Power conversion device

Abstract

This power conversion device comprises: a plurality of semiconductor packages; and a heat dissipation member that is in thermal contact with the plurality of semiconductor packages. Furthermore, the heat dissipation member comprises: a frame that includes a plurality of heat dissipation fins and a fin base on which the plurality of heat dissipation fins are formed, and that holds the fin base such that the fin base is displaceable; and a flow-path cover that presses the fin base toward the plurality of semiconductor packages. The flow-path cover has a convex pressing portion that abuts the tips of the heat dissipation fins that are spaced apart, by at least a prescribed distance, from both ends of the plurality of heat dissipation fins in the arrangement direction of the plurality of semiconductor packages.

Description

Power Conversion Device

[0001] The present invention relates to a power conversion device.

[0002]

[0003] Power conversion devices are required to have high efficiency, small size, and high heat dissipation. Patent Document 1 discloses a semiconductor device comprising: a plate-shaped semiconductor module having a first main surface and a second main surface facing opposite each other; a first heat dissipation member thermally coupled to the first main surface; a second heat dissipation unit arranged parallel to the second main surface and having a plate-shaped base thermally coupled to the second main surface; and a circuit unit arranged on the second main surface side of the semiconductor module, the base being arranged between the circuit unit and the semiconductor module and defining a connection passage for arranging a connection member for providing electrical connection between the circuit unit and the semiconductor module.

[0003] JP 2012-028401 A

[0004] The invention described in Patent Document 1 leaves room for improvement in terms of heat dissipation.

[0005] A power conversion device according to a first aspect of the present invention comprises a plurality of semiconductor packages and a heat dissipation member in thermal contact with the plurality of semiconductor packages, the heat dissipation member including a plurality of heat dissipation fins and a fin base on which the plurality of heat dissipation fins are formed, and further comprises a frame that holds the fin base in a displaceable manner, and a flow path cover that presses the fin base toward the plurality of semiconductor packages, the flow path cover having a convex pressing portion that abuts against the tips of the plurality of heat dissipation fins that are located a predetermined distance or more away from both ends of the plurality of semiconductor packages in the arrangement direction.

[0006] According to the present invention, the heat dissipation member can easily come into contact with the semiconductor package in the center, improving heat dissipation.

[0007] Cross-sectional view of the power conversion device in the first embodiment Cross-sectional view of the power conversion device in the first modification Cross-sectional view of the power conversion device in the second modification Cross-sectional view of the power conversion device in the second embodiment Cross-sectional view of the power conversion device in the third embodiment

[0008] -First Embodiment- A first embodiment of a power conversion device will be described below with reference to FIGS. 1 and 2. FIG.

[0009] FIG. 1 is an exploded perspective view of a power conversion device 1. The power conversion device 1 includes an insulating plate 8, a heat dissipation member 3, a frame 4, and a flow path cover 5. Although not shown in FIG. 1, a semiconductor package 2 is disposed below the insulating plate 8. Note that a TIM (thin-metal-insulator-metal) described below is not shown in this figure. The flow path cover 5 is made of aluminum, copper, stainless steel, or the like. The frame 4 is joined to the flow path cover 5 by brazing, laser welding, adhesive, or the like. The insulating plate 8 is made of an insulating material such as ceramics or resin.

[0010] The heat dissipation member 3 includes a fin base 31, a plurality of heat dissipation fins 32, and a flange portion 33. The heat dissipation member 3 also includes a protrusion 34, which will be described later, but is not visible in Fig. 1. The fin base 31 is thermally connected to the heat dissipation surface of the semiconductor package 2, which is the member to be dissipated, via an insulating plate 8. Note that although the heat dissipation fins 32 are illustrated as cylindrical pin fins, they may have other shapes and the shape of the heat dissipation fins 32 is not limited.

[0011] The frame 4 is formed with the same number of openings 41 as the heat dissipation members 3, and the heat dissipation members 3 are fitted into these openings 41. Details of how the heat dissipation members 3 are fitted into the openings 41 will be described later with reference to FIG. 2. The flow path cover 5 covers the heat dissipation members 3 and the frame 4 to form a closed space. Hereinafter, this closed space will be referred to as the refrigerant flow path. The flow path cover 5 is equipped with an inlet pipe 93 and an outlet pipe 94, and the refrigerant flows from the inlet pipe 93 to the outlet pipe 94, i.e., from left to right in the figure. The refrigerant passes through the heat dissipation fins 32, allowing efficient heat transfer from the heat dissipation fins 32 to the refrigerant. Details of the flow path cover 5 will be described later with reference to FIG. 2.

[0012] FIG. 2 is a cross-sectional view of the power conversion device 1. FIG. 2 is a cross-sectional view taken along line II-II of FIG. 1, and is illustrated as a cross section perpendicular to the direction of refrigerant flow. The area surrounded by the heat dissipation member 3, the frame 4, and the flow path cover 5 is the refrigerant flow path 90. In FIG. 2, an insulating plate 8 having TIM 81 disposed on both sides is disposed between the semiconductor package 2 and the heat dissipation member 3. The heat dissipation member 3 includes a fin base 31, a plurality of heat dissipation fins 32, a flange portion 33, and a protrusion 34. A sealing member 85 is disposed between the flange portion 33 and the frame 4. The sealing member 85 is a flexible member such as an adhesive or a rubber elastic material.

[0013] The fin base 31 is disposed so as to be displaceable relative to the frame 4 and the flow path cover 5. The pressing portion 52 is formed in a convex shape on the flow path cover 5, and when fastened with the fastening member 12, the pressing portion 52 deforms and can apply pressure to the heat dissipation fins 32. The pressing portion 52 is provided approximately near the center shown in FIG. 2. This "near the center" can also be referred to as a position that is a predetermined distance or more away from both ends of the semiconductor packages 2 in the arrangement direction. The presence of the pressing portion 52 allows pressure to be applied evenly to the multiple semiconductor packages 2.

[0014] 2, a TIM 81 is disposed between the semiconductor package 2 and the heat dissipation member 3, but this is not an essential component. Adhesives, soldering, brazing, sintering, etc. may be used instead of the TIM 81, or the semiconductor package 2 and the heat dissipation member 3 may be directly bonded. The insulating plate 8 protrudes laterally from the semiconductor package 2 in the drawing to ensure a creepage distance. The TIM 81 is a thermal interface material and is made of grease, gap filler, etc. The flange portion 33 of the heat dissipation member 3 is located where the fin base 31 and frame 4 overlap, and is connected to the frame 4 via a seal member 85.

[0015] The protrusion 34 is a region that protrudes downward from the fin base 31 as shown in the figure. The presence of the protrusion 34 forms a space 34V between the flange 33 and the insulating plate 8. Therefore, even if the flange 33 is deformed by a large force from the flow path cover 5 and the frame 4 when forming the refrigerant flow path 90, the flange 33 will not come into contact with the insulating plate 8 as long as the amount of deformation is within the space 34V. If the deformed flange 33 were to come into contact with the insulating plate 8, the large load could damage the insulating plate 8, specifically, cause a crack. Therefore, it can be said that the presence of the flange 33 helps prevent damage to the insulating plate 8.

[0016] 2 in the formation area of ​​the heat dissipation fins 32. By making the length of the pressing portion 52 in the horizontal direction shown in the figure equal to or less than half the total length of the formation area of ​​the heat dissipation fins 32, the pressure applied to the heat dissipation fins 32 is shifted to the center, making it easier to apply pressure to the semiconductor package 2 in the center. If the pressing portion 52 were not present, only both ends of the heat dissipation fins 32 would be fixed, making it difficult to apply pressure to the center, and there is a possibility that contact between the semiconductor package 2 arranged near the center and the heat dissipation member 3 would be insufficient, resulting in insufficient heat dissipation.

[0017] By forming the flange portion 33 thin, the flange portion 33 becomes more easily deformed when fastened to the fastening portion 11 using the fastening member 12. For example, the flange portion 33 is thinner than the protrusion 34. Therefore, by actively deforming the flange portion 33, warping of other portions of the heat dissipation member 3, particularly warping of the central portion, can be reduced. Furthermore, because the flange portion 33 is more easily deformed, the amount of displacement of the heat dissipation fins 32 relative to the frame 4 increases, improving the ability to follow package tolerances.

[0018] The first embodiment described above provides the following advantageous effects. (1) The power converter 1 includes a plurality of semiconductor packages 2 and a heat dissipation member 3 in thermal contact with the plurality of semiconductor packages 2. The heat dissipation member 3 includes a plurality of heat dissipation fins 32 and a fin base 31 on which the plurality of heat dissipation fins 32 are formed. The power converter 1 includes a frame 4 that displaceably holds the fin base 31, and a flow path cover 5 that presses the fin base 31 toward the plurality of semiconductor packages 2. The flow path cover 5 has convex pressing portions 52 that abut against tips of the plurality of heat dissipation fins 32 that are a predetermined distance or more away from both ends of the plurality of semiconductor packages 2 in the arrangement direction. This makes it easier for the heat dissipation member 3 to come into contact with the semiconductor packages 2 in the center, improving heat dissipation.

[0019] (2) The semiconductor packages 2 are in thermal contact with the heat dissipation member 3 via the insulating plate 8. The fin base 31 has a flange portion 33 that overlaps the frame 4 in the plate thickness direction, and a protrusion portion 34 that protrudes further toward the insulating plate 8 than the flange portion 33 and abuts against the insulating plate 8. This prevents damage to the insulating plate 8.

[0020] (3) The length of the pressing portion 52 along the arrangement direction is equal to or less than half the total length of the formation area of ​​the plurality of heat dissipation fins 32. If the pressing portion 52 is extremely long, for example, spanning the entire width of the heat dissipation fin 32, the entire fin will be pressed, and the pressing force at the center will be weak. Therefore, it is desirable that the length of the pressing portion 52 be equal to or less than approximately half the total length of the formation area of ​​the plurality of heat dissipation fins 32.

[0021] (4) The pressing portion 52 is provided at approximately the center in the arrangement direction of the flow path cover 5. Therefore, the pressing force can be clearly applied to the center portion, where the pressing force is weaker when only both ends are fixed.

[0022] (5) The flange portion 33 is formed to be thinner than the protruding portion 34. Therefore, the flange portion 33 is actively deformed, which can reduce warping in other portions of the heat dissipating member 3, particularly in the central portion.

[0023] FIG. 3 is a cross-sectional view of the power conversion device 1 in Modification 1. The difference from FIG. 2 in the first embodiment is that the seal member 85 has been replaced with a fixed seal member 85a. The fixed seal member 85a is a metal joint formed of brazing material or the like. However, the fixed seal member 85a is not an essential component, and friction stir welding or welding may also be used. In the first embodiment, a highly flexible seal member 85 was used, but because the flange portion 33 is deformable, the displacement of the heat dissipation fins 32 can be ensured even when the fixed seal member 85a is used.

[0024] This modification provides the following advantageous effects: (6) The flange portion 33 and the frame 4 are joined by metal bonding, which reduces the number of components of the power conversion device 1.

[0025] (Modification 2) Fig. 4 is a cross-sectional view of the power conversion device 1 in Modification 2. The difference from Fig. 2 in the first embodiment is that the heat dissipation member 3 does not include the flange portion 33 and the protrusion portion 34, but instead includes a sealing groove 86. A sealing member 87 is disposed in the sealing groove 86. The sealing member 87 is, for example, an O-ring.

[0026] This modification provides the following advantageous effects: (7) At least one of the fin base 31 and the frame 4 has a sealing groove 86 in which a sealing member 85 is disposed. The fin base 31 and the frame 4 are sealed in the axial direction via a sealing member 87. This eliminates the need to apply a liquid sealing material, simplifying the manufacturing process. Furthermore, because the pin fins can be displaced during axial sealing, the ability to follow package thickness tolerances can be ensured.

[0027] In this modified example, the sealing groove 86 is provided in the heat dissipation member 3, but the sealing groove 86 may be provided in the frame 4, or the sealing groove 86 may be provided in the heat dissipation member 3 and the frame 4.

[0028] - Second embodiment - A second embodiment of a power conversion device will be described with reference to Figure 5. In the following description, the same components as those in the first embodiment are denoted by the same reference numerals, and differences will be mainly described. Points that are not particularly described are the same as those in the first embodiment. This embodiment differs from the first embodiment mainly in that a semiconductor package is mounted on a printed circuit board.

[0029] FIG. 5 is a cross-sectional view of a power conversion device 1A according to the second embodiment. The difference from FIG. 2 according to the first embodiment is that a printed circuit board 800 is added. The printed circuit board 800 has a wiring pattern 810 that forms an inverter circuit. The wiring pattern 810 is formed in multiple layers along the surface of the printed circuit board 800. The printed circuit board 800 also has through holes 820 that are electrically and thermally connected to the wiring pattern 810. The through holes 820 are holes that penetrate the printed circuit board 800 in the thickness direction, and a metal film is formed inside the holes. The semiconductor package 2 according to this embodiment is used in an inverter circuit and is connected to the printed circuit board 800 by wiring (not shown).

[0030] Each semiconductor package 2 includes a semiconductor element 201, a first conductor 202, a second conductor 203, and a molded resin 204. A bonding material such as solder is disposed between the semiconductor element 201 and the first and second conductors 202 and 203. The molded resin 204 covers the semiconductor element 201, the first conductor 202, and the second conductor 203, but the upper end face of the first conductor 202 and the lower end face of the second conductor 203 are exposed. Therefore, heat generated by the semiconductor element 201 is dissipated upward in the figure via the first conductor 202 and the insulating plate 8 to the heat dissipation member 3, and downward in the figure via the second conductor 203 to the printed circuit board 800.

[0031] According to the second embodiment described above, the following advantageous effects can be obtained. (8) The power conversion device 1A includes a printed circuit board 800 having a plurality of wiring patterns 810 that form an inverter circuit. A plurality of semiconductor packages 2 are mounted in a line on the printed circuit board 800. This allows the inductance of the printed circuit board 800 to be reduced. Furthermore, the power conversion device 1A including the printed circuit board 800 can be made smaller, and mounting is easier.

[0032] -Third embodiment- A third embodiment of a power conversion device will be described with reference to Figure 6. In the following description, the same components as those in the second embodiment are denoted by the same reference numerals, and differences will be mainly described. Points that are not particularly described are the same as those in the second embodiment. This embodiment differs from the second embodiment mainly in that both sides of the semiconductor package 2 are cooled.

[0033] FIG. 6 is a cross-sectional view of a power conversion device 1B according to the third embodiment. The difference between the second embodiment and FIG. 5 is that a heat dissipation configuration using a refrigerant is also provided below the printed circuit board 800. That is, the configuration of the upper half including the semiconductor package 2 in FIG. 6 is the same as that of the second embodiment. Hereinafter, the upper surface of the semiconductor package 2 shown in the figure will be referred to as the first surface 2a, and the lower surface shown in the figure will be referred to as the second surface 2b. The second surface 2b can also be referred to as the surface opposite to the first surface 2a.

[0034] The power conversion device 1B includes two heat dissipation members 3 of the same shape, i.e., a first heat dissipation member 3a and a second heat dissipation member 3b. The power conversion device 1B includes two frames 4 of the same shape, i.e., a first frame 4a and a second frame 4b. The power conversion device 1B includes two flow path covers 5 of the same shape, i.e., a first flow path cover 5a and a second flow path cover 5b. The first heat dissipation member 3a, the first frame 4a, and the first flow path cover 5a form a coolant flow path for dissipating heat emitted from the first surface 2a of the semiconductor package 2. The second heat dissipation member 3b, the second frame 4b, and the second flow path cover 5b form a coolant flow path for dissipating heat emitted from the second surface 2b of the semiconductor package 2.

[0035] The third embodiment described above provides the following advantageous effects. (9) The semiconductor packages 2 each have a first surface 2a and a second surface 2b opposite to the first surface 2a. The heat dissipation member 3 includes a first heat dissipation member 3a that dissipates heat emitted from the first surface 2a and a second heat dissipation member 3b that dissipates heat emitted from the second surface 2b. The frame 4 includes a first frame 4a that contacts the first heat dissipation member 3a and a second frame 4b that contacts the second heat dissipation member 3b. The flow path cover 5 includes a first flow path cover 5a that contacts the first heat dissipation member 3a and the first frame 4a and a second flow path cover 5b that contacts the second heat dissipation member 3b and the second frame 4b. The second surfaces 2b of the semiconductor packages 2 are in thermal contact with the second heat dissipation member 3b via the printed circuit board 800. This allows the semiconductor packages 2 to be cooled from both sides.

[0036] The above-described embodiments and modifications may be combined with each other. Although various embodiments and modifications have been described above, the present invention is not limited to these. Other embodiments conceivable within the scope of the technical concept of the present invention are also included within the scope of the present invention.

[0037] REFERENCE SIGNS LIST 1, 1A, 1B: Power conversion device 2: Semiconductor package 3: Heat dissipation member 4: Frame 5: Flow path cover 8: Insulating plate 31: Fin base 32: Heat dissipation fin 33: Flange portion 34: Protrusion 52: Pressing portion 86: Sealing groove 201: Semiconductor element 800: Printed circuit board 810: Wiring pattern 820: Through hole

Claims

1. A power conversion device comprising: a plurality of semiconductor packages; and a heat dissipation member in thermal contact with the plurality of semiconductor packages, wherein the heat dissipation member includes a plurality of heat dissipation fins and a fin base on which the plurality of heat dissipation fins are formed; and further comprising: a frame that displaceably holds the fin base; and a flow path cover that presses the fin base toward the plurality of semiconductor packages, wherein the flow path cover has convex pressing portions that abut against tips of the plurality of heat dissipation fins that are located a predetermined distance or more away from both ends of the plurality of semiconductor packages in the arrangement direction.

2. A power conversion device as claimed in claim 1, wherein the plurality of semiconductor packages are in thermal contact with the heat dissipation member via an insulating plate, and the fin base has a flange portion that overlaps with the frame in the plate thickness direction, and a protrusion that protrudes further towards the insulating plate than the flange portion and abuts against the insulating plate.

3. A power conversion device according to claim 1, wherein the length of the pressing portion along the arrangement direction is equal to or less than half the total length of the formation area of ​​the plurality of heat dissipation fins.

4. The power converter according to claim 1, wherein the pressing portion is provided at approximately the center of the flow path cover in the arrangement direction.

5. A power converter according to claim 2, wherein the flange portion is formed to be thinner than the protrusion portion.

6. The power converter according to claim 5, wherein the flange portion and the frame are joined by metal bonding.

7. A power conversion device according to claim 1, wherein at least one of the fin base and the frame has a groove for a sealing material, and the fin base and the frame are sealed in the axial direction via the sealing material.

8. A power conversion device according to claim 1, further comprising a printed circuit board having a plurality of wiring patterns forming an inverter circuit, and the plurality of semiconductor packages are mounted in a row on the printed circuit board.

9. A power conversion device as described in claim 8, wherein the plurality of semiconductor packages have a first surface and a second surface opposite to the first surface, the heat dissipation member includes a first heat dissipation member that dissipates heat emitted from the first surface and a second heat dissipation member that dissipates heat emitted from the second surface, the frame includes a first frame in contact with the first heat dissipation member and a second frame in contact with the second heat dissipation member, the flow path cover includes a first flow path cover in contact with the first heat dissipation member and the first frame, and a second flow path cover in contact with the second heat dissipation member and the second frame, and the second surfaces of the plurality of semiconductor packages are in thermal contact with the second heat dissipation member via the printed circuit board.

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