JP2021145469A - Inverter device - Google Patents

Abstract

To provide an inverter device that can effectively take EMC countermeasures while reducing the size as a whole.SOLUTION: An inverter unit 20 of an inverter control device 10 is an inverter device for driving a motor. The inverter unit 20 includes a capacitor unit 141 that smooths a voltage from a battery BT, a power module unit 13 that supplies a drive current to an electric motor 15, an inverter control unit 11 that outputs a control signal to the power module unit 13, and a shield body 16 that shields electromagnetic field noise from the power module unit 13 with respect to the inverter control unit 11. The power module unit 13, the capacitor unit 14, the shield body 16, and the inverter control unit 11 are arranged in this order, and a separation distance between the shield body 16 and the power module unit 13 is larger than a separation distance between the shield body 16 and the inverter control unit 11.SELECTED DRAWING: Figure 1

Description

The present invention relates to an inverter device.

Electromagnetic field noise (EMC) also increases in an inverter device such as an electric vehicle (EV) that inputs a large current to a drive motor.
Already, an inverter device (power conversion device) in which an electromagnetic shield plate (shield) is arranged below the control circuit board for the purpose of heat dissipation and grounding has been disclosed. For example, Patent Document 1 discloses an inverter device (power conversion device).
However, the positional relationship between the capacitor used in the inverter device and the electromagnetic shield plate is not disclosed. Further, when the purpose is to dissipate heat, it is necessary to firmly fix the electromagnetic shield plate to the resin case (housing), and it cannot be attached by a simple method.

Japanese Unexamined Patent Publication No. 2012-20000

The present invention has been made in view of the above problems, and an object of the present invention is to provide an inverter device capable of effectively taking EMC countermeasures while aiming for miniaturization as a whole.

An exemplary invention of the present application is an inverter device for driving a motor, which outputs a control signal to a capacitor unit that smoothes a voltage from a power source, a power module unit that supplies a drive current to the motor, and the power module unit. It has an inverter control unit and a shield that shields electromagnetic field noise from the power module unit from the inverter control unit, and the power module unit, the capacitor unit, the shield, and the inverter control unit The inverter device is arranged in this order, and the distance between the shield and the power module unit is larger than the distance between the shield and the inverter control unit.

According to the exemplary invention of the present application, since the distance between the power module unit that is the source of the electromagnetic field noise and the shield can be secured, the electromagnetic field noise can be attenuated to some extent before reaching the shield. can. Therefore, since the electromagnetic field noise to be shielded by the shield is reduced, the size (thickness) of the shield can be reduced accordingly. Therefore, it is possible to effectively take EMC measures while reducing the size of the inverter device as a whole.

FIG. 1 is a schematic configuration diagram of a vehicle equipped with the inverter device of the present invention. FIG. 2 is an exploded perspective view of the inverter device shown in FIG. FIG. 3 is a perspective view showing a state in which the shield is removed from the capacitor unit.

Hereinafter, embodiments according to the present invention will be described in detail with reference to the accompanying drawings.
FIG. 1 is a schematic configuration diagram of a vehicle equipped with the inverter device of the present invention, FIG. 2 is an exploded perspective view of the inverter device shown in FIG. 1, and FIG. 3 is a perspective view showing a state in which a shield is removed from the capacitor unit. Is.
In FIGS. 2 and 3, the X-axis, the Y-axis orthogonal to the X-axis, and the Z-axis orthogonal to the X-axis and the Y-axis will be defined and described. Further, the upper side in FIGS. 2 and 3 is referred to as "upper" or "upper", and the lower side is referred to as "lower" or "lower".

In FIG. 1, the electric motor 15 is, for example, a three-phase AC motor and is a driving force source for a vehicle. The rotating shaft of the electric motor 15 is connected to the speed reducer 6 and the differential gear 7. As a result, the driving force (torque) of the electric motor 15 is transmitted to the pair of wheels 5a and 5b via the speed reducer 6, the differential gear 7, and the drive shaft (drive shaft) 8.

The inverter unit (inverter device) 20 of the inverter control device 10 includes a power module unit 13 that supplies drive power to the electric motor 15, a power module control unit 12 that outputs a drive signal to the power module unit 13, and power. The inverter control unit 11 that outputs a control signal to the module control unit 12, the capacitor unit 14 that smoothes the voltage from the battery BT, and the shield that shields the electromagnetic field noise from the power module unit 13 from the inverter control unit 11. It has 16.
The inverter unit 20 is controlled by a control signal from the control unit 3 that controls the entire vehicle, and drives the electric motor 15.

The power module unit 13 is formed by connecting two power switching elements for each of the U phase, V phase, and W phase (the power switching element of the upper arm and the power switching element of the lower arm), for a total of six power switching elements. It has a bridge circuit (power conversion circuit).
Examples of the power switching element include an IGBT (Insulated Gate Bipolar Transistor) and a MOSFET (Metal Oxide Semiconductor Field Effect Transistor).

The power module unit 13 switches on / off of the power switching element by a drive signal (PWM control signal) from the power module control unit 12. As a result, the DC power from the battery (power supply) BT is converted into AC power (three-phase AC power) to drive the electric motor 15.

The battery BT is a source of electric energy that is a power source of a vehicle, and is composed of, for example, a plurality of secondary batteries.
In the inverter unit 20, a capacitor unit 14 is arranged at a connection portion with the battery BT. The capacitor unit 14 is connected between the high potential line (positive electrode potential B +) and the low potential line (negative electrode potential B− (GND)). The capacitor unit 14 has a function of smoothing the input voltage from the battery BT, and includes a large-capacity smoothing capacitor (film capacitor).

As shown in FIG. 2, the power module unit 13, the power module control unit 12, the capacitor unit 14, the shield 16, and the inverter control unit 11 are arranged in order from the lower side along the Z-axis direction.
The separation distance between the shield 16 and the power module unit 13 is larger than the distance between the shield 16 and the inverter control unit 11.
According to such a configuration, a sufficient distance between the power module unit 13 which is a source of electromagnetic field noise and the shield 16 can be secured, so that the electromagnetic field noise is attenuated to some extent by the time it reaches the shield 16. Can be done. Therefore, since the electromagnetic field noise to be shielded by the shield body 16 is reduced, the size (thickness) of the shield body 16 can be reduced accordingly. Therefore, it is possible to effectively take EMC measures while reducing the size of the inverter unit 20 as a whole. Further, the range in which the electromagnetic field noise bypassing the shield 16 affects the inverter control unit 11 is small.

The shield 16 has a main body 160 and a plurality of communication holes 161 that communicate the main body 160 in the thickness direction (the power module unit 13 side and the inverter control unit 11 side are in the Z-axis direction). The main body 160 is made of a flat plate having a rectangular shape in a plan view.
The inverter control unit 11 has a wiring board 110 having a rectangular shape in a plan view, and an electronic component 111 mounted on the wiring board 110 and having an integrated circuit. In the present embodiment, the main body 160 of the shield 16 exists between the electronic component 111 and the capacitor unit 14 (power module unit 13). In other words, the communication hole 161 of the shield 16 does not exist directly under the electronic component 111, and the electronic component 111 is mounted on the wiring board 110 at a position deviated from the communication hole 161 when viewed from the inverter control unit 11 side. Has been done.

The electronic component 111 including the integrated circuit is particularly susceptible to electromagnetic field noise. More effective EMC countermeasures can be taken by interposing the main body 160 on a straight line connecting the power module unit 13 which is a source of electromagnetic field noise and the electronic component 111. Among the power module units 13, it is preferable that the main body 160 is interposed on a straight line connecting the IGBT element and the electronic component 111, which easily emit electromagnetic noise. Examples of the electronic component 111 include a microcomputer, a memory, a sensor, a harness, and the like.
Further, a plurality of electronic components 111 may be mounted on the wiring board 110, or electronic components not provided with integrated circuits may be mounted on the wiring board 110.

The constituent material of the shield 16 is not particularly limited, and examples thereof include aluminum, an aluminum alloy, and an electromagnetic field sheet. Above all, the shield 16 is preferably made of an aluminum alloy. Aluminum alloys are preferable because they can be obtained and processed at low cost and have a high shielding effect on electromagnetic field noise.
The shield 16 is mounted on the capacitor unit 14. At the time of assembling the inverter unit 20, the shield 16 can be mounted on the capacitor unit 14 at the same time, so that the assembling work is easy.

As shown in FIGS. 2 and 3, the capacitor unit 14 has a plurality of convex portions 141 projecting from the upper surface of the housing 140 to the positive side in the Z-axis direction. Each convex portion 141 penetrates the communication hole 161 of the shield 16 from the power module unit 13 side to the inverter control unit 11 side in a state where the shield 16 is mounted on the capacitor unit 14. As a result, the capacitor unit 14 and the shield 16 are accurately positioned.
The outer shape of each convex portion 141 has a circular shape, and the shape of each communication hole 161 also has a circular shape corresponding to the outer shape of each convex portion 141, but the shape is not limited thereto.
Further, the wiring board 110 of the inverter control unit 11 is fixed to the upper end of each convex portion 141 by, for example, screwing.
The housing 140 of the capacitor unit 14 can be manufactured, for example, by injection molding of a resin material.

The shield 16 includes a plurality of projecting pieces 162 projecting on the negative side in the Z-axis direction on the outer peripheral edge of the main body 160. Each projecting piece 162 is located on the side of the condenser unit 14 with the shield 16 mounted on the condenser unit 14. As a result, the positioning of the capacitor unit 14 and the shield 16 is made more accurate. From the viewpoint of improving the positioning accuracy, it is preferable that the projecting pieces 162 are provided in at least one set on the two opposing sides of the main body 160, and in addition to this, other opposing sides different from the above two sides. It is more preferable that at least one set is provided on the two sides.
The inverter unit 20 further has a hooking unit 17 on which the capacitor unit 14 and the projecting piece 162 are hooked. By providing the hooking portion 17, when the shielding body 16 is attached to the capacitor unit 14, they can be temporarily fixed.

In the illustrated configuration, the hook portion 17 is composed of a hole portion 171 provided so as to penetrate the projecting piece 162 in the thickness direction and a claw portion 172 provided on the side surface of the capacitor unit 14 so as to project laterally. ing. When the shield 16 is attached to the capacitor unit 14 when assembling the inverter portion 20, the claw portion 172 is inserted into the hole portion 171 and is caught. With such a simple configuration, the shield 16 can be easily temporarily fixed to the capacitor unit 14.
Further, the hole portion 171 is formed at the lower end portion of the projecting piece 162 (a portion away from the boundary portion with the main body portion 160). Therefore, when the shielding body 16 is manufactured by processing one plate material, even if the projecting piece 162 is bent with respect to the main body portion 160, the deformation around the hole portion 171 is prevented or suppressed, so that the shielding body When the 16 is mounted on the capacitor unit 14, the position deviation from the claw portion 172 is unlikely to occur. When the housing 140 of the capacitor unit 14 is manufactured by injection molding of a resin material, the claw portion 172 can be easily formed by providing a structure in which a convex portion is provided on the mating surface of the injection molding mold. ..

In the case of the present embodiment, the length (height) H of each convex portion 141 in the Z-axis direction is larger than the length L from the tip end (lower end in the Z-axis direction) of the projecting piece 162 to the central axis of the hole portion 171. It is set. According to this configuration, the shield 16 is guided in each communication hole 161 by each convex portion 141, so that the operation of hooking the claw portion 172 on the hole portion 171 while positioning the capacitor unit 14 and the shield 16 is performed. It can be carried out. Therefore, the assembly work of the inverter unit 20 can be performed more easily and reliably.
The hooking portion 17 may be provided on the projecting piece 162 and may be composed of a claw portion that protrudes toward the condenser unit 14 side and a recess that is provided on the side surface of the condenser unit 14 and on which the claw portion is hooked.

The capacitor unit 14 is provided with a plurality of capacitor-side tongue pieces 142 projecting sideways on its side surface. Each capacitor-side tongue piece 142 is formed with a through hole 142a penetrating in the thickness direction (Z-axis direction).
Further, the shield body 16 includes a shield body side tongue piece 163 having a portion protruding laterally on the outer peripheral edge of the main body portion 160. A through hole 163a penetrating in the thickness direction (Z-axis direction) is formed in a portion of the shield-side tongue piece 163 that projects laterally.
Then, in the present embodiment, with the shield 16 mounted on the capacitor unit 14, all the through holes 142a of the plurality of capacitor-side tongue pieces 142 and the through holes 163a of the corresponding shield-side tongue pieces 163 overlap each other. It is configured in.

With the above configuration, the capacitor unit 14 and the shield 16 can be fastened together with screws, so that the man-hours for assembling the inverter unit 20 can be reduced and the shield 16 and the capacitor unit 14 can be firmly fixed. can.
Further, since the fixing by the hook portion 17 may be temporary fixing (temporary fixing), the sizes of the hole portion 171 and the claw portion 172 may be reduced.
With the shield 16 mounted on the capacitor unit 14, a part of the through holes 142a of the plurality of capacitor-side tongue pieces 142 and the through holes 163a of the corresponding shield-side tongue pieces 163 are configured to overlap each other. May be good.

The inverter device of the present invention has been described above based on preferred embodiments, but the present invention is not limited thereto.
For example, in the configuration of the above embodiment, the inverter device of the present invention may be added with any other configuration or may be replaced with any configuration exhibiting the same function.

3 Control unit 5a, 5b Wheels 6 Reducer 7 Differential gear 8 Drive shaft 10 Inverter control unit 11 Inverter control unit 110 Wiring board 111 Electronic components 12 Power module control unit 13 Power module unit 14 Capacitor unit 140 Housing 141 Convex part 142 Condenser Side tongue piece 142a Through hole 15 Electric motor 16 Shield 160 Main body 161 Communication hole 162 Projection piece 163 Shield side tongue piece 163a Through hole 17 Hook part 171 Hole 172 Claw part 20 Inverter part BT Battery H Length (height)
L length

Claims (10)

It is an inverter device for driving a motor.
A capacitor unit that smoothes the voltage from the power supply and
A power module unit that supplies drive current to the motor,
An inverter control unit that outputs a control signal to the power module unit,
It has a shield that shields electromagnetic field noise from the power module unit from the inverter control unit.
The power module unit, the capacitor unit, the shield, and the inverter control unit are arranged in this order.
An inverter device characterized in that the distance between the shield and the power module unit is larger than the distance between the shield and the inverter control unit. The inverter device according to claim 1, wherein the shield is mounted on the capacitor unit. The shield has a main body and a communication hole for communicating the power module unit side and the inverter control unit side.
The inverter control unit has an electronic component including an integrated circuit.
The inverter device according to claim 1 or 2, wherein the main body is present between the electronic component and the power module unit. The third aspect of claim 3, wherein the capacitor unit has a convex portion that penetrates the communication hole of the shield from the power module unit side to the inverter control unit side with the shield mounted on the capacitor unit. Inverter device. The inverter device according to any one of claims 2 to 4, wherein the shield is attached to the capacitor unit, and the shield includes protrusions located on the side of the capacitor unit. The inverter device according to claim 5, further comprising a hooking portion on which the capacitor unit and the projecting piece are hooked. The inverter device according to claim 6, wherein the hook portion includes a hole portion provided in the projecting piece and a claw portion provided in the capacitor unit and hooked on the hole portion. The shield has a communication hole for communicating the main body, the power module unit side, and the inverter control unit side.
The capacitor unit has a convex portion that penetrates the communication hole of the shield from the power module unit side to the inverter control unit side with the shield mounted on the capacitor unit.
The inverter device according to claim 7, wherein the length of the convex portion is larger than the length from the tip of the projecting piece to the central axis of the hole. The capacitor unit includes a plurality of capacitor-side tongue pieces having through holes.
The shield comprises a plurality of shield-side tongue pieces having through holes.
Claims 3 to 3 in which at least one through hole of the plurality of capacitor-side tongue pieces and at least one of the through-holes of the plurality of shield-side tongue pieces overlap with the shield attached to the capacitor unit. 8. The inverter device according to any one of 8. The inverter device according to any one of claims 1 to 9, wherein the shield is made of an aluminum alloy.

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