JP2009303292A - Power control unit for electric vehicle - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To enhance the vibration noise characteristic of an electric vehicle with regard to a power control unit structure for the electric vehicle. <P>SOLUTION: The power control unit 20 for the electric vehicle includes a plurality of cylindrical capacitor elements 25, a capacitor case 24 in which the plurality of cylindrical capacitor elements 25 are accommodated side by side, a housing 21 to which the capacitor case 24 is fitted, and a bracket 26 provided in the outer face region of the bottom plate 24a of the capacitor case 24 corresponding to the space regions 30, 30b between the respective cylindrical faces of the capacitor elements 25 arranged in the capacitor case 24 side by side and the inner face of the capacitor case 24 and connecting the capacitor case 24 to the housing 21. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a structure of a power control unit for an electric vehicle.

  An electric vehicle such as a hybrid vehicle or an electric vehicle has a motor generator for traveling, a secondary battery that supplies vehicle driving power, and a motor that converts DC power of the secondary battery into three-phase AC power for driving the motor generator. And an inverter device that supplies the generator. The inverter device converts DC power and AC power to each other by a switching operation of the switching element, and includes a capacitor for smoothing a pulsed current generated by the operation of the switching element. The inverter device houses a switching element, a capacitor, and a control board for controlling the switching element in a housing, and is arranged together with the motor generator, for example, in a hood in front of the vehicle. In this case, for example, as described in Patent Document 1, the inverter device is arranged on the upper part of the motor generator so as to be integrated with the motor generator, and is configured to increase the space efficiency in the hood. .

  Since the capacitor element attached inside the inverter device is cylindrical, the capacitor element is held by the case. As the case of the capacitor element, for example, as shown in Patent Document 2, a cylindrical part that accommodates the capacitor element is connected and integrated by a rib plate.

Japanese Patent Laid-Open No. 2001-11998 JP 2003-199363 A

  By the way, the inverter device converts current by switching operation of a switching element, and smoothes and outputs the current by a capacitor. For this reason, vibration of the switching frequency may occur in the capacitor element. Since the capacitor element cases of the prior art described in Patent Document 1 and Patent Document 2 are structured to hold down the capacitor elements that vibrate with increased rigidity such as ribs, the vibration of the capacitor elements is transferred from the capacitor case to the inverter. Propagation to the housing of the apparatus may cause a part of the vehicle body such as a pillar to vibrate to generate high-frequency noise, which causes a problem of reducing vibration noise characteristics. In addition, since the capacitor case of the prior art is attached to the housing with a bracket provided on the periphery of the case, the center portion is easy to bend and vibration may be amplified and propagated to the housing. There was a problem of causing a drop in

  Therefore, an object of the present invention is to improve the vibration noise characteristics of an electric vehicle.

  A power control unit for an electric vehicle according to the present invention includes a plurality of cylindrical capacitor elements, a capacitor case in which a plurality of cylindrical capacitor elements are arranged and stored, a housing to which the capacitor case is attached, and a capacitor case. The capacitor case is provided on the outer surface region of the capacitor case corresponding to the gap region between the cylindrical surface of the capacitor element and the inner surface of the capacitor case or the gap region between the cylindrical surfaces of the capacitor elements arranged in the capacitor case. And a bracket to be connected.

  In the power control unit for an electric vehicle of the present invention, the bracket is preferably provided in an outer surface region of the capacitor case corresponding to the center of the gap region, and the bracket is provided on a surface on the lower side in the gravity direction of the capacitor case. It is also suitable as being provided.

  The present invention has an effect of improving the vibration noise characteristics of an electric vehicle.

  Preferred embodiments of the present invention will be described below with reference to the drawings. As shown in FIG. 1, the electric vehicle 10 is mounted in a motor generator 11 mounted in an engine room 12 in front of the vehicle, a power control unit 20 attached to the upper portion of the motor generator 11, and mounted on the rear of the vehicle. And a secondary battery 13 for supplying electric power for driving the vehicle. The DC power of the secondary battery 13 is boosted by the power control unit 20, converted into three-phase AC power, and supplied to the motor generator 11.

  As shown in FIG. 2, the power control unit 20 includes an aluminum casing 21, a plastic capacitor case 24 attached to the lower part of the casing 21, and a casing 21 disposed on the capacitor case 24. A boosting converter board 23 attached and an inverter board 22 disposed on the boosting converter board 23 and attached to the casing 21 are provided. The boost converter board 23 is formed with a boost converter circuit that boosts and outputs the voltage from the secondary battery 13. The inverter board 22 is an inverter that converts the DC power of the secondary battery 13 into three-phase AC power. A circuit is formed.

  As shown in FIGS. 2 and 3, a cylindrical capacitor element 25 is accommodated side by side in the capacitor case 24, and a gap region 30 between the capacitor case 24 and the capacitor element 25 is filled with a potting material 29. . The potting material 29 is a resin such as urethane. The depth of the capacitor case 24 is substantially the same as the diameter of the capacitor element 25 accommodated therein, and the inner width of the capacitor case 24 is substantially equal to the total length of the diameters of the plurality of capacitor elements 25 accommodated therein. It has become. For this reason, the upper end and the lower end of the cylindrical surface of the capacitor element 25 are in contact with the inner surface of the upper plate and the bottom plate 24a of the capacitor case 24, respectively, and the capacitor elements 25 are in contact with each other in the horizontal direction and the capacitor elements 25 at both ends. Are in contact with the inner surfaces of both side plates 24b of the capacitor case 24, respectively. A potting material 29 enters the triangular gap region 30 between the capacitor element 25 and the inner surface of the bottom plate 24 a of the capacitor case 24. The thickness of the potting material 29 is substantially zero at the portion where the capacitor element 25 and the inner surface of the bottom plate 24 a of the capacitor case 24 are in contact with each other, but gradually increases toward the center between the capacitor elements 25, and the center between the capacitor elements 25. The thickness is approximately the same as the radius of the capacitor element 25. The potting material 29 also enters the triangular gap region 30b between the side plate 24b of the capacitor case 24 and the capacitor element 25 accommodated so as to be in contact with the side plate 24b of the capacitor case 24. The gap area 30 b is about half the size of the gap area 30.

  A bracket 26 is attached to an area on the lower surface of the bottom plate 24a of the capacitor case 24 corresponding to the gap areas 30 and 30b filled with the potting material 29. In this embodiment, as shown in FIG. 2, the brackets 26 are attached to a total of twelve places including both side plates 24 b of the front and rear capacitor cases 24 and four intermediate places. A mounting lug 28 is provided on the inner surface side of the bottom plate 21 a of the housing 21 corresponding to the bracket 26. Each bracket 26 is fixed to each mounting lug 28 by a bolt 27. Thus, the capacitor case 24 is configured to be supported from the lower side in the gravity direction.

  When the power control unit 20 configured as described above operates, vibration generated in the capacitor element 25 at the switching frequency of the inverter element is attenuated by the potting material 29 filled in the gap regions 30 and 30b and propagates to the bracket 26. To do. For this reason, the vibration propagated to the bracket 26 is reduced, and the vibration propagated from the capacitor case 24 to the housing 21 is reduced.

  In this embodiment, in this way, the position of the bracket 26 provided on the bottom plate 24a of the capacitor case 24 is set to a position corresponding to the gap regions 30 and 30b between the capacitor elements 25, so that the vibration from the capacitor element 25 is reduced. After being attenuated efficiently by the potting material 29, it can be propagated to the bracket 26, and the vibration of the housing 21 can be reduced. For this reason, the noise vibration of the electric vehicle 10 generated by the vibration of the casing 21 can be reduced. In the present embodiment, since the bottom plate 24a of the capacitor case 24 is attached to the housing 21 by the 12 brackets 26, vibration of the plastic capacitor case 24 can be reduced. Also, vibration noise of the electric vehicle 10 can be reduced.

  In the present embodiment, the position of the bracket 26 is described as the center between the capacitor elements 25. However, if the bracket 26 is provided at a position corresponding to the gap regions 30 and 30b filled with the potting material 29, the position is not limited to the center. You may provide in the position by either capacitor | condenser element 25. FIG.

  With reference to FIG. 4, another embodiment of the present invention will be described. Parts similar to those of the embodiment described with reference to FIGS. 1 to 3 are denoted by the same reference numerals, and description thereof is omitted. As shown in FIG. 4, in this embodiment, 3 × 3 nine cylindrical capacitor elements 25 are arranged upright on the capacitor case 24. As shown in FIG. 4A, when the capacitor case 24 is viewed from the upper surface, a diamond-shaped gap region 30a is formed between the cylindrical surfaces of the capacitor elements 25, and the inner surface of the side plate 24b of the capacitor case 24 Between them, triangular gap regions 30 and 30b are formed. A bracket 26 is provided on the lower surface of the bottom plate 24a of the capacitor case 24 corresponding to each gap region 30, 30a, 30b. In the present embodiment, 16 brackets 26 are provided. As shown in FIG. 4B, an attachment lug 28 is provided on the inner surface side of the bottom plate 21 a of the housing 21 corresponding to the bracket 26. Each bracket 26 is fixed to each mounting lug 28 by a bolt 27.

  This embodiment also has the same effect as the embodiment described above.

It is explanatory drawing which shows the electric vehicle carrying the power control unit in embodiment of this invention. It is a perspective view of the power control unit in the embodiment of the present invention. It is explanatory drawing which shows the cross section of the housing | casing and capacitor | condenser case of the power control unit in embodiment of this invention. It is explanatory drawing which shows the housing | casing of the power control unit in other embodiment of this invention, a capacitor | condenser case horizontal cross section, and a longitudinal cross-section.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 10 Electric vehicle, 11 Motor generator, 12 Engine room, 13 Secondary battery, 20 Power control unit, 21 Case, 21a Bottom plate, 22 Inverter board, 23 Boost converter board, 24 Capacitor case, 24a Bottom plate, 24b Side plate, 25 Capacitor Element, 26 Bracket, 27 Bolt, 28 Mounting lug, 29 Potting material, 30, 30a, 30b Gap area.

Claims (3)

A power control unit for an electric vehicle,
A plurality of cylindrical capacitor elements;
A capacitor case in which a plurality of cylindrical capacitor elements are stored side by side;
A housing to which a capacitor case is attached;
Provided in a capacitor case outer surface region corresponding to a gap region between the cylindrical surface of the capacitor element arranged in the capacitor case and the inner surface of the capacitor case or a gap region between the cylindrical surfaces of the capacitor element arranged in the capacitor case, A bracket for connecting the capacitor case and the housing;
A power control unit for an electric vehicle characterized by comprising: The power control unit for an electric vehicle according to claim 1,
The bracket should be provided on the outer surface area of the capacitor case corresponding to the center of the gap area,
A power control unit for electric vehicles. The power control unit for an electric vehicle according to claim 1 or 2,
The bracket is provided on the lower surface of the capacitor case in the direction of gravity.
A power control unit for electric vehicles.

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