Control Circuit of Electric Machine, Electric Machine System and Vehicle Parking Brake System

Abstract

The present application relates to a control circuit of an electric motor, an electric motor system, and a vehicle parking brake system. The control circuit of the electric motor includes: a drive circuit (1) configured to drive the electric motor in different rotational directions of the electric motor; a redundant circuit (2) including a redundant drive circuit (21) and a switching circuit (22). The redundant drive circuit (21) is connected in parallel with the drive circuit (1) and alternatively drives the electric motor in the case of a failure of a switching device of the drive circuit (1). The switching circuit (22) connects corresponding switching devices of the drive circuit (1) and the redundant drive circuit (21). The switching circuit (22) includes at least one switching device, and the at least one switching device is connected in series with each other. When a switching device of the drive circuit (1) fails, the switching device is correspondingly triggered to turn on the corresponding switching device of the redundant drive circuit (21).

Description

Technical Field

[0001] The present application relates to the design of a control circuit for an electric motor, and more particularly, to a redundant circuit for an electric motor. Background Art

[0002] Currently, in the prior art, electric motors are widely used in many fields and are driven and controlled by a control circuit or a drive circuit. In some applications, when certain switching devices in the control circuit or drive circuit of the electric motor fail, the electric motor cannot be driven by the drive circuit and thus cannot operate normally, which may pose a danger in some applications (such as when the vehicle uses the electric motor for electric braking).

[0003] Therefore, especially in existing vehicles, when using the electric motor for electric braking or parking braking, a redundant drive circuit is usually not provided for the electric motor. In this case, when the drive circuit of the electric motor fails, the driver often needs to manually perform the corresponding braking or parking operation. Summary of the Invention

[0004] The purpose of the present application is to provide a control circuit for an electric motor, including:

[0005] A drive circuit configured to drive the electric motor in different rotational directions of the electric motor;

[0006] A redundant circuit including a redundant drive circuit and a switching circuit. The redundant drive circuit is connected in parallel with the drive circuit and drives the electric motor alternatively when the switching device of the drive circuit fails. The switching circuit connects the switching devices corresponding to each other in circuit positions of the drive circuit and the redundant drive circuit. The switching circuit includes at least one switching device, and the at least one switching device is connected in series with each other. The switching device is triggered correspondingly when the switching device of the drive circuit fails to turn on the switching device corresponding to the redundant drive circuit in the circuit position.

[0007] According to a second aspect of the present application, an electric motor system is provided, including an electric motor and a control circuit of the electric motor, wherein the control circuit of the electric motor is configured as the control circuit according to any embodiment of the present application.

[0008] According to a third aspect of the present application, a vehicle parking braking system is provided, including: an electric motor system, the electric motor system including a caliper motor installed in a wheel hub, the electric motor being used to brake the wheel, characterized in that the electric motor system further includes the control circuit according to any embodiment of the present application for the electric motor. Brief Description of the Drawings

[0009] With reference to the accompanying drawings, the disclosure of the present invention will become more readily understandable. It is readily understandable to those skilled in the art that these drawings are merely for illustrative purposes and are not intended to limit the scope of protection of the present invention. Herein:

[0010] Figure 1 Exemplarily shown is a circuit structure diagram of a control circuit of a motor disclosed in the present application; and

[0011] Figure 2a Exemplarily shown is a current flow of the control circuit of the motor in the case where a device in the motor control circuit fails; and

[0012] Figure 2b Exemplarily shown is another current flow of the control circuit of the motor in the case where a device in the motor control circuit fails. Detailed implementation manners

[0013] First, refer to the appendix Figure 1 , in which is exemplarily shown a control circuit of a motor disclosed in the present application. Herein, the control circuit of the motor includes a drive circuit 1 and a redundant circuit 2. Among them, the drive circuit 1 is used to control the forward or reverse rotation of the motor through different current flows inside it. Of course, it is also feasible that in some usage scenarios, the drive circuit 1 only drives the motor to rotate in a single direction. Within the scope of the present application, the redundant circuit 2 includes a redundant drive circuit 21 and a switch circuit 22. Among them, the redundant drive circuit 21 is connected in parallel with the drive circuit 1 after the power supply. The mutual connection between the drive circuit 1 and the redundant drive circuit 21 is realized through the switch circuit 22. Within the scope of the present application, the switch circuit 22 connects the corresponding switching devices in the drive circuit 1 and the redundant drive circuit 21, so that when a certain switching device in the drive circuit 1 fails, the corresponding switching device in the redundant drive circuit 21 can work alternatively to drive the motor 10. Within the scope of the present application, the switch circuit 22 includes at least one switching device, and the at least one switching device is connected in series with each other. And among them, the switching device is correspondingly triggered and turned on when the switching device in the drive circuit 1 fails, so as to connect the drive circuit 1 and the redundant drive circuit 21.

[0014] Within the scope of the present application, the switching device being "correspondingly triggered" means that, depending on the different positions of the failed switching device in the drive circuit 1 relative to the motor to be driven, or rather, relative to the circuit position of the motor to be driven (refer to Figure 1 , for example, the upper left bridge Q1 or the upper right bridge Q2 of the drive H-bridge circuit of the motor to be driven, where the "upper" here refers to the bridge arm close to the voltage source), the switching device in the switch circuit 22 corresponding to this position in the drive circuit 1 (refer toFigure 1 For example, when the switching device used to turn on (such as Q9, Q10 or Q11, Q12) is triggered, the switching device (such as Q5 or Q6 or other combinations) at the circuit position corresponding to the failed switching device in the redundant drive circuit 21 (replacing the switching device function corresponding to the drive circuit 1) can work instead. For example, when a certain switching device in the drive circuit 1 is damaged, the switching device in the switching circuit 22 for connecting the damaged switching device and the switching device replacing it in the redundant drive circuit 21 is turned on, or the switching device in the switching circuit 22 for connecting the drive circuit 1 and the redundant drive circuit 21 is turned on. The above triggering methods of the switching devices in the switching circuit 22 are all within the scope claimed in this application.

[0015] It should also be noted here that in the scope of this application, "the corresponding circuit position" refers to the position of the electrical component relative to the voltage source or the motor to be driven in the direction of current flow. For example, in Figure 1 , for the switching device Q1, the switching device with the corresponding circuit position can be Q5.

[0016] In some embodiments of this application, the control circuit further includes a detection circuit 3. Here, the detection circuit 3 is used to detect whether the switching devices in the switching circuit 22 can work. Specifically, the detection circuit 3 includes voltage-dividing resistors R5 and R7. Among them, the voltage-dividing resistors are connected after the circuit position of the switching device to be detected in the switching circuit 22 (that is, viewed from the direction of current flow). By measuring the voltage after flowing through the switching device to be detected and the voltage-dividing resistors, the detection circuit 3 can determine whether the switching device to be detected is normally turned on when needed. By detecting the conductivity of the switching devices in the switching circuit 22, it is avoided that in the case where the redundant drive circuit 21 needs to be used, the components of the redundant drive circuit 21 cannot be normally connected, resulting in the situation that the motor 10 cannot be normally driven.

[0017] In some embodiments of the present application, the drive circuit 1 and the redundant drive circuit 21 are configured as H-bridge circuits. Herein, the H-bridge circuit includes two bridge arms disposed on both sides of the H-shape, and each bridge arm respectively has legs above and below the H-shaped crossbar. Herein, the H-bridge circuit includes switching devices Q1, Q2, Q3, and Q4, and Q5, Q6, Q7, and Q8 disposed in the four legs of the H-bridge. Among them, the switching circuit 22 connects the H-bridge arm of the drive circuit 1 to the corresponding H-bridge arm of the redundant drive circuit 21. Further, in some embodiments of the present application, for each bridge arm of the H-bridge circuit, the switching circuit 22 connects the drive circuit 1 and the redundant drive circuit 21 through two switching devices Q9, Q10, and Q11, and Q12. That is to say, the switching circuit 22 can be connected between the H-bridge arm and the crossbar of the drive circuit 1 and the redundant drive circuit 21, or between the voltage-dividing resistors (such as R1, R2, R3, or R4 in the appendix Figure 1 ), and the H-bridge arm, as seen in Figure 1 .

[0018] In the control circuit described above, it can also be set that the voltage-dividing resistors R5 and R7 of the detection circuit 3 obtain (measure) the voltage between two switching devices. That is to say, a branch is led out between the two switching devices Q9 and Q10 and Q11 and Q12 of the switching circuit 22 to connect the voltage-dividing resistor. This access method of the detection circuit using the voltage-dividing resistor can be respectively used to detect the conduction conditions of the two switching devices. For example, when it is necessary to detect whether the first switching device, such as Q9 (or Q11), is normally conducted, the second switching device Q10 (or Q12) is disconnected, so that when the first switching device is normally conducted, the current passes through the first switching device Q9 (or Q11) and then through the voltage-dividing resistor, and the subsequent detection circuit or ADC can thereby measure the voltage drop across the voltage-dividing resistor. Otherwise, since the first switching device fails to be correctly conducted (it is disconnected), the detection end cannot detect the voltage output or can only detect a very small weak voltage output.

[0019] In the present application, the switching devices in the above-described various circuits can be MOS transistors or other components having the same / similar functions, which all fall within the scope of the present application.

[0020] Preferably, the control circuit involved in the present application is applicable to the following motor system, in which there are multiple motors and each motor has its own control circuit. In such a case, the redundant circuit 2 of each motor is the drive circuit 1 of another motor. This setting method simplifies and optimizes the topology of the redundant circuit.

[0021] Next, taking an embodiment as an example, it will be described how the switching circuit 22 and the redundant drive circuit 21 work to drive the motor when a switching device, such as a MOS transistor, in the drive circuit 1 fails.

[0022] Corresponding to Figure 1 the circuit topology of Figure 2a and Figure 2b shows the operating principle of the circuit under this topology. Referring to Figure 2a , the switching device (Q1) in the upper left leg of the driving H-bridge circuit fails and cannot conduct normally. At this time, the current first flows into the switching device in the upper left leg of the redundant driving H-bridge circuit, and then flows through the two switching devices Q10 and Q9 in the switching circuit 22 to reach the crossbar (motor 10) in the driving H-bridge circuit, and then flows out from the motor 10 and reaches the lower right leg Q4 of the H-bridge circuit (see Figure 2a the thickened current flow line in). In this case, the switching device Q5 in the upper left leg of the redundant H-bridge circuit replaces the switching device Q1 in the upper left leg of the driving H-bridge circuit that has failed.

[0023] Of course, for example, when the switching device (Q1) in the upper left leg of the driving H-bridge fails, there is another way for the current to flow. Referring to Figure 2b it can be seen that the current first flows into the switching device Q5 in the upper left leg of the redundant driving H-bridge circuit at this time, and then flows through the two switching devices Q10 and Q9 in the switching circuit 22 to reach the crossbar (motor 10) in the driving H-bridge circuit, and then flows out from the motor 10 and the voltage-dividing resistor R1 connected thereto, passes through the switching devices Q11 and Q12 of the switching circuit 22, and finally reaches the lower right leg Q8 of the H-bridge circuit of the redundant drive circuit 21 (see Figure 2b the thickened current flow line in). In this case, the redundant H-bridge circuit replaces the driving H-bridge circuit.

[0024] When it is necessary to use the detection circuit 3 to detect whether the switching components of the switching circuit 22 are conducting normally, one switching component can be disconnected first to detect whether the other "should-be" conducting switching component is conducting normally.

[0025] This application also relates to a motor system, including a motor and a control circuit of the motor, and the control circuit of the motor is configured to be the control circuit according to any embodiment of this application.

[0026] The present application further relates to a vehicle parking brake system, comprising: an electric motor system, the electric motor system including an electric motor installed in a wheel hub, the electric motor being used for braking the wheel, characterized in that the electric motor system further includes a control circuit as described in any embodiment of the present application for the electric motor. In this parking brake system, the electric motor system includes two electric motors respectively installed in the left and right wheels of the vehicle, wherein the control circuit of each electric motor is designed such that the redundant circuit 2 of each electric motor is the drive circuit of the other electric motor.

Claims

1. A control circuit for an electric motor, characterized in that, comprising: A drive circuit (1), the drive circuit (1) being configured to drive an electric motor (10) in different rotational directions of the electric motor; A redundancy circuit (2), including a redundant drive circuit (21) and a switch circuit (22), wherein the redundant drive circuit (21) is connected in parallel with the drive circuit (1) and alternatively drives the electric motor (10) in the case of a failure of a switching device of the drive circuit (1), and the switch circuit (22) connects the switching devices corresponding in circuit position of the drive circuit (1) and the redundant drive circuit (21) to each other, wherein the switch circuit (22) includes at least one switching device, the at least one switching device being connected in series with each other, and wherein the at least one switching device is correspondingly triggered when a switching device of the drive circuit (1) fails to turn on the switching device corresponding in circuit position of the redundant drive circuit (21).

2. The control circuit according to claim 1, characterized in that, The control circuit further includes a detection circuit (3), wherein the detection circuit (3) is configured to detect whether the switching devices of the switch circuit (22) are operating normally.

3. The control circuit according to claim 2, characterized in that, The detection circuit (3) includes a voltage-dividing resistor, wherein the voltage-dividing resistor is connected after the switching device to be detected of the switch circuit (22) along the direction of current flow.

4. The control circuit according to claim 3, characterized in that, The drive circuit (1) and the redundant drive circuit (21) are configured as H-bridge circuits, the H-bridge circuits including switching devices respectively provided in four legs of the H-bridge, wherein the switch circuit (22) connects the H-bridge arms of the drive circuit (1) to the H-bridge arms at corresponding circuit positions of the redundant drive circuit (21).

5. The control circuit according to claim 4, characterized in that, For each bridge arm of the H-bridge circuit, the switch circuit (22) connects the drive circuit (1) and the redundant drive circuit (21) through two switching devices.

6. The control circuit according to claim 5, characterized in that, The voltage-dividing resistor of the detection circuit (3) is connected in parallel between the two switching devices.

7. The control circuit according to any one of claims 1 to 6, characterized in that, The switching device is configured to include a MOS transistor.

8. The control circuit according to claim 1, characterized in that, The control circuit is suitable for a motor system in which there are multiple electric motors and each electric motor has its own control circuit, wherein the redundancy circuit (2) of each electric motor is the drive circuit (1) of another electric motor.

9. A motor system, including an electric motor and a control circuit for the electric motor, characterized in that, The control circuit for the electric motor is configured as the control circuit according to any one of claims 1 to 8.

10. A vehicle parking brake system, including: A motor system, the motor system includes a caliper motor installed in a wheel hub, the motor being used to brake the wheel, characterized in that the motor system further includes a control circuit as described in any one of claims 1 to 8 for the motor.

11. The vehicle parking brake system according to claim 10, characterized in that the motor system includes two motors respectively installed in the left and right wheels of the vehicle, wherein the control circuit of each motor is designed such that the redundant circuit (2) of each motor is the drive circuit (1) of the other motor.

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