Motor drive circuit

Abstract

This document discloses an example of a motor drive circuit that can suppress a significant increase in the number of switching elements even when the number of electric motors increases. [Solution] The motor drive circuit 1 includes a selection switching element 51, 52 provided on the power supply side and ground side of each of the multiple electric motors 3 that energizes or disconnects the drive current supplied to the electric motor 3, four drive switching elements 61 to 64 that constitute a motor bridge circuit for supplying the drive current, and a control unit 2 that controls the opening and closing operation of the multiple selection switching elements 51, 52 and the four drive switching elements 61 to 64, and the multiple electric motors 3 are connected in parallel to the power supply side and the ground side.

Description

Technical Field

[0001] The present disclosure relates to a motor drive circuit that drives a plurality of electric motors.

Background Art

[0002] For example, in the motor drive circuit described in Patent Document 1, a plurality of switching elements are arranged in series in a circuit through which a drive current of a motor flows, and by controlling the opening and closing of these switching elements, the electric motor to be driven is selected.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] The present disclosure discloses an example of a motor drive circuit that can select an "electric motor to be driven" in a manner different from that of Patent Document 1 and can suppress a large increase in the number of switching elements even when the number of electric motors increases.

Means for Solving the Problems

[0005] A motor drive circuit that drives a plurality of electric motors (3) mounted on a vehicle seat preferably includes at least one of the following constituent elements. That is, selection switching elements (51, 52) provided on the power supply side and the ground side of each of the plurality of electric motors (3) for energizing or interrupting the drive current supplied to the electric motor (3), four drive switching elements (61 to 64) constituting a motor bridge circuit for supplying the drive current, and a control unit (2) for controlling the opening and closing operations of the plurality of selection switching elements (51, 52) and the four drive switching elements (61 to 64).

[0006] Furthermore, the multiple electric motors (3) are connected in parallel to the power supply side and the ground side, and when the control unit (2) operates a specific electric motor (3) among the multiple electric motors (3), it is desirable to close the selection switching elements (51, 52) located on the power supply side and the ground side of that electric motor (3).

[0007] As a result, the motor drive circuit can select the "electric motor to be driven" in a different manner than that described in Patent Document 1, and it is possible to suppress a large increase in the number of selection switching elements (51, 52) even if the number of electric motors (3) increases.

[0008] The motor drive circuit may have the following configuration, for example. In other words, it is desirable that the multiple selection switching elements (51, 52) and the four driving switching elements (61-64) are field-effect transistors.

[0009] Incidentally, the symbols in each of the parentheses above are just examples showing the correspondence with the specific configurations etc. described in the embodiments described later, and this disclosure is not limited to the specific configurations etc. indicated by the symbols in the parentheses above. [Brief explanation of the drawing]

[0010] [Figure 1] This is a diagram showing a motor drive circuit according to the first embodiment. [Modes for carrying out the invention]

[0011] The following "Embodiments of the Invention" are examples of embodiments that fall within the technical scope of this disclosure. In other words, the features defining the invention as described in the claims are not limited to the specific configurations and structures shown in the embodiments below.

[0012] This embodiment is an example in which the motor drive circuit according to this disclosure is applied to a seat installed in a vehicle or other vehicle (hereinafter referred to as a vehicle seat). Unless otherwise specified, at least one of the components described with reference numerals is provided.

[0013] (First Embodiment) <1. Overview of the motor drive circuit (see Figure 1)> The motor drive circuit 1 according to this embodiment is a motor bridge circuit for driving one of several (four in Figure 1) electric motors 31 to 34 mounted on a vehicle seat (not shown).

[0014] Each of the electric motors 31 to 34 constitutes a drive source for electric devices (not shown) installed in the vehicle seat, such as a sliding device, a reclining device, a lifting device, and an ottoman. In the following, electric motor 3 refers to any of the electric motors 31 to 34, or to the collective term for the electric motors 31 to 34.

[0015] <2. Configuration of the motor drive circuit (motor bridge circuit) (see Figure 1)> The motor drive circuit 1 according to this embodiment includes at least a plurality of selection switching elements 51, 52, four drive switching elements 61 to 64, and a control unit 2. Each of the electric motors 31 to 34 is connected in parallel to the power supply side and the ground side.

[0016] The selection switching elements 51 and 52 are provided on the power supply side and ground side of each electric motor 3 and are switches for energizing or interrupting the drive current supplied to the electric motor 3. Specifically, a selection switching element 51 is provided on the power supply side (left side of the page) of each electric motor 3.

[0017] A selection switching element 52 is provided on the ground side (right side of the page) of each electric motor 3. The selection switching elements 51 and 52 open and close the circuit through which the drive current flows on the power supply side and the ground side of the electric motor 3.

[0018] The four driving switching elements 61 to 64 are switches that constitute a motor bridge circuit for supplying driving current to the electric motor 3. Specifically, when the electric motor 3 rotates forward, the driving switching elements 61 and 64 are closed, and the driving switching elements 62 and 63 are open.

[0019] When the electric motor 3 rotates reversely, the driving switching elements 62 and 63 are closed, and the driving switching elements 61 and 64 are open. Each of the selection switching elements 51, 52 and the four driving switching elements 61 to 64 is a field effect transistor (FET).

[0020] The control unit 2 is a microcomputer-type control unit that controls the opening and closing operations of the plurality of selection switching elements 51, 52 and the four driving switching elements 61 to 64. The control unit 2 according to the present embodiment controls the opening and closing of each of the switching elements 51, 52, 61 to 64 via the FET drivers 41, 42.

[0021] Specifically, the selection driver 41 applies a predetermined potential to the gates of the plurality of selection switching elements 51, 52. The driving driver 42 applies a predetermined potential to the gates of the driving switching elements 61 to 64. The operations of the respective FET drivers 41, 42 are controlled by the control unit 2.

[0022] When the control unit 2 operates a specific electric motor among the electric motors 31 to 34, the selection switching elements 51, 52 arranged on the power supply side and the ground side of the specific electric motor 3 are closed.

[0023] At this time, the control unit 2 opens the selection switching elements 51, 52 other than the selection switching elements 51, 52 arranged on the power supply side and the ground side of the specific electric motor 3. Thereby, only the specific electric motor 3 operates.

[0024] Note that there is at least one specific electric motor 3, that is, an electric motor 3 to be operated. For this reason, the control unit 2 can also select multiple electric motors 3 to be operated.

[0025] <3. Features of the motor drive circuit according to this embodiment> In the motor drive circuit 1 according to this embodiment, the number of selection switching elements 51 and 52 is "number of electric motors 3 × 2", and the number of drive switching elements 61 to 64 is always 4, regardless of the number of electric motors 3.

[0026] Then, when supplying drive current to a specific electric motor 3, the control unit 2 closes two selection switching elements and two drive switching elements. In other words, in this embodiment, by closing four switching elements, a specific electric motor 3 can be operated.

[0027] Therefore, in this embodiment, even if the number of electric motors 3 increases, it is possible to suppress a large increase in the number of selective switching elements 51 and 52. As a result, in this embodiment, a large increase in the number of switching elements required for PWM control and flowing freewheel current is suppressed, and thus the low efficiency and increased heat generation of the motor drive circuit 1 can be suppressed.

[0028] (Other embodiments) The switching element in the above-described embodiment was a field-effect transistor (FET). However, this disclosure is not limited to this. That is, the disclosure may also describe a switching element configured as an electromagnetic relay such as a relay.

[0029] In the embodiments described above, the FET drivers 41 and 42 and the control unit 2 were separate. However, this disclosure is not limited thereto. That is, the disclosure may also include, for example, a configuration in which functions equivalent to the FET drivers 41 and 42 are incorporated into the control unit 2.

[0030] In the embodiments described above, the vehicle seat according to this disclosure was applied to a vehicle. However, the application of the invention disclosed herein is not limited to this. That is, the disclosure can be applied, for example, to seats used in vehicles such as railway cars, ships and aircraft, as well as to stationary seats used in theaters, homes, etc.

[0031] Furthermore, this disclosure is not limited to the embodiments described above, but is sufficient to be consistent with the intent of the disclosures described in the embodiments described above. Therefore, it may be a configuration in which at least two of the embodiments described above are combined, or a configuration in which any of the illustrated components or components described with reference numerals in the embodiments described above are omitted. [Explanation of symbols]

[0032] 1… Motor drive circuit 2… Control Unit 3… Electric motor 41, 42… FET driver 51, 52… Selective switching elements 61-64… Driving switching elements

Claims

1. In a motor drive circuit that drives multiple electric motors mounted on a vehicle seat, A selection switching element is provided on the power supply side and ground side of each of the multiple electric motors, which energizes or disconnects the drive current supplied to the electric motor, The motor bridge circuit for supplying the aforementioned drive current comprises four drive switching elements, The system comprises a control unit that controls the opening and closing operations of a plurality of selection switching elements and the four drive switch elements, Multiple electric motors are connected in parallel to the power supply side and the ground side. Furthermore, the control unit, when operating a specific electric motor among a plurality of electric motors, closes the selection switching elements located on the power supply side and ground side of the electric motor in the motor drive circuit.

2. The motor drive circuit according to claim 1, wherein the plurality of selection switching elements and the four driving switching elements are field-effect transistors.

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