JP7555261B2 - Electrical circuit and power conversion device - Google Patents

Description

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

Power conversion devices that use switching of power semiconductor elements have high conversion efficiency and are therefore widely used in consumer, automotive, railway, and substation equipment. Power semiconductor elements generate heat when electricity is passed through them, so devices incorporating power semiconductor elements are provided with a cooling member. The cooling member includes a fin base and multiple fins erected on the fin base, and cools the power semiconductor elements by circulating a coolant between the fins.

Patent Document 1 discloses a technology in which, in a semiconductor device in which a sealing member is sealed in a transfer molding process, a slit is formed through the fin in the thickness direction, and a partition is provided in the molding die at a position corresponding to the slit, so that the partition suppresses deformation of the fin base due to pressure during molding.

International Publication No. WO2013/114647

The device described in Patent Document 1 had the problem that heat dissipation was reduced because fins could not be formed in the slits of the fin base.

The electric circuit body according to the present invention is an electric circuit body including a power semiconductor element, a conductor plate joined to the power semiconductor element, a cooling member arranged to face the power semiconductor element with the conductor plate interposed therebetween, a sheet member sandwiched between the conductor plate and the cooling member and adhered or joined to the conductor plate, and a sealing member that seals the power semiconductor element, the conductor plate, the sheet member, and the cooling member, wherein the cooling member includes a fin base having a predetermined thickness and one surface of which is exposed from the sealing member, a plurality of fins standing on the one surface of the fin base, and and an end portion covered by the sealing material at the outer periphery of the fin base, the multiple fins including multiple boundary fins each arranged on or adjacent to the boundary between a conductor plate region of the fin base facing the conductor plate and an outer periphery region of the conductor plate region, the spacing between the fins arranged in the outer periphery region being no more than twice the thickness of the fin base, the spacing between the boundary fins being no more than twice the thickness of the fin base, and narrower than the spacing between each fin of the multiple fins arranged within the conductor plate region excluding the boundary fins .

The present invention prevents the fin base from being occupied by slits or other parts other than the fins, and suppresses deformation of the fin base without reducing heat dissipation.

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. 2 is a cross-sectional perspective view of a power module. 5A to 5C are cross-sectional views showing a method for manufacturing an electric circuit body. 5(d) to 5(f) are cross-sectional views showing a method for manufacturing an electric circuit body. 1A and 1B are enlarged views of the transfer molding process. 13A and 13B are diagrams illustrating the relationship between the spacing between fins and the thickness of the fin base. FIG. 2 is a plan view of a fin base on which fins having a rectangular cross-sectional shape are provided. FIG. 2 is a plan view of a fin base on which fins having a circular cross-sectional shape are provided in an upright manner. FIG. 2 is a plan view of a fin base on which fins having a circular cross-sectional shape are erected on the boundary. FIG. 2 is a partially enlarged plan view of a fin base on which fins are provided. FIG. 2 is a semi-transparent plan view of the power module. FIG. 2 is a circuit diagram of a power module. FIG. 1 is a circuit diagram of a power conversion device using an electric circuit body. FIG. 2 is an external perspective view of the power conversion device. FIG. 2 is a cross-sectional perspective view of the power conversion device.

Embodiments of the present invention will be described below 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 the electric circuit body 400, and Fig. 2 is a cross-sectional view of the electric circuit body 400 taken along line XX shown in Fig. 1. Fig. 3 is a cross-sectional view of the electric circuit body 400 taken along line YY shown in Fig. 1.
As shown in FIG. 1, the electric circuit body 400 is composed of three power modules 300 and a cooling member 340. The power module 300 has a function of converting DC current and AC current using power semiconductor elements, and generates heat when electricity is passed through it. For this reason, the cooling member 340 is structured to be cooled by circulating a coolant through it. The coolant used is water or an antifreeze solution in which ethylene glycol is mixed with water. The cooling member 340 has a plurality of pin-shaped fins erected on the fin base of the cooling member 340. The cooling member 340 is preferably made of aluminum, which has high thermal conductivity and is lightweight. The cooling member 340 is manufactured by extrusion molding, forging, brazing, or the like.

The power module 300 has a positive terminal 315B and a negative terminal 319B on one side that are connected to the capacitor module 500 of the DC circuit (see FIG. 15 described later). The other side of the positive terminal 315B and the negative terminal 319B has power terminals through which a large current flows, such as the AC terminal 320B that is connected to the motor generators 192, 194 of the AC circuit (see FIG. 15 described later). The other side also has signal terminals used to control the power module 300, such as the lower arm gate signal terminal 325L, the mirror emitter signal terminal 325M, the Kelvin emitter signal terminal 325K, and the upper arm gate signal terminal 325U.

2, the active element 155 and the diode 156 are provided as the first power semiconductor element forming the upper arm circuit. Examples of the semiconductor material constituting the active element 155 include Si, SiC, GaN, GaO, and C. When the body diode of the active element 155 is used, the diode 156 may be omitted. The collector side of the active element 155 and the cathode side of the diode 156 are joined to the second conductor plate 431. The emitter side of the active element 155 and the anode side of the diode 156 are joined to the first conductor plate 430. Solder or sintered metal may be used for these connections. The first conductor plate 430 and the second conductor plate 431 are not particularly limited as long as they have high electrical conductivity and thermal conductivity, but copper-based or aluminum-based materials are preferable. These may be used alone, or may be plated with Ni, Ag, or the like to improve the bonding with the solder or sintered metal.

The cooling member 340 is in close contact with the first conductive plate 430 via the first sheet member 440. The first sheet member 440 is formed by laminating a resin insulating layer and a metal foil. A heat conductive member (not shown) is provided between the first sheet member 440 and the cooling member 340, and the metal foil side of the first sheet member 440 is in close contact with the heat conductive member. The heat conductive member is not particularly limited as long as it is a material with high thermal conductivity, but it is preferable to use a highly heat conductive material such as a metal, ceramic, or carbon-based material in combination with a resin material.

The cooling member 340 is closely attached to the second conductive plate 431 via the second sheet member 441. The second sheet member 441 is formed by laminating a resin insulating layer and a metal foil. A thermally conductive member is provided between the second sheet member 441 and the cooling member 340, and the metal foil side of the second sheet member 441 is closely attached to the thermally conductive member. From the viewpoint of heat dissipation, it is desirable that the width of the cooling member 340 is wider than the widths of the sheet members 440 and 441.

The sheet members 440, 441 are sandwiched between the conductive plates 430, 431 and the cooling member 340 and are adhered or joined to the conductive plates 430, 431. The power semiconductor elements 155, 156, the conductive plates 430, 431, the sheet members 440, 441, and the cooling member 340 are integrally sealed with the sealing member 360 by a transfer molding process to form the electric circuit body 400.

The cooling member 340 is disposed facing the power semiconductor elements 155, 156 with the conductor plates 430, 431 interposed therebetween. The cooling member 340 includes a fin base 371 of a predetermined thickness, one side of which is exposed from the sealing member 360, and a plurality of fins 370 erected on one side of the fin base 371. The end of the fin base 371 is covered by the sealing member 360 on the outer periphery of the fin base 371. As will be described in detail later, in the conductor plate region S1 (see FIG. 7(a)) facing the conductor plates 430, 431 of the cooling member 340 and the outer periphery region S2 (see FIG. 7(a)) on the outer periphery of the conductor plate region S1, the distance between the fins 370 disposed in the outer periphery region S2 is less than twice the thickness of the fin base 371.

3, the first conductor plate 430, the second conductor plate 431, the third conductor plate 432, and the fourth conductor plate 433, in addition to carrying current, also serve as heat transfer members that transfer heat generated by the first power semiconductor elements 155, 156 and the second power semiconductor elements 157, 158 to the cooling member 340. Since the conductor plates 430, 431, 432, 433 have different potentials from the cooling member 340, as shown in FIG. 2, sheet members 440, 441 are interposed between the conductor plates 430, 431, 432, 433 and the cooling member 340. The first power semiconductor elements 155, 156 and the second power semiconductor elements 157, 158 may be simply referred to as power semiconductor elements 159.

The sheet members 440 and 441 are not particularly limited as long as they are adhesive to the cooling member 340 and the conductive plates 430, 431, 432, and 433, but an epoxy resin-based resin insulating layer with powdered inorganic filler dispersed therein is preferable. This is because it provides a good balance between adhesion and heat dissipation.

The conductive plates 430, 431, 432, and 433 are preferably made of a material with high electrical conductivity and high thermal conductivity, and may be made of metal materials such as copper or aluminum, or composite materials of metal materials and high thermal conductivity materials such as diamond, carbon, or ceramic.

Figure 4 is a cross-sectional perspective view of the power module 300 taken along line X-X shown in Figure 1. As shown in Figure 4, the end of the first sheet member 440 and the end of the fin base 371 are covered with a sealing member 360. The first sheet member 440 overlapping the surface of the first conductive plate 430 is the heat dissipation surface. The cooling member 340 is tightly attached to the heat dissipation surface of the first sheet member 440 to ensure close contact with the cooling member 340 and to prevent loss of heat dissipation.

The cooling member 340 is preferably made of aluminum, which has high thermal conductivity and is lightweight. It is manufactured by extrusion molding, forging, brazing, etc. The cooling member 340 is bonded to the fin base 371 via a sealing member (not shown) to form a watertight structure. The outer periphery of the fin base 371 has a thin-walled portion 374 that prevents resin leakage from the transfer mold, and this portion deforms during transfer molding, absorbing thickness variations while preventing resin leakage from the transfer mold.

Figures 5(a)-(c) and 6(d)-(f) are cross-sectional views showing a manufacturing method for the electric circuit body 400. Figures 5(a)-(c) and 6(d) are cross-sectional views of one power module taken along line Y-Y in Figure 1, and Figures 6(e)-(f) are cross-sectional views of one power module taken along line X-X in Figure 1.

Figure 5 (a) is a diagram showing the solder connection process and the wire bonding process. The collector side of the active element 155, which is the first power semiconductor element, is connected to the second conductor plate 431. The emitter side of the active element 155 is connected to the first conductor plate 430. Similarly, the collector side of the active element 157, which is the second power semiconductor element, is connected to the fourth conductor plate 433. The emitter side of the active element 157 is connected to the third conductor plate 432. In this way, the circuit body 310 is formed. Then, the first sheet member 440 and the fin base 371 equipped with the fins 370 are arranged on one side of the circuit body 310, and the second sheet member 441 and the fin base 371 equipped with the fins 370 are arranged on the other side of the circuit body 310, to provide the assembly 311.

5(b) to 5(c) are diagrams showing the transfer molding process.
5B, the transfer molding device 601 includes a spring mechanism 602. A vacuum degassing mechanism for vacuum-adsorbing the sheet members 440, 441, etc. to the mold is omitted from the illustration. The assembly 311, which has been preheated to 175° C., is placed in the mold, which has been preheated to a constant temperature of 175° C.

Next, as shown in FIG. 5(c), the mold is closed and the sealing member 360 is injected into the mold cavity. At this time, the thin-walled portion 374 provided on the outer periphery of the fin base 371 is deformed by the mold, absorbing the variation in thickness of the assembly 311 and also serving as a lid to prevent the sealing member 360 from flowing into the fin 370 side. When the mold is closed, the tip of the fin 370 is pressurized by the spring mechanism 602, and this pressure is greater than the injection pressure of the sealing member 360 during transfer molding. The heating in the mold and the pressure force of the spring mechanism 602 are added to the pressure force, and the sheet members 440 and 441 undergo a hardening reaction, and the sheet members 440 and 441 are bonded to the fin base 371 and the conductor plates 430, 431, 432, and 433. However, the fin base 371 may be deformed by the injection pressure of the sealing member 360 during transfer molding. In this embodiment, as described below, deformation of the fin base 371 is suppressed.

Figure 6 (d) shows the curing process. The power module 300 sealed with the sealing member 360 is removed from the transfer molding device 601, cooled to room temperature, and cured for at least two hours.

Figure 6 (e) is a diagram showing the installation process of the cooling member 340. A sealing member 372 is placed around the fin base 371, and a lid 373 is attached to the fin base 371 to form the cooling member 340.

Figure 6(f) shows the electric circuit body 400 manufactured by the above process. In this way, the cooling members 340 are installed on both sides of the power module 300, and the electric circuit body 400 is manufactured.

Figure 7 is an enlarged view of the dotted line portion H in Figure 5(c) during the transfer molding process. Figure 7(a) shows this embodiment, and Figure 7(b) shows a comparative example in which this embodiment is not applied.

7A shows the transfer molding process, in which the mold is closed and pressure P is applied by the spring mechanism 602. The spring mechanism 602 also applies pressure P to the tip of the fin 370. In addition, when the sealing member 360 is injected, the injection pressure Q is applied to the fin base 371 and the conductor plate 432 as hydrostatic pressure. Since the pressure P by the spring mechanism 602 is set to be greater than the injection pressure Q, the sheet member 440 is heated and pressurized between the fin base 371 and the conductor plate 432 and adhered. In this embodiment, as will be described in detail later, in the conductor plate region S1 facing the conductor plate 432 of the fin base 371 and the peripheral region S2 on the periphery of the conductor plate region S1, the distance between the fins 370 arranged in the peripheral region S2 is set to be less than twice the thickness of the fin base 371. This suppresses deformation of the fin base 371.

In the comparative example shown in FIG. 7B, when the spacing between the fins 370 is large and the thickness of the fin base 371 is thin, the injection pressure Q causes deformation R of the fin base 371 between the fins 370. In this case, the fin base 371 separates from the sheet member 440 at the end of the conductor plate 432, resulting in poor adhesion of the sheet member 440. The sealing member 360 penetrates into the area where deformation R of the fin base 371 occurs, but the sealing member 360 does not penetrate into gaps of 20 μm or less to suppress resin burrs on the mold. As a result, peeling with an air layer may occur in the sheet member 440 at the end of the conductor plate 432 due to the amount of deformation of the fin base 371, in which case the insulation and heat dissipation of the electric circuit body 400 is reduced.

8(a) and 8(b) are diagrams for explaining the relationship between the spacing of the fins 370 and the thickness of the fin base 371. The distance (spacing) between the fins 370 is D, and the thickness of the fin base 371 between the fins 370 is T.
8A shows the case where D≦2T. The pressure force P from the spring mechanism 602 is first applied to the tip of the fin 370. This pressure force P spreads at an angle of approximately 45 degrees across the thickness T of the fin base 371, as shown by the dotted line t. When the relationship D≦2T is satisfied, the entire back surface of the fin base 371 becomes an area P1 where the surface pressure is high due to the pressure force P of the spring mechanism 602.

8B shows the case where D>2T. On the back surface of the fin base 371, the pressure P from the spring mechanism 602 causes the thickness T of the fin base 371 to expand at an angle of approximately 45 degrees as shown by the dotted line t. As a result, when the thickness T of the fin base 371 is thin or the distance D is large, a region P1 with high surface pressure and a region P2 with low surface pressure are formed. The region P2 with low surface pressure cannot withstand the injection pressure Q in the transfer molding process, so deformation of the fin base 371 occurs. From this principle, it has been clarified that when the tip of the fin 370 is supported by a mold in the transfer molding process, the relationship D≦2T must be satisfied in order to suppress deformation of the fin base 371. Note that this relationship does not need to be satisfied in all areas where the fin 370 is provided.

9 is a plan view of a fin base 371 on which fins 370 are provided. In this figure, a case where the cross-sectional shape of fins 370 is rectangular will be described as an example.
In the conductor plate region S1 facing the conductor plate of the fin base 371, the distance (spacing) D of the fins 370 and the thickness T of the fin base 371 do not need to satisfy the relationship D≦2T, and the fins 370 necessary for heat dissipation of the power semiconductor element 159 may be appropriately arranged. On the other hand, in the peripheral region S2 on the periphery of the conductor plate region S1, the injection pressure Q of the transfer molding process is applied to the fin base 371 via the sealing member 360. For this reason, the relationship D≦2T is satisfied, that is, the spacing d1 between the fins 370 arranged in the peripheral region S2 is set to be equal to or less than twice the thickness of the fin base 371. This suppresses the deformation of the fin base 371, thereby preventing the sheet member 440 from peeling off and maintaining good insulation and heat dissipation of the electric circuit body 400.

The distance d2 between the fin 370 arranged in the conductor plate region S1 and the fin 370 arranged adjacent to the fin 370 in the peripheral region S2 is less than twice the thickness T of the fin base 371. Here, the fin 370 arranged in the conductor plate region S1 may be arranged on the boundary between the conductor plate region S1 and the peripheral region S2. Deformation of the fin base 371 can be more effectively suppressed when the fin 370 is on the boundary between the conductor plate region S1 and the peripheral region S2.

Furthermore, the distance d3 between the fins 370 arranged on the boundary between the conductor plate region S1 and the outer peripheral region S2 is equal to or less than twice the thickness of the fin base 371. Here, the distance d3 between the fins 370 arranged on the boundary between the conductor plate region S1 and the outer peripheral region S2 may be arranged narrower than the distance d4 between the fins arranged within the conductor plate region S1.
Furthermore, the distance d5 between the fin 370 arranged on the boundary between the conductive plate region S1 and the outer circumferential region S2 and the fin 370 arranged in the outer circumferential region S2 is equal to or less than twice the thickness of the fin base 371.

The spacing d1 between the fins 370 arranged parallel to the flow of the refrigerant F through the cooling member is narrower than the spacing d3 between the fins 370 arranged perpendicular to the flow of the refrigerant F.

10 is a plan view of a fin base 371 on which fins 370 are provided. In this figure, a case where the cross-sectional shape of fins 370 is circular will be described as an example.
In the conductor plate region S1 facing the conductor plate of the fin base 371, the distance (spacing) D of the fins 370 and the thickness T of the fin base 371 do not need to satisfy the relationship D≦2T, and the fins 370 necessary for heat dissipation of the power semiconductor element 159 may be appropriately arranged. On the other hand, in the peripheral region S2 on the periphery of the conductor plate region S1, the injection pressure Q in the transfer molding process is applied to the fin base 371 via the sealing member 360. For this reason, the relationship D≦2T is satisfied, that is, the spacing d1 between the fins 370 arranged in the peripheral region S2 is set to be equal to or less than twice the thickness of the fin base 371. This suppresses the deformation of the fin base 371, thereby preventing the sheet member 440 from peeling off and maintaining good insulation and heat dissipation of the electric circuit body 400.

The distance d2 between the fin 370 arranged in the conductor plate region S1 and the fin 370 arranged adjacent to the fin 370 in the peripheral region S2 is less than twice the thickness T of the fin base 371. Here, the fin 370 arranged in the conductor plate region S1 may be arranged on the boundary between the conductor plate region S1 and the peripheral region S2. Deformation of the fin base 371 can be more effectively suppressed when the fin 370 is on the boundary between the conductor plate region S1 and the peripheral region S2.

The spacing d1 between the fins 370 arranged parallel to the flow of the refrigerant F through the cooling member is narrower than the spacing d3 between the fins 370 arranged perpendicular to the flow of the refrigerant F.

11 is a plan view of a fin base 371 on which fins 370 are provided. In this figure, a case where the cross-sectional shape of fins 370 is circular and fins 370 are disposed on the boundary between conductive plate region S1 and outer circumferential region S2 will be described as an example.
The distances d1, d3 between the fins 370 arranged on the boundary between the conductor plate region S1 and the outer peripheral region S2 are set to be equal to or less than twice the thickness of the fin base 371. This suppresses deformation of the fin base 371, thereby preventing peeling of the sheet member 440 and maintaining good insulation and heat dissipation properties of the electric circuit body 400.

Here, the distances d1, d3 between the fins 370 arranged on the boundary between the conductor plate region S1 and the outer peripheral region S2 may be narrower than the distance d4 between the fins arranged within the conductor plate region S1.
Furthermore, the distance d5 between the fin 370 arranged on the boundary between the conductive plate region S1 and the outer circumferential region S2 and the fin 370 arranged in the outer circumferential region S2 is equal to or less than twice the thickness of the fin base 371.

The spacing d1 between the fins 370 arranged parallel to the flow of the refrigerant F through the cooling member is narrower than the spacing d3 between the fins 370 arranged perpendicular to the flow of the refrigerant F.

FIG. 12 is a partially enlarged plan view of a fin base 371 on which fins 370 are provided.
The distance between the fins in the direction parallel to the flow F of the refrigerant is Dv, and the distance between the fins in the direction perpendicular to the flow F of the refrigerant is Dp. If Dp is small, the refrigerant does not flow easily and the pressure loss in the water passage increases, making it necessary to increase the output of the pump to flow the refrigerant. On the other hand, even if Dv is made small, the pressure loss in the water passage does not increase. Therefore, by making Dp>Dv, the decrease in pressure loss in the water passage is suppressed. Furthermore, the spacing Dp, d1 of the fins 370 in the outer circumferential region S2 can be made small to satisfy D≦2T.

According to this embodiment, deformation of the fin base 371 due to transfer molding can be suppressed, and peeling of the sheet member 440 at the end of the conductor plate 432 can be prevented, so that the insulation and heat dissipation properties of the electric circuit body 400 can be maintained in good condition.

Figure 13 is a semi-transparent plan view of the power module 300 in this embodiment. Figure 14 is a circuit diagram of the power module 300 in this embodiment.

As shown in Figures 13 and 14, the positive terminal 315B 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 signal terminal 325U is output from the gate and emitter sense of the active element 155 of the upper arm circuit. The negative terminal 319B 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 signal terminal 325L is output from the gate and emitter sense of the active element 157 of the lower arm circuit. The AC side terminal 320B 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.

A first conductor plate (upper arm circuit emitter side) 430 and a second conductor plate (upper arm circuit collector side) 431 are arranged above and below the active element 155 and diode 156 of the first power semiconductor element (upper arm circuit). A third conductor plate (lower arm circuit emitter side) 432 and a fourth conductor plate (lower arm circuit collector side) 433 are arranged above and below the active element 157 and diode 158 of the second power semiconductor element (lower arm circuit).

The power 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 power module 300 can be reduced, resulting in a smaller size.

FIG. 15 is a circuit diagram of a power conversion device 200 using the electric circuit body 400.
The power conversion device 200 includes inverter circuits 140 and 142, an inverter circuit 43 for auxiliary equipment, and a capacitor module 500. The inverter circuits 140 and 142 are configured with an electric circuit body 400 (not shown) including a plurality of power modules 300, which are connected to form a three-phase bridge circuit. When the current capacity is large, the current capacity can be increased by connecting further power modules 300 in parallel and making these parallel connections corresponding to each phase of the three-phase inverter circuit. In addition, the current capacity can be increased by connecting active elements 155 and 157 and diodes 156 and 158, which are power semiconductor elements built into the power module 300, in parallel.

The inverter circuit 140 and the inverter circuit 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 140 and the like is well known, a detailed explanation will be omitted here.

As described above, the upper arm circuit includes an upper arm active element 155 and an upper arm diode 156 as power semiconductor elements for switching, and the lower arm circuit includes a lower arm active element 157 and a lower arm diode 158 as power semiconductor elements for switching. The active elements 155 and 157 receive a drive signal output from one or the other of the two driver circuits that make up the driver circuit 174 and perform a switching operation to convert the DC power supplied from the battery 136 into three-phase AC power.

As described above, the upper arm active element 155 and the lower arm active element 157 have a collector electrode, an emitter electrode, and a gate electrode. The upper arm diode 156 and the lower arm diode 158 have two electrodes, a cathode electrode and an anode electrode. As shown in FIG. 13, 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.

Note that a MOSFET (metal-oxide semiconductor field-effect transistor) may be used as the active element, in which case the upper arm diode 156 and the lower arm diode 158 are not required.

The positive terminal 315B and negative terminal 319B of each upper and lower arm series circuit are connected to DC terminals 362A and 362B for connecting capacitors of the capacitor module 500, respectively. 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 320B of each power module 300. The AC side terminal 320B of each power module 300 of each phase is 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, 182, and 188 are connectors.

The upper and lower arm series circuits include a temperature sensor (not shown), and temperature information of the upper and lower arm series circuits is input to the control circuit 172. In addition, voltage information of the DC positive pole side of the upper and lower arm series circuits is input to the control circuit 172. The control circuit 172 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, protecting the upper and lower arm series circuits from over-temperature or over-voltage.

16 is an external perspective view of the power conversion device 200 shown in FIG. 15, and FIG. 17 is a cross-sectional perspective view of the power conversion device 200 shown in FIG. 16 taken along line XV-XV.
As shown in FIG. 16, the power conversion device 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, and a cooling water inlet pipe 13 and a cooling water outlet pipe 14 communicating with the cooling flow path protrude from one side of the housing 12. The lower case 11 has an opening on the upper side (Z direction), 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 against the outside. The upper case 10 and the lower case 11 may be integrally configured. By forming the housing 12 into a simple rectangular parallelepiped shape, it becomes easy to attach it to a vehicle or the like, and also improves productivity.

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 cooling water inlet pipe 13 and the cooling water outlet pipe 14 are led out.

As shown in FIG. 17, the electric circuit body 400 is housed in the housing 12. The control circuit 172 and the driver circuit 174 are arranged above the electric circuit body 400, and the 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 320B of the electric circuit body 400 is connected to the bus bar through the current sensor 180. In addition, the positive side terminal 315B and the negative side terminal 319B, which are DC terminals of the electric circuit body 400, are respectively connected to the positive and negative terminals of the capacitor module 500 (DC terminals 362A and 362B in FIG. 13).

According to the embodiment described above, the following advantageous effects can be obtained.
(1) The electric circuit body 400 includes a power semiconductor element 159, conductive plates 430, 431, 432, and 433 joined to the power semiconductor element 159, a cooling member 340 arranged to face the power semiconductor element 159 with the conductive plates 430, 431, 432, and 433 in between, sheet members 440 and 441 sandwiched between the conductive plates 430, 431, 432, and 433 and the cooling member 340 and bonded or adhered to the conductive plates 430, 431, 432, and 433, and a sealing member for sealing the power semiconductor element 159, the conductive plates 430, 431, 432, and 433, the sheet members 440 and 441, and the cooling member 340. and a sealing member 360 that is provided between the fin base 371 and the fin base 371. The cooling member 340 includes a fin base 371 of a predetermined thickness, one side of which is exposed from the sealing member 360, a plurality of fins 370 standing on one side of the fin base 371, and an end portion that is covered by the sealing member 360 on the outer periphery of the fin base 371, and in a conductor plate region S1 that faces the conductor plates 430, 431, 432, and 433 of the fin base 371 and an outer periphery region S2 on the outer periphery of the conductor plate region S1, the spacing between the fins 370 arranged in the outer periphery region S2 is equal to or less than twice the thickness of the fin base 371. This prevents the fin base from being occupied by slits or the like other than the fins, and makes it possible to suppress deformation of the fin base without reducing heat dissipation.

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, the above-described embodiment may be combined with multiple examples.

155: First power semiconductor element (upper arm circuit active element), 156: First power semiconductor element (upper arm circuit diode), 157: Second power semiconductor element (lower arm circuit active element), 158: Second power semiconductor element (lower arm circuit diode), 159: Power semiconductor element, 172: Control circuit, 174: Driver circuit, 180: Current sensor, 181, 182, 188: Connector, 192, 194: Motor generator, 200: Power conversion device, 300: Power module, 310: Circuit body, 311: Assembly body, 315B: Positive side terminal, 319B: Negative side terminal, 320B: AC side terminal, 325: Signal terminal, 325K: Kelvin emitter signal terminal, 325L: Lower arm gate signal terminal, 325M: Mirror emitter 325U: upper arm gate signal terminal, 340: cooling member, 360: sealing member, 370: fin, 371: fin base, 372: sealing member, 400: electric circuit body, 430: first conductor plate (upper arm circuit emitter side), 431: second conductor plate (upper arm circuit collector side), 432: third conductor plate (lower arm circuit emitter side), 433: fourth conductor plate (lower arm circuit collector side), 440: first sheet member (emitter side), 441: second sheet member (collector side), 500: capacitor module, 601: transfer molding device, 602: spring mechanism, D: fin spacing, P: pressure applied by spring mechanism, Q: injection pressure of sealing member, S1: conductor plate area, S2: outer peripheral area, T: thickness of fin base.

Claims (6)

An electric circuit body comprising: a power semiconductor element; a conductor plate joined to the power semiconductor element; a cooling member arranged to face the power semiconductor element with the conductor plate interposed therebetween; a sheet member sandwiched between the conductor plate and the cooling member and adhered or joined to the conductor plate; and a sealing member that seals the power semiconductor element, the conductor plate, the sheet member, and the cooling member,
the cooling member includes a fin base having a predetermined thickness and one surface of the fin base exposed from the sealing member, a plurality of fins standing on the one surface of the fin base, and an end portion of the fin base that is covered by the sealing member on an outer periphery thereof,
the plurality of fins include a plurality of boundary fins each disposed on a boundary between a conductor plate region of the fin base facing the conductor plate and an outer peripheral region of the conductor plate region, or adjacent to the boundary;
The distance between the fins arranged in the outer peripheral region is equal to or less than twice the thickness of the fin base,
An electrical circuit body in which the spacing between the boundary fins is less than twice the thickness of the fin base and is narrower than the spacing between each of the multiple fins that are arranged within the conductor plate region, excluding the boundary fins . 2. The electric circuit body according to claim 1,
the boundary fins include a first fin disposed adjacent to the boundary in the conductor plate region and a second fin disposed adjacent to the boundary in the outer circumferential region;
An electric circuit body, wherein the distance between the first fin and the second fin is equal to or less than twice the thickness of the fin base. 2. The electric circuit body according to claim 1,
the boundary fin is disposed on the boundary;
An electrical circuit body, wherein the distance between the boundary fin and the fins disposed in the outer peripheral region is equal to or less than twice the thickness of the fin base. 2. The electric circuit body according to claim 1,
An electric circuit body in which the intervals between the fins arranged parallel to the flow of the coolant through the cooling member are narrower than the intervals between the fins arranged perpendicular to the flow of the coolant. 5. The electric circuit body according to claim 1,
the conductor plates are disposed on both sides of the power semiconductor element, and one side of each of the conductor plates is joined to the power semiconductor element;
the sheet member is adhered or joined to the other surface of each of the conductive plates,
The cooling member is an electric circuit body bonded via each of the sheet members. A power conversion device comprising the electric circuit body according to any one of claims 1 to 4 , for converting DC power into AC power.

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