JP2014171307A - Motor control device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a motor control device capable of reducing power consumption while assuring an appropriate operation of a state amount monitor circuit.SOLUTION: A microcomputer 41 is constructed to, when an A/D conversion value VD converted at an A/D converter 43 is read, supply electric power by turning on a relay 46 of an ignition voltage monitor circuit part 50. As a result, only when the A/D conversion value VD converted at the A/D converter 43 is read, electric power is supplied to the ignition voltage monitor circuit part 50, which makes it possible to reduce power consumption as compared with a case where electric power is supplied to the ignition voltage monitor circuit part 50 at all times.

Description

  The present invention relates to a motor control device having a state quantity monitor circuit.

  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. (ECU) is provided.

  The ECU includes a drive circuit unit that supplies a drive voltage to the motor, and a control unit (microcomputer) that controls the operation of the drive circuit unit. The microcomputer is supplied with a voltage from a vehicle-mounted battery provided outside.

  For this reason, conventionally, as seen in Patent Literature 1, by switching between a wake-up state in which control by a microcomputer is performed and a sleep state in which control of the microcomputer is not performed according to the vehicle state, switching to the sleep state The power consumption in the ECU is reduced.

JP 2010-0776577 A

  However, in the above method, even when switching to the sleep state, power is continuously supplied to the state quantity monitor circuit, so there is a concern that power may be consumed even when power is unnecessary. The present invention has been made in view of such circumstances, and an object of the present invention is to provide a motor control device that can reduce power consumption while ensuring proper operation of a state quantity monitor circuit.

  In order to solve the above-described problem, a motor control device according to claim 1 is a state quantity monitoring unit that monitors a state quantity of the motor control apparatus, and an A / D that converts a state quantity detected by the state quantity monitoring unit. Conversion means, switching means for switching power supply and interruption of the state quantity monitoring means, and control means for switching the switching means, wherein the control means converts the state quantity by the A / D conversion means. The gist of the invention is to supply power to the state quantity monitoring means by the switching means.

  The control unit is configured to supply power to the state quantity monitoring unit by the switching unit when the A / D conversion unit converts the state quantity. As a result, since power is supplied to the state quantity monitoring means only when the A / D conversion means converts the state quantity, the power consumption is compared with the case where power is always supplied to the state quantity monitoring means. Can be reduced.

  According to a second aspect of the present invention, the timing for converting the state quantity by the A / D conversion means is determined in advance, and power is supplied to the state quantity monitoring means by interruption processing by a timer. This is the gist.

The timing for converting the state quantity by the A / D conversion means is determined in advance, and power is supplied to the state quantity monitoring means by interrupt processing by a timer.
As a result, the supply and cut-off of power to the state quantity monitoring means are repeated regularly at regular intervals, so that even more power is consumed than when the supply and cut-off of power to the state quantity monitoring means are repeated at random. Electric power can be reduced.

  The motor control device according to claim 3 further includes state quantity abnormality determination means for determining abnormality of the state quantity detected by the A / D conversion means, and the control means is in a state by the state quantity abnormality determination means. The gist of the invention is that when the abnormality of the quantity is confirmed, the switching means cuts off the power supply to the state quantity monitoring means.

  A state quantity abnormality determining means for determining an abnormality of the state quantity detected by the A / D conversion means is further provided. When the state quantity abnormality is confirmed by the state quantity abnormality determining means, the control means The power supply to the state quantity monitoring means is cut off. As a result, when the state quantity abnormality is determined by the state quantity abnormality determining means, the power supply to the state quantity monitoring means is completely cut off, so that the power consumption can be further reduced.

  According to the motor control device of the present invention, power consumption can be reduced while ensuring proper operation of the state quantity monitor circuit.

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 block diagram of the state determination process task by the motor control apparatus of embodiment. The flowchart which shows the process sequence of the state determination processing task which switches supply of the electric power to an ignition voltage monitor circuit part, 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 (hereinafter referred to as ECU).

  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, and a motor rotation angle sensor 22 are connected to the ECU 27. The ECU 27 is based on the output signals of these sensors, and the vehicle speed V, the steering torque τ, and the motor rotation angle. θm is detected.

  As shown in FIG. 2, the ECU 27 includes a drive circuit unit 40 that supplies a three-phase AC voltage to the motor 21 and a control unit 41 that controls the drive of the motor 21 via the drive circuit unit 40 (hereinafter referred to as a microcomputer: Control means).

  The drive circuit unit 40 has a known configuration in which a plurality of MOSFETs are connected in a bridge shape. The drive circuit unit 40 converts the DC voltage supplied from the in-vehicle battery BT via the power supply relay 45 into the three-phase by turning on / off the plurality of MOSFETs based on the gate signal input from the microcomputer 41. Convert to AC voltage (U phase, V phase, W phase). The converted three-phase AC voltage is supplied to the motor 21 as a motor drive voltage, so that the motor 21 is driven.

  Between the drive circuit unit 40 and the motor 21, a current sensor 49 for detecting each phase current value I of the U phase, the V phase, and the W phase is provided. 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.

  The microcomputer 41 is based on the motor rotation angle θm, the vehicle speed V, the steering torque τ, 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.

The power source for the microcomputer 41 is connected to the in-vehicle battery BT via the diode D1 and an ignition switch IGSW that is an engine start switch.
The power source for the microcomputer 41 is also connected to the in-vehicle battery BT via a diode D2 in the middle of the wiring connecting the power relay 45 and the drive circuit unit 40.
That is, when either the ignition switch IGSW or the power supply relay 45 is turned on, power is supplied to the microcomputer 41 from the in-vehicle battery BT.

Next, a procedure in which the microcomputer 41 switches on / off of the power supply relay 45 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 and the diode D1, and the microcomputer 41 is activated. The activated microcomputer 41 includes an electronic component mounted on itself such as a CPU and a memory, a motor rotation angle sensor 22, a vehicle speed sensor 25, a torque sensor 26, a current sensor 49, a drive circuit unit 40, and the like. A so-called initial check is performed to confirm the overall normal operation.

  Then, when it is confirmed through the initial check that the entire electric power steering apparatus is normal, the power supply relay 45 is turned on. Thereby, a DC voltage is supplied from the vehicle-mounted battery BT to the drive circuit unit 40, and the motor 21 starts motor drive control.

  Further, when the ignition switch IGSW is turned off by the driver, the power supply to the microcomputer 41 through the ignition switch IGSW is cut off, but the microcomputer 41 is supplied with power through the power supply relay 45, The operating state can be maintained. At this time, when the microcomputer 41 detects that the ignition switch IGSW is turned off, the microcomputer 41 has a condition for stopping the motor drive control based on the outputs of the motor rotation angle sensor 22, the vehicle speed sensor 25, the torque sensor 26, and the current sensor 49. It is determined whether or not it is established. When the condition for stopping the motor drive control is satisfied, the power supply relay 45 is turned off. As a result, the supply of drive current from the in-vehicle battery BT to the drive circuit unit 40 is interrupted, and the microcomputer 41 stops.

  Furthermore, the ECU 27 has an ignition voltage monitor circuit unit (state quantity monitor means) 50 for monitoring whether or not a predetermined voltage is supplied from the in-vehicle battery BT via the ignition switch IGSW. The ignition voltage monitor circuit unit 50 includes a relay (switching means) 46, voltage dividing resistors R11 and R12, and a filter capacitor C11. When the relay 46 is turned on, the ignition voltage is divided by the voltage dividing resistors R 11 and R 12 and input to the A / D converter (A / D conversion means) 43.

  Next, the microcomputer 41 determines whether the ignition voltage input by the A / D converter 43 is normal or abnormal. A series of program processing performed by the microcomputer 41 is generally called a processing task. The above-described ignition voltage monitoring operation by the A / D converter and abnormality determination processing are performed during the state determination processing task.

Next, a configuration diagram of a state determination processing task by the motor control device 27 of the present embodiment will be described based on FIG.
As shown in FIG. 3, in the memory 42 of the microcomputer 41, a state determination processing task is programmed at an address assigned for each interrupt timer. In this embodiment, every time interrupt time t1 ms, interrupt 1 is accessed, and a state determination processing task 1 (in this embodiment, an ignition voltage monitor and an abnormality determination process) programmed into interrupt 1 is started. Further, every time interrupt time t2 ms, interrupt 2 is accessed, and state determination processing task 2 programmed in interrupt 2 is activated. Thereafter, the remaining tasks are sequentially processed according to the above processing procedure.

When the A / D conversion means (A / D converter) converts the state quantity, the motor control device 27 of the present embodiment uses the switching means (relay) to supply power to the state quantity monitoring means (ignition voltage monitor). It is configured to supply.
Next, a processing procedure of a state determination processing task for switching between supply and interruption of power to the ignition voltage monitor circuit by the motor control device 27 of the present embodiment will be described based on FIG.
First, the microcomputer 41 determines whether or not the abnormality confirmation flag is off (step S101). If the abnormality confirmation flag is off (step S101: YES), the microcomputer 41 turns on the relay 46 to turn on the ignition. Power is supplied to the voltage monitor circuit (step S102). Next, the microcomputer 41 reads the A / D conversion value VD converted by the A / D converter 43 (step S103). Then, the microcomputer 41 turns off the relay 46 and cuts off the power to the ignition voltage monitor circuit (step S104).
These steps are processed by the above-described interruption by the timer.

Next, the microcomputer 41 determines whether or not the A / D conversion value VD converted by the A / D converter 43 is normal (VL ≦ VD ≦ VU, step S105, state quantity abnormality determination means).
If the A / D conversion value VD is not normal (VD <VL or VD> VU, step S105: NO), the microcomputer 41 increments the abnormality confirmation counter CTR (CTR = CTR + 1, step S106).

  Next, the microcomputer 41 determines whether or not the abnormality confirmation counter CTR is equal to or greater than a predetermined count value CTR0 (step S107). When the abnormality confirmation counter CTR is equal to or larger than the predetermined count value CTR0 (CTR ≧ CTR0, step S107: YES), the microcomputer 41 determines that the ignition voltage abnormality is confirmed and turns on the abnormality confirmation flag (step S108), and finishes the state determination processing task.

  On the other hand, the microcomputer 41 determines that the abnormality confirmation counter CTR is smaller than the predetermined count value CTR0 (CTR <CTR0, step S107: NO), or the A / D conversion value VD converted by the A / D converter 43 is normal. If this is the case (VL ≦ VD ≦ VU, Step S105: YES), the state determination processing task is terminated without performing any processing.

  Further, when the abnormality determination flag is on (step S101: NO), the microcomputer 41 determines that there is no need to monitor the ignition voltage and does not turn on the relay 46. That is, the state determination processing task is terminated without supplying power to the ignition voltage monitor circuit.

As described above, according to the motor control device 27 of the present embodiment, the following operations and effects can be obtained.
When the microcomputer 41 reads the A / D conversion value VD converted by the A / D converter 43, the microcomputer 41 turns on the relay 46 of the ignition voltage monitor circuit unit 50 and supplies power to the ignition voltage monitor circuit unit 50. The configuration. As a result, power is supplied to the ignition voltage monitor circuit unit 50 only when the A / D conversion value VD converted by the A / D converter 43 is read, so power is always supplied to the ignition voltage monitor circuit unit 50. Compared with the case where it is doing, power consumption can be reduced.

  Further, the microcomputer 41 further includes A / D conversion value VD abnormality determining means (step S105) for determining abnormality of the A / D conversion value VD converted by the A / D converter 43, and the A / D conversion value. When the abnormality of the A / D conversion value VD converted by the A / D converter 43 is determined by the VD abnormality determination means, the relay 46 of the ignition voltage monitor circuit unit 50 is turned off and the ignition voltage monitor circuit unit 50 is turned off. The power supply is cut off. As a result, when the abnormality of the A / D conversion value VD is confirmed by the A / D conversion value VD abnormality determination means, the abnormality confirmation abnormality flag is turned on and the power supply to the ignition voltage monitor circuit unit 50 is completely cut off. Therefore, power consumption can be further reduced.

In addition, the said embodiment can also be implemented with the following forms which changed this suitably.
In the block diagram illustrated in FIG. 2 of the above embodiment, the ignition voltage monitor circuit unit is presented as the state quantity monitor circuit. However, the present invention is not limited to this, and the power voltage monitor circuit unit and the motor rotation angle sensor voltage are not limited thereto. You may apply to the monitor circuit part, the voltage monitor circuit part for torque sensors, and the voltage monitor circuit part for vehicle speed sensors.

In the flowchart illustrated in FIG. 4 of the above embodiment, the ignition voltage abnormality determination unit is presented as the A / D conversion value VD abnormality determination unit. However, the present invention is not limited to this, and the power voltage abnormality determination unit, motor rotation You may apply to the voltage abnormality determination means for angle sensors, the voltage abnormality determination means for torque sensors, and the voltage abnormality determination means for vehicle speed sensors.

In the processing illustrated in FIG. 3 of the above embodiment, the state determination processing task is processed by the timer interrupt, but the state determination processing task may be processed in the program order without using the timer interrupt.

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.

In the above embodiment and its modifications, the case where the present invention is applied to an electric power steering device for a vehicle is illustrated, but the application target of the present invention is not limited thereto. The present invention is not limited to a motor control device mounted on a vehicle, but can be applied to any motor control device having a microcomputer, a state quantity monitor circuit, and a state quantity abnormality determination unit.

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, 23: Deceleration mechanism,
24: EPS actuator (steering force assist device),
25: Vehicle speed sensor, 26: Torque sensor, 27: Motor controller (ECU),
40: drive circuit unit, 41: control unit (microcomputer, control means), 42: memory,
43: A / D converter (A / D conversion means), 45: Relay for power supply,
46: Relay (switching means), 49: Current sensor,
50: Ignition voltage monitor circuit unit (state quantity monitor means),
V: vehicle speed, τ: steering torque, θm: motor rotation angle, I: current value of each phase,
IGSW: Ignition switch, BT: In-vehicle battery,
D1, D2: Diode,
VD: A / D conversion value, VL: A / D conversion lower limit value, VU: A / D conversion upper limit value,
CTR: Abnormality confirmation counter, CTR0: Predetermined count value

Claims (3)

State quantity monitoring means for monitoring the state quantity of the motor control device;
A / D conversion means for converting the state quantity detected by the state quantity monitoring means;
Switching means for switching between supply and interruption of power of the state quantity monitoring means;
Control means for switching the switching means,
The control means supplies power to the state quantity monitoring means by the switching means when the A / D conversion means converts the state quantity;
A motor control device. The timing for converting the state quantity by the A / D conversion means is determined in advance, and power is supplied to the state quantity monitoring means by interrupt processing by a timer.
The motor control device according to claim 1. A state quantity abnormality determining means for determining an abnormality of the state quantity detected by the A / D conversion means;
The control means shuts off the power supply to the state quantity monitoring means by the switching means when an abnormality of the state quantity is confirmed by the state quantity abnormality determining means;
The motor control device according to claim 1 or 2, wherein

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