JP2014007784A - Motor controller, and electrically-driven power steering device using the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a motor controller and electrically-driven power steering device using the motor controller capable of making abnormality generated in a device be appropriately detected.SOLUTION: A control unit acquires detection values related to drive of a motor (S100); determines whether or not the detection values are abnormal (S102, S105, and S108); controls the drive of the motor so as to output an assist torque by using a torque detection value, rotation angle detection value, and current detection value which are the acquired detection values (S112), when it is determined that the detection values are not abnormal; and, when it is determined that at least one of the detection values is abnormal, controls the drive of the motor so as to output another assist torque differing from the assist torque by using the remaining detection values except the abnormal detection value (S114). Thereby, abnormality generated in a device is made to be appropriately detected.

Description

  The present invention relates to an electric motor control device and an electric power steering device using the same.

  Conventionally, there has been known an electric power steering device that drives a motor without using a detection value detected by the sensor in which an abnormality has occurred and continues steering assist when an abnormality occurs in a sensor related to control of driving of the motor. ing. For example, in Patent Document 1, the steering assist is continued even when an abnormality occurs in the position sensor of the electric motor.

JP 200326020 A

By the way, in recent years, control technology has been improved, and even when the motor is driven by sensorless control without using a sensor in which an abnormality has occurred, it is possible to perform control in substantially the same manner as when no abnormality has occurred in the sensor. . Therefore, there is a possibility that the driving of the electric motor is continued without noticing that an abnormality has occurred in the sensor.
The present invention has been made in view of the above-described problems, and an object of the present invention is to provide an electric motor control device capable of appropriately sensing that an abnormality has occurred in the device, and an electric power steering device using the same. Is to provide.

The electric motor control device of the present invention controls the driving of an electric motor having a stator, a rotor provided to be rotatable relative to the stator, and a winding set wound around the stator. The electric motor control device includes detection value acquisition means, abnormality determination means, normal time drive control means, and backup control means.
The detection value acquisition means acquires a detection value related to driving of the electric motor. The abnormality determination means determines whether an abnormality has occurred in the detected value. When it is determined by the abnormality determining means that the detected value is not abnormal, the normal-time drive control means uses the detected value acquired by the detected value acquiring means and outputs the first output torque. Control the drive. Further, when it is determined by the abnormality determination means that an abnormality has occurred in at least one of the detected values, the backup control means uses the other detection values other than the detection value in which the abnormality has occurred, and uses the first output torque The drive of the electric motor is controlled so as to output a second output torque different from the output torque.

  Since the backup control unit controls the driving of the electric motor without using the detected value in which the abnormality has occurred, the driving of the electric motor can be continued even if an abnormality occurs in the detected value due to a failure of the sensor or the like. In addition, since the backup control unit controls the drive of the electric motor so as to output the second output torque different from the first output torque that is output in the normal state, it appropriately senses that an abnormality has occurred in the device. Can be made.

  In addition, for example, when the motor control device is applied to an electric power steering device, even if a detection value is abnormal due to a failure of a sensor or the like, the driving of the motor is continued without using the detection value where the abnormality has occurred. Assist can be continued. In addition, since the driver can properly detect the occurrence of a failure, other parts may also fail and the motor cannot be driven while continuing to use it without noticing the failure of the device. It is possible to avoid the situation where the assist cannot be performed.

It is a mimetic diagram showing the whole electric power steering device composition by a 1st embodiment of the present invention. 1 is a circuit diagram showing a circuit configuration of an electric power steering apparatus according to a first embodiment of the present invention. It is a flowchart explaining the motor drive process by 1st Embodiment of this invention. It is a flowchart explaining the motor drive process by 1st Embodiment of this invention. It is explanatory drawing explaining the case where a torque sensor fails in the electric power steering device by 1st Embodiment of this invention. In the electric power steering apparatus according to the first embodiment of the present invention, it is an explanatory diagram for explaining a case where a rotation angle sensor has failed. In the electric power steering device according to the first embodiment of the present invention, it is an explanatory diagram for explaining a case where a current sensor has failed. It is a figure explaining the assist torque by 1st Embodiment of this invention, Comprising: (a) is at the time of normal time drive control in which the failure has not arisen in the sensor, (b) is backup control in which the failure has occurred in the sensor. It's time. It is a figure explaining the assist torque by 2nd Embodiment of this invention, Comprising: (a) is at the time of normal time drive control in which the failure has not arisen in the sensor, (b) is backup control in which the failure has occurred in the sensor. It's time.

Hereinafter, an electric motor control device according to the present invention will be described with reference to the drawings. Hereinafter, in a plurality of embodiments, substantially the same configuration is denoted by the same reference numeral, and description thereof is omitted.
(First embodiment)
1 and 2 show an electric motor control device according to a first embodiment of the present invention and an electric power steering device using the same.
A motor control device 1 as an electric motor control device controls driving of a motor 10 as an electric motor. The motor control device 1 is applied together with the motor 10 to an electric power steering device 2 for assisting (assisting) the steering operation (steering) of the vehicle.

FIG. 1 is a diagram illustrating an overall configuration of a steering system 90 including an electric power steering device 2 that employs a motor control device 1.
A steering wheel 91 steered by the driver is connected to a steering shaft 92. A pinion gear 96 is provided at the tip of the steering shaft 92, and the pinion gear 96 meshes with the rack shaft 97. A pair of wheels 98 are connected to both ends of the rack shaft 97 via tie rods or the like. Accordingly, when the driver rotates the steering wheel 91, the steering shaft 92 connected to the steering wheel 91 rotates, and the rotational motion of the steering shaft 92 is converted into the linear motion of the rack shaft 97 by the pinion gear 96. The pair of wheels 98 are steered so as to have an angle corresponding to the linear movement displacement of the shaft 97.

  The electric power steering apparatus 2 includes a motor 10 that outputs an assist torque as an output torque, a reduction gear 94 that decelerates rotation of the motor 10 and transmits the rotation to the steering shaft 92, and the motor control apparatus 1.

  In the present embodiment, the motor 10 is a three-phase brushless motor, and includes a stator, a rotor, and a shaft (not shown). The rotor is a member that rotates together with the shaft. A permanent magnet is attached to the surface of the rotor and has a magnetic pole. The stator accommodates the rotor inside, and the rotor is rotatably supported inside the stator. The stator has protrusions that protrude inwardly at predetermined angles, and a U1 coil 111, a V1 coil 112, a W1 coil 113, a U2 coil 121, a V2 coil 122, and a W2 coil 123 are wound around the protrusion. It has been turned. The U1 coil 111, the V1 coil 112, and the W1 coil 113 are Δ-connected to form the first winding set 11. Similarly, the U2 coil 121, the V2 coil 122, and the W2 coil 123 are Δ-connected to form the second winding set 12 (see FIG. 2). The first winding set 11 and the second winding set 12 correspond to “winding sets”.

The motor control device 1 is configured by an ECU (not shown). The ECU includes a first inverter unit 21, a second inverter unit 22, a control unit 30, and the like.
As shown in FIG. 2, the first inverter unit 21 is provided between the battery 50 and the first winding set 11, and switching elements 211 to 216 are bridged to switch the energization to the first winding set 11. It is connected. A power relay 51 is provided between the first inverter unit 21 and the battery 50.
The second inverter unit 22 is provided between the battery 50 and the second winding set 12, and switching elements 221 to 226 are bridge-connected in order to switch energization to the second winding set 12. A power relay 52 is provided between the second inverter unit 22 and the battery 50.

  In the present embodiment, the first inverter unit 21 is provided correspondingly to control the energization of the first winding set 11 of the motor 10, and the second inverter unit 22 is configured to control the energization of the second winding set 12. Correspondingly provided. In other words, it can be said that the motor 10 is driven by two systems. Hereinafter, the combination of the first winding set 11 and the first inverter unit 21 will be referred to as a first system 100, and the combination of the second winding set 12 and the second inverter unit 22 will be referred to as a second system 200.

  As the switching elements 211 to 216 and 221 to 226 and the power relays 51 and 52, for example, a MOSFET (metal-oxide-semiconductor field-effect transistor) which is a kind of field effect transistor is used. Of course, an IGBT other than the MOSFET may be used. Hereinafter, the switching elements 211 to 216 and 221 to 226 are referred to as MOSs 211 to 216 and 221 to 226.

The MOS 211 of the first inverter unit 21 has a drain connected to the high potential side of the battery 50 and a source connected to the drain of the MOS 214. The source of the MOS 214 is grounded via a shunt resistor 751. A connection point between the MOS 211 and the MOS 214 is connected to one end of the U1 coil 111. A terminal voltage detection unit 761 that detects the U1 terminal voltage Vu1 is connected to a connection point between the MOS 211 and the MOS 214.
The MOS 212 has a drain connected to the high potential side of the battery 50 and a source connected to the drain of the MOS 215. The source of the MOS 215 is grounded via a shunt resistor 752. A connection point between the MOS 212 and the MOS 215 is connected to one end of the V1 coil 112. Further, a terminal voltage detection unit 762 that detects the V1 terminal voltage Vv1 is connected to a connection point between the MOS 212 and the MOS 215.
The MOS 213 has a drain connected to the high potential side of the battery 50 and a source connected to the drain of the MOS 216. The source of the MOS 216 is grounded through a shunt resistor 753. A connection point between the MOS 213 and the MOS 216 is connected to one end of the W1 coil 113. A terminal voltage detection unit 763 for detecting the W1 terminal voltage Vw1 is connected to a connection point between the MOS 213 and the MOS 216.

The MOS 221 of the second inverter unit 22 has a drain connected to the high potential side of the battery 50 and a source connected to the drain of the MOS 224. The source of the MOS 224 is grounded via a shunt resistor 754. A connection point between the MOS 221 and the MOS 224 is connected to one end of the U2 coil 121. Further, a terminal voltage detection unit 764 for detecting the U2 terminal voltage Vu2 is connected to a connection point between the MOS 221 and the MOS 224.
The MOS 222 has a drain connected to the high potential side of the battery 50 and a source connected to the drain of the MOS 225. The source of the MOS 225 is grounded via a shunt resistor 755. A connection point between the MOS 222 and the MOS 225 is connected to one end of the V2 coil 122. A terminal voltage detector 765 that detects the V2 terminal voltage Vv2 is connected to a connection point between the MOS 222 and the MOS 225.
The MOS 223 has a drain connected to the high potential side of the battery 50 and a source connected to the drain of the MOS 226. The source of the MOS 226 is grounded via a shunt resistor 756. A connection point between the MOS 223 and the MOS 226 is connected to one end of the W2 coil 123. A terminal voltage detector 766 that detects the W2 terminal voltage Vw2 is connected to a connection point between the MOS 223 and the MOS 226.

  The control unit 30 is configured as a normal computer, and includes a CPU, a ROM, an I / O, a bus line that connects these configurations, and the like. In the present embodiment, a current sensor 75, a voltage sensor 76, a torque sensor 82, a rotation angle sensor 83, a vehicle speed sensor (not shown), and the like are connected to the control unit 30. Note that the control lines between the sensors and the control unit 30 are omitted in order to avoid complication.

  The current sensor 75 includes shunt resistors 751 to 756. The control unit 30 acquires the both-end voltages detected by the shunt resistors 751 to 756, and calculates the U1 current Iu1, the V1 current Iv1, the W1 current Iw1, the U2 current Iu2, the V2 current Iv2, and the W2 current Iw2. Specifically, the U1 current Iu1, the V1 current Iv1, and the W1 current Iw1 are calculated based on the both-end voltages of the shunt resistors 751 to 753. Further, the U2 current Iu2, the V2 current Iv2, and the W2 current Iw2 are calculated based on the both-end voltages of the shunt resistors 754 to 756.

The U1 current Iu1, the V1 current Iv1, the W1 current Iw1, the U2 current Iu2, the V2 current Iv2, and the W2 current Iw2 correspond to “each phase current”, and are hereinafter referred to as “each phase current” as appropriate.
Further, the both-end voltage, which is the “detection value” detected by the shunt resistors 751 to 756, corresponds to the “current detection value related to each phase current”. Furthermore, in the control unit 30, it can be said that “current detection values are acquired for each winding set from the current sensor”.

  The voltage sensor 76 includes terminal voltage detectors 761 to 766. In the control part 30, the terminal voltage of each phase detected by the terminal voltage detection parts 761-766 is acquired. In addition, the terminal voltage which is the “detection value” detected by the terminal voltage detection units 761 to 766 corresponds to “the voltage detection value related to the terminal voltage of each phase of the winding set”.

  As shown in FIG. 1, the torque sensor 82 is provided on a torsion bar 93 that connects a portion on the steering wheel 91 side and a portion on the pinion gear 96 side of the steering shaft 92, and the torsion angle of the torsion bar 93 A detection value corresponding to is output. The torsion angle of the torsion bar 93 is the difference between the angle due to the force applied to the steering wheel 91 side portion of the steering shaft 92 and the angle due to the force applied to the pinion gear 96 side portion of the steering shaft 92. The magnetic flux density corresponding to this angle difference is detected by a plurality of Hall elements. In this embodiment, the magnetic flux density corresponding to the angle difference is detected by two Hall elements. The control unit 30 acquires the magnetic flux density detected by one hall element as the main signal Tm and the magnetic flux density detected by the other hall element as the sub signal Ts, and based on the main signal Tm and the sub signal Ts, the steering torque Tq is calculated. The main signal Tm and the sub signal Ts, which are “detected values” detected by the torque sensor 82, correspond to “torque detected values related to steering torque”. Here, for convenience, the two detection values are called a main signal Tm and a sub signal Ts, but the two detection values may or may not be superior.

  The rotation angle sensor 83 is a general resolver and is provided near the rotor of the motor 10. The control unit 30 calculates the electrical angle θ of the motor 10 based on the sin signal and the cos signal detected by the rotation angle sensor 83. The electrical angle θ corresponds to the “rotation angle”, and the sin signal and the cos signal that are “detection values” detected by the rotation angle sensor 83 correspond to the “rotation angle detection value related to the rotation angle”.

  Based on the steering torque Tq, the electrical angle θ of the motor 10, the phase currents Iu1, Iv1, Iw1, Iu2, Iv2, Iw2, the vehicle traveling speed SP detected by the vehicle speed sensor 95, etc. The driving of the motor 10 is controlled by controlling on / off of the MOSs 211 to 216 and 221 to 226 of the first inverter unit 21 and the second inverter unit 22.

Specifically, the control unit 30 converts the U1 current Iu1, the V1 current Iv1, and the W1 current Iw1 into a dq current detection value Id1 and a q axis current detection value Iq1 based on the electrical angle θ of the motor 10. To do. Further, the assist torque determination unit 31 determines the assist torque based on the steering torque Tq and the vehicle traveling speed SP. Further, a current command value is calculated based on the assist torque, and a d-axis current command value Id1 ^* and a q-axis current command value Iq1 ^* are obtained from the current command value and the electrical angle θ. Then, a current feedback calculation is performed from the d-axis current command value Id1 ^* and the q-axis current command value Iq1 ^* , the d-axis current detection value Id1 and the q-axis current detection value Iq1, and the d-axis voltage command value Vd1 ^* and q A shaft voltage command value Vq1 ^* is calculated. Specifically, a current deviation ΔId1 between the d-axis current command value Id1 ^* and the d-axis current detection value Id1 and a current deviation ΔIq1 between the q-axis current command value Iq1 ^* and the q-axis current detection value Iq1 are calculated, In order to follow the command values Id1 ^* and Iq1 ^* , the voltage command values Vd1 ^* and Vq1 ^* are calculated so that the current deviations ΔId1 and ΔIq1 converge to zero. Based on the electrical angle θ of the motor 10, the calculated voltage command values Vd1 ^* , Vq1 ^* are converted into three-phase voltage command values Vu1 ^* , Vv1 ^* , Vw1 ^* , and the three-phase voltage command values Vu1 ^* , Vv1 ^*. , Vw1 ^* is controlled to turn on / off the MOSs 211 to 216 constituting the first inverter unit 21. Thereby, AC power is generated in the first inverter unit 21, and the AC power is supplied to the first winding set 11, whereby the motor 10 is driven.
In the second inverter unit 22, the same control is performed using the U2 current Iu2, the V2 current Iv2, the W2 current Iw2, and the like. Thereby, AC power is generated in the second inverter unit 22, and this AC power is supplied to the second winding set 12, thereby driving the motor 10.

In the present embodiment, when an abnormality occurs in the detection value due to a failure of the sensors or the like, backup control for controlling the driving of the motor 10 is performed without using the detection value in which the abnormality has occurred.
Therefore, in the present embodiment, drive control of the motor 10 executed by the control unit 30 will be described with reference to FIGS. 3 and 4. Note that this processing is executed at predetermined intervals when steering assist by the electric power steering device 2 is being executed.

  As shown in FIG. 3, in the first step S <b> 100 (hereinafter, “step” is omitted and simply indicated by the symbol “S”), various detection values related to driving of the motor 10 are acquired. In this embodiment, the voltage across the shunt resistors 751 to 756 constituting the current sensor 75, the terminal voltage detected by the terminal voltage detectors 761 to 766 constituting the voltage sensor 76, and the main signal Tm detected by the torque sensor 82 are used. The sub signal Ts and the sin signal and the cos signal detected by the rotation angle sensor 83 are acquired.

  In S101, it is determined whether normal control is being performed. If it is determined that the normal control is not being performed (S101: NO), that is, if any one of the detected values is abnormal and the backup control is being performed, the process proceeds to S202 in FIG. When it is determined that the normal control is being performed (S101: YES), the process proceeds to S102.

  In S102, it is determined whether or not the main signal Tm and the sub signal Ts, which are torque detection values, are normal. When the main signal Tm and the sub signal Ts are normal (S102: YES), that is, when there is no abnormality in the main signal Tm and the sub signal Ts, the process proceeds to S103. When the main signal Tm or the sub signal Ts is not normal (S102: NO), that is, when the main signal Tm or the sub signal Ts is abnormal, the process proceeds to S104.

In S103, where there is no abnormality in the main signal Tm and the sub signal Ts (S102: YES), the steering torque Tq is calculated using both the main signal Tm and the sub signal Ts. In the present embodiment, when the main signal Tm and the sub signal Ts are normal, the main signal Tm and the sub signal Ts are as shown in FIG. 5A, and the main signal Tm and the sub signal Ts are used. A steering torque Tq is calculated based on the formula (1).
Tq = (Tm−Ts) × K1 (1)

In S104, where the abnormality occurs in the main signal Tm or the sub signal Ts (S102: NO), an abnormality flag is set, and the steering torque Tq is calculated using the signal in which no abnormality has occurred. For example, if an abnormality occurs in the sub signal Ts, the main signal Tm is used, and if an abnormality occurs in the main signal Tm, the steering torque Tq is calculated using the sub signal Ts. As shown in FIG. 5B, assuming that an abnormality has occurred in the sub-signal Ts, the steering torque Tq is calculated based on the equation (2) using only the main signal Tm.
Tq = Tm × K2 (2)

Further, when abnormality occurs in the main signal Tm, the steering torque Tq is calculated based on the equation (3) using only the sub signal Ts.
Tq = Ts × K3 (3)

  In the above equation (1), K1 is a conversion coefficient for converting the difference value between the main signal Tm and the sub signal Ts acquired as a voltage signal into the steering torque Tq. Further, K2 in the above equation (2) is a conversion coefficient for converting the main signal Tm into the steering torque Tq, and K3 in the above equation (3) is for converting the sub signal Ts into the steering torque Tq. Is the conversion coefficient. The conversion coefficients K1, K2, and K3 are different values and are stored in the control unit 30 in advance.

  In subsequent S105, it is determined whether or not the sin signal and the cos signal, which are rotation angle detection values, are normal. When the sin signal and the cos signal are normal (S105: YES), that is, when there is no abnormality in the sin signal and the cos signal, the process proceeds to S106. When at least one of the sin signal and the cos signal is not normal (S105: NO), that is, when at least one of the sin signal and the cos signal is abnormal, the process proceeds to S107.

In S106, where there is no abnormality in the sin signal and the cos signal (S105: YES), the sin signal and the cos signal are as shown in FIG. 6A, and the sin signal and the cos signal are used. The electrical angle θ of the motor 10 is calculated based on the formula (4).
θ = tan ⁻¹ (sin signal / cos signal) (4)

  In S107, when the abnormality occurs in at least one of the sin signal and the cos signal (S105: NO), an abnormality flag is set, and the electrical angle θ is estimated using the terminal voltage detected by the voltage sensor 76. To do. Here, as an example, the U1 terminal voltage Vu1, the V1 terminal voltage Vv1, and the W1 terminal voltage Vw1 detected by the terminal voltage detection units 761 to 763 of the first inverter unit 21 as shown in FIG. 6B are used. To estimate the electrical angle θ. First, the d-axis voltage Vd and the q-axis voltage Vq are calculated by three-phase to two-phase conversion of the terminal voltages Vu1, Vv1, and Vw1. Using the calculated d-axis voltage Vd and q-axis voltage Vq, the motor voltage Vm is calculated based on Equation (5).

Further, using the motor voltage Vm calculated by Expression (5), the angle difference value Δθ from the previous calculation is calculated based on Expression (6).
Δθ = {Vm−RIm−L (di / dt)} / Ke (6)
In the above formula (6), R is the motor resistance, Im is the motor current, L is the inductance, di / dt is the time derivative of the motor current Im, and Ke is the counter electromotive voltage constant. The motor current Im is calculated based on, for example, the following formula (8) or formula (9).

Then, regarding the electrical angle θ of the motor 10, assuming that the current calculated value is θ _n and the previous calculated value is θ _n−1 , the current calculated value θ _n adds the angle difference value Δθ to the previous calculated value θ _n−1. Is calculated.
That is, the current calculation value θ _n is calculated by the equation (7).
θ _n = θ _n-1 + Δθ (7)

Θ _n calculated by Equation (7) is used for various calculations in place of the electrical angle θ calculated based on the sin signal and the cos signal.
Here, the calculation of θ _n using the U1 terminal voltage Vu1, the V1 terminal voltage Vv1, and the W1 terminal voltage Vw1 of the first system 100 has been described as the terminal voltage. The U2 terminal voltage Vu2, the V2 terminal voltage Vv2, and the W2 terminal voltage Vw2 may be used, or the terminal voltages of the first system 100 and the second system 200 may be used.

  In subsequent S108, it is determined whether or not the voltage across the shunt resistors 751 to 756, which are current detection values, is normal. When the current detection value is normal (S108: YES), that is, when there is no abnormality in the current detection value, the process proceeds to S109. When the current detection value is not normal (S108: NO), that is, when an abnormality has occurred in the current detection value, the process proceeds to S110. Here, it is assumed that there is no double failure, and if an abnormality has occurred in the current detection value of one system, the other system is normal.

  In S109, where there is no abnormality in the current detection value (S108: YES), each phase current Iu1, Iv1, Iw1, and two phase currents calculated from the voltage across the shunt resistors 751 to 756, which are current detection values, Various calculations are performed using Iu2, Iv2, and Iw2. In this embodiment, when there is no abnormality in the detected current value, the phase currents Iu1, Iv1, Iw1, Iu2, Iv2, and Iw2 are as shown in FIGS. 7A and 7B. The phase currents Iu1, Iv1, Iw1 of the first system 100 shown in FIG. 7A are equal to the phase currents Iu2, Iv2, Iw2 of the second system 200 shown in FIG. 7B.

  In S110, which shifts to the case where an abnormality has occurred in the current detection value (S108: NO), an abnormality flag is set and one phase current calculated using the current detection value of the system in which no abnormality has occurred is obtained. To perform various calculations. That is, when an abnormality occurs in the voltage across the shunt resistors 751 to 753 that are current detection values of the first system 100, the voltage is calculated from the voltage across the shunt resistors 754 to 756 that are current detection values of the second system 200. Various calculations are performed using the phase currents Iu2, Iv2, and Iw2 of the second system 200. Further, as shown in FIG. 8D, when an abnormality occurs in the voltage across the shunt resistors 754 to 756 that are current detection values of the second system 200, the first system 100 shown in FIG. Various calculations are performed using the phase currents Iu1, Iv1, and Iw1 of the first system 100 calculated from the voltage across the shunt resistors 751 to 753, which are current detection values.

  Here, the motor current Im calculated based on the two phase currents Iu1, Iv1, Iw1, Iu2, Iv2, and Iw2 will be described. First, the d-axis current Id1 and the q-axis current Iq1 are calculated by three-phase two-phase conversion based on the U1 current Iu1, the V1 current Iv1, and the W1 current Iw1, which are the phase currents of the first system 100. Further, based on the U2 current Iu2, the V2 current Iv2, and the W2 current Iw2 that are the phase currents of the second system 200, the d-axis current Id2 and the q-axis current Iq2 are calculated by three-phase two-phase conversion. At this time, the motor current Im is calculated based on the equation (8).

  The motor current Im calculated based on the phase currents Iu1, Iv1, Iw1 of the first system 100, which is one system, will be described. First, based on the phase currents Iu1, Iv1, and Iw1 of the first system 100, the d-axis current Id1 and the q-axis current Iq1 are calculated by three-phase to two-phase conversion. At this time, the motor current Im is calculated based on the equation (9).

  Here, comparing the equations (8) and (9), when the phase currents Iu1, Iv1, Iw1 and Iu2, Iv2, Iw2 are equal, the d-axis currents Id1 and Id2, and the q-axis currents Iq1 and Iq2 Therefore, the motor current Im calculated by the equation (9) is ½ of the motor current Im calculated by the equation (8).

  In subsequent S111, it is determined whether or not an abnormality has occurred in the detection value detected by the torque sensor 82, the rotation angle sensor 83, or the current sensor 75. Here, for example, the determination is made based on whether or not an abnormality flag is set. When no abnormality has occurred in the detection values detected by the torque sensor 82, the rotation angle sensor 83, and the current sensor 75 (hereinafter, simply referred to as “when no sensor abnormality has occurred”) (S111: NO), that is, When the abnormality flag is not set, the process proceeds to S112. When an abnormality has occurred in the detection value detected by the torque sensor 82, the rotation angle sensor 83, or the current sensor 75 (hereinafter, simply referred to as “sensor abnormality has occurred”) (S111: YES), S113. Migrate to

  In S112, when the sensor abnormality does not occur (S111: NO), the steering torque Tq calculated based on the main signal Tm and the sub signal Ts, which are torque detection values acquired from the torque sensor 82, and the rotation angle sensor. 83 based on the electrical angle θ calculated based on the sin signal and the cos signal that are the rotation angle detection values acquired from 83, and the voltage across the shunt resistors 751 to 756 that are the current detection values acquired from the current sensor 75. Using the respective phase currents Iu1, Iv1, Iw1, Iu2, Iv2, Iw2 calculated as described above, the drive of the motor 10 is controlled by the normal-time drive control. In the normal driving control, as shown in FIG. 8A, the assist amount determination unit 31 determines a current command value according to the steering torque Tq so that the assist torque becomes L1, and the current command value. The drive of the motor 10 is controlled based on the above.

  In S113, when the sensor abnormality has occurred (S111: YES), it is determined whether or not there is one detected value in which abnormality has occurred. When it is determined that there is not one detected value having an abnormality (S113: NO), that is, when there are two or more detected values having an abnormality, the process proceeds to S115. If it is determined that there is only one detected value (S113: YES), the process proceeds to S114.

In S114, the drive of the motor 10 is controlled by backup control that does not use the detected value in which an abnormality has occurred. In the backup control, the drive control of the motor 10 is performed using various calculation values calculated without using the detection values in which the abnormality has occurred in S104, S107, and S110 according to the abnormal part.
Further, in the backup control, as shown in FIG. 8B, the assist amount determination unit 31 determines a current command value corresponding to the steering torque Tq so that the assist torque becomes L2 smaller than L1, and the current The drive of the motor 10 is controlled based on the command value. In the backup control of the present embodiment, the first system 100 and the second system 200 are used, and the control is performed so that the assist torque is smaller than the normal time drive control as a whole.

Thus, when the sensor abnormality occurs, the assist torque is smaller than when the sensor abnormality does not occur, and the torque required for the driver to steer the steering wheel 91 increases, that is, the steering wheel 91 feels heavy. This makes it easier for the driver to sense that a failure has occurred in the device. If the driver senses that there is a failure in the device, it can be a motivation to bring the vehicle to a repair shop at an early stage, so other parts can break down by continuing to use it without noticing the occurrence of the failure. Thus, it is possible to avoid a situation in which steering assist cannot be performed.
The assist torque L1 corresponds to “first output torque”, and the assist torque L2 corresponds to “second output torque”.

  When it is determined that there are two or more detected values in which an abnormality has occurred (S113: NO), the drive of the motor 10 is stopped and the steering assist by the electric power steering device 2 is stopped.

As shown in FIG. 4, the processing in S202 to S210 that is shifted to when the backup control is being performed (S101: NO) is the same as the processing in S102 to S110 in FIG.
In S211, it is determined whether or not there is one detected value in which an abnormality has occurred. When it is determined that there is not one detected value having an abnormality (S211: NO), that is, when it is determined that there are two or more detected values having an abnormality, the process proceeds to S213. If it is determined that there is only one detected value (S211: NO), the process proceeds to S212.

In S212, the sensor abnormality at the same location continues and no other sensor abnormality occurs, so the backup control similar to S114 is continued.
When it is determined that there are two or more detected values in which an abnormality has occurred (S213: YES), the driving of the motor 10 is stopped and the steering assist by the electric power steering device 2 is performed as in S115. Stop.

  Further, the abnormality determination of the detection value of each sensor in S102, S105, S108, S202, S205, and S208 may be performed by any method. For example, it may be determined that an abnormality has occurred by continuing to output a predetermined lower limit value, falling below a predetermined lower limit value, continuing to output a predetermined upper limit value, exceeding a predetermined upper limit value, etc. it can.

As described above in detail, the motor control device 1 includes a stator, a rotor provided to be rotatable relative to the stator, and a motor having the first winding set 11 and the second winding set 12 wound around the stator. 10 drive is controlled.
In the control unit 30, the following processing is executed. A detection value relating to driving of the motor 10 is acquired (S100), and it is determined whether or not an abnormality has occurred in the detection value (S102, S105, S108, S202, S205, S208). When it is determined that there is no abnormality in the detected value (S111: NO), the assist torque L1 is output using the detected torque value, the rotation angle detected value, and the current detected value that are the acquired detected values. The drive of the motor 10 is controlled (S112). In addition, when it is determined that an abnormality has occurred in at least one of the detection values (S111: YES and S113: YES, S211: YES), other detection values other than the detection value in which an abnormality has occurred are used to assist. The drive of the motor 10 is controlled so as to output an assist torque L2 different from the torque L1 (S114, S212).

  In the present embodiment, when an abnormality occurs in at least one of the detected values, the drive of the motor 10 is controlled by the backup control without using the detected value where the abnormality has occurred, so the drive of the motor 10 is continued. be able to. Further, since the drive of the motor 10 is controlled so as to output the assist torque L2 different from the assist torque L1 that is output when no abnormality is detected in the detected value, it is appropriately detected that the apparatus is abnormal. Can be made.

  The motor control device 1 of this embodiment is applied to an electric power steering device 2. In the present embodiment, by performing the above-described backup control, even if the detected value is abnormal due to a failure of the sensor or the like, the driving of the motor 10 is continued and the steering assist of the steering wheel 91 can be continued. Further, since the assist torque L2 that is different from the assist torque L1 that is output when there is no abnormality in the detected value is output, it is possible to make the driver appropriately sense that an abnormality has occurred in the device. As a result, it is possible to avoid a situation in which the steering assist cannot be performed due to failure of other parts and failure to drive the electric motor while the use is continued without noticing the failure of the sensor or the like.

  In the present embodiment, the driving of the motor 10 is controlled so that the assist torque L2 when the detected value is abnormal is smaller than the assist torque L1 when the detected value is not abnormal. As a result, the torque required for the driver to steer the steering wheel 91 increases, and the steering wheel 91 feels heavy, so that the driver can appropriately sense that an abnormality has occurred in the detected value.

  The motor 10 outputs assist torque related to steering. In addition, the control unit 30 includes a main signal Tm and a sub signal Ts that are torque detection values related to the steering torque Tq detected by the torque sensor 82, and a rotation angle related to the electrical angle θ of the motor 10 detected by the rotation angle sensor 83. The sin signal and cos signal that are detection values, and the voltage across the shunt resistors 751 to 756 that are current detection values related to the respective phase currents of the winding sets 11 and 12 detected by the current sensor 75 are obtained, and these are obtained. Use to control the drive of the motor 10. Thereby, the drive of the motor 10 can be controlled appropriately.

  The control unit 30 acquires the main signal Tm and the sub signal Ts that are two torque detection values from the torque sensor 82. If it is determined that an abnormality has occurred in a part of the detected torque value (S102: NO, S202: NO), the detected torque value is used (S104, S204) and the motor 10 is driven. Control. Thereby, even if abnormality has arisen in a part of torque detection value, the drive of the motor 10 can be controlled appropriately.

  Further, the control unit 30 acquires voltage detection values related to the terminal voltages of the respective phases of the winding sets 11 and 12 detected by the voltage sensor 76 (S100), and determines that an abnormality has occurred in the rotation angle detection value. If so (S105: NO, S205: NO), the electrical angle θ estimated based on the voltage detection value is used (S107, S207), and the drive of the motor 10 is controlled. Thereby, even if abnormality of a rotation angle detection value arises, the drive of the motor 10 can be controlled appropriately.

  Furthermore, the motor 10 of the present embodiment has a first winding set 11 and a second winding set 12, and a current sensor 75 is provided for each winding set 11, 12. The control unit 30 acquires a current detection value for each of the winding groups 11 and 12. If it is determined that an abnormality has occurred in the current detection values of some of the winding groups (S108: NO, S208: NO), the current detection of the winding group that does not include the current detection values in which the abnormality has occurred The value is used (S110, S210) to control the driving of the motor 10. Thereby, even if abnormality arises in a part of current detection value, the drive of the motor 10 can be controlled appropriately.

  In the present embodiment, the control unit 30 constitutes “detected value acquisition means”, “abnormality determination means”, “normal drive control means”, and “backup control means”. Further, S100 in FIG. 3 corresponds to processing as a function of “detection value acquisition means”, S102, S105, S108, S202, S205, and S208 correspond to processing as a function of “abnormality determination means”, and S112. Corresponds to processing as a function of “normal drive control means”, and S114 and S212 correspond to processing as a function of “backup control means”.

(Second Embodiment)
A motor control apparatus according to a second embodiment of the present invention will be described with reference to FIG. Since this embodiment is different from the first embodiment only in backup control, only backup control will be described, and description of other configurations, details of control, and the like will be omitted. Further, FIG. 9A is the same as FIG.

  In the backup control of the present embodiment, as shown in FIG. 9B, the assist amount determination unit 31 outputs torque obtained by adding the pulse command value Lp to the assist torque L1 so that the assist torque pulsates. Then, a current command value corresponding to the steering torque Tq is determined, and driving of the motor 10 is controlled based on the current command value. In the present embodiment, the torque obtained by adding the pulse command value Lp to the assist torque L1 corresponds to the “second output torque”.

  As a result, in addition to the same effects as in the above embodiment, when the detected value is abnormal, the assist torque pulsates so that the driver can appropriately sense that the apparatus is abnormal. .

(Other embodiments)
(A) In other embodiments, as in the above embodiment, when the electric motor is driven by a plurality of systems and it is determined that an abnormality has occurred in the detected value, to some winding groups The power supply may be cut off. In the example of the first embodiment, when it is determined that an abnormality has occurred in the detected value, the power supply relay 52 is shut off, and the motor 10 is driven only by the first system 100 without using the second system 200. Alternatively, the power relay 51 may be cut off, and the motor 10 may be driven only by the second system 200 without using the first system 100. In this case, as shown in the above formulas (8) and (9), the electric power related to the driving of the motor 10 is about half that when driving with two systems.
In other words, “the second output torque is made smaller than the first output torque by cutting off the power supply to a part of the winding sets”. Thereby, there exists an effect similar to the said embodiment. Further, by reducing the number of systems related to the drive control of the electric motor, it is possible to simplify the control when an abnormality occurs in the detected value.

  (A) In the first embodiment, the assist torque when the detected value is abnormal is controlled to be smaller than the assist torque when the detected value is not abnormal. Further, in the second embodiment, the pulse command value is added so that pulsation occurs in the assist torque when an abnormality occurs in the detected value. In another embodiment, these may be combined, and the pulse command value may be added to the assist torque that is smaller than the assist torque when no abnormality has occurred to cause pulsation. As means for reducing the assist torque, all the systems related to the driving of the electric motor may be used, or only a part of the systems may be used as described in (a) above.

(C) In the above embodiment, the electric motor is driven by two systems. However, in another embodiment, one system may be used, or three or more systems may be used.
(D) In the above embodiment, when an abnormality occurs in the current detection value of one system, the drive of the motor is controlled using the current detection value of the other system. In another embodiment, when an abnormality occurs in the current detection value, so-called current sensorless control may be performed.

  (E) In the above embodiment, a torque sensor, a rotation angle sensor, a current sensor, and a voltage sensor are provided, and detection values from these sensors are acquired. In other embodiments, some sensors may be omitted, for example, by omitting the rotation angle sensor and estimating the electrical angle θ from each phase current, terminal voltage, or the like. Further, for example, another sensor such as a steering angle sensor for detecting the steering angle of the steering wheel is provided, and the detection value from the sensor is acquired to control the driving of the electric motor. If this occurs, backup control similar to that in the above embodiment may be performed.

(F) In the above embodiment, the abnormality determination of the torque detection value, the rotation angle detection value, and the current detection value is executed as a series of processes. In other embodiments, the order of abnormality determination may be changed, or abnormality determination may be performed for each detected value.
(G) In the above embodiment, when an abnormality occurs in two or more detection values, the driving of the electric motor is stopped. However, in other embodiments, even if an abnormality occurs in a plurality of detection values, the electric motor If the drive can be continued, the drive of the electric motor may be continued by the backup control.
(H) In the above embodiment, the motor control device is applied to the electric power steering device, but may be applied to other devices.
As mentioned above, this invention is not limited to the said embodiment at all, In the range which does not deviate from the meaning of invention, it can implement with a various form.

1 ... Motor control device (motor control device)
2 ... Electric power steering device 10 ... Motor (electric motor)
11, 12... Winding set 30... Control unit (detection value acquisition means, abnormality determination means, normal time drive control means, backup control means)
75 ... Current sensor 76 ... Voltage sensor 82 ... Torque sensor 83 ... Rotation angle sensor

Claims (9)

An electric motor control device (1) for controlling the driving of an electric motor (10) having a stator, a rotor provided to be rotatable relative to the stator, and a winding set (11, 12) wound around the stator. And
Detection value acquisition means (S101) for acquiring a detection value relating to driving of the electric motor;
An abnormality determination means (S102, S105, S108, S202, S205, S208) for determining whether an abnormality has occurred in the detected value;
When it is determined by the abnormality determining means that no abnormality has occurred in the detected value, the electric motor is driven to output a first output torque using the detected value acquired by the detected value acquiring means. Normal-time drive control means (S112) for controlling;
When it is determined by the abnormality determination means that an abnormality has occurred in at least one of the detection values, the detection value other than the detection value in which an abnormality has occurred is used, and the first output torque is Backup control means (S114, S212) for controlling the drive of the electric motor to output different second output torque;
An electric motor control device comprising:   2. The motor control device according to claim 1, wherein the backup control unit pulsates the second output torque by adding a pulse command value to a torque command value related to control of driving of the motor. 3.   3. The motor control device according to claim 1, wherein the backup control unit controls driving of the motor so that the second output torque is smaller than the first output torque. 4. The winding group is plural,
The said backup control means makes the said 2nd output torque smaller than the said 1st output torque by interrupting | blocking the electric power supply to a part of said coil | winding set, The Claim 3 characterized by the above-mentioned. Electric motor control device. The electric motor outputs assist torque related to steering,
The detection value acquisition means includes a torque detection value related to the steering torque detected by the torque sensor (82), a rotation angle detection value related to the rotation angle of the motor detected by the rotation angle sensor (83), and a current sensor. Obtaining a current detection value relating to each phase current of the winding set detected by (75);
The said normal time drive control means controls the drive of the said electric motor using the said torque detection value, the said rotation angle detection value, and the said electric current detection value, The any one of Claims 1-4 characterized by the above-mentioned. The electric motor control device described in 1. The detection value acquisition means acquires at least two torque detection values from the torque sensor,
When it is determined by the abnormality determining means that an abnormality has occurred in a part of the torque detection value,
The motor control apparatus according to claim 5, wherein the backup control unit controls driving of the motor using the torque detection value in which no abnormality has occurred. The detection value acquisition means acquires a voltage detection value related to a terminal voltage of each phase of the winding set detected by the voltage sensor (76),
When it is determined by the abnormality determination means that an abnormality has occurred in the rotation angle detection value,
The motor control device according to claim 5, wherein the backup control unit controls driving of the motor using the rotation angle estimated based on the voltage detection value. The winding group is plural,
The current sensor is provided for each winding set,
The detection value acquisition means acquires the current detection value for each winding set from the current sensor,
When it is determined by the abnormality determining means that an abnormality has occurred in the current detection values of some of the winding sets,
The said backup control means controls the drive of the said motor using the said current detection value of the said coil | winding set which does not contain the said current detection value in which abnormality has arisen. The electric motor control device according to one item. The motor control device according to any one of claims 1 to 8,
The electric motor for outputting an assist torque for steering;
An electric power steering device (2) comprising:

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