Inverter device

Abstract

This inverter device comprises: a housing that houses a circuit including a power semiconductor; a substrate that closes an opening of the housing; and a sealing material that is disposed between the substrate and the power semiconductor and covers and seals the power semiconductor. The substrate has a first fin that extends toward the power semiconductor, and a second fin that extends toward a member different from the power semiconductor.

Description

Inverter Device

[0001] The present disclosure relates to an inverter device.

[0002] 2. Description of the Related Art Conventionally, an inverter device is known in which fins are provided on a shield plate of a power semiconductor in order to cool the power semiconductor that generates heat.

[0003] Japanese Patent Application Publication No. 2006-49555

[0004] The inverter device of Patent Document 1 has an insulating material (sealing material) between the power semiconductor and the shield plate. While the allowable temperature of power semiconductors has increased in recent years, there are cases where the allowable temperature of the sealing material exceeds the allowable temperature.

[0005] An object of the present disclosure is to provide an inverter device that can reduce the temperature of the sealing material.

[0006] The inverter device according to the present disclosure comprises a housing that houses a circuit including a power semiconductor, a substrate that closes an opening in the housing, and a sealing material that is disposed between the substrate and the power semiconductor and covers the power semiconductor, and the substrate has a first fin that extends toward the power semiconductor and a second fin that extends toward a member different from the power semiconductor.

[0007] According to this inverter device, the temperature of the sealing material can be reduced by the first fin and the second fin.

[0008] According to the present disclosure, an inverter device capable of lowering the temperature of the sealing material can be provided.

[0009] Fig. 1 is a top view of an inverter device according to an embodiment of the present disclosure, Fig. 2 is a cross-sectional view taken along line AA in Fig. 1, and Fig. 3 is an enlarged view of a first fin and a second fin in Fig. 2.

[0010] Hereinafter, an embodiment of the present disclosure will be described with reference to the drawings.

[0011] As shown in FIGS. 1 and 2 , the inverter device 1 includes a housing 2, a substrate 4, a plurality of power semiconductors 6, a bus bar 8, a plurality of aluminum wires 10, and a sealing material 12. The inverter device 1 of this embodiment is a device for controlling a motor (not shown) of an electric vehicle, a hybrid vehicle, or a plug-in hybrid vehicle that allows external charging / external power supply. The inverter device 1 includes an IGBT (Insulated Gate Bipolar Transistor) or a MOSFET (Metal Oxide Semiconductor Field Effect Transistor) as the power semiconductor 6 that converts direct current (DC) flowing from a battery (not shown) for driving the motor into alternating current suitable for the motor. A plurality of such inverter devices 1 are housed in an inverter case formed of aluminum die-cast or the like to form a single inverter module.

[0012] The housing 2 houses a circuit including a power semiconductor 6. The housing 2 of this embodiment has a substantially rectangular bottom wall 2a and side walls 2b arranged on all four sides of the bottom wall 2a and extending from the bottom wall 2a in a direction intersecting the bottom wall 2a. The housing 2 houses a circuit including a power semiconductor 6 in a space surrounded by the bottom wall 2a and the side walls 2b. The housing 2 of this embodiment is made of resin or insulating metal. However, the housing 2 may be made of other materials.

[0013] 2, a surface 2c of the bottom wall 2a of this embodiment is formed with a plurality of first protrusions 2d protruding from the surface 2c. A circuit including a power semiconductor 6 is fixed to a rear surface 2e of the bottom wall 2a of the housing 2. The first protrusions 2d have the function of dissipating heat emitted from the circuit fixed to the rear surface 2e. The first protrusions 2d may be made of a metal with high thermal conductivity, such as aluminum, in addition to resin.

[0014] The substrate 4 closes the opening of the housing 2 surrounded by the four side walls 2b, and is fixed to the housing 2 with bolts (not shown) or the like. The substrate 4 has a front surface 4a, a back surface 4b formed on the opposite side of the front surface 4a and facing the power semiconductor 6, a first fin 4c, a second fin 4d, and a second protrusion 4e.

[0015] 3, the first fin 4c extends from the back surface 4b toward the region between the bus bar 8 of the power semiconductor 6 and the aluminum wire 10. The second fin 4d extends toward a member other than the power semiconductor 6, such as the aluminum wire 10 or the bus bar 8, which is positioned closer to the substrate 4 than the power semiconductor 6. Therefore, the first fin 4c is longer than the second fin 4d. In other words, the first fin 4c extends to a position closer to the power semiconductor 6, which is a heat source, than the second fin 4d. This makes it easier for the first fin 4c to receive the heat received by the sealing material 12.

[0016] The first fin 4c and the second fin 4d extend into the sealing material 12. This allows the sealing material 12 to dissipate heat received from the power semiconductors 6 through the first fin 4c and the second fin 4d. As shown in FIG. 1 , the first fin 4c and the second fin 4d each extend along the longitudinal direction of the housing 2. In this embodiment, one first fin 4c and two second fins 4d are arranged for each power semiconductor 6. However, the numbers of first fins 4c and second fins 4d may be changed as appropriate. Furthermore, the first fin 4c facing one power semiconductor 6 is arranged independently of the first fin 4c of the adjacent power semiconductor 6. Like the first fins 4c, the second fins 4d are also arranged independently of each other. By arranging the first fins 4c and the second fins 4d in this manner to correspond to each of the multiple power semiconductors 6, it is possible to efficiently dissipate heat from the power semiconductors 6 while avoiding interference between the second fins 4d, the bus bars 8 connected to each power semiconductor 6, and the aluminum wires 10.

[0017] 2, the surface 4a of the substrate 4 is uneven. In this embodiment, second protrusions 4e are formed so as to protrude from the surface 4a in a direction intersecting the direction in which the surface 4a extends. The second protrusions 4e have the function of dissipating heat received by the first fins 4c and the second fins 4d.

[0018] Of the substrate 4, at least the first fin 4c and the second fin 4d are made of a material with a thermal conductivity better than that of the sealing material 12. One example of such a material is aluminum. Furthermore, it is preferable that the second fin 4d is made of a material with higher insulating properties than the first fin 4c. One example of such a material is aluminite. The thermal conductivity of aluminite is about 230 W / m·K, which is equivalent to that of aluminum. The electrical resistivity of aluminite is about 1012 Ω·m, which is about 2.65×10 －８ The insulating properties are higher than those of the metal fin 4c (Ω·m). Such a material makes it easier to prevent a short circuit that occurs when the second fin 4d comes into contact with the bus bar 8 or the aluminum wire 10. The substrate 4 may have the first fin 4c formed of aluminum, and only the second fin 4d formed of aluminite. The substrate 4 may have other portions, different from the first fin 4c and the second fin 4d, formed of other metals. The first fin 4c may also be formed of aluminite. However, forming the first fin 4c of aluminum and only the second fin 4d of aluminite results in lower manufacturing costs.

[0019] As shown in FIGS. 1 and 2 , a plurality of power semiconductors 6 are arranged in the space of the housing 2. In this embodiment, six power semiconductors 6 are arranged in the housing 2. The power semiconductors 6 are incorporated into a high-voltage circuit 6a. The plurality of power semiconductors 6 are connected to a low-voltage circuit (not shown) that controls the high-voltage circuit 6a, respectively, by a plurality of aluminum wires 10. The plurality of aluminum wires 10 extend from an outer region of the power semiconductors 6 toward a side wall 2b of the housing 2. The plurality of power semiconductors 6 are each connected to a bus bar 8, and receive power from a drive battery via the bus bar 8 and supply power to a motor. The bus bar 8 is connected to an inner region of the power semiconductors 6 and extends longitudinally through approximately the center of the housing 2 in the short-side direction.

[0020] The sealing material 12 is a member that covers the power semiconductors 6. The sealing material 12 is made of a material such as gel, mold resin, or epoxy resin. After the power semiconductors 6 and the high-voltage circuit 6a are installed, the liquid resin is poured into the sealing material 12 to seal the power semiconductors 6 and the high-voltage circuit 6a. The sealing material 12 has a lower thermal conductivity than aluminum and aluminite. Therefore, heat from the sealing material 12 is dissipated to the outside of the inverter device 1 through the first fin 4c and the second fin 4d, which are inserted into the sealing material 12 and have higher thermal conductivity.

[0021] An air layer is provided between the sealing material 12 and the substrate 4. The air layer has the function of cooling the first fin 4c, the second fin 4d, and the surface of the sealing material 12 facing the substrate 4 by air flowing through the air layer.

[0022] In recent years, power semiconductors 6 have been replaced by silicon IGBTs with silicon carbide MOSFETs, which have higher heat resistance. However, the sealing material 12 that covers the power semiconductors 6 is made of materials such as gallium, molding resin, and epoxy resin, which has the problem of being inferior in heat resistance to silicon carbide MOSFETs.

[0023] However, according to the inverter device 1 of the present disclosure, the heat of the sealing material 12 is transferred to the first fin 4 c and the second fin 4 d and then dissipated to the outside of the housing 2 via the second protrusion 4 e, thereby suppressing the temperature rise of the sealing material 12.

[0024] As described above, according to the present disclosure, it is possible to provide an inverter device 1 that can reduce the temperature of the sealing material 12 .

[0025] Although the embodiments of the present disclosure have been described above, the present disclosure is not limited to the above-described embodiments, and various modifications are possible without departing from the spirit of the invention. In particular, the multiple modifications described in this specification can be combined as needed.

[0026] (a) In the above embodiment, a rectangular housing 2 has been described as an example, but the present disclosure is not limited to this.

[0027] (b) In the above embodiment, an example has been described in which six power semiconductors 6 are arranged inside the housing 2, but the present disclosure is not limited to this. The number of power semiconductors 6 may be changed as appropriate. Furthermore, the arrangement of the power semiconductors 6 may also be changed as appropriate.

[0028] Although various embodiments have been described above with reference to the drawings, it goes without saying that the present invention is not limited to such examples. It is clear that a person skilled in the art can conceive of various modifications or alterations within the scope of the claims, and it is understood that these also naturally fall within the technical scope of the present invention. Furthermore, the components of the above-described embodiments may be combined in any manner without departing from the spirit of the invention.

[0029] This application is based on a Japanese patent application (Patent Application No. 2023-180812) filed on October 20, 2023, the contents of which are incorporated herein by reference.

[0030] REFERENCE SIGNS LIST 1 inverter device 2 housing 2c front surface 2e rear surface 4 substrate 4a front surface 4b rear surface 4c first fin 4d second fin 4e second protrusion 6 power semiconductor 6a high voltage circuit 8 bus bar 10 aluminum wire 12 sealing material

Claims

1. a housing that houses a circuit including a power semiconductor; a substrate that closes the opening of the housing; a sealing material disposed between the substrate and the power semiconductor and covering the power semiconductor; an air layer disposed between the substrate and the sealing material; Equipped with the substrate has a first fin extending toward the power semiconductor and a second fin extending toward a member different from the power semiconductor, the first fin and the second fin extend into the sealing material through the air layer; Inverter device.

2. The first fin extends to a position closer to the heat source than the second fin. The inverter device according to claim 1 .

3. a housing that houses a circuit including a power semiconductor; a substrate that closes the opening of the housing; a sealing material disposed between the substrate and the power semiconductor and covering the power semiconductor; Equipped with the substrate has a first fin extending toward the power semiconductor and a second fin extending toward a member different from the power semiconductor, The inverter device, wherein the second fins are formed of a material having higher insulating properties than the first fins.

4. the substrate has a back surface facing the power semiconductor and a front surface formed on the opposite side of the back surface, the first fin and the second fin are formed on the back surface, The surface is formed with irregularities. The inverter device according to any one of claims 1 to 3.

5. the first fin and the second fin are formed of a material having a higher thermal conductivity than the sealing material; The inverter device according to any one of claims 1 to 4.

6. the material having a higher thermal conductivity than the sealing material is aluminum or aluminite; the first fin is formed of aluminum or aluminite; The second fin is formed of aluminite. The inverter device according to claim 5 .

7. a housing that houses a circuit including a power semiconductor; a substrate that closes the opening of the housing; a sealing material disposed between the substrate and the power semiconductor and covering the power semiconductor; Equipped with the substrate has a first fin extending toward the power semiconductor and a second fin extending toward a member different from the power semiconductor, the first fin is disposed above the power semiconductor; The second fins are disposed at positions sandwiching the first fin. Inverter device.

8. the substrate has a back surface facing the power semiconductor and a front surface formed on the opposite side of the back surface, the first fin and the second fin are formed on the back surface, The surface is formed with irregularities. The inverter device according to claim 7.

9. the first fin and the second fin are formed of a material having a higher thermal conductivity than the sealing material; The inverter device according to claim 7 or 8.

10. the material having a higher thermal conductivity than the sealing material is aluminum or aluminite; the first fin is formed of aluminum or aluminite; The second fin is formed of aluminite. The inverter device according to claim 9.