JPWO2020075693A1 - Motor control system, motor and electric power steering device - Google Patents

Abstract

One aspect of the motor control system according to the present invention is a motor control system that supplies electric power to a motor, a power supply circuit that generates a constant voltage, an inverter circuit for driving a coil winding of the motor, and an inverter circuit. The first motor control unit and the second motor each include a power supply relay circuit that cuts off the power supply to the inverter and a CPU that calculates the control amount based on the information from the sensor and outputs the control signal to the inverter circuit. It has a control unit. The first motor control unit supplies power to the first coil winding, which is one of the two independent coil windings, and the second motor control unit supplies two independent coil windings. The first motor control unit has a first abnormality detection circuit that detects an abnormality in the second motor control unit, and supplies power to the second coil winding, which is the other winding set in the above. Is a motor control system having a second abnormality detection circuit for detecting an abnormality in the first motor control unit.

Description

The present invention relates to a motor control system, a motor and an electric power steering device.

As a conventional electric power steering device, a motor is provided with two sets of coil windings, and a control unit having two sets of inverter circuits capable of independently driving the two sets of coil windings is provided, and two sets of inverter circuits are provided. Some of them controlled and continued to drive the motor only in the group that was operating normally in the event of an abnormality. In addition to the inverter circuit of the control unit, an electric power steering device is known as a dual system to prepare for a failure (Patent Document 1).

Japanese Registered Patent: No. 38393358

In Patent Document 1, the first ECU 21 and the second ECU 22 are necessary for the actual rotation positions of the first motor 36 and the second motor 37 calculated by themselves, the detected values of the sensors of their own system, and the motor control. It has a mutual monitoring function that constantly communicates and exchanges other information and error information α with each other. Here, when the abnormality detection is communicated between the ECUs, a time lag occurs because the ECU on the side where the abnormality has occurred detects the circuit or power supply abnormality and then transmits the abnormality detection to the other ECU by communication. Further, when an ECU communication abnormality occurs, neither system has a means for detecting the abnormality on the other side, so that there is a problem that the other abnormality cannot be detected when a secondary failure leading to an assist abnormality occurs, or the ECU abnormality and the ECU. There is a problem that it is not possible to isolate the abnormalities.

One embodiment of the motor control system according to the present invention supplies power to a motor comprising a rotor, a stator having two independent sets of coil windings, and a rotation angle sensor that acquires rotation angle information of the rotor. A motor control system that controls based on information from a power supply circuit that generates a constant voltage, an inverter circuit that drives the coil windings of the motor, a power supply relay circuit that cuts off the power supply to the inverter circuit, and information from the sensor. It includes a first motor control unit and a second motor control unit, each of which includes a CPU that calculates an amount and outputs a control signal to an inverter circuit. The first motor control unit supplies power to the first coil winding, which is one of the two independent coil windings, and the second motor control unit supplies two independent coil windings. The first motor control unit has a first abnormality detection circuit that detects an abnormality in the second motor control unit, and supplies power to the second coil winding, which is the other winding set in the above. Has a second abnormality detection circuit for detecting an abnormality in the first motor control unit.

One aspect of the motor according to the present invention is to receive power from the motor control system, a rotor that rotates about a central axis, a rotation angle sensor that acquires rotation angle information of the rotor, and the motor control system. A stator and a stator are provided.

Further, one aspect of the electric power steering device according to the present invention includes a motor controlled by the motor control system, a device control unit that manages an operating state of the electric power steering device, and a torque sensor.

According to an exemplary embodiment of the present invention, the motor control system can detect an abnormality without a time lag by directly monitoring an output abnormality of another system, and can quickly shift to control after a failure. can. Therefore, the motor can maintain the drive even if one system fails. Further, the electric power steering device can assist steering without impairing the operability of the driver's steering wheel.

FIG. 1 is a diagram showing a schematic configuration of an electric power steering device according to an embodiment of the present invention. FIG. 2 is a schematic view of a motor according to an embodiment of the present invention. FIG. 3 is a flowchart according to an embodiment of the present invention.

Hereinafter, embodiments of the motor control system of the present disclosure, a motor having the motor control system, and an electric power steering device having the motor will be described in detail with reference to the drawings. However, in order to avoid unnecessarily redundant explanations below and facilitate understanding by those skilled in the art, unnecessarily detailed explanations may be omitted. For example, detailed explanations of already well-known matters and duplicate explanations for substantially the same configuration may be omitted.

FIG. 1 is a diagram showing an example of a schematic configuration of the electric power steering system 10. The electric power steering system 10 is a device that assists the driver in operating the steering wheel in a transportation device such as an automobile. As shown in FIG. 1, the electric power steering system 10 includes a steering wheel (hereinafter, also referred to as “steering wheel”) 12, an electric power steering device 20, and wheels 82.

The electric power steering device 20 includes a torque sensor 22, a motor 7, and a device control unit 80. The motor control system 30 is integrally attached to the motor 7. The torque sensor 22 is attached to the steering shaft 14. The torque sensor 22 detects the torque applied to the steering shaft 14 when the steering shaft 14 is rotated by the operation of the steering wheel 12 by the driver. The torque signal, which is the detection signal of the torque sensor 22, is output to the motor control system 30. The device control unit 80 manages the operating state of the power steering device 20. Further, the device control unit 80 communicates or controls the operating state with respect to other components in an automobile or the like.

The motor control system 30 controls the motor 7 by supplying a drive current to the motor 7. The motor control system 30 can drive the motor 7 by using not only the torque signal but also other information such as the vehicle speed.

The driving force generated by the motor 7 is transmitted to the wheels 82 via the gearbox 84. As a result, the steering angle of the wheel 82 changes. In this way, the electric power steering device 20 amplifies the torque of the steering shaft 14 by the motor 7 to change the steering angle of the wheels 82. Therefore, the driver can operate the steering wheel 12 with a light force.

<Structure Example of Motor 7> FIG. 2 is a block diagram showing an example of the configuration of the motor 7. As shown in FIG. 2, the motor 7 includes a rotor (not shown) that rotates about a central axis, a stator 70, and a rotation angle sensor 761. The stator 70 includes a first coil winding 71, which is one winding set in two independent coil windings, and a second coil winding 72, which is the other winding set in two independent coil windings. And. The first coil winding 71 includes a U-phase winding M1, a V-phase winding M2, and a W-phase winding M3. The second coil winding 72 includes a U-phase winding N1, a V-phase winding N2, and a W-phase winding N3. The rotation angle sensor 761 detects the rotation angle information θ of the rotor.

The motor control system 30 includes a microcomputer, a drive circuit, and the like, and is composed of two systems for driving and controlling the double-wound motor 7. By adopting the configuration of two systems by the redundant design, even if one system fails, the motor 7 can be continuously driven by the other system, so that the reliability can be improved. The motor control system 30 includes a first motor control unit 100 on the first system side and a second motor control unit 200 on the second system side.

The first motor control unit 100 cuts off the power supply to the first power supply circuit 101 that generates a constant voltage, the first inverter circuit 102 for driving the coil winding of the motor 7, and the first inverter circuit 102. It includes a first power supply relay circuit 111, a CPU 1 that outputs a control signal to the first inverter circuit 102, and a first abnormality detection circuit 104. Further, the second motor control unit 200 supplies electric power to the second power supply circuit 201 that generates a constant voltage, the second inverter circuit 202 for driving the coil winding of the motor 7, and the second inverter circuit 202. It includes a second power supply relay circuit 211 that shuts off, a CPU 2 that outputs a signal to the second inverter circuit control 202, and a second abnormality detection circuit 204. That is, each of the first motor control unit and the second motor control unit includes a power supply circuit, an inverter circuit, a power supply relay circuit, a CPU, and an abnormality detection circuit.

The first power supply circuit 101 is a power supply for driving each circuit element of the first motor control unit 100. For example, the first power supply circuit 101 supplies electric power to the coil winding of the motor, each element of the first inverter circuit 102, and the CPU 1. Since the second power supply circuit 201 has the same function as the first power supply circuit 101, the description thereof will be omitted.

The first motor control unit 100 supplies electric power to the first coil winding 71. The second motor control unit 200 supplies electric power to the second coil winding 72. The first inverter circuit 102 is connected to the first coil winding 71. The second inverter circuit 202 is connected to the second coil winding 72. Each of the inverter circuits 102 and 202 includes a bridge circuit composed of three legs including a high-side switching element and a low-side switching element. Each of the first inverter circuit 102 and the second inverter circuit 202 has three shunt resistors 81 and 82. One shunt resistor is located on the low side of the low side switching element in one leg. Each shunt resistor is connected to each phase of the coil winding and therefore functions as a current sensor.

The first power supply relay circuit 111 is connected to the high side side of the first inverter circuit 102. The first power supply relay circuit 111 controls the supply of electric power to the first inverter circuit 102 by turning the switching element on and off. Since the second power supply relay circuit 211 also has the same configuration as the first inverter circuit, the description thereof will be omitted.

The CPU 1 includes a microcontroller, an input / output circuit, an AD converter, a load drive circuit, a ROM (Read On Memory), a communication module, and the like. The CPU 1 controls the drive of the motor 7 based on the torque command of the torque sensor 22. The CPU 1 calculates a control amount based on the rotation angle information θ output from the rotation angle sensor 761, and outputs a control signal to the first inverter circuit 102. Similarly, the CPU 2 calculates the control amount based on the rotation angle information θ output from the rotation angle sensor 761, and outputs the control signal to the second inverter circuit 202.

Each of the first motor control unit 100 and the second motor control unit 200 includes a communication unit. The first motor control unit 100 includes a first communication unit 91, and the first motor control unit 200 includes a second communication unit 92. The CPU 1 communicates with the device control unit 80 via the first communication unit 91. Similarly, the CPU 2 communicates with the device control unit 80 via the second communication unit 92. The communication unit may be, for example, a communication cable provided separately from the CPU, or a communication module provided in the CPU. The communication unit is connected to the CPU so as to be able to communicate with the CPU. The communication unit communicates the communication data with the device control unit 80 according to a communication protocol such as CAN. The communication unit may be wired or wireless.

The first abnormality detection circuit 104 and the second abnormality detection circuit 204 are composed of circuits such as a comparator. The abnormality detection circuit detects the current value output from the shunt resistors 81 and 82. The abnormality detection circuit determines an abnormality of the switching element when it exceeds a predetermined threshold value or does not exceed a predetermined threshold value. At this time, the CPU communicates the abnormality determination with the device control unit 80 via the communication unit. The abnormality detection circuit is not limited to detecting the current value output from the shunt resistors 81 and 82. For example, the abnormality detection circuit may detect the voltage applied to the shunt resistors 81 and 82. Further, the abnormality detection circuit is not limited to detecting the states of the shunt resistors 81 and 82. The abnormality detection circuit may detect the driving state of other components. For example, the abnormality detection circuit may detect the voltage value or the current value between the motor terminals, or may detect the current value or the voltage value of the power supply circuit.

Here, with reference to FIG. 3, in the present embodiment, consider a case where the first coil winding 71 has an abnormality in which a current value equal to or greater than a threshold value flows through the U-phase winding M1. (Step 1: S1) The first abnormality detection circuit 104 identifies the phase in which the abnormal current flows based on the current value of the shunt resistor 81. (Step 2: S2) The first motor control unit 100 determines whether or not the first inverter circuit 102 can be driven normally. (Step 3: S3) When the first motor control unit 100 determines that the first inverter circuit 102 is abnormal in step 2, the first motor control unit 100 controls the switching of the first power supply relay circuit 111. And cut off the power supply. (Step 4: S4) The second abnormality detection circuit 204 determines that the first inverter circuit 102 is not being driven based on the current value of the shunt resistor 81. (Step 5: S5) The CPU 2 notifies the device control unit 80 of the determined abnormal state via the second communication unit 92. (Step 6: S6) The device control unit 80 outputs a command to the CPU 2 to supplement the output of the first motor control unit 100. According to this embodiment, since it is possible to directly monitor the output abnormality of another system, it is possible to detect the abnormality without a time lag and shift to the control after the failure. In this embodiment, the second abnormality detection circuit 204 monitors only the output of the first inverter circuit 102. Therefore, it is possible to detect an abnormality leading to an output abnormality of another system and save the number of AD ports.

Further, in the present embodiment, consider a case where the first inverter 102 cannot be driven due to an abnormality such as a voltage. In this case, step 1, step 2 and step 3 are omitted regardless of the above example. (Step 4: S4) The second abnormality detection circuit 204 determines that the first inverter circuit 102 is not being driven based on the signal of the shunt resistor 81. (Step 5: S5) The CPU 2 notifies the device control unit 80 of the determined abnormal state via the second communication unit 92. (Step 6: S6) The device control unit 80 outputs a command to the CPU 2 to supplement the output of the first motor control unit 100.

In the present embodiment, in step 3, the first motor control unit 100 controls the switching of the first power supply relay circuit 111, but the second motor control unit 200 may control the switching, and the device The control unit 80 may control the switching. In the above example, the case where an overcurrent occurs in an arbitrary phase is considered, but a communication abnormality of the communication unit is also considered. In this case, the other normal motor control unit may determine the operating state of one inverter circuit based on the detected values of the shunt resistors 81 and 82. That is, in step 1, the second abnormality detection circuit 204 may specify the phase through which the abnormal current flows based on the current value of the shunt resistor 81. After that, the normal CPU may control one power supply relay circuit, or the device control unit 80 may control one power supply relay circuit. According to this configuration, when a communication abnormality occurs in one of the CP∪, even if any phase of the coil winding is lost, the transition after the failure can be made quickly.

The first inverter circuit 102 and the second inverter circuit 202 may include three motor relays that control the power supply to each phase of the coil winding. Each motor relay is connected between the high-side switching element corresponding to each phase and each phase of the coil winding. Each of the motor relays makes it possible to stop the power supply only for a specific phase when an abnormality occurs in one phase. Therefore, even if one phase fails, it is possible to prevent the output of the motor 30 from being significantly reduced. In this embodiment, in step 1, after identifying the phase in which the abnormal current flows, the motor control unit controls the switching of the motor relay and stops the power supply to the phase in which the abnormal current flows.

Each of the first motor control unit 100 and the second motor control unit 200 further includes an insulating element. The first motor control unit 100 includes a first insulating element 51. The second motor control unit 200 includes a second insulating element 52. The first insulating element 51 is connected between the first abnormality detection circuit 104 and the shunt resistor 81 of the second inverter circuit 202. Further, the second insulating element 52 is connected between the second abnormality detection circuit 204 and the shunt resistor 82 of the first inverter circuit 102. According to this configuration, for example, when a steep surge current flows through the first motor control unit 100, the surge current also flows through the second abnormality detection circuit 204 to the second motor control unit 200 or the CPU 2, and the motor control system 30 It is possible to prevent the whole from becoming dysfunctional. Further, when the second motor control unit 200 does not share the GND with the first motor control unit 100, the GND of the second abnormality detection circuit 204 and the first motor control unit 100 and the GND are different. Therefore, since the GND of the second abnormality detection circuit 204 is shared with the first motor control unit 100 via the second insulating element 52, the measurement accuracy of the current value of the shunt resistor can be improved.

The electric power steering device 20 is configured to include the device control unit 80, but the present invention is not limited to this. The device control unit 80 may be a control device that controls other parts in a vehicle or the like.

In this embodiment, the first motor control unit 100 and the second motor control unit 200 may be configured in one circuit board or in another circuit board. Further, the first power supply circuit 101 and the second power supply circuit 201 may be provided outside the motor 7 with a configuration different from that of the first motor control unit 100 and the second motor control unit 200.

In the present embodiment, the abnormality detection circuit uses a shunt resistor to detect an abnormality, but the present invention is not limited to this. For example, the anomaly detection circuit may monitor the current value or the voltage value using an A / D converter. Further, the abnormality detection circuit may monitor the state of the output port of the CPU. More specifically, the first motor control unit 100 includes a pre-driver PrDr1 for driving the switching element. Further, the second motor control unit 200 includes a pre-driver PrDr2 for driving the switching element. The CPU 1 outputs a control signal such as a PWM signal to the pre-driver PrDr1 or the first inverter circuit 102. Here, the second abnormality detection circuit 204 may determine whether or not there is an abnormality by monitoring a control signal such as a PWM signal output by the CPU 1. According to this configuration, the second abnormality detection circuit 204 can monitor the digital signal, so that even if the first motor control unit and the second motor control unit do not share the GND, the accuracy is high. Can be detected. Similarly, the first abnormality detection circuit 104 may monitor the control signal output by the CPU 2 to the pre-driver PrDr2 or the second inverter circuit 202. The above configurations can be appropriately combined within a range that does not contradict each other.

10 ... Electric power steering system 20 ... Electric power steering device 30 ... Motor control system 7 ... Motor 70 ... Stator 71 ... First coil winding 72 ... Second coil winding 100 ... 1st motor control unit 101 ... 1st power supply circuit 102 ... 1st inverter circuit 111 ... 1st power supply relay circuit 200 ... 2nd motor control unit 201 ... 2nd power supply circuit 202 ... 2nd inverter circuit 211 ... 2nd power relay circuit

Claims (12)

A motor control system that supplies power to a motor including a rotor, a stator having two independent sets of coil windings, and a rotation angle sensor that acquires rotation angle information of the rotor, and generates a constant voltage. The power supply circuit, the inverter circuit for driving the coil winding of the motor, the power supply relay circuit that cuts off the power supply to the inverter circuit, and the control amount calculated based on the information from the sensor, and the inverter circuit A first motor control unit and a second motor control unit each include a CPU that outputs a control signal to the coil, and the first motor control unit is one of the two independent coil windings. Power is supplied to the first coil winding which is a wire set, and the second motor control unit supplies power to the second coil winding which is the other winding set in the two independent coil windings. The first motor control unit has a first abnormality detection circuit that detects an abnormality in the second motor control unit, and the second motor control unit detects an abnormality in the first motor control unit. It has an abnormality detection circuit. The motor control system according to claim 1, wherein the first abnormality detection circuit detects an abnormality in the second coil winding, and the second abnormality detection circuit detects an abnormality in the first coil winding. To detect. The motor control system according to claim 1 or 2, wherein the first inverter circuit which is the inverter circuit in the first motor control unit and the second inverter circuit which is the inverter circuit in the second motor control unit. Each of the above is provided with a bridge circuit composed of three legs including a high-side switching element and a low-side switching element, and each of the first inverter circuit and the second inverter circuit has three shunt resistors, and the first abnormality is described above. The detection circuit detects the signal of the shunt resistance of the second inverter, and the second abnormality detection circuit detects the signal of the shunt resistance of the first inverter. The motor control system according to any one of claims 1 to 3, wherein each of the first motor control unit and the second motor control unit further includes a communication unit, and the communication unit is an apparatus. The abnormality judgment result is output to the control unit. The motor control system according to any one of claims 1 to 4, wherein the first abnormality detection circuit detects an abnormality in the first coil winding, and the first motor control unit determines the abnormality. The switching of the first power supply relay circuit is controlled, the second abnormality detection circuit detects an abnormality of the second coil winding, and the second motor control unit controls the switching of the second power supply relay circuit. do. The motor control system according to any one of claims 1 to 5, wherein the first motor control unit controls switching of the second power supply relay circuit, and the second motor control unit controls switching of the second power supply relay circuit. It controls the switching of the first power supply relay circuit. The motor control system according to any one of claims 1 to 6, wherein each of the first motor control unit and the second motor control unit further includes an insulating element, and the insulating element includes an insulating element. It is connected between the first abnormality detection circuit or the second abnormality detection circuit and the shunt resistor. The motor control system according to any one of claims 1 to 7, wherein each of the first inverter circuit and the second inverter circuit includes three motor relays of the three motor relays. Each is connected between the high-side switching element corresponding to each phase and each phase of the coil winding, and the power supply to each phase of the coil winding is stopped. From the motor control system according to any one of claims 1 to 8, a rotor that rotates about a central axis, a rotation angle sensor that acquires rotation angle information of the rotor, and the motor control system. It includes a stator that receives power supply. The electric power steering device includes a device control unit that manages an operating state of the electric power steering device, the motor according to claim 9, and a torque sensor. The electric power steering device according to claim 10, wherein the device control unit controls switching between the first power supply relay circuit and the second power supply relay circuit. The electric power steering device according to claim 10 or 11, when the device control unit is notified that either the first motor control unit or the second motor control unit is abnormal. A command for improving the output is output to the normal first motor control unit or the second motor control unit.

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