JP2014117064A - Motor controller - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a motor controller capable of reducing an electric power consumption while ensuring suitable motor operation.SOLUTION: A motor controller 27 includes: a driving circuit 40 for supplying a three-phase AC voltage to a motor 21; a micro computer 41 for controlling the drive of the motor 21 through the driving circuit 40; and a pre-driver circuit 48 for amplifying a PWM drive signal output from the micro computer 41. Furthermore, the motor controller 27 includes a motor rotational angle sensor dedicated input/output signal generating circuit 43 for outputting an excitation signal of a motor rotational angle sensor 22 and receiving an output signal of the motor rotational angle sensor 22 as an input signal. Here, a relay 46 is provided so that it switches on and off the supply of electric power to the motor rotational angle sensor dedicated input/output signal generating circuit 43. Then, if it is not necessary to drive the motor 21, the micro computer 41 allows the relay 46 to switch off the electric power supply to the motor rotational angle sensor dedicated input/output signal generating circuit 43.

Description

  The present invention relates to a motor control device that controls driving of a motor.

  2. Description of the Related Art There is known an electric power steering device that assists a driver's steering operation by applying a motor assist torque to a vehicle steering mechanism. The electric power steering apparatus includes a torque sensor that detects a steering torque applied to a steering mechanism in accordance with a driver's steering operation, and a motor control apparatus that controls driving of the motor based on the detected steering torque of the torque sensor. Is provided.

  The motor control device includes a drive circuit that supplies a drive current to the motor, and a control unit (microcomputer) that controls the operation of the drive circuit. The microcomputer calculates a current command value that is a target value of the motor drive current based on the detected steering torque of the torque sensor.

  Then, in order to make the actual driving current value of the motor coincide with the current command value, a driving signal corresponding to the deviation is generated based on the value of the motor position sensor arranged at the rear of the motor, and the signal amplifying unit (pre- The driver signal amplifies the drive signal and converts it into a gate signal.

  By outputting this to the drive circuit, the drive of the motor is controlled. By such motor drive control, an assist torque corresponding to the steering torque is applied from the motor to the steering mechanism, and the driver's steering operation is assisted.

  A resolver has generally been applied to the motor rotation angle sensor of such a motor control device because of its robustness to the usage environment (see, for example, Patent Document 1).

JP 2000-55695 A

However, continuously supplying power to the motor rotation angle sensor input / output signal generation circuit, which is the input / output signal generation circuit of the motor rotation angle sensor (resolver), as in the motor control device described above, requires no power consumption. There is a concern that consumption will continue even in such cases.
The present invention has been made in view of such circumstances, and an object thereof is to provide a motor control device capable of reducing power consumption while ensuring proper operation of the motor.

  In order to solve the above-described problem, a motor control device according to claim 1 includes a control unit that controls driving of the motor by outputting a driving signal to a driving circuit that supplies driving power to the motor; Motor rotation angle detection means for detecting a rotation angle, motor rotation angle detection means input / output signal generation means for generating an input / output signal of the motor rotation angle detection means, and motor rotation angle detection means input / output signal generation means Switching means for switching between supply and interruption of electric power, and the motor is mounted on the vehicle, and the control means is configured to turn on the ignition switch of the vehicle, and then the control means It is determined that it is not necessary to drive the motor until drive control is started, and the input / output signal generation for the motor rotation angle detection means is performed by the switching means. To cut off power supply to the unit, and the gist.

  The motor rotation angle sensor input / output signal generation circuit is a part that controls the drive of the motor. Therefore, in the situation where it is not necessary to drive the motor, there is no problem even if the motor rotation angle sensor input / output signal generation circuit stops Absent. That is, the input / output signal generation circuit for the motor rotation angle sensor is required to operate at least while the motor is being driven. Using this, as in the above configuration, a switching unit that switches between power supply and interruption of the motor rotation angle sensor input / output signal generation circuit is provided, and after the driver turns on the ignition switch, the microcomputer Until the drive control starts, the power supply to the motor rotation angle sensor input / output signal generation circuit is cut off. Compared to the case where power is constantly supplied to the motor rotation angle sensor input / output signal generation circuit. Thus, power consumption at the time of engine start can be reduced.

  According to a second aspect of the present invention, in the motor control device according to the first aspect, after the ignition switch of the vehicle is turned on, the control means performs a normal operation of the motor drive system by an initial check. The gist is to determine that the drive control of the motor has been started by detecting the start of the in-vehicle engine that can be confirmed.

  When the motor controlled by the microcomputer is an in-vehicle motor, the normal operation of the motor drive system can be confirmed by the initial check after the vehicle ignition switch is turned on, and the start of the in-vehicle engine can be detected. Therefore, the drive control of the motor is often started. For this reason, according to the said structure, the microcomputer can judge easily whether the motor drive control was started.

  According to a third aspect of the present invention, in the motor control device according to the first or second aspect, the control means uses the motor as a drive source after the control means starts driving control of the motor. It is determined that there is no need to drive the motor when an abnormality occurs in the device to be operated or the ignition switch of the vehicle is turned off, and the switching means generates the input / output signal for the motor rotation angle detecting means. The gist is to cut off the power supply to the means.

  When the motor to be controlled by the microcomputer is an in-vehicle motor, when an abnormality occurs in the motor-driven device after the microcomputer starts motor drive control, or when the vehicle ignition switch is turned off. There is no need to drive the motor. Therefore, according to the above configuration, when the microcomputer does not need to drive the motor after starting the motor drive control, the power supply to the input / output signal generation circuit for the motor rotation angle sensor is cut off. Therefore, power consumption can be reduced.

  According to a fourth aspect of the present invention, in the motor control device according to any one of the first to third aspects, the motor is provided in an electric power steering device of a vehicle and applies an assist torque to a steering mechanism of the vehicle. A steering torque detecting means for detecting a steering torque, a steering angular speed calculating means for calculating a steering angular speed from a rotation angle of the motor detected from the motor rotation angle detecting means, and the control means. Since the start of the drive control of the motor, the absolute value of the steering angular velocity calculated by the steering angular velocity calculating means is less than a predetermined steering angular velocity, and the absolute value of the steering torque detected by the steering torque detecting means is the steering If the torque is less than the predetermined value, it is determined that it is not necessary to drive the motor, and the input / output signal generation for the motor rotation angle detection means is performed by the switching means. To cut off power supply to the unit, and the gist.

  In the electric power steering device for a vehicle, when the absolute value of the steering angular velocity is less than the predetermined value of the steering angular velocity and the absolute value of the steering torque is less than the predetermined value of the steering torque, the driver is not operating the steering mechanism. It is considered that there is no need to apply assist torque to the steering shaft. That is, there is no need to drive the motor. Therefore, according to the above configuration, particularly in the electric power steering apparatus, the power supply to the input / output signal generation circuit for the motor rotation angle sensor is cut off, so that the power consumption can be reduced accurately.

According to a fifth aspect of the present invention, in the motor control device according to any one of the first to third aspects, the motor includes a first shaft on a steering wheel side and a steered wheel side in a steering shaft of a vehicle. Provided in a transmission ratio variable device that varies the transmission ratio between the second shaft and the rotation based on its own drive is added to the rotation of the first shaft and transmitted to the second shaft, The transmission ratio is variable,
The control means needs to drive the motor when the steering wheel is in a steering holding state or when the steering wheel is in a neutral position after the control means starts driving control of the motor. The gist of the present invention is that the power supply to the input / output signal generating means for the motor rotation angle detecting means is interrupted by the switching means.

  In the transmission ratio variable device provided in the steering shaft of the vehicle, it is considered that the steering shaft is not rotating when the steering wheel is in the steered state or when the steering wheel is in the neutral position. There is no need to drive the motor. Therefore, according to the above configuration, particularly in the transmission ratio variable device, power supply to the motor rotation angle sensor input / output signal generation circuit is interrupted, so that power consumption can be accurately reduced.

  According to the motor control device of the present invention, it is possible to reduce power consumption while ensuring proper operation of the motor.

The block diagram which shows typically the structure about the electric power steering apparatus (EPS) of a vehicle which is the application object of the motor control apparatus of this invention. The block diagram which shows the structure about one Embodiment of the motor control apparatus of this invention. The flowchart which shows the procedure of the process which switches supply of electric power to the input / output signal generation circuit for motor rotation angle sensors, and interruption | blocking by the motor control apparatus of embodiment.

Hereinafter, an embodiment of the present invention embodied in a column-type electric power steering apparatus (hereinafter referred to as EPS) will be described with reference to the drawings.
As shown in FIG. 1, in the EPS 1 of the present embodiment, a steering shaft 3 to which a steering 2 is fixed is connected to a rack shaft 5 via a rack and pinion mechanism 4. The rotation of the steering shaft 3 accompanying the steering operation is converted into a reciprocating linear motion of the rack shaft 5 by the rack and pinion mechanism 4. The steering shaft 3 of this embodiment is formed by connecting a column shaft 8, an intermediate shaft 9, and a pinion shaft 10. Then, the reciprocating linear motion of the rack shaft 5 accompanying the rotation of the steering shaft 3 is transmitted to a knuckle (not shown) via tie rods 11 connected to both ends of the rack shaft 5, so that the steering angle of the steered wheels 12 is increased. Has been changed.

  The EPS 1 controls the EPS actuator 24 (steering force assisting device) as a steering force assisting device that applies assisting force for assisting the steering operation to the steering system using the motor 21 as a driving source, and the operation of the EPS actuator 24. And a motor control device 27.

  The EPS actuator 24 of the present embodiment is a column type EPS actuator, and the motor 21 that is a drive source thereof is drivingly connected to the column shaft 8 via a speed reduction mechanism 23. The rotation of the motor 21 is decelerated by the speed reduction mechanism 23 and transmitted to the column shaft 8 so that the motor torque is applied to the steering system as an assist force.

  On the other hand, a vehicle speed sensor 25, a torque sensor 26 (steering torque detection means), and a motor rotation angle sensor 22 (motor rotation angle detection means) are connected to the motor control device 27. Based on the output signal of the sensor, the vehicle speed V, the steering torque Th, and the motor rotation angle θm are detected.

  The torque sensor 26 is a twin resolver type torque sensor. The motor control device 27 calculates the steering torque Th based on the output signals of a pair of resolvers provided at both ends of a torsion bar (not shown). Further, the motor control device 27 calculates a target assist force based on each detected state quantity, and supplies the drive power to the motor 21 that is the drive source to operate the EPS actuator 24, that is, to the steering system. The assist force to be applied is controlled.

Next, an electrical configuration in the EPS 1 of the present embodiment will be described.
FIG. 2 is a block diagram showing the configuration of one embodiment of the motor control device of the present invention. As shown in the figure, the motor control device 27 is output from the microcomputer 41 that controls the driving of the motor 21 and the microcomputer 41 via the driving circuit 40 that supplies a three-phase AC voltage to the motor 21 and the driving circuit 40. A pre-driver circuit 48 for amplifying the PWM drive signal. Further, the motor control device 27 outputs an excitation signal of the motor rotation angle sensor 22 and receives an output signal of the motor rotation angle sensor 22 as an input signal. The motor rotation angle sensor input / output signal generation circuit 43 (motor rotation). Corner detection means input / output signal generation means).

  The drive circuit 40 has a known configuration in which a plurality of MOSFETs are connected in a bridge shape. The drive circuit 40 is configured to turn on / off a plurality of MOSFETs based on a gate signal input from the microcomputer 41 via the pre-driver circuit 48, so that the DC voltage supplied via the relay 45 from the in-vehicle battery BT. Is converted into an AC voltage of three phases (U phase, V phase, W phase). The converted three-phase AC voltage is supplied as a motor drive voltage to the motor 21 via the feeder line W1, whereby the motor 21 is driven.

  The power supply line W1 is provided with a current sensor 49 that detects each phase current value I of the U phase, the V phase, and the W phase. The output of the current sensor 49 is taken into the microcomputer 41. The outputs of the torque sensor 26, the motor rotation angle sensor 22, and the vehicle speed sensor 25 are also taken into the microcomputer 41.

  Furthermore, the microcomputer 41 is connected to the engine control device 28 via an in-vehicle network CN such as CAN, and serial communication of various data can be performed between the microcomputer 41 and the engine control device 28. ing. For example, when the on-board engine (not shown) is started, the engine control device 28 notifies the microcomputer 41 of that fact (engine start notification). That is, the microcomputer 41 can know that the in-vehicle engine has been started by the engine start notification from the engine control device 28.

  The microcomputer 41 is based on the motor rotation angle θm, the vehicle speed V, the steering torque Th, and the phase current values I detected through the motor rotation angle sensor 22, the vehicle speed sensor 25, the torque sensor 26, and the current sensor 49, respectively. The drive of the motor 21 is controlled. Specifically, the microcomputer 41 sets a target value of the assist torque to be applied to the steering shaft 3 based on the steering torque Th and the vehicle speed V, and based on the value, the target value (current) of the drive current of the motor 21 is set. Command value).

  Further, the microcomputer 41 converts each phase current value I into a current value (actual current value) in the d / q coordinate system by using the motor rotation angle θm. And the microcomputer 41 calculates the voltage command value in a d / q coordinate system by performing the current feedback control based on those deviations so that an actual current value may follow a current command value. Further, the calculated voltage command value in the d / q coordinate system is converted into a voltage command value for each phase using the motor rotation angle θm, and this is subjected to PWM conversion to generate a PWM drive signal. The microcomputer 41 outputs the generated PWM drive signal to the pre-driver circuit 48.

  The pre-driver circuit 48 amplifies the PWM drive signal from the microcomputer 41, generates a gate signal, and applies it to the gate terminals of a plurality of MOSFETs provided in the drive circuit 40. As a result, the plurality of MOSFETs are turned on / off according to the PWM drive signal, whereby the drive circuit performs PWM drive, and the motor 21 performs an operation according to the current command value. By such drive control of the motor 21 by the microcomputer 41, assist torque is applied to the steering shaft 3, and assist control for assisting steering operation is executed.

  In addition, the motor control device 27 includes a power supply IC 42 that supplies power to the microcomputer 41. The power supply IC 42 for the microcomputer 41 is connected to the in-vehicle battery BT via a diode D1 and an ignition switch IGSW that is an engine start switch. The power supply IC 42 is connected via a diode D2 in the middle of the wiring connecting the relay 45 and the drive circuit 40. That is, when one of the ignition switch IGSW and the relay 45 is turned on, power is supplied from the in-vehicle battery BT to the microcomputer 41 via the power supply IC 42.

  The power source of the motor rotation angle sensor input / output signal generation circuit 43 is also connected to the in-vehicle battery BT through the same supply path as the power supply IC 42 for the microcomputer 41. However, a relay 46 is provided in the middle of the wiring connecting the diodes D 1 and D 2 and the motor rotation angle sensor input / output signal generation circuit 43. That is, power is supplied from the in-vehicle battery BT to the motor rotation angle sensor input / output signal generation circuit 43 on condition that either the ignition switch IGSW or the relay 45 is turned on and the relay 46 is turned on. Is done. In the present embodiment, the relay 46 serves as switching means for switching between supply and interruption of power to the motor rotation angle sensor input / output signal generation circuit 43.

  On the other hand, in the motor control device 27, switching of the relays 45 and 46 on / off is executed by the microcomputer 41. Next, a procedure in which the microcomputer 41 switches the relay 45 on / off will be described.

  First, when the ignition switch IGSW is turned on by the driver, electric power is supplied from the in-vehicle battery BT to the microcomputer 41 via the ignition switch IGSW, the diode D1, and the power supply IC 42, and the microcomputer 41 is activated. The activated microcomputer 41 confirms the normal operation of the entire electric power steering apparatus including electronic components mounted on itself such as a CPU and a memory, a vehicle speed sensor 25, a torque sensor 26, a current sensor 49, and a drive circuit 40. The so-called initial check is performed.

  Then, when it is confirmed through the initial check that the entire electric power steering apparatus is normal, the relay 45 is turned on. As a result, a DC voltage is supplied from the in-vehicle battery BT to the drive circuit 40, and the motor 21 can be driven. Thereafter, the microcomputer 41 starts motor drive control when detecting that the vehicle-mounted engine is started based on the engine start notification transmitted from the engine control device 28.

  Further, when the driver turns off the ignition switch IGSW, the power supply to the microcomputer 41 through the ignition switch IGSW is cut off, but the microcomputer 41 is in an operating state by the power supply through the relay 45. Can be maintained. At this time, when the microcomputer 41 detects an off operation of the ignition switch IGSW, the output of the motor rotation angle sensor 22, the vehicle speed sensor 25, the torque sensor 26, and the current sensor 49, and the engine state sequentially notified from the engine control device 28. Based on the above, it is determined whether a condition for stopping the motor drive control is satisfied. When the condition for stopping the motor drive control is satisfied, the relay 45 is turned off. As a result, the supply of drive current from the in-vehicle battery BT to the drive circuit 40 is interrupted, and the microcomputer 41 stops.

On the other hand, the microcomputer 41 switches on / off of power to the motor rotation angle sensor input / output signal generation circuit 43 by switching on / off of the relay 46 when the microcomputer 41 is in an operating state.
Next, this process will be described in detail.
First, the motor rotation angle sensor input / output signal generation circuit 43 generates an input signal (excitation signal) of the motor rotation angle sensor 22 based on the reference clock from the microcomputer 41 and inputs the input signal to the motor rotation angle sensor 22. The motor rotation angle sensor input / output signal generation circuit 43 receives the output signal output from the motor rotation angle sensor 22. The microcomputer 41 calculates the motor rotation angle θm based on the motor rotation angle sensor output signal.

  Then, the microcomputer 41 performs motor drive control based on the motor rotation angle θm obtained by calculation. In view of the object, the motor rotation angle sensor input / output signal generation circuit 43 is required to operate at least while the motor 21 is being driven. In other words, in a situation where it is not necessary to drive the motor 21, there is no problem even if the power supply to the motor rotation angle sensor input / output signal generation circuit 43 is cut off.

  Here, as a situation where it is not necessary to drive the motor 21, firstly, a period from when the ignition switch IGSW is turned on until the microcomputer 41 starts motor drive control can be considered. During this time, since the microcomputer 41 does not execute motor drive control, there is no need to drive the motor 21. Moreover, the following situations (a1) to (a3) can be considered as situations where the motor 21 does not need to be driven after the microcomputer 41 starts the motor drive control.

  (A1) When the absolute value of the steering angular velocity Vh calculated from the motor rotational angle θm detected by the motor rotational angle sensor 22 is less than the steering angular velocity predetermined value Vh1, and the absolute value of the detected steering torque Th of the torque sensor 26 is When the steering torque is less than the predetermined value Th1. In this case, since it is considered that the driver is not operating the steering wheel 2, it is not necessary to apply assist torque to the steering shaft 3. That is, there is no need to drive the motor 21. The steering angular velocity predetermined value Vh1 and the steering torque predetermined value Th1 are set to values that can determine whether or not the assist torque should be applied to the steering shaft 3.

  (A2) A case where an abnormality occurs in the electric power steering apparatus, such as any element that constitutes the electric power steering apparatus, or an abnormality occurs in the wiring system, and the operation must be stopped. In this case, there is no need to drive the motor 21.

  (A3) When the ignition switch IGSW is turned off. In this case, since it is not necessary to execute the assist control, there is no need to drive the motor 21.

  As described above (a1) to (a3), in a situation where it is not necessary to drive the motor 21, the microcomputer 41 turns off the relay 46, whereby the power to the motor rotation angle sensor input / output signal generation circuit 43 is supplied. In other situations, power is supplied to the motor rotation angle sensor input / output signal generation circuit 43 by turning on the relay 46.

  Next, with reference to FIG. 3, a process performed by the microcomputer 41 for switching power supply to the motor rotation angle sensor input / output signal generation circuit 43 and switching between interruptions will be described together with its operation. 3 is started when power is supplied to the microcomputer 41, that is, when the ignition switch IGSW is turned on, and is interrupted when the power supply to the microcomputer 41 is cut off. At the start of this process, the relay 46 is in an off state, that is, the power supply to the motor rotation angle sensor input / output signal generation circuit 43 is cut off.

  As shown in FIG. 3, the microcomputer 41 first determines whether or not the initial electric check has confirmed that the entire electric power steering apparatus is normal (step S101). (Step S101: YES), it is determined whether or not the in-vehicle engine is started (Step S102).

  If the microcomputer 41 detects the start of the vehicle-mounted engine based on the engine start notification from the engine control device 28 (step S102: YES), it starts motor drive control. During this time, that is, from when the ignition switch IGSW is turned on until the motor drive control is started, the relay 46 is kept off, and the power supply to the input / output signal generation circuit 43 for the motor rotation angle sensor is not supplied. Since it is cut off, it is possible to reduce power consumption when starting the engine.

  Next, after starting the motor drive control, the microcomputer 41 calculates the absolute value of the steering angular velocity Vh calculated from the detected motor rotational angle θm of the motor rotational angle sensor 22 to be equal to or greater than the steering angular velocity predetermined value Vh1, or Then, it is monitored whether or not the absolute value of the detected steering torque Th of the torque sensor 26 is equal to or greater than the steering torque predetermined value Th1 (step S103).

  Then, the absolute value of the steering angular velocity Vh calculated from the detected motor rotation angle θm of the motor rotation angle sensor 22 is equal to or greater than the steering angular velocity predetermined value Vh1, or the absolute value of the detected steering torque Th of the torque sensor 26 is When the steering torque is greater than or equal to the predetermined value Th1 (step S103: YES), the microcomputer 41 determines that the driver has performed the steering operation, and the motor 21 is driven.

  Next, the microcomputer 41 turns on the relay 46 under the condition that the electric power steering device is normal (step S104: YES) and the ignition switch IGSW is on (step S105: YES). Then, electric power is supplied to the motor rotation angle sensor input / output signal generation circuit 43 (step S106).

  On the other hand, when the driver does not perform the steering operation, the absolute value of the steering angular velocity Vh calculated from the detected motor rotational angle θm of the motor rotational angle sensor 22 is less than the steering angular velocity predetermined value Vh1 and detected by the torque sensor 26. If the absolute value of the steering torque Th is less than the steering torque predetermined value Th1 (step S103: NO), the microcomputer 41 turns off the relay 46 to supply power to the motor rotation angle sensor input / output signal generation circuit 43. Shut off (step S107).

  Further, when an abnormality occurs in the electric power steering device (step S104: NO), or when the ignition switch IGSW is turned off (step S105: NO), the microcomputer 41 turns off the relay 46, The power supply to the motor rotation angle sensor input / output signal generation circuit 43 is cut off (step S107). As a result, when the microcomputer 41 does not need to drive the motor 21 after starting the motor drive control, the power supply to the motor rotation angle sensor input / output signal generation circuit 43 is cut off. Therefore, power consumption can be reduced.

As described above, according to the motor control device 27 of the present embodiment, the following effects can be obtained.
(1) The motor control device 27 is provided with a relay 46 that cuts off the power supply to the input / output signal generation circuit 43 for the motor rotation angle sensor. When the microcomputer 41 does not need to drive the motor 21, the power supply to the motor rotation angle sensor input / output signal generation circuit 43 is cut off by the relay 46. Thereby, power consumption can be reduced compared with the case where electric power is always supplied to the motor rotation angle sensor input / output signal generation circuit 43 while ensuring proper operation of the motor 21 in the electric power steering apparatus. .

  (2) The microcomputer 41 determines that it is not necessary to drive the motor 21 from when the ignition switch IGSW is turned on until the drive control of the motor 21 is started, and the relay 46 is used for the motor rotation angle sensor. The power supply to the input / output signal generation circuit 43 is cut off. Thereby, the power consumption at the time of engine starting can be reduced.

  (3) The microcomputer 41 does not need to drive the motor 21 in the electric power steering device when any of the above conditions (a1) to (a3) is satisfied after the drive control of the motor 21 is started. Therefore, the relay 46 interrupts the power supply to the motor rotation angle sensor input / output signal generation circuit 43. Thus, when the microcomputer 41 does not need to drive the motor 21 after the drive control of the motor 21 is started, power supply to the motor rotation angle sensor input / output signal generation circuit 43 is cut off. Therefore, in particular, in the electric power steering apparatus, power consumption can be accurately reduced.

In addition, the said embodiment can also be implemented with the following forms which changed this suitably.
In the process illustrated in FIG. 3 of the above embodiment, all processes in steps S103 to S105 may be omitted. In this case, the microcomputer 41 detects the start of the vehicle-mounted engine in the process of step S102 (step S102: YES), and then turns on the relay 46 to supply power to the motor rotation angle sensor input / output signal generation circuit 43. (Step S106). Even in such a configuration, the power supply to the motor rotation angle sensor input / output signal generation circuit 43 is cut off after the ignition switch IGSW is turned on until the microcomputer 41 starts the motor drive control. , Power consumption can be reduced.

In the process illustrated in FIG. 3 of the above embodiment, either of the processes in steps S101 and S102 may be omitted. In this case, the microcomputer 41 executes steps S103 to S107 of the process shown in FIG. 3 at the start of the motor drive control. Even in such a configuration, the power supply to the motor rotation angle sensor input / output signal generation circuit 43 is cut off in a situation where it is not necessary to drive the motor 21 after the microcomputer 41 starts the drive control of the motor 21. Therefore, power consumption can be reduced.

In the above embodiment, the present invention is applied to the electric power steering device for a vehicle. For example, in the steering shaft 3 of the vehicle, between the first shaft on the steering 2 side and the second shaft on the steered wheel 12 side. You may apply this invention to the transmission ratio variable apparatus which makes a transmission ratio variable. Specifically, as is well known, the transmission ratio variable device adds the rotation based on the driving of the motor 21 to the rotation of the first shaft and transmits the rotation to the second shaft, thereby transmitting the first shaft and the second shaft. Therefore, the present invention may be applied to a motor control device that controls the driving of the motor 21. By the way, in the transmission ratio variable device, after the microcomputer 41 starts the motor drive control, the situation where it is not necessary to drive the motor 21 includes the above (a2) and (a3), and the above (a1). As alternative situations, the following situations (c1) and (c2) can be considered.

(C1) When the steering wheel 2 is in the holding state. In this case, since it is considered that the steering shaft 3 is not rotating, it is not necessary to drive the motor 21. In addition, what is necessary is just to perform the detection that the steering 2 is a steering hold state, for example based on the angular velocity (rotational speed) of the steering shaft 3 being below a predetermined value.
(C2) The steering 2 is in the neutral position. Also in this case, since it is considered that the steering shaft 2 is not rotating, it is not necessary to drive the motor 21. The detection that the steering 2 is in the neutral position may be performed using, for example, a detection value of a steering angle sensor that detects the steering angle of the steering 2.

In the above-described embodiment and its modifications, the case where the present invention is applied to an electric power steering device for a vehicle and a transmission ratio variable device is illustrated, but the application target of the present invention is not limited to this. The present invention is not limited to a motor control device mounted on a vehicle, and can be applied to any motor control device having a microcomputer and an input / output signal generation circuit 43 for a motor rotation angle sensor.

In the present embodiment, the present invention is embodied in the column assist EPS, but the present invention may be applied to a rack assist EPS or a pinion assist EPS.

1: Electric power steering device (EPS), 2: Steering,
3: Steering shaft, 4: Rack and pinion mechanism, 5: Rack shaft,
8: column shaft, 9: intermediate shaft, 10: pinion shaft, 11: tie rod, 12: steered wheel, 21: motor,
22: Motor rotation angle sensor (motor rotation angle detection means: resolver), 23: Deceleration mechanism,
24: EPS actuator (steering force assist device),
25: Vehicle speed sensor, 26: Torque sensor (steering torque detection means),
27: Motor control device, 28: Engine control device,
40: drive circuit, 41: microcomputer (control means), 42: power supply IC,
43: Motor rotation angle sensor input / output signal generation circuit (motor rotation angle detection means input / output signal generation means),
45, 46: Relay (switching means), 48: Pre-driver circuit, 49: Current sensor,
V: vehicle speed, Th: steering torque, Th1: steering torque predetermined value, θm: motor rotation angle,
Vh: Steering angular velocity, Vh1: Steering angular velocity predetermined value, I: Current value of each phase,
IGSW: Ignition switch, BT: In-vehicle battery,
D1, D2: Diode, W1: Feed line

Claims (5)

Control means for controlling driving of the motor by outputting a driving signal to a driving circuit for supplying driving power to the motor;
Motor rotation angle detecting means for detecting the rotation angle of the motor;
An input / output signal generation means for motor rotation angle detection means for generating an input / output signal of the motor rotation angle detection means;
Switching means for switching power supply and interruption of the input / output signal generation means for the motor rotation angle detection means,
The motor is mounted on a vehicle;
The control means determines that it is not necessary to drive the motor after the ignition switch of the vehicle is turned on until the control means starts driving control of the motor, and the switching means Cutting off the power supply to the input / output signal generating means for the motor rotation angle detecting means;
A motor control device. The motor control device according to claim 1,
After the ignition switch of the vehicle is turned on, the control means can confirm normal operation of the drive system of the motor by an initial check, and can detect the start of the on-vehicle engine, thereby driving the motor. Determining that control has begun,
A motor control device. In the motor control device according to claim 1 or 2,
The control means is configured such that after the control means starts driving control of the motor, an abnormality occurs in a device using the motor as a drive source, or when an ignition switch of a vehicle is turned off, the motor The power supply to the motor rotation angle detection means input / output signal generation means is cut off by the switching means,
A motor control device. In the motor control device according to any one of claims 1 to 3,
The motor is provided in an electric power steering device of a vehicle, and applies assist torque to a steering mechanism of the vehicle.
Steering torque detection means for detecting steering torque;
Steering angular velocity calculation means for calculating a steering angular velocity from the rotation angle of the motor detected from the motor rotation angle detection means;
The control means detects the absolute value of the steering angular velocity calculated by the steering angular velocity calculating means after the control means starts driving control of the motor, and is detected by the steering torque detecting means. If the absolute value of the steering torque is less than the steering torque predetermined value, it is determined that it is not necessary to drive the motor, and the switching means uses the power to the input / output signal generation means for the motor rotation angle detection means. Shut off the supply,
A motor control device. In the motor control device according to any one of claims 1 to 3,
The motor is provided in a transmission ratio variable device that varies a transmission ratio between the first shaft on the steering wheel side and the second shaft on the steered wheel side in the steering shaft of the vehicle, and rotates based on its own drive. Is transmitted to the second shaft by adding to the rotation of the first shaft, thereby making the transmission ratio variable,
The control means needs to drive the motor when the steering wheel is in a steering holding state or when the steering wheel is in a neutral position after the control means starts driving control of the motor. Cutting off the power supply to the motor rotation angle detection means input / output signal generation means by the switching means,
A motor control device.

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