Drive control device of electric motor

Abstract

To provide a drive control device of electric motor suppressing reduction of an output torque of an electric motor even if a fault occurs in one drive system of a plurality of drive systems.SOLUTION: A drive control device of electric motor according to the present invention, in one embodiment, has a first drive system including a first drive circuit supplying power to a first winding set of an electric motor, a second drive system including a second drive circuit supplying power to a second winding set of the electric motor, a bypass circuit connecting between the first drive circuit and the first winding set, and between the second drive circuit and the second winding set, and a relay provided to the bypass circuit. When the first drive system is normal and the second drive system is abnormal, the operation of the second drive circuit is stopped and the relay is turned on, and power is supplied to the second winding set from the first drive circuit through the bypass circuit.SELECTED DRAWING: Figure 2

Description

Technical Field

[0001] The present invention relates to a drive control device for an electric motor.

Background Art

[0002] The motor control device disclosed in Patent Document 1 includes a main motor drive circuit that drives and controls a polyphase electric motor, a backup motor drive circuit that drives and controls the polyphase electric motor when an abnormality occurs in the main motor drive circuit, and an abnormality diagnosis unit that diagnoses abnormalities in the main motor drive circuit and the backup motor drive circuit. The normal drive state in which the polyphase electric motor is driven only by the main motor drive circuit, and when the diagnosis result by the abnormality diagnosis unit of the main motor drive circuit is abnormal in the normal drive state, the motor current of the abnormal phase output unit is cut off, and the cut-off phase output unit is switched to the phase output unit of the backup motor drive circuit of the same phase to drive the polyphase electric motor, and a backup drive state.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] By the way, in a drive control device for an electric motor having a first winding set and a second winding set, a first drive system including a first drive circuit that supplies power to the first winding set, and a second drive system including a second drive circuit that supplies power to the second winding set. When a failure occurs in either the first drive system or the second drive system, if the drive control by the failed system is stopped, although the output of the electric motor is continued, the output torque of the electric motor will decrease. Here, when the electric motor is, for example, an electric motor that generates a steering force or a steering assist force in a vehicle's steering device, there is a problem that the steering performance deteriorates due to a decrease in the output torque of the electric motor.

[0005] The present invention has been made in view of the conventional situation, and its object is to provide a drive control device for an electric motor that can suppress a decrease in the output torque of the electric motor even when a failure occurs in one of a plurality of drive systems.

Means for Solving the Problems

[0006] The drive control device for an electric motor according to the present invention, in one aspect, is a drive control device for an electric motor having a first winding set and a second winding set, including a first drive system including a first drive circuit that supplies power to the first winding set, a second drive system including a second drive circuit that supplies power to the second winding set, a bypass circuit that connects between the first drive circuit and the first winding set and between the second drive circuit and the second winding set, and a relay provided in the bypass circuit. When the first drive system and the second drive system are normal, the relay is turned off. When the first drive system is normal and the second drive system is abnormal, the operation of the second drive circuit is stopped and the relay is turned on, and power is configured to be supplied from the first drive circuit to the second winding set through the bypass circuit.

[0007] Further, the drive control device for an electric motor according to the present invention, in one aspect, is a drive control device for an electric motor having a first winding set and a second winding set, including a first drive system including a first drive circuit that supplies power to the first winding set, a second drive system including a second drive circuit that supplies power to the second winding set, a bypass circuit that connects between the first drive circuit and the first winding set and between the second drive circuit and the second winding set, a relay provided in the bypass circuit, a diagnostic unit that detects abnormalities in the first drive system and the second drive system, and a relay control unit that turns on the relay when an abnormality in the first drive system or the second drive system is detected.

Advantages of the Invention

[0008] According to the present invention, even if a failure occurs in one of the plurality of drive systems, a decrease in the output torque of the electric motor can be suppressed.

Brief Description of the Drawings

[0009]

Figure 1

Figure 2

Figure 3

Embodiments for Carrying Out the Invention

[0010] Hereinafter, an embodiment of a drive control device for an electric motor according to the present invention will be described with reference to the drawings. FIG. 1 is a configuration diagram showing an aspect of an electric power steering apparatus for a vehicle as an application example of a drive control device for an electric motor according to the present invention.

[0011] The electric power steering apparatus 200 is mounted on a vehicle 100 which is a four-wheel automobile. The electric power steering apparatus 200 includes a steering mechanism 210 that steers the front wheels 110, 110 which are the steered wheels of the vehicle 100, and a motor unit 220 that applies a steering force to the steering mechanism 210. Note that the electric power steering apparatus 200 performs the application of the steering force by the motor unit 220 to assist the steering operation by the driver of the vehicle 100 or for autonomous steering.

[0012] The motor unit 220 includes an electric motor 230 and a drive control device 240 that controls the electric motor 230. The electric motor 230 is, for example, a three-phase synchronous motor and has two winding sets, a first winding set and a second winding set, which are composed of a U-phase coil, a V-phase coil, and a W-phase coil.

[0013] The drive control device 240 includes a first drive system (System 1) that controls the power supply to the first winding set of the electric motor 230, and a second drive system (System 2) that controls the power supply to the second winding set of the electric motor 230. That is, in the drive control device 240, the drive systems are redundant. During normal operation, each drive system outputs an output equivalent to 50% of the required torque of the electric motor 230, so that the electric motor 230 outputs the required torque.

[0014] The steering mechanism 210 includes a steering wheel 201, a steering shaft 202, a pinion shaft 203, a rack shaft 204, and an operation torque sensor 206 that detects the operation torque of the steering wheel 201. In addition, the torque generated by the electric motor 230 is transmitted to the rack shaft 204 via the speed reduction mechanism 205.

[0015] When the driver of the vehicle 100 rotates the steering wheel 201, the steering mechanism 210 transmits the operation torque to the pinion shaft 203 via the steering shaft 202. Then, the steering mechanism 210 converts the rotational motion of the pinion shaft 203 into a linear motion of the rack shaft 204, and steers the front wheels 110, 110 connected to both ends of the rack shaft 204.

[0016] When the drive control device 240 performs assistance for the steering operation by the driver, based on a signal related to the operation torque acquired from the operation torque sensor 206, a signal related to the vehicle speed acquired from the vehicle speed sensor 207, etc., it calculates an assist torque command value that is the target value of motor control. Then, the drive control device 240 controls the power supply to the electric motor 230 by performing PWM (Pulse Width Modulation) control on the inverter circuit based on the calculated assist torque command value.

[0017] FIG. 2 is a circuit diagram showing the winding sets of the electric motor 230 and the first drive system and the second drive system of the drive control device 240. The electric motor 230 has a first winding set 230A and a second winding set 230B. The first winding set 230A consists of a U-phase coil UA, a V-phase coil VA, and a W-phase coil WA, and the second winding set 230B consists of a U-phase coil UA, a V-phase coil VA, and a W-phase coil WA.

[0018] The first drive system 240A (system 1) that controls the power supply to the first winding set 230A includes a first MPU (Microprocessor Unit) 241A, a first gate drive circuit 242A, and a first inverter circuit 243A. Similarly, the second drive system 240B (system 2) that controls the power supply to the second winding set 230B includes a second MPU (Microprocessor Unit) 241B, a second gate drive circuit 242B, and a second inverter circuit 243B. Here, the first MPU 241A and the second MPU 241B can communicate with each other through inter-microcomputer communication (hereinafter abbreviated as inter-microcontroller communication).

[0019] The first inverter circuit 243A (first drive circuit) is a three-phase bridge circuit provided with three sets of semiconductor switching elements 51 - 56 for driving the coils UA, VA, WA of the first winding set 230A. Similarly, the second inverter circuit 243B (second drive circuit) is a three-phase bridge circuit provided with three sets of semiconductor switching elements 61 - 66 for driving the coils UB, VB, WB of the second winding set 230B. In this embodiment, N-channel MOSFETs are used as the semiconductor switching elements 51 - 56 and the semiconductor switching elements 61 - 66.

[0020] The first gate drive circuit 242A (first pre-driver IC) outputs gate signals for turning on and off the semiconductor switching elements 51 - 56 of the first inverter circuit 243A respectively according to the control command signals from the first MPU 241A. Further, the second gate drive circuit 242B (second pre-driver IC) outputs gate signals for turning on and off the semiconductor switching elements 61-66 of the second inverter circuit 243B in accordance with the control command signal from the second MPU 241B, respectively.

[0021] Also, phase relays 75-77 for turning on and off the current supply from the first inverter circuit 243A to the first winding set 230A are respectively provided on the drive lines 71-73 connecting the first inverter circuit 243A and the coils UA, VA, WA of the first winding set 230A. The phase relays 75-77 are turned on and off by the output of the first gate drive circuit 242A. When the first MPU 241A self-diagnoses an abnormality in the first drive system 240A, it stops the PWM control of the first inverter circuit 243A and outputs an off command for the phase relays 75-77 to the first gate drive circuit 242A to stop the power supply from the first drive system 240A to the first winding set 230A.

[0022] Similarly, phase relays 85-87 for turning on and off the current supply from the second inverter circuit 243B to the second winding set 230B are respectively provided on the drive lines 81-83 connecting the second inverter circuit 243B and the coils UB, VB, WB of the second winding set 230B. The phase relays 85-87 are turned on and off by the output of the second gate drive circuit 242B. When the second MPU 241B self-diagnoses an abnormality in the second drive system 240B, it stops the PWM control of the second inverter circuit 243B and outputs an off command for the phase relays 85-87 to the second gate drive circuit 242B to stop the power supply from the second drive system 240B to the second winding set 230B.

[0023] Here, the abnormalities of the first drive system 240A and the second drive system 240B are, for example, states in which a short or open fault has occurred in any of the semiconductor switching elements 51-56, 61-66 of the inverter circuits 243A, 243B. Also, as will be described later, when an abnormality occurs in either one of the two redundant drive systems 240A and 240B, the drive control device 240 has a function of supplying power to the first winding set 230A and the second winding set 230B from the normal drive system.

[0024] Hereinafter, the details of the above-described phase relays 75 - 77 and 85 - 87 will be described. The phase relay 75 is provided on the drive line 71 that connects between the semiconductor switching elements 51 and 52 of the first inverter circuit 243A and the coil UA of the first winding set 230A. Also, the phase relay 76 is provided on the drive line 72 that connects between the semiconductor switching elements 53 and 54 of the first inverter circuit 243A and the coil VA of the first winding set 230A. Furthermore, the phase relay 77 is provided on the drive line 73 that connects between the semiconductor switching elements 55 and 56 of the first inverter circuit 243A and the coil WA of the first winding set 230A.

[0025] Similarly, the phase relay 85 is provided on the drive line 81 that connects between the semiconductor switching elements 61 and 62 of the second inverter circuit 243B and the coil UB of the second winding set 230B. Also, the phase relay 86 is provided on the drive line 82 that connects between the semiconductor switching elements 63 and 64 of the second inverter circuit 243B and the coil VB of the second winding set 230B. Furthermore, the phase relay 87 is provided on the drive line 83 that connects between the semiconductor switching elements 65 and 66 of the second inverter circuit 243B and the coil WB of the second winding set 230B.

[0026] The phase relays 75 - 77 and 85 - 87 are each formed by connecting a first N-channel MOSFET (first semiconductor switching element) and a second N-channel MOSFET (second semiconductor switching element) in series. Furthermore, the source of the first N-channel MOSFET and the source of the second N-channel MOSFET are connected such that the direction in which the parasitic diode of the first N-channel MOSFET conducts current is opposite to the direction in which the parasitic diode of the second N-channel MOSFET conducts current.

[0027] Then, the second MPU 241B monitors the voltage between the first N-channel MOSFET and the second N-channel MOSFET of each of the phase relays 75 - 77. Similarly, the first MPU 241A monitors the voltage between the first N-channel MOSFET and the second N-channel MOSFET of each of the phase relays 85 - 87. Here, the first MPU 241A diagnoses an abnormality in the second drive system 240B based on voltage monitoring at the phase relays 85 - 87, and the second MPU 241B diagnoses an abnormality in the first drive system 240A based on voltage monitoring at the phase relays 75 - 77.

[0028] That is, the first MPU 241A functions as a first diagnostic unit that diagnoses the presence or absence of an abnormality in the second drive system 240B by monitoring the voltage between the first N-channel MOSFET and the second N-channel MOSFET of each of the phase relays 85 - 87. Also, the second MPU 241B functions as a second diagnostic unit that diagnoses the presence or absence of an abnormality in the first drive system 240A by monitoring the voltage between the first N-channel MOSFET and the second N-channel MOSFET of each of the phase relays 75 - 77.

[0029] In addition, when an abnormality occurs in either one of the two redundant drive systems 240A and 240B, a U-phase bypass circuit 90U, a V-phase bypass circuit 90V, and a W-phase bypass circuit 90W are provided for supplying power from the normal drive system to the first winding set 230A and the second winding set 230B. The U-phase bypass circuit 90U, the V-phase bypass circuit 90V, and the W-phase bypass circuit 90W are circuits that connect between the first inverter circuit 243A and the first winding set 230A and between the second inverter circuit 243B and the second winding set 230B.

[0030] Specifically, the U-phase bypass circuit 90U connects the drive line 71 between the phase relay 75 and the coil UA of the first winding set 230A, and the drive line 81 between the phase relay 85 and the coil UB of the second winding set 230B. Also, the V-phase bypass circuit 90V connects the drive line 72 between the phase relay 76 and the coil VA of the first winding set 230A, and the drive line 82 between the phase relay 86 and the coil VB of the second winding set 230B. Furthermore, the W-phase bypass circuit 90W connects the drive line 73 between the phase relay 77 and the coil WA of the first winding set 230A, and the drive line 83 between the phase relay 87 and the coil WB of the second winding set 230B.

[0031] And each of the U-phase bypass circuit 90U, the V-phase bypass circuit 90V, and the W-phase bypass circuit 90W is provided with bypass relays 91U, 91V, and 91W for turning on and off the current supply through the bypass circuits 90U, 90V, and 90W. The bypass relays 91U, 91V, and 91W are formed by connecting a first N-channel MOSFET and a second N-channel MOSFET in series. Furthermore, the drain of the first N-channel MOSFET and the drain of the second N-channel MOSFET are connected so that the direction in which the parasitic diode of the first N-channel MOSFET conducts current is opposite to the direction in which the parasitic diode of the second N-channel MOSFET conducts current.

[0032] And each N-channel MOSFET constituting the bypass relays 91U, 91V, and 91W is configured to turn on when an on control signal is output from at least one of the first gate drive circuit 242A and the second gate drive circuit 242B. In the present application, the on state and off state of the phase relays 75 - 77, 85 - 87 and the bypass relays 91U, 91V, 91W refer to the state where a pair of N-channel MOSFETs (semiconductor switching elements) constituting the relay are both on or both off.

[0033] And the drive control device 240 includes a diagnostic unit that diagnoses abnormalities in the first drive system 240A and the second drive system 240B, and a relay control unit that turns on the bypass relays 91U, 91V, and 91W when an abnormality is detected in the first drive system 240A or the second drive system 240B. That is, when the first drive system 240A and the second drive system 240B are normal, the drive control device 240 turns off the bypass relays 91U, 91V, and 91W, supplies power from the first drive system 240A to the first winding set 230A, and supplies power from the second drive system 240B to the second winding set 230B.

[0034] On the other hand, for example, when the first drive system 240A is normal and the second drive system 240B is abnormal, the drive control device 240 turns off the phase relays 85 - 87 while turning on the bypass relays 91U, 91V, and 91W, so that power is supplied from the first inverter circuit 243A to the second winding set 230B via the bypass circuits 90U, 90V, and 90W. Thereby, even if an abnormality occurs in the second drive system 240B that prevents normal power supply to the second winding set 230B, the power supply to the second winding set 230B is continued, and a decrease in the output torque of the electric motor 230 is suppressed.

[0035] Hereinafter, the functions of the diagnostic unit and the relay control unit included in the drive control device 240 will be described in detail. The first MPU 241A of the first drive system 240A has the function of a first diagnostic unit that diagnoses the presence or absence of an abnormality in the second drive system 240B by monitoring the voltage between the first N-channel MOSFET and the second N-channel MOSFET of each of the phase relays 85 - 87, and the function of a first relay control unit that turns on the bypass relays 91U, 91V, and 91W based on the diagnostic result by the first diagnostic unit.

[0036] Similarly, the second MPU 241B of the second drive system 240B has the function of a second diagnosis unit that diagnoses the presence or absence of an abnormality in the first drive system 240A by monitoring the voltage between the first N-channel MOSFET and the second N-channel MOSFET of each of the phase relays 75-77, and the function of a second relay control unit that turns on the bypass relays 91U, 91V, and 91W based on the diagnosis result by the second diagnosis unit.

[0037] Thus, the diagnosis unit included in the drive control device 240 has a first diagnosis unit included in the first drive system 240A and a second diagnosis unit included in the second drive system 240B. Also, the relay control unit included in the drive control device 240 has a first relay control unit included in the first drive system 240A and a second relay control unit included in the second drive system 240B.

[0038] FIG. 3 is a flowchart showing the control processes of the first diagnosis unit and the first relay control unit of the first MPU 241A, and the second diagnosis unit and the second relay control unit of the second MPU 241B. In the following, for the sake of simplicity of explanation, each step of the flowchart of FIG. 3 will be described as the functions of the first diagnosis unit and the first relay control unit of the first MPU 241A. However, the second MPU 241B also performs the control process shown in the flowchart of FIG. 3 to achieve the functions of the second diagnosis unit and the second relay control unit.

[0039] When the first MPU 241A is activated by power-on, in step S301, it starts monitoring for abnormalities in the second drive system 240B. Next, in step S302, the first MPU 241A performs inter-microcontroller communication with the second MPU 241B. Then, in step S303, the first MPU 241A determines whether the inter-microcontroller communication with the second MPU 241B is normal.

[0040] Here, if the inter-microcontroller communication with the second MPU 241B is normal, the first MPU 241A proceeds to step S304 and monitors the voltage between the first N-channel MOSFET and the second N-channel MOSFET of each of the phase relays 85 - 87. Then, in the next step S305 (first diagnostic unit), the first MPU 241A compares the detected value of the voltage between the first N-channel MOSFET and the second N-channel MOSFET of each of the phase relays 85 - 87 with a preset threshold value based on the voltage when the second drive system 240B is normally supplying power to the second winding set 230B, and determines whether an abnormality has occurred in the second drive system 240B.

[0041] If the first MPU 241A determines that the result of the voltage monitoring is normal and the second drive system 240B is operating normally, after determining in step S306 that there is no system abnormality in the second drive system 240B, it returns to step S301. On the other hand, if the first MPU 241A determines that the result of the voltage monitoring is abnormal and an abnormality has occurred in the second drive system 240B, it proceeds to step S307 and transmits a signal indicating that an abnormality has been detected in the second drive system 240B to the second MPU 241B via inter-microcontroller communication.

[0042] After notifying the second MPU 241B of the abnormality detection in step S307, the first MPU 241A proceeds to step S311 and determines whether a system abnormality has occurred in the second drive system 240B. Here, the first MPU 241A proceeds from step S311 to step S312 (first relay control unit) and controls the bypass relays 91U, 91V, 91W to be turned on to supply power from the first inverter circuit 243A to the second winding set 230B via the bypass circuits 90U, 90V, 90W.

[0043] That is, even if a system abnormality occurs in the second drive system 240B, the power supply to the first winding set 230A and the second winding set 230B is continued, and a decrease in the output torque (assist torque) of the electric motor 230 is suppressed. In addition, when a system abnormality occurs in the second drive system 240B, the first MPU 241A supplies power from the first inverter circuit 243A to the first winding set 230A and the second winding set 230B by performing PWM control on the first inverter circuit 243A according to parameters calibrated in advance.

[0044] Furthermore, the first MPU 241A proceeds from step S312 to step S314, activates a warning device provided in the driver's seat or the like of the vehicle 100, and warns the driver of the occurrence of an abnormality in the electric power steering device 200. Even if a system abnormality occurs in the second drive system 240B, the power supply to the first winding set 230A and the second winding set 230B continues. However, since it is in a fail-safe state where an abnormality has occurred in one of the redundant drive systems, the driver is warned to prompt maintenance of the electric power steering device 200. Note that the warning device is a warning lamp, a liquid crystal device, a warning buzzer, a voice guidance device, or the like.

[0045] On the other hand, in step S303, when the first MPU 241A determines that the inter-microcomputer communication with the second MPU 241B is abnormal, it proceeds to step S308 to determine the occurrence of a communication abnormality between the MPUs. Next, the first MPU 241A proceeds to step S309 and, similar to step S304, monitors the voltage between the first N-channel MOSFET and the second N-channel MOSFET of each of the phase relays 85 - 87.

[0046] Then, in step S310 (first diagnostic unit), the first MPU 241A determines whether an abnormality has occurred in the voltage in the phase relays 85 - 87. Here, when the first MPU 241A determines that there is an abnormality in the voltage in the phase relays 85 - 87, after determining the occurrence of a system abnormality in the second drive system 240B in step S311, it proceeds to step S312 (the first relay control unit), controls the bypass relays 91U, 91V, 91W to be turned on, and supplies power from the first inverter circuit 243A to the second winding set 230B via the bypass circuits 90U, 90V, 90W as well.

[0047] Also, when the first MPU 241A determines in step S310 that the voltage in the phase relays 85 - 87 is normal, it proceeds to step S313. In step S313, the first MPU 241A determines that although there is no abnormality in the power supply from the second drive system 240B to the second winding set 230B, there is an abnormality in the microcomputer - to - microcomputer communication with the second MPU 241B. Then, the first MPU 241A proceeds to step S314 and activates a warning device that warns of the occurrence of an abnormality in the electric power steering device 200 based on the determination result of the communication abnormality.

[0048] Each of the technical ideas described in the above - mentioned embodiments can be used in appropriate combination as long as there is no contradiction. In addition, although the content of the present invention has been specifically described with reference to the preferred embodiments, it is obvious that those skilled in the art can adopt various modified forms based on the basic technical idea and teachings of the present invention.

[0049] It is obvious that the drive control device for an electric motor according to the present invention can be applied not only to the vehicle - use electric power steering device 200. For example, in a steer - by - wire type steering device in which the steering wheel and the steered wheels are mechanically separated and the steering motor is controlled based on the signal of the operation angle of the steering wheel, the drive control device for an electric motor according to the present invention can be applied with the steering motor as the control target.

[0050] Also, when an abnormality occurs in one of the two drive systems 240A and 240B and power is supplied to the first winding set 230A and the second winding set 230B by the normal drive system, the output torque of the electric motor 230 is not limited to being maintained at the same level as when both drive systems 240A and 240B are normal, and a configuration can be adopted that generates an output torque exceeding 50%. Also, in a system where the electric motor 230 has three or more winding sets and the drive control device 240 has the same number of drive systems as the number of winding sets, a system can be adopted in which, instead of the drive system in which an abnormality has occurred, the normal drive system supplies power to the winding set via a bypass circuit.

Explanation of Signs

[0051] 100…Vehicle, 200…Electric power steering device, 230…Electric motor, 230A…First winding set, 230B…Second winding set, 240…Drive control device, 240A…First drive system, 240B…Second drive system, 90U…U-phase bypass circuit, 90V…V-phase bypass circuit, 90W…W-phase bypass circuit, 91U, 91V, 91W…Bypass relay

Claims

1. A drive control device for an electric motor having a first winding set and a second winding set, comprising: a first drive system including a first drive circuit that supplies power to the first winding set; a second drive system including a second drive circuit that supplies power to the second winding set; a bypass circuit that connects between the first drive circuit and the first winding set and between the second drive circuit and the second winding set; a relay provided in the bypass circuit; and when the first drive system and the second drive system are normal, the relay is turned off; when the first drive system is normal and the second drive system is abnormal, the operation of the second drive circuit is stopped and the relay is turned on, and power is supplied from the first drive circuit to the second winding set through the bypass circuit. A drive control device for an electric motor.

2. A drive control device for an electric motor having a first winding set and a second winding set, comprising: a first drive system including a first drive circuit that supplies power to the first winding set; a second drive system including a second drive circuit that supplies power to the second winding set; a bypass circuit that connects between the first drive circuit and the first winding set and between the second drive circuit and the second winding set; a relay provided in the bypass circuit; a diagnosis unit that detects abnormalities in the first drive system and the second drive system; and a relay control unit that turns on the relay when an abnormality in the first drive system or the second drive system is detected. A drive control device for an electric motor.

3. The drive control device for an electric motor according to claim 2, wherein the diagnosis unit includes a first diagnosis unit included in the first drive system and a second diagnosis unit included in the second drive system, the first diagnosis unit monitors the voltage between the second drive circuit and the second winding set to detect an abnormality in the second drive system, and the second diagnosis unit monitors the voltage between the first drive circuit and the first winding set to detect an abnormality in the first drive system. A drive control device for an electric motor.

4. The drive control device for an electric motor according to claim 3, wherein a phase relay formed by connecting a first semiconductor switching element and a second semiconductor switching element in series is provided between the first drive circuit and the first winding set and between the second drive circuit and the second winding set, and the first diagnosis unit and the second diagnosis unit monitor the voltage between the first semiconductor switching element and the second semiconductor switching element. Drive control device for an electric motor. **Claim 5** The drive control device for an electric motor according to claim 3, wherein the first diagnostic unit transmits a signal indicating that an abnormality in the second drive system has been detected to the second drive system, and the second diagnostic unit transmits a signal indicating that an abnormality in the first drive system has been detected to the first drive system. Drive control device for an electric motor. **Claim 6** The drive control device for an electric motor according to claim 5, wherein the relay control unit includes a first relay control unit provided in the first drive system and a second relay control unit provided in the second drive system, the first relay control unit turns on the relay when the first diagnostic unit detects an abnormality in the second drive system, and the second relay control unit turns on the relay when the second diagnostic unit detects an abnormality in the first drive system. Drive control device for an electric motor.

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