JP2017093005A - Power conversion device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To implement a power conversion device that inhibits an element of a capacitor from being at high temperatures by positively cooling a bus bar for handling high frequency drive while cooling a switching element that might be at high temperatures.SOLUTION: A power conversion device comprises: a switching element that performs switching between on and off to convert input power; a capacitor that smooths the input power; a cooler that cools the switching element and the capacitor that are arranged on the same plane; a first connection unit that is connected to the switching element and is extracted from a position close to a surface of the switching element in contact with the cooler; a second connection unit that is connected to the capacitor as well as the first connection unit and is extracted from a position close to a surface of the capacitor in contact with the cooler; and an electric insulation heat conduction material having one end in contact with a connection part between the first connection unit and the second connection unit and the other end in contact with the cooler.SELECTED DRAWING: Figure 2

Description

  The present invention relates to a power converter for driving a rotating electrical machine represented by a permanent magnet AC synchronous motor.

  In recent years, vehicles equipped with electric powertrain components such as hybrid vehicles, plug-in hybrid vehicles, and electric vehicles have become widespread. These vehicles are equipped with a motor (rotary electric machine) for obtaining a driving force and an inverter for driving the motor, that is, a power converter. This power converter uses a power semiconductor element to convert battery power from direct current to alternating current, and is equipped with a smoothing capacitor for the purpose of removing ripples generated during the conversion. About this power converter, there is a need for downsizing because of its ease of mounting. The volume ratio occupied by the smoothing capacitor in the power conversion device is large, and therefore proposals for reducing the size have been made.

  In order to reduce the size of the capacitor, it is effective to suppress the temperature rise. For example, in Japanese Patent Application Laid-Open No. 2008-148530 (Patent Document 1), a part of a connection conductor connecting capacitor elements is a capacitor positive / negative terminal, and another part is a heat transfer section. We proposed an inverter device that can be downsized by reducing the thermal resistance of the heat transfer path from the capacitor element to the cooler by using an electrical insulating heat sink that contacts the heat transfer section ing.

JP 2008-148530 A

  On the other hand, in recent years, it has been considered to apply a wide band gap semiconductor such as silicon carbide (SiC) to the switching element in order to reduce the size and increase the efficiency of the power conversion device. And by using high frequency drive, a passive component can be reduced in size. Considering such high-frequency drive, the temperature rise of the bus bar is larger than the temperature rise of the capacitor compared to the connection conductor (hereinafter referred to as bus bar) connecting the element to the positive and negative terminals. That is, when considering high frequency driving, it can be said that the capacitor is more effective in actively cooling the bus bar than the element.

  Here, referring to Patent Document 1, it is not possible to take into consideration that the heat of the bus bar moves to the element when the temperature rise of the bus bar becomes larger than the temperature rise of the element due to high frequency driving. In other words, it is a proposal to dissipate and cool as a path to transfer heat from the element to the heat sink via the bus bar (heat transfer part), but it cannot deal with heat transfer from the bus bar (heat transfer part) to the element. It can be said.

  The present invention solves such problems and realizes a power conversion device that actively cools a bus bar and does not bring a capacitor element to a high temperature in order to support high-frequency driving while cooling a switching element that becomes high temperature. Objective.

  A power conversion device according to the present invention is a power conversion device that exchanges power with a rotating electrical machine mounted on a vehicle. A switching element that converts input power by switching on and off, and smoothes the input power. A condenser, a cooler that cools the switching element and the capacitor on the same plane, and a first connected to the switching element and taken out from a position close to the surface of the switching element that contacts the cooler. A second connection portion connected to the capacitor and taken out from a position close to a surface of the capacitor in contact with the cooler, the first connection portion, and the first connection portion. One surface is in contact with either the connection portion of the second connection portion and the connection portion of the second connection portion or the first connection portion and the second connection portion, and the other surface is in contact with the cooler. An electrically insulating thermally conductive material which is those with.

  According to the power conversion device of the present invention, with the above configuration, the bus bar can be more actively cooled than the capacitor element while cooling the switching element that is at a high temperature. For this reason, when high-frequency driving is used, even if the bus bar temperature rises larger than the capacitor element, the bus bar is actively cooled to mitigate the temperature rise, and the bus bar heat propagates to the capacitor element. Can also be deterred.

It is a figure which shows schematic structure of the motor vehicle carrying the electric power train component using the power converter device which concerns on Embodiment 1 of this invention. It is a figure which shows the components arrangement | positioning and connection structure of the power converter device which concerns on Embodiment 1 of this invention. It is a figure which shows the components arrangement | positioning and connection structure of a power converter device which concern on Embodiment 2 of this invention. It is a figure which shows the components arrangement | positioning and connection structure of a power converter device which concern on Embodiment 3 of this invention.

  Hereinafter, preferred embodiments of a power conversion device according to the present invention will be described in detail with reference to the drawings.

Embodiment 1 FIG.
FIG. 1 shows a schematic configuration of an automobile equipped with an electric power train component using a power conversion device according to Embodiment 1 of the present invention.
In FIG. 1, the code | symbol 10 shows a power converter device, and the power converter device 10 performs direct current | flow and alternating current power conversion between the high voltage battery 20 and the motor 30 which store electric power. The power conversion device 10 includes a capacitor 11 for smoothing power, switching elements 12a, 12b, 12c, 12d, 12e, and 12f driven by control, and switching elements 12a, 12b, 12c, 12d, 12e, and 12f. Diodes 13a, 13b, 13c, 13d, 13e, and 13f provided in the direction are provided. In this embodiment, the high voltage battery 20 is a nickel metal hydride battery or a lithium ion battery, and the switching elements 12a, 12b, 12c, 12d, 12e, and 12f are silicon (Si) IGBTs or silicon carbide (SiC). A MOSFET and a capacitor 11 are used for the capacitor and a film capacitor may be used.

FIG. 2 shows a component arrangement and a connection configuration of the power conversion device 10 according to the first embodiment.
In FIG. 2, the capacitor 11 is provided with a first connection portion 14. The capacitor 11 has an element enclosed in a case made of resin or the like, and the first connection portion 14 connected to the element is drawn out of the capacitor 11. The switching element 12a is provided with a second connection portion 15. The capacitor 11 and the switching element 12a are arranged in the cooler 16.

  Reference numeral 17 denotes an electrically insulating heat conducting material, and the electrically insulating heat conducting material 17 is composed of an electrically insulating material 17a and a heat conducting material 17b. In the above description, the relationship between the switching element 12a, the capacitor 11, and the cooler 16 has been described. However, the relationship between the switching element 12b, 12c, 12d, 12e, and 12f, the capacitor 11, and the cooler 16 respectively. Is similarly configured. Further, as shown by a broken line in FIG. 2, a fluid path L may be formed in the cooler 16 and the cooling fluid may be passed through the fluid path L. In this case, the cooling effect of the switching elements 12a, 12b, 12c, 12d, 12e, 12f, the electrically insulating heat conductive material 17, and the capacitor 11 can be further enhanced. Here, considering that the heat generating part is an element and the element is covered with a case, the capacitor 11 is formed in a portion where the fluid path L is in contact with the electrically insulating heat conductive material 17 of the cooler 16, It is good also as a structure which is not formed in the site | part under the capacitor | condenser 11. FIG. By doing so, the structure of the cooler 16 is simplified, the development and manufacturing processes are reduced, and the cost can be reduced, which is effective.

  In the present embodiment, it is assumed that the capacitor 11 is for ripple removal, but for example, a capacitor for a noise filter may be included. In FIG. 2, the switching elements 12a, 12b, 12c, 12d, 12e, and 12f are used. However, the switching elements 12a, 12b, 12c, 12d, 12e, and 12f may be used. It may be built in.

  The electrical insulating material 17a uses resin, and the heat transfer material 17b uses grease. Further, it is assumed that the first connection portion 14 and the second connection portion 15 are connected by welding, but the connection means of the first connection portion 14 and the second connection portion 15 is not limited to this. Also good. In the present embodiment, the electrically insulating heat conductive material 17 may be mounted in the cooler 16 in advance, or may be fixed in advance to the first connection portion 14 or the second connection portion 15.

  As described above, the power conversion device 10 according to the first embodiment takes out the first connecting portion 14 from a position close to the surface of the capacitor 11 that contacts the cooler 16 and also connects the second connecting portion 15 to the switching element. It is taken out from a position close to the surface in contact with the cooler 16 of 12a. Further, the first connecting portion 14 and the second connecting portion 15 are configured to be connected to each other, and one of the connecting portions of the first connecting portion 14 and the second connecting portion 15 is in contact with the cooler 16. An electrically insulating heat conductive material 17 is provided in contact therewith. Thereby, the 1st connection part 14 and the 2nd connection part 15, ie, a bus bar, can be actively cooled rather than the element of the capacitor | condenser 11, cooling the switching element 12a used as high temperature. For this reason, even when high frequency driving is achieved, even if the temperature rise of the bus bar is larger than the element of the capacitor 11 in this situation, the bus bar is actively cooled, so that the temperature rise is mitigated and the bus bar Propagation of heat to the element of the capacitor 11 can also be suppressed.

  The electrically insulating heat conducting material 17 uses resin as the electrically insulating material 17a and uses grease as the heat conducting material 17b to actively dissipate the heat of the bus bar while ensuring electrical insulation. Can do.

  In addition, since the electrically insulating heat conducting material 17 uses resin as the electrically insulating material 17a and uses grease as the heat conducting material 17b and is in contact with the cooler 16, the first connecting portion 14 and An elastic deformation part that absorbs a change in the dimension of the second connection part 15 is provided, and a dimensional tolerance between the capacitor 11 and the first connection part 14 or the switching element 12a and the second connection part 15 can be absorbed. it can.

  Furthermore, the electric insulating heat conductive material 17 is configured to be fixed to the cooler 16 or the first connection portion 14 or the second connection portion 15 in advance, so that the ease of assembly can be secured and the bus bar Active cooling can be realized.

  Moreover, in this Embodiment, although the structure which contact | connects one surface of the electrically insulating heat conductive material 17 to the connection part of the 1st connection part 14 and the 2nd connection part 15 was demonstrated, the 1st connection part 14 and Even if it is configured to be in contact with any of the second connection portions 15, the same effect as described above can be obtained.

Embodiment 2. FIG.
Next, a power converter according to Embodiment 2 of the present invention will be described. The power conversion device according to the second embodiment is the same as the power conversion device 10 described in the first embodiment, in which the first connection portion 14 and the second connection portion 15 are connected via bolts to electrically insulate heat conduction. The material 17 is provided with a cap nut portion, and the first connecting portion 14 and the second connecting portion 15 are fastened by screwing the bolt into the cap nut portion. Hereinafter, the power converter according to Embodiment 2 will be described with reference to FIG.

  FIG. 3 shows the component arrangement and connection configuration of the power conversion device according to the second embodiment. In FIG. 3, the code | symbol 17c shows the cap nut part provided in the electrically insulating heat conductive material 17, and when the volt | bolt 18 screws together with the cap nut part 17c, the 1st connection part 14 and the 2nd connection part are shown. 15 is fastened.

  In the present embodiment, the electrically insulating heat conductive material 17 provided with the cap nut portion 17c may be mounted in the cooler 16 in advance, or the first connecting portion 14 or the second connecting portion 15 may be mounted. It is good also as a structure fixed beforehand.

  By doing so, the first connecting portion 14 and the second connecting portion 15 are connected via the bolt 18, and the electrically insulating heat conducting material 17 is provided with the cap nut portion 17 c, The connecting portion 14 and the second connecting portion 15 are fastened to the cap nut portion 17c by the bolt 18 so that the nut is added and the first connecting portion 14 and the second connecting portion 15 are fastened by the bolt 18. Therefore, it is possible to suppress a decrease in heat transfer to the cooler 16 due to an increase in thermal resistance due to the above, and an obstacle to downsizing due to the need for an additional space for the nut.

  In addition, the configuration in which the electrically insulating heat conductive material 17 is fixed to the cooler 16 or the first connection portion 14 or the second connection portion 15 in advance makes it easy to assemble, while ensuring ease of assembly. Active cooling can be realized.

Embodiment 3 FIG.
Next, a power converter according to Embodiment 3 of the present invention will be described. FIG. 4 is a diagram illustrating a component arrangement and a connection configuration of the power conversion device according to the third embodiment.
In the first embodiment, the capacitor 11 is provided with the first connection portion 14, the switching element 12 a is provided with the second connection portion 15, and the first connection portion 14 and the second connection portion 15 are connected by welding. The embodiment has been described. In the second embodiment, the capacitor 11 is provided with the first connection portion 14, the switching element 12 a is provided with the second connection portion 15, and the first connection portion 14 and the second connection portion 15 are electrically insulated. The embodiment in which the first connecting portion 14 and the second connecting portion 15 are connected by screwing a bolt into the cap nut portion provided in the heat conductive material 17 has been described.

  In the power conversion device 10 according to the third embodiment, a capacitor 11 and a switching element 12a are connected by a single connecting portion 19. That is, one end of the connection portion 19 is connected to the switching element 12 a and is taken out from a position close to the surface of the switching element 12 a that contacts the cooler 16, and the other end is connected to the capacitor 11 to the cooler 16 of the capacitor 11. It is taken out from the position close to the contact surface. In addition, about another structure, it is the same as that of Embodiment 1, and description is abbreviate | omitted by attaching | subjecting the same code | symbol.

  Also in the power conversion device 10 according to the third embodiment, the same effects as those described in the first embodiment can be obtained.

  As described above, the power conversion device according to Embodiments 1 to 3 of the present invention has been described. However, within the scope of the present invention, the embodiments can be freely combined, the embodiments can be appropriately modified, It can be omitted.

DESCRIPTION OF SYMBOLS 10 Power converter device, 11 Capacitor, 12a, 12b, 12c, 12d, 12e, 12f Switching element, 13a, 13b, 13c, 13d, 13e, 13f Diode, 14 1st connection part, 15 2nd connection part, 16 Cooler, 17 Electrical insulating heat conduction material, 17a Electrical insulation material, 17b Heat conduction material, 17c Cap nut part, 18 bolt, 19 connection part, 20 High voltage battery, 30 Motor, L Fluid path

In recent years, vehicles equipped with electric powertrain components such as hybrid vehicles, plug-in hybrid vehicles, and electric vehicles have become widespread. These vehicles are equipped with a motor (rotary electric machine) for obtaining a driving force and an inverter for driving the motor, that is, a power converter. This power converter uses a power semiconductor element to convert battery power from direct current to alternating current, and is equipped with a smoothing capacitor for the purpose of removing ripples generated during the conversion. About this power converter, there is a need for downsizing because of its ease of mounting. The volume ratio occupied by the smoothing capacitor in the power conversion device is large, and therefore proposals for reducing the size have been made.

A power conversion device according to the present invention is a power conversion device that exchanges power with a rotating electrical machine mounted on a vehicle. A switching element that converts input power by switching on and off, and smoothes the input power. A condenser, a cooler that cools the switching element and the capacitor by arranging them on the same plane, and one end connected to the switching element and taken out from a position close to the surface of the switching element that contacts the cooler; One connection part, the other end of which is connected to the capacitor and taken out from a position close to the surface of the capacitor that contacts the cooler, and one surface that contacts the connection part and the other surface that contacts the cooler A heat conductive material.

Claims (9)

In a power conversion device that exchanges power with a rotating electrical machine mounted on a vehicle,
A switching element that converts input power by switching on and off; and
A capacitor for smoothing the input power;
A cooler that cools the switching element and the capacitor by arranging them on the same plane;
A first connection portion connected to the switching element and taken out from a position close to a surface of the switching element that contacts the cooler;
A second connection portion connected to the first connection portion, connected to the capacitor, and taken out from a position close to a surface of the capacitor in contact with the cooler;
One surface is in contact with the connection portion of the first connection portion and the second connection portion, or one of the first connection portion and the second connection portion, and the other surface is in contact with the cooler. A heat conductive material;
A power conversion device comprising:   2. The power conversion device according to claim 1, wherein the electrically insulating heat conductive material includes an elastic deformation portion that absorbs a change in dimensions of the first connection portion and the second connection portion. .   3. A cap nut portion is provided on the electrically insulating heat conductive material, and the first connection portion and the second connection portion are fastened to the cap nut portion by bolts. The power converter described. In a power conversion device that exchanges power with a rotating electrical machine mounted on a vehicle,
A switching element that converts input power by switching on and off; and
A capacitor for smoothing the input power;
A cooler that cools the switching element and the capacitor by arranging them on the same plane;
One end is connected to the switching element and taken out from a position close to the surface of the switching element that contacts the cooler, and the other end is connected to the capacitor from a position close to the surface of the capacitor that contacts the cooler The removed connection, and
One surface is in contact with the connection portion, the other surface is in contact with the cooler, an electrically insulating heat conductive material,
A power conversion device comprising:   The power conversion device according to claim 4, wherein the electrically insulating heat conductive material includes an elastic deformation portion that absorbs a change in a dimension of the connection portion.   The power conversion device according to any one of claims 1 to 5, wherein the electrically insulating heat conductive material is made of an electrically insulating resin and thermally conductive grease.   The power conversion device according to any one of claims 1 to 6, wherein the electrically insulating heat conductive material is fixed to the cooler in advance.   4. The power conversion device according to claim 1, wherein the electrically insulating heat conductive material is fixed in advance to the first connection portion or the second connection portion. 5.   The power converter according to any one of claims 1 to 8, wherein the cooler has a fluid path for passing a cooling fluid through at least a portion in contact with the electrically insulating heat conductive material.