JP2012161177A - Power conversion device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a power conversion device in which heat dissipation efficiency of power switching elements can be improved.SOLUTION: A power conversion device 2 comprises a plurality of power switching elements 15 constituting a predetermined bridge circuit, and a heat sink 22 for dissipating heat of the power switching elements 15. The heat sink 22 is divided into a plurality of blocks 22A which are electrically insulated by being separated from each other. Each of the power switching elements 15 is attached to each of the blocks 22A in contact therewith without interposing an insulating sheet therebetween.

Description

  The present invention relates to a power converter, and more particularly to a power converter using a plurality of power switching elements.

  For example, Patent Document 1 below discloses a power conversion device (AC-DC converter) for charging a battery mounted on an electric vehicle with a commercial power source. The output from the commercial power supply is rectified by the full-wave rectifier circuit and input to the boost type power factor correction circuit. The output from the boost type power factor correction circuit is converted into a high frequency voltage by a bridge circuit and input to a transformer. The output from the transformer is rectified by a full-wave rectifier circuit, smoothed by a smoothing circuit, and supplied to the battery. The bridge circuit is configured using a plurality of power switching elements such as IGBTs.

  In general, the power switching elements are arranged and mounted on a single heat sink in order to effectively dissipate heat generated from the power switching elements. At this time, each power switching element is mounted on the heat sink via an insulating sheet in order to prevent a plurality of power switching elements from being unintentionally electrically connected via the conductive heat sink.

JP-A-9-233818

  However, since the insulating sheet has a large thermal resistance (for example, the thermal resistance of an insulating sheet having a thermal conductivity of 1 W / m ° C. and a thickness of 0.2 mm is about 0.83 ° C./W), the heat from the power switching element to the heat sink There is a problem that conduction is hindered by the insulating sheet, and as a result, the heat dissipation efficiency of the power switching element decreases.

  The present invention has been made in view of such circumstances, and an object thereof is to obtain a power conversion device capable of improving the heat dissipation efficiency of a power switching element.

  A power conversion device according to a first aspect of the present invention includes a plurality of switching elements that constitute a predetermined bridge circuit, and a heat sink for radiating heat from the plurality of switching elements, and the heat sinks are separated from each other. Are divided into a plurality of electrically insulated blocks, and each of the switching elements is attached in contact with each of the blocks without interposing an insulating sheet between the blocks. It is characterized by.

  According to the power conversion device according to the first aspect, each switching element is attached in contact with each block without interposing an insulating sheet between the block and the heat sink block. Since the insulating sheet is not interposed between the switching element and the block, it is possible to avoid a situation in which heat conduction from the switching element to the heat sink is hindered by the insulating sheet. As a result, the heat dissipation efficiency of the switching element can be improved as compared with the case where an insulating sheet is used. Moreover, the heat sink is divided into a plurality of blocks that are electrically insulated by being separated from each other. Therefore, it is possible to avoid a situation in which a plurality of switching elements are unintentionally electrically connected via a conductive heat sink.

  The power converter device according to the second aspect of the present invention, in the power converter device according to the first aspect, in particular, a first storage unit for storing the plurality of blocks arranged in a predetermined direction, And a second housing part for housing a predetermined pressing plate, wherein the pressing plate has a plurality of recesses having a shape corresponding to the outer shape of the switching element along a predetermined direction. Each block accommodated in the first accommodating portion is formed by accommodating the fixing plate in which the switching elements are fitted in the concave portions and accommodating the fixing plate in the second accommodating portion. The switching elements are in contact with each other.

  According to the power converter which concerns on a 2nd aspect, it accommodated in the 1st accommodating part by accommodating and fixing the holding plate by which each switching element was inserted by each recessed part in a 2nd accommodating part. Each switching element contacts each block. Therefore, compared with the case where each switching element is screwed to each block individually, positioning work and fixing work can be simplified.

  The power conversion device according to the third aspect of the present invention is the power conversion device according to the second aspect, and in particular, the second accommodating portion has a first positioning structure formed on the holding plate. The second positioning structure corresponding to the first positioning structure is formed, and the pressing plate is fixed to the heat sink, so that the first positioning structure and the second positioning structure The plurality of switching elements are pressed against the heat sink.

  According to the power converter of the third aspect, the plurality of switching elements are pressed against the heat sink by the first positioning structure and the second positioning structure by fixing the pressing plate to the heat sink. When the switching element is pressed against the heat sink, the switching element is surely in contact with the heat sink. As a result, the heat conduction from the switching element to the heat sink becomes good, and the heat dissipation efficiency of the switching element can be improved. In addition, since the positioning can be performed collectively with respect to the plurality of switching elements, the positioning work when mounting the plurality of switching elements on the heat sink is simplified, and the working efficiency can be improved.

  According to the present invention, it is possible to improve the heat dissipation efficiency of the power switching element.

It is a figure which simplifies and shows the application example of the power converter device which concerns on embodiment of this invention. It is a circuit diagram which simplifies and shows the structure of a power converter device. It is a perspective view which shows the structure of a thermal radiation part. It is a side view which shows the structure of a thermal radiation part. It is a perspective view which decomposes | disassembles and shows a thermal radiation part. It is a perspective view which shows the structure of a frame. It is a perspective view which shows the structure of a pressing plate. It is a perspective view which shows the structure of a block. It is a perspective view which shows the structure of a power switching element.

  Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. In addition, the element which attached | subjected the same code | symbol in different drawing shall show the same or corresponding element.

  FIG. 1 is a diagram schematically illustrating an application example of a power conversion device 2 according to an embodiment of the present invention. The power conversion device 2 is applied to an electric vehicle such as an electric vehicle or a hybrid electric vehicle, and is used as a charging device for charging a battery 3 mounted on the electric vehicle with a commercial power source 1.

  FIG. 2 is a circuit diagram showing a simplified configuration of the power conversion device 2. As shown in the connection relationship of FIG. 2, the power conversion device 2 includes a rectifier circuit 5, a power factor correction circuit 6, a bridge circuit 7, a transformer 8, a rectifier circuit 9, and a smoothing circuit 10. The bridge circuit 7 is configured using a plurality of power switching elements 15 such as IGBTs (Insulated Gate Bipolar Transistors). The output from the commercial power source 1 is rectified by the rectifier circuit 5 and input to the power factor correction circuit 6. The output from the power factor correction circuit 6 is converted into a high frequency voltage by the bridge circuit 7 and input to the transformer 8. The output from the transformer 8 is rectified by the rectifier circuit 9, smoothed by the smoothing circuit 10, and supplied to the battery 3.

  Since the power switching device 15 generates heat when the power conversion device 2 operates, the power conversion device 2 is provided with a heat radiating unit 100 for radiating heat generated from the power switching device 15 by the heat sink 22.

  FIG. 3 is a perspective view showing the structure of the heat radiating unit 100. FIG. 4 is a side view showing the structure of the heat radiating unit 100 viewed from the X direction of the XYZ orthogonal coordinates shown in FIG. FIG. 5 is an exploded perspective view showing the heat radiating unit 100. As illustrated in FIGS. 3 to 5, the heat radiating unit 100 includes a frame body 20, a pressing plate 21, and a heat sink 22. The frame body 20 and the pressing plate 21 are made of resin or the like, and the heat sink 22 is made of metal or the like. Further, as shown in FIG. 5, the heat sink 22 is divided into a plurality of (six in this example) blocks 22A. Referring to FIG. 3, the heat sink 22 is cooled by sending cooling air into the one side surface of the frame body 20 from the X direction by a fan (not shown). The cooling air is discharged from the other side surface of the frame body 20.

  6, 7, 8, and 9 are perspective views showing a single structure of the frame body 20, the pressing plate 21, the block 22 </ b> A, and the power switching element 15, respectively.

  Referring to FIG. 6, a plurality of (six in this example) first accommodating portions 31 for accommodating one block 22 </ b> A are formed in frame 20. The 1st accommodating part 31 is spaced apart and formed along the X direction. Further, the frame body 20 is formed with a second housing portion 32 for housing the presser plate 21. A positioning structure 60 having an upper surface 61 and an inclined surface 62 is formed in the second housing portion 32. Further, the frame body 20 is formed with an opening 33 between each first housing portion 31 and the second housing portion 32, whereby the first housing portion 31 and the second housing portion 32 are spatially separated. It is connected to.

  Referring to FIG. 7, a plurality (six in this example) of recesses 41 for accommodating one power switching element 15 is formed in each pressing plate 21. The recesses 41 are formed apart from each other along the X direction. The formation pitch of the recesses 41 is set to be equal to the formation pitch of the first housing portions 31 in the frame body 20. The shape of the recess 41 corresponds to the outer shape of the power switching element 15, and it is possible to fit and fix one power switching element 15 in one recess 41. In addition, the pressing plate 21 is formed with a positioning structure 50 having a bottom surface 51 and an inclined surface 52. The inclination angle of the inclined surface 52 is set equal to the inclination angle of the inclined surface 62 in the frame body 20.

  Referring to FIG. 8, heat radiation fins are formed on block 22A to increase the heat radiation efficiency by increasing the surface area.

  Referring to FIG. 9, the power switching element 15 is packaged with resin, and for example, three leads connected to the gate electrode, collector electrode, and emitter electrode of the IGBT protrude from the package body.

  With reference to FIG. 5, each block 22 </ b> A is accommodated in each first accommodating portion 31 of the frame 20 when the heat radiating portion 100 is assembled. Since the first accommodating portions 31 are separated from each other, the blocks 22A accommodated in the first accommodating portion 31 are also separated from each other, whereby the adjacent blocks 22A are electrically insulated from each other. In addition, each power switching element 15 is fitted in each recess 41 of the pressing plate 21. Then, the holding plate 21 in a state where the power switching elements 15 are fitted in all the concave portions 41 is accommodated in the second accommodating portion 32 of the frame body 20. Then, as shown in FIG. 3, the frame 20 and the pressing plate 21 are fixed to each other by being screwed at a plurality of locations. As a result, the heat dissipating surface of each power switching element 15 protruding from the pressing plate 21 enters the opening 33 of the frame body 20, thereby contacting each block 22 </ b> A. In heat radiating portion 100 according to the present embodiment, no insulating sheet is interposed between each power switching element 15 and each block 22A. Moreover, you may apply | coat grease between each power switching element 15 and each block 22A as needed.

  Further, referring to FIG. 4, by fixing frame 20 and pressing plate 21, bottom surface 51 and inclined surface 52 of positioning structure 50 of pressing plate 21, upper surface 61 of positioning structure 60 of frame 20 and The inclined surfaces 62 are in contact with each other. Thereby, each power switching element 15 is pressed against each block 22A, and the contact of both is ensured.

  Thus, according to the power conversion device 2 according to the present embodiment, each power switching element 15 is attached in contact with each block 22A without interposing an insulating sheet between the heat sink 22 and the block 22A. ing. Since the insulating sheet is not interposed between the power switching element 15 and the block 22A, it is possible to avoid a situation where the heat conduction from the power switching element 15 to the heat sink 22 is hindered by the insulating sheet. As a result, the heat dissipation efficiency of the power switching element 15 can be improved as compared with the case where an insulating sheet is used. Moreover, the heat sink 22 is divided into a plurality of blocks 22A that are electrically insulated by being separated from each other. For this reason, it is possible to avoid a situation in which the plurality of power switching elements 15 are unintentionally electrically connected via the conductive heat sink 22.

  Further, according to the power conversion device 2 according to the present embodiment, the holding plate 21 in which each power switching element 15 is fitted in each recess 41 is accommodated in the second accommodating portion 32 of the frame body 20 and fixed. Accordingly, each power switching element 15 comes into contact with each block 22 </ b> A accommodated in the first accommodating portion 31. Therefore, compared with the case where each power switching element 15 is screwed to each block 22A individually, positioning work and fixing work can be simplified.

  In addition, according to the power conversion device 2 according to the present embodiment, the plurality of power switching elements 15 are pressed against the heat sink 22 by the positioning structures 50 and 60 by fixing the pressing plate 21 to the heat sink 22. When the power switching element 15 is pressed against the heat sink 22, the power switching element 15 reliably contacts the heat sink 22. As a result, the heat conduction from the power switching element 15 to the heat sink 22 is improved, so that the heat dissipation efficiency of the power switching element 15 can be improved. In addition, since the positioning can be performed collectively with respect to the plurality of power switching elements 15, the positioning work when mounting the plurality of power switching elements 15 on the heat sink 22 can be simplified, and the working efficiency can be improved. It becomes.

  The embodiment disclosed this time should be considered as illustrative in all points and not restrictive. The scope of the present invention is defined not by the above-mentioned meaning but by the scope of claims for patent, and is intended to include all modifications within the scope and meaning equivalent to the scope of claims for patent.

DESCRIPTION OF SYMBOLS 2 Power converter 7 Bridge circuit 15 Power switching element 20 Frame 21 Holding plate 22 Heat sink 22A Block 31 1st accommodating part 32 2nd accommodating part 41 Recessed part 50,60 Positioning structure

Claims (3)

,
A plurality of switching elements constituting a predetermined bridge circuit;
A heat sink for radiating heat of the plurality of switching elements;
With
The heat sink is divided into a plurality of blocks that are electrically insulated by being separated from each other,
Each said switching element is a power converter device which is attached in contact with each said block, without interposing an insulating sheet between the said blocks. A first accommodating portion for arranging and accommodating the plurality of blocks along a predetermined direction;
A second accommodating portion for accommodating a predetermined pressing plate;
Further comprising a frame having
In the pressing plate, a plurality of concave portions having a shape corresponding to the outer shape of the switching element are formed along a predetermined direction,
Each switching element is accommodated in each block accommodated in the first accommodating part by accommodating and fixing the holding plate in which the switching element is fitted in each concave part in the second accommodating part. The power conversion device according to claim 1, wherein A first positioning structure is formed in the second housing portion,
The pressing plate is formed with a second positioning structure corresponding to the first positioning structure,
The power converter according to claim 2, wherein the plurality of switching elements are pressed against the heat sink by the first positioning structure and the second positioning structure by fixing the pressing plate to the heat sink.

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