between intermediate conductor 440 and conductor plates 430 and 432 sandwiching insulating sheet 443, or the distance between intermediate conductor 440 and cooling member 340, does not cause partial discharge during normal operation.

[0026] From an electrical perspective, the P region where the insulating sheet 443, sealing material 360, and conductor plate 433 meet is generally referred to as a triple point. This triple point is the boundary between components with different dielectric constants, making it susceptible to potential concentration, necessitating improved insulation reliability. Furthermore, mechanical forces can easily cause voids such as pores, cracks, and peeling at the triple point, necessitating improved insulation reliability. Furthermore, not limited to the triple point, the region of the insulating sheet 443 opposite the end of the conductor plate 433 is susceptible to peeling due to thermal stress and other factors during operation of the power conversion device 200, necessitating improved insulation reliability.

[0027] Since insulating sheet 443 includes electrically conductive intermediate conductor 440, even if potential concentration occurs due to the low dielectric constant of the insulating sheet 443 when voids occur within the insulating sheet 443, the potential concentration on the voids, etc., can be offset by intermediate conductor 2. In insulating sheet 443, the proportion of the area occupied by intermediate conductor 440 in the cross-section of insulating sheet 443 is preferably 20% or greater.

[0028] like Figure 4 As shown, the intermediate conductor 440 is divided into a plurality of equal widths within the insulating sheet 443 and arranged at equal intervals. The widths and intervals of the divided and arranged intermediate conductors 440 are merely examples and can be appropriately determined based on the structure, configuration, and electrical characteristics of the semiconductor module 300. For example, the intermediate conductor 440 may be divided into a plurality of sections and arranged at least in the region facing the end of the conductor plate 433.

[0029] Since the intermediate conductor 440 of the insulating sheet 443 is divided into a plurality of parts, even if the intermediate conductor 440 divided by the pores is partially short-circuited, the entire intermediate conductor 440 does not reach the same potential, thereby suppressing potential concentration in the intermediate conductor 440 other than the short-circuited portion.

[0030] For example, at the triple point shown at location P, even if potential concentration or mechanical forces cause pinholes, cracks, or delamination, potential concentration throughout the intermediate conductor 440 can be suppressed, improving insulation reliability. Consequently, by thinning the insulating sheet 443 according to the driving voltage, heat dissipation from the semiconductor module 300 is improved, enabling miniaturization. Furthermore, the insulation performance of the power conversion device 200 is enhanced, contributing to an increase in the output density of the power conversion device 200.

[0031] Furthermore, not limited to the triple point, even if peeling due to thermal stress or the like occurs in the region of the insulating sheet 443 opposite the end of the conductor plate 433, the insulation reliability can be improved by configuring the intermediate conductor 440 in a plurality of sections in the region.

[0032] Figure 5 FIG. 3 is a semi-transmissive top view of the semiconductor module 300 . Figure 6 is a circuit diagram of the semiconductor module 300 .

[0033] like Figure 5 、 Figure 6 As shown, positive-side terminal 325P is output from the collector side of the upper arm circuit and connected to the positive side of a battery or capacitor. Upper-arm gate terminal 325U is output from the gate of active element 155 of the upper arm circuit. Negative-side terminal 325M is output from the emitter side of the lower arm circuit and connected to the negative side of a battery or capacitor or GND. Lower-arm gate terminal 325L is output from the gate of active element 157 of the lower arm circuit. AC-side terminal 325A is output from the collector side of the lower arm circuit and connected to the motor. In the case of grounded neutral point, the lower arm circuit is connected to the negative side of the capacitor instead of GND.

[0034] The emitter detection terminal 325E of the upper arm outputs a signal from the emitter of the active element 155 in the upper arm circuit, while the emitter detection terminal 325E of the lower arm outputs a signal from the emitter of the active element 157 in the lower arm circuit. The collector detection terminal 325C of the upper arm outputs a signal from the collector of the active element 155 in the upper arm circuit, while the collector detection terminal 325C of the lower arm outputs a signal from the collector of the active element 157 in the lower arm circuit.

[0035] Furthermore, conductor plates (upper arm circuit emitter side) 430 and conductor plates (upper arm circuit collector side) 431 are arranged above and below the 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 the active element 157 and diode 158 of the semiconductor element (lower arm circuit).

[0036] The semiconductor module 300 of this embodiment has a two-in-one (2-in-1) structure, integrating two branch circuits, an upper arm circuit and a lower arm circuit, into a single module. Alternatively, a structure may be used in which multiple upper arm circuits and lower arm circuits are integrated into a single module. In this case, the number of output terminals from the semiconductor module 300 can be reduced, leading to miniaturization.

[0037] Figure 7 is an enlarged cross-sectional view of the circuit body 400 of Modification 1, and Figure 4 Likewise, it is equivalent to Figure 3 Part A of Figure 4 The same parts are denoted by the same symbols and their descriptions are simplified.

[0038] exist Figure 4 , an example is shown in which the intermediate conductor 440 is divided into a plurality of parts with the same width in the insulating sheet 443 and arranged at the same intervals. Figure 7 As shown, in the first modification, the number of divisions of the intermediate conductor 440 in the region facing the end portion of the conductor plate 433 is greater than the number of divisions in the region facing the center portion of the conductor plate 433 .

[0039] The region of the insulating sheet 443 facing the end of the conductor plate 433 is susceptible to peeling due to thermal stress during operation of the power conversion device 200 . However, increasing the number of divisions of the intermediate conductor 440 in this region can improve insulation reliability.

[0040] Figure 8 This is a top view of the insulating sheet 443 in the second variant. The intermediate conductor 440 in the insulating sheet 443 is indicated by a diagonal grid, and the periphery of the end portions of the conductor plates 430 and 432 is indicated by a dotted line. Figure 5 The semi-transmissive top view is different from that shown in FIG. Figure 8 and the following Figure 9 、 Figure 10 The diagram is shown in FIG.

[0041] like Figure 8 As shown, the smaller intermediate conductor 440 among the divided intermediate conductors 440 is arranged around the ends of the conductor plates 430 and 432 located on the insulating sheet 443. Furthermore, the smaller intermediate conductor 440 among the divided intermediate conductors 440 is arranged around the ends of the insulating sheet 443.

[0042] According to variant example 2, even if the divided intermediate conductor 440 is locally short-circuited with any of the conductor plates 430, 432 sandwiching the insulating sheet 443 or the cooling member 340, the entire intermediate conductor 440 will not be at the same potential, and the potential concentration on the intermediate conductor 440 outside the short-circuited portion can be suppressed.

[0043] Figure 9 1 is a plan view of an insulating sheet 443 according to Modification 3. The intermediate conductor 440 in the insulating sheet 443 is indicated by hatched grids, and the peripheries of the end portions of the conductor plates 430 and 432 are indicated by dotted lines. like Figure 9 As shown, the intermediate conductor 440 of the insulating sheet 443 is divided into a spherical grid. The area of ​​the spheres is smaller than the area of ​​the conductor plates 430 and 432 and is appropriately determined based on the structure, configuration, and electrical characteristics of the semiconductor module 300. The divided intermediate conductors 440 are appropriately arranged around the ends of the conductor plates 430 and 432. Furthermore, the shape is not limited to spherical; ellipsoidal, semicircular, or other shapes are also possible, and a mixture of these shapes is also possible. Furthermore, regardless of whether the shapes are the same or different, the areas of the divided intermediate conductors 440 can be the same or different.

[0044] According to Modification 3, it is possible to omit the trouble of designing the division position and area of ​​the intermediate conductor 440 according to the positions of the conductor plates 430 and 432. In addition, the insulation reliability can be improved.

[0045] Figure 10 4 is a plan view of an insulating sheet 443 in Modification 4. The intermediate conductor 440 in the insulating sheet 443 is indicated by hatched grids, and the peripheries of the end portions of the conductor plates 430 and 432 are indicated by dotted lines. like Figure 10 As shown, the intermediate conductors 440 of the insulating sheet 443 are divided into a rhombus-shaped grid. The area of ​​the rhombus is smaller than the area of ​​the conductor plates 430 and 432 and is appropriately determined based on the structure, configuration, and electrical characteristics of the semiconductor module 300. The divided intermediate conductors 440 are appropriately arranged around the ends of the conductor plates 430 and 432. Furthermore, the shapes are not limited to rhombuses; triangles, quadrilaterals, other polygons, or a combination of these shapes are also possible. Furthermore, regardless of whether the shapes are the same or different, the areas of the divided intermediate conductors 440 can be the same or different.

[0046] According to Modification 4, it is possible to omit the trouble of designing the division position and area of ​​the intermediate conductor 440 according to the positions of the conductor plates 430 and 432. In addition, the insulation reliability can be improved.

[0047] Figure 11 is an enlarged cross-sectional view of the circuit body 400 of Modification 5, and Figure 7 Likewise, it is equivalent to Figure 3 Part A of Figure 7 The same parts are denoted by the same symbols and their descriptions are simplified.

[0048] exist Figure 7 , an example is shown in which an insulating sheet 443 has an intermediate conductor 440 built into the insulating sheet 443 in the thickness direction. Figure 11 As shown, in Modification 5, two intermediate conductors 440 are embedded in the insulating sheet 443 in the thickness direction of the insulating sheet 443. The arrangement is not limited to two; multiple conductors may be provided. Furthermore, the distance between the intermediate conductors 440 and the conductive plates 430, 432, or the cooling member 340 sandwiching the insulating sheet 443 is greater than the diameter of the filler particles mixed in the insulating sheet 443.

[0049] By increasing the number of intermediate conductors 440 , potential sharing between the intermediate conductors 440 and any of the conductive plates 430 and 432 sandwiching the insulating sheet 443 or the cooling member 340 becomes more effective. This allows for multiple protection against short circuits.

[0050] Figure 12 2 is a circuit diagram of a power conversion device 200 using a semiconductor module 300 . Power conversion device 200 includes inverter circuit units 140 and 142, an auxiliary inverter circuit unit 43, and a capacitor module 500. Inverter circuit units 140 and 142 include multiple semiconductor modules 300, which are connected to form a three-phase bridge circuit. When the current capacity is high, semiconductor modules 300 are further connected in parallel. By performing these parallel connections corresponding to the phases of the three-phase inverter circuit, it is possible to cope with the increase in current capacity. Furthermore, by connecting active elements 155 and 157 and diodes 156 and 158, which are semiconductor elements built into semiconductor modules 300, in parallel, it is also possible to cope with the increase in current capacity.

[0051] The inverter circuit unit 140 and the inverter circuit unit 142 have the same basic circuit configuration, and their control methods and operations 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 thereof will be omitted here.

[0052] The upper arm circuit includes an upper arm active element 155 and an upper arm diode 156, both serving as switching semiconductor elements, and the lower arm circuit includes a lower arm active element 157 and a lower arm diode 158, both serving as switching semiconductor elements. Active elements 155 and 157 perform switching operations in response to drive signals output from one or the other of the two drive circuits constituting drive circuit 174, thereby converting DC power supplied from battery 136 into three-phase AC power.

[0053] The upper arm active element 155 and the lower arm active element 157 include a collector electrode, an emitter electrode, and a gate electrode. The upper arm diode 156 and the lower arm diode 158 include two electrodes, a cathode electrode and an anode electrode. Figure 6 As shown, the cathode electrodes of diodes 156 and 158 are electrically connected to the collector electrodes of active elements 155 and 157, and the anode electrodes are electrically connected to the emitter electrodes of active elements 155 and 157. This allows current to flow from the emitter electrodes of upper-arm active element 155 and lower-arm active element 157 to the collector electrodes in the forward direction. Active elements 155 and 157 are, for example, IGBTs.

[0054] Alternatively, a MOSFET may be used as the active element. In this case, the upper arm diode 156 and the lower arm diode 158 are unnecessary.

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

[0056] The control circuit 172 generates timing signals 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, sensors (e.g., current sensor 180), etc. The drive circuit 174 generates drive signals for switching the upper-arm active element 155 and the lower-arm active element 157 based on the timing signals output from the control circuit 172. Reference numerals 181 and 188 denote connectors.

[0057] The upper and lower arm series circuits include temperature sensors (not shown). Temperature information from the upper and lower arm series circuits is input to a microcomputer. Furthermore, voltage information on the DC positive side of the upper and lower arm series circuits is input to the microcomputer. Based on this information, the microcomputer performs overtemperature and overvoltage detection. If overtemperature or overvoltage is detected, the microcomputer stops switching all upper and lower arm active elements 155 and 157, protecting the upper and lower arm series circuits from overtemperature or overvoltage.

[0058] Figure 13 yes Figure 12 The external perspective view of the power conversion device 200 is shown. Figure 14 yes Figure 13The power conversion device 200 is shown in a perspective view in cross section along line XV-XV.

[0059] The power conversion device 200 includes a frame 12 formed into a roughly rectangular parallelepiped shape by a lower shell 11 and an upper shell 10. A circuit body 400, a capacitor module 500, etc. are housed inside the frame 12. The 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 connected to the cooling flow path protrude from one side of the frame 12. The upper side of the lower shell 11 is open, and the upper shell 10 is installed on the lower shell 11 to block the opening of the lower shell 11. The upper shell 10 and the lower shell 11 are formed of aluminum alloy or the like and are sealed and fixed relative to the outside. The upper shell 10 and the lower shell 11 can also be formed as a whole. By making the frame 12 into a simple rectangular parallelepiped shape, it is easy to install it on a vehicle or the like, and it is 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 the connector 17. 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] like Figure 14 As shown, a circuit body 400 is housed within the housing 12. The control circuit 172 and the drive circuit 174 are arranged on the circuit body 400, and a capacitor module 500 is housed on the DC terminal side of the circuit body 400. By placing the capacitor module at the same height as the circuit body 400, the power conversion device 200 can be made thinner, increasing the flexibility of its placement in the vehicle. The AC-side terminal 325A of the circuit body 400 passes through the current sensor 180 and is connected to the connector 188. Furthermore, the positive-side terminal 325P and the negative-side terminal 325M, which serve as the DC terminals of the semiconductor module 300, are connected to the positive and negative terminals 362A and 362B of the capacitor module 500, respectively.

[0062] According to the embodiment described above, the following effects can be obtained. (1) A circuit body 400 comprises: conductor plates 430, 431, 432, 433 to which semiconductor elements 155, 156, 157, 158 are bonded; a cooling member 340 disposed opposite the conductor plates 430, 431, 432, 433 to cool heat generated by the semiconductor elements 155, 156, 157, 158; and an insulating sheet 443 disposed between the conductor plates 430, 431, 432, 433 and the cooling member 340, the insulating sheet 443 having an intermediate conductor 440 disposed opposite the conductor plates 430, 431, 432, 433, the intermediate conductor 440 being divided into a plurality of portions relative to the conductor plates 430, 431, 432, 433 corresponding to one of the semiconductor elements 155, 156, 157, 158, thereby forming a capacitor electrically connected in parallel with the conductor plates 430, 431, 432, 433. This improves the insulation reliability of the circuit body.

[0063] The present invention is not limited to the above-described embodiment, and other embodiments that can be considered within the scope of the technical concept of the present invention are also included in the scope of the present invention as long as the characteristics of the present invention are not impaired. In addition, a configuration combining the above-described embodiment and multiple modified examples is also possible. Explanation of symbols

[0064] 10…Upper casing, 11…Lower casing, 13…Refrigerant inlet pipe, 14…Refrigerant outlet pipe, 17, 21, 181, 182, 188…Connectors, 18…AC terminal, 43, 140, 142…Inverter circuit, 155, 156, 157, 158…Semiconductor element, 172…Control circuit, 174…Drive circuit, 180…Current sensor, 192, 194…Motor generator, 200…Power converter, 300…Semiconductor module, 310…Circuit body, 325P…positive terminal, 325M…negative terminal, 325A…AC terminal, 325C…collector detection terminal, 325L…lower arm gate terminal, 325E…emitter detection terminal; 325U…upper arm gate terminal, 340…cooling member, 360…sealing material, 400…circuit body, 430, 431, 432, 433…conductor plates, 440…intermediate conductor, 443…insulating sheet; 444…surface conductor layer, 453…heat conduction member, 500…capacitor module.

Claims

1. A circuit body, characterized in that: have: a conductor plate bonded to the semiconductor element; a cooling member disposed opposite to the conductor plate and configured to cool heat generated by the semiconductor element; and an insulating sheet disposed between the conductor plate and the cooling member, The insulating sheet has an intermediate conductor built in, which is opposite to the conductor plate. The intermediate conductor is divided into a plurality of parts and arranged with respect to the conductor plate corresponding to one of the semiconductor elements, and forms a capacitor electrically connected in parallel with the conductor plate.

2. The circuit body according to claim 1, wherein: The intermediate conductor is divided into a plurality of parts and arranged in a region facing an end portion of the conductor plate.

3. The circuit body according to claim 1, wherein: The number of divisions of the region of the intermediate conductor facing the end portion of the conductor plate is greater than the number of divisions of the region of the intermediate conductor facing the center portion of the conductor plate.

4. The circuit body according to claim 1, wherein: The intermediate conductor is divided into a lattice shape.

5. The circuit body according to claim 1, wherein: The insulating sheet has a plurality of intermediate conductors embedded therein in a thickness direction of the insulating sheet.

6. The circuit body according to claim 1, wherein: The insulating sheet is made of ceramic.

7. The circuit body according to claim 1, wherein: In the insulating sheet, the ratio of the area occupied by the intermediate conductor in the cross section of the insulating sheet is 20% or more.

8. The circuit body according to any one of claims 1 to 7, characterized in that: The conductor plates are formed on both sides of the semiconductor element. The cooling member is arranged on both sides facing the conductor plates. The insulating sheets are respectively arranged between the conductor plate and the cooling member.

9. A power conversion device, characterized in that: A circuit body according to any one of claims 1 to 7 is provided for converting direct current into alternating current and vice versa.

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