JP2022067840A - Power conversion device - Google Patents

Abstract

To provide a vehicle power conversion device which simply reduces electromagnetic noise leaking from a power conversion unit.SOLUTION: A power conversion device 10 comprises: a power conversion unit 12 which has a conductive case; and a wiring harness 14 which is fixed to the power conversion unit. The wiring harness has: a power cable 16; connectors 18 and 20; an insulating protector 24; a conductive cap 26; and an earth cable 34. The connectors are positioned at one end of the power cable and have conductive covers 20a fixed to the conductive case of the power conversion device. The insulating protector covers a portion of the power cable and is fixed to a body of a vehicle through a conductive fastener. The conductive cap is installed on the insulating protector and electrically connected to the body of the vehicle through the fastener. The earth cable is fixed to the conductive cover at one end thereof and to the conductive cap of the insulating protector at the other end thereof.SELECTED DRAWING: Figure 1

Description

The techniques disclosed herein relate to power converters for vehicles.

Patent Document 1 discloses a power conversion device. This power conversion device includes a power conversion unit, a power cable, and a connector for connecting the power conversion unit and the power cable. In this power conversion device, a cover is attached so as to surround the connector, and electromagnetic noise generated in the power conversion unit is suppressed from leaking from the connector and its attachment position.

JP-A-2019-205317

In the above-mentioned power conversion device, after connecting the power cable to the power conversion unit via the connector, it is necessary to further attach a cover surrounding the connector. In addition, the presence of the cover increases the size of the entire device. The present specification provides a technique capable of reducing electromagnetic noise leaking from a power conversion unit by a simpler configuration.

The techniques disclosed herein are embodied in power converters for vehicles. This power conversion device includes a power conversion unit having a conductive case and a wire harness attached to the power conversion unit. The wire harness includes a power cable, a connector, an insulating protector, a conductive cap, and a ground wire. The connector is located at one end of the power cable and includes a conductive cover attached to the conductive case of the power conversion unit. The insulating protector covers a part of the power cable and is fixed to the vehicle body of the vehicle via a conductive fastener. The conductive cap is provided on the insulating protector and is electrically connected to the vehicle body via the fastener. One end of the ground wire is fixed to the conductive cover of the connector, and the other end is fixed to the conductive cap of the insulating protector.

In the above-mentioned power conversion device, a ground wire is preliminarily incorporated in the wire harness attached to the power conversion unit. One end of the ground wire is fixed to the conductive cover of the connector, and the connector is attached to the power conversion unit to be electrically connected to the conductive case of the power conversion unit. The other end of the ground wire is fixed to the conductive cap of the insulating protector, and by attaching the insulating protector to the vehicle body, it is electrically connected to the vehicle body via the conductive fastener. In this way, the conductive case of the power conversion unit and the conductive cover of the connector can be easily grounded to the vehicle body simply by attaching the wire harness to the vehicle body on which the power conversion unit is mounted. By grounding these cases and covers, leakage of electromagnetic noise generated in the power conversion unit is effectively reduced.

Here, in a general power conversion unit, it is said that leakage of electromagnetic noise is likely to occur at the mounting position of the connector. In this regard, in the above-mentioned power conversion device, the mounting position of the connector is covered with the conductive cover of the connector, and the conductive cover is directly grounded by the ground wire. As a result, the electromagnetic noise leaked from the power conversion unit is more effectively reduced.

The figure which shows the power conversion apparatus 10 of an Example. The figure which shows the wire harness 14 alone. The figure which shows the wire harness 114 of one modification.

The power conversion device 10 of the embodiment will be described with reference to the drawings. The power conversion device 10 of this embodiment is a power conversion device for a vehicle. This power conversion device 10 can be adopted in a so-called electric vehicle. The electric vehicle referred to here means a vehicle having a traveling motor for driving the wheels and mainly traveling on the road surface. Such electric vehicles include, but are not limited to, for example, electric vehicles that are charged by external power, hybrid vehicles that have an engine for power generation, and fuel cell vehicles that have a fuel cell as a power source. not.

As shown in FIG. 1, the power conversion device 10 includes a power conversion unit 12 and a wire harness 14. The power conversion device 10 is provided between a power source (battery or fuel cell) and a traveling motor, and is a device for performing power conversion between the two. The power conversion unit 12 includes a power conversion circuit 12a and an aluminum case 12b. Although not particularly limited, the power conversion circuit 12a has a DC-DC converter and an inverter, and can mutually convert DC power and AC power. The aluminum case 12b is made of an aluminum alloy and has conductivity. The aluminum case 12b accommodates the power conversion circuit 12a inside, and is configured to surround the power conversion circuit 12a. The aluminum case 12b suppresses electromagnetic noise generated from the power conversion circuit 12a from being radiated to the outside. The aluminum case 12b is an example of a conductive case in the present technique. The power conversion unit 12 is not limited to the aluminum case 12b, and may include a conductive case made of another conductive material.

As shown in FIGS. 1 and 2, the wire harness 14 includes a power cable 16 and two connectors 18 and 20. The two connectors 18 and 20 are located at one end 16a of the power cable 16. As an example, as shown in FIGS. 1 and 2, one of the two connectors 18 and 20 is a first connector 18 for DC power, and the other is a second connector 20 for AC power. Each of the connectors 18 and 20 is detachably attached to the power conversion unit 12, and electrically connects the power cable 16 to the power conversion circuit 12a in the power conversion unit 12.

Each of the connectors 18 and 20 includes conductive covers 18a and 20a. The conductive covers 18a and 20a are detachably attached to the aluminum case 12b of the power conversion unit 12 by using bolts 22. Each bolt 22 is made of, for example, metal and has conductivity. Therefore, the conductive covers 18a and 20a and the aluminum case 12b of the power conversion unit 12 are electrically connected via bolts 22. In the respective connectors 18 and 20, the conductive covers 18a and 20a are configured to surround the terminals and wirings located inside the connectors 18 and 20, and suppress the leakage of electromagnetic noise from the connectors 18 and 20.

The wire harness 14 further includes an insulating protector 24 and a conductive cap 26. The insulating protector 24 is made of an insulating material such as resin. The insulating protector 24 is arranged adjacent to the two connectors 18 and 20 and is configured to cover a part of the power cable 16. The insulating protector 24 is fixed to a vehicle body (more accurately, a bracket 28 provided on the vehicle body) via fasteners 30 such as bolts and nuts. The conductive cap 26 is made of, for example, metal and has conductivity. The conductive cap 26 is provided on the insulating protector 24, and is particularly located at a fixing point by the fastener 30. As a result, when the insulating protector 24 is fixed to the vehicle body, the conductive cap 26 comes into direct contact with the fastener 30. The fastener 30 is made of, for example, metal and has conductivity. Therefore, the conductive cap 26 is electrically connected to the bracket 28 on the vehicle body side via the conductive fastener 30.

The vehicle body and the bracket 28 are made of a metal such as a steel material and have conductivity. The vehicle body is grounded to the road surface via wheels. Therefore, when the insulating protector 24 is attached to the bracket 28 on the vehicle body side by the conductive fastener 30, the conductive cap 24 is grounded to the road surface via the fastener 30, the bracket 28 and the vehicle body in this order. Will be. The specific configuration of the conductive cap 26 and the fastener 30 is not particularly limited. For example, the conductive cap 26 and the fastener 30 do not have to be entirely made of a conductive material. When the fastener 30 is fastened to the vehicle body side (not limited to the bracket 28), the conductive cap 26 only needs to be electrically connected to the vehicle body side via the fastener 30, and only the portion necessary for that purpose is required. It may have conductivity.

The power conversion device 10 further includes a bush 32. The bush 32 is installed between the bracket 28 on the vehicle body side and the aluminum case 12b of the power conversion unit 12. The bush 32 is made of a material having viscoelasticity such as a rubber material, and reduces vibration transmitted from the vehicle body side to the power conversion unit 12. The bush 32 is imparted with a certain degree of conductivity by an additive, but has a relatively large electric resistance. Therefore, it is difficult to sufficiently ground the aluminum case 12b of the power conversion unit 12 to the vehicle body side only with the bush 32.

As shown in FIG. 1, the wire harness 14 further includes a ground wire 34. The ground wire 34 is, for example, a conductive wire having an insulating film. One end 34a of the ground wire is fixed to the conductive cover 18a of the first connector 18 by, for example, a bolt 36. The other end 34b of the ground wire is fixed to the conductive cap 26 of the insulating protector 24. Although not particularly limited, the other end 34b of the ground wire is fixed to the fixing portion by the fastener 30 described above, and is configured to be held by the fastener 30. As described above, the conductive cover 18a of the first connector 18 is electrically connected to the aluminum case 12b of the power conversion unit 12, and the conductive cap 26 of the insulating protector 24 is connected via the fastener 30. It is electrically connected to the bracket 28 on the vehicle body side. Therefore, the aluminum case 12b of the power conversion unit 12 and the conductive cover 18a of the first connector 18 are electrically connected to the bracket 28 on the vehicle body side by the ground wire 34 and are grounded to the road surface. One end of the ground wire 34 may be connected to the second connector 20 instead of the first connector 18. The type, use, and function of the connector to which one end of the ground wire 34 is connected are not particularly limited, and may be, for example, either an AC power connector or a DC power connector.

With the above configuration, in the power conversion device 10 of this embodiment, the ground wire 34 is preliminarily incorporated in the wire harness 14 attached to the power conversion unit 12. One end 34a of the ground wire 34 is fixed to the conductive cover 18a of the first connector 18. Therefore, when the first connector 18 is attached to the power conversion unit 12, one end 34a of the ground wire 34 is electrically connected to the aluminum case 12b of the power conversion unit 12. On the other hand, the other end 34b of the ground wire 34 is fixed to the conductive cap 26 of the insulating protector 24. Therefore, by attaching the insulating protector 24 to the bracket 28 on the vehicle body side, the other end 34b of the ground wire 34 is electrically connected to the vehicle body via the conductive fastener 30.

As described above, according to the configuration of this embodiment, the aluminum case 12b of the power conversion unit 12 and the conductive covers 18a of the connectors 18 and 20 are simply attached to the vehicle body on which the power conversion unit 12 is mounted. , 20a can be easily grounded to the vehicle body. By grounding the aluminum case 12b and the conductive covers 18a and 20a, electromagnetic noise generated from the power conversion circuit 12a in the power conversion unit 12 is effectively suppressed from leaking (radiating or propagating) to the outside. be able to.

In particular, in the power conversion device 10 of the present embodiment, one end 34a of the ground wire 34 is connected to the conductive cover 18a of the first connector 18, and the conductive cover 18a is directly connected to the ground wire 34 ( That is, it is grounded (at a short distance and with low resistance). In this regard, in the power conversion unit 12, the power conversion circuit 12a, which is a source of electromagnetic noise, is covered with an aluminum case 12b, whereby leakage of electromagnetic noise is suppressed. However, at the position where the connectors 18 and 20 are attached, it is necessary to form an opening in the aluminum case 12b, and there is a problem that electromagnetic noise leaks through the opening.

In response to this problem, in the power conversion device 10 of the present embodiment, the openings formed in the aluminum case 12b are covered by the conductive covers 18a and 20a of the connectors 18 and 20, and the first connector 18 is used. The conductive cover 18a is directly grounded by the ground wire 34. According to such a configuration, electromagnetic noise leaking (radiating or propagating) from the power conversion unit 12 to the outside can be suppressed more effectively. The ground wire 34 may be connected to or in addition to the conductive cover 18a of the first connector 18 to the conductive cover 20a of the second connector 20. Two or more ground wires 34 may be used for that purpose or for other purposes.

FIG. 3 shows a wire harness 114 as a modified example. The number of connectors 18 and 20 of the wire harness 114 is changed as compared with the wire harness 14 shown in FIGS. 1 and 2. That is, the wire harness 114 of this modification includes only the first connector 18 for DC power, and the second connector 20 for AC power is omitted. As described above, the wire harnesses 14 and 114 may include at least one connector 18 and 20, and the number of connectors 18 and 20 is not particularly limited. The number of connectors 18 and 20 can be appropriately changed according to the power conversion unit 12, and the form of other parts of the wire harness 14 and 114 may be appropriately changed according to the number of connectors 18 and 20.

Although some specific examples have been described in detail above, these are merely examples and do not limit the scope of claims. The techniques described in the claims include various modifications and modifications of the specific examples exemplified above. The technical elements described herein or in the drawings exhibit their technical usefulness alone or in combination.

10: Power conversion device 12: Power conversion unit 12b: Aluminum case 14: Wire harness 16: Power cable 18: First connector 18a: Conductive cover 20: Second connector 20a: Conductive cover 24: Insulation protector 26: Conductive Sex cap 28: Bracket 34: Earth wire

Claims (1)

A power converter for vehicles
A power conversion unit with a conductive case and
With a wire harness attached to the power conversion unit,
The wire harness is
Power cable and
A connector located at one end of the power cable and having a conductive cover attached to the conductive case of the power conversion unit.
An insulating protector that covers a part of the power cable and is fixed to the vehicle body of the vehicle via a conductive fastener.
A conductive cap provided on the insulating protector and electrically connected to the vehicle body via the fastener.
One end is fixed to the conductive cover of the connector, and the other end is provided with a ground wire fixed to the conductive cap of the insulating protector.
Power converter.

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