JP2017038487A - Motor control device, electric power steering apparatus, and vehicle - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a motor control device capable of surely controlling drive of an electric motor even when failure is generated in a motor electric angle detection section for detecting a motor electric angle, and to provide an electric power steering apparatus and a vehicle.SOLUTION: A motor control device includes a motor electric angle estimation section 63 for calculating a motor electric angle estimation value θme on the basis of an output shaft rotation angle detection value θos of a steering shaft 12, which is detected by an output side rotation angle sensor 13c. When a resolver 23a and an angle calculation section 60 are normal, drive of a 3-phase electric motor 22 is controlled on the basis of a motor electric angle θm calculated by the angle calculation section 60. On the other hand, when at least one of the resolver 23a and the angle operation section 60 is abnormal, the drive of the 3-phase electric motor 22 is controlled on the basis of the motor electric angle estimation value θme estimated by the motor electric angle estimation section 63.SELECTED DRAWING: Figure 8

Description

  The present invention relates to a motor control device that drives and controls a multiphase electric motor mounted on an electric power steering device.

As a motor control device that controls an electric motor of an electric power steering device mounted on a vehicle, for example, a control device for a multiphase rotating machine described in Patent Document 1 is disclosed.
In the conventional example described in Patent Document 1, the rotor rotational position θ is detected by a position sensor such as a resolver, and the U-phase which is a three-phase voltage command value based on the command voltages Vd1, Vq1 and the rotor rotational position θ. The command voltage Vuu ^* 1, the V-phase command voltage Vvu ^* 1, and the W-phase command voltage Vwu ^* 1 are calculated.

Japanese Patent No. 4999836

However, since the conventional example of Patent Document 1 does not consider the case where the position sensor that detects the rotor rotational position fails, it is difficult to accurately drive and control the multiphase rotating machine after the failure.
Therefore, the present invention has been made paying attention to the unsolved problems of the above conventional example, and even when a failure occurs in the motor electrical angle detector that detects the motor electrical angle (rotor rotational position), the electric motor is provided. An object of the present invention is to provide a motor control device, an electric power steering device, and a vehicle capable of continuously and accurately controlling the drive.

  In order to solve the above-described object, a motor control device according to a first aspect of the present invention generates a steering assist force based on the steering angle detected by a steering angle detection unit that detects a steering angle of a steering. When the motor electrical angle estimator for estimating the motor electrical angle of the phase electric motor and the motor electrical angle detector for detecting the motor electrical angle are normal, the polyphase is based on the motor electrical angle detected by the motor electrical angle detector. A motor drive control unit that drives and controls the electric motor, and controls the multiphase electric motor based on the estimated motor electrical angle estimated by the motor electrical angle estimation unit when the motor electrical angle detection unit is abnormal.

An electric power steering apparatus according to the second aspect of the present invention includes the motor control apparatus according to the first aspect.
Furthermore, a vehicle according to a third aspect of the present invention includes the electric power steering device according to the second aspect.

According to the present invention, the motor electrical angle of the multiphase electric motor is estimated based on the steering angle detected by the steering angle detection unit. When the motor electrical angle detector that detects the motor electrical angle is abnormal, the multiphase electric motor can be driven and controlled based on the estimated motor electrical angle estimated by the motor electrical angle estimator. As a result, even when the motor electrical angle detection unit is abnormal, it is possible to continuously drive the multiphase electric motor.
In addition, since the electric power steering apparatus is configured to include the motor control apparatus having the above-described effects, the multiphase electric motor can be driven and controlled by the estimated motor electric angle even when an abnormality occurs in the motor electric angle detection unit. The steering assist function of the electric power steering device can be continued.
Furthermore, since the vehicle is configured to include the electric power steering device having the above-described effects, the steering assist function of the electric power steering device can be continued even when an abnormality occurs in the motor electrical angle detection unit. It becomes possible to improve.

It is a figure showing an example of 1 composition of vehicles concerning a 1st embodiment of the present invention. 1 is a schematic configuration diagram illustrating a torque sensor according to a first embodiment of the present invention. It is sectional drawing which shows the structure of the three-phase electric motor which concerns on 1st Embodiment of this invention. It is a schematic diagram which shows the winding structure of the three-phase electric motor of FIG. It is a circuit diagram which shows the specific structure of the motor control apparatus which concerns on 1st Embodiment of this invention. It is a characteristic diagram which shows the relationship between the steering torque at the time of normal, and a steering auxiliary current command value. It is a characteristic diagram which shows the relationship between the steering torque at the time of abnormality, and a steering auxiliary current command value. It is a block diagram which shows the specific structural example of the motor electrical angle detection circuit which concerns on 1st Embodiment of this invention. It is a block diagram which shows the specific structural example of the relative offset amount estimation part which concerns on 1st Embodiment of this invention. It is a wave form diagram explaining the relationship between the origin of a motor electrical angle, and the reference value of an output shaft rotation angle. (A) is a wave form diagram which shows an example of the torque command value for estimating a motor electrical angle origin, (b) is a motor output torque at the time of inputting the drive current by the command value of (a) into an electric motor. It is a wave form diagram which shows an example of a response waveform. It is a block diagram which shows the specific structure of the 1st estimated angle correction | amendment part which concerns on 1st Embodiment of this invention. It is a figure which shows an example of the relationship between the load torque by the deformation characteristic of the mechanical element of an electric motor, and a motor electrical angle. It is a figure for demonstrating correction | amendment of the motor electrical angle estimated value in a zero cross timing. It is a block diagram which shows the specific structure of the 2nd estimated angle correction | amendment part which concerns on 2nd Embodiment of this invention. 16 (a) and 16 (c) are diagrams showing interphase counter electromotive voltage waveforms during motor positive / negative rotation, and FIGS. 16 (b) and (d) are amplitudes of interphase counter electromotive voltage waveforms during motor positive / negative rotation. It is a figure which shows the relationship of a relationship and a code | symbol. It is a figure which shows the magnitude relationship of a phase back electromotive force waveform, and the switching timing of a code | symbol. It is a block diagram which shows the specific structure of the 3rd estimated angle correction | amendment part which concerns on 3rd Embodiment of this invention. It is a wave form diagram which shows an example of the relationship between the waveform of 1st counter electromotive voltage EMF1, and the waveform of 2nd counter electromotive voltage EMF2. It is a block diagram which shows the specific structure of the 4th estimated angle correction | amendment part which concerns on 4th Embodiment of this invention.

Next, based on the drawings, first to fourth embodiments of the present invention will be described. In the following description of the drawings, the same or similar parts are denoted by the same or similar reference numerals. However, it should be noted that the drawings are schematic and dimensional relationships and ratios are different from actual ones.
In addition, the following first to fourth embodiments exemplify apparatuses and methods for embodying the technical idea of the present invention, and the technical idea of the present invention is the material of components, The shape, structure, arrangement, etc. are not specified below. The technical idea of the present invention can be variously modified within the technical scope defined by the claims described in the claims.

(First embodiment)
(Constitution)
As shown in FIG. 1, the vehicle 1 according to the first embodiment of the present invention includes front wheels 2FR and 2FL and rear wheels 2RR and 2RL as left and right steered wheels. The front wheels 2FR and 2FL are steered by the electric power steering device 3.
The electric power steering device 3 has a steering wheel 11, and a steering force applied to the steering wheel 11 from a driver is transmitted to the steering shaft 12. The steering shaft 12 has an input shaft 12a and an output shaft 12b. One end of the input shaft 12a is connected to the steering wheel 11, and the other end is connected to one end of the output shaft 12b via the torque sensor 13.

  The steering force transmitted to the output shaft 12 b is transmitted to the lower shaft 15 via the universal joint 14 and further transmitted to the pinion shaft 17 via the universal joint 16. The steering force transmitted to the pinion shaft 17 is transmitted to the tie rod 19 via the steering gear 18 to steer the front wheels 2FR and 2FL as steered wheels. Here, the steering gear 18 is configured in a rack and pinion type having a pinion 18a coupled to the pinion shaft 17 and a rack 18b meshing with the pinion 18a. Therefore, the steering gear 18 converts the rotational motion transmitted to the pinion 18a into the straight motion in the vehicle width direction by the rack 18b.

A steering assist mechanism 20 that transmits a steering assist force to the output shaft 12b is connected to the output shaft 12b of the steering shaft 12. The steering assist mechanism 20 is a multiphase composed of, for example, a three-phase brushless motor that generates a steering assist force that is connected to the reduction gear 21 and a reduction gear 21 that is connected to the output shaft 12b. And a three-phase electric motor 22 as an electric motor.
The torque sensor 13 detects the steering torque applied to the steering wheel 11 and transmitted to the input shaft 12a. As shown in FIG. 2, the torque sensor 13 converts the steering torque into a torsional angular displacement of a torsion bar 13a (not shown) interposed between the input shaft 12a and the output shaft 12b, and converts the torsional angular displacement into the input shaft 12a. The input side rotation angle sensor 13b arranged on the output side and the output side rotation angle sensor 13c arranged on the output shaft 12b side are converted into an angle difference and detected.

In the first embodiment, the input side rotation angle sensor 13b and the output side rotation angle sensor 13c are sensors that detect relative rotation angles.
Further, as shown in FIG. 3, the three-phase electric motor 22 includes a stator 22S having teeth Te that are formed inwardly on the inner peripheral surface to form a slot SL, and an inner peripheral side of the stator 22S. And an 8-pole surface magnet type rotor 22R having a permanent magnet PM disposed on the surface thereof so as to be rotatably opposed to the teeth Te. Here, the number of teeth Te of the stator 22S is set to, for example, n = 2 by the number of phases × 2n (n is an integer equal to or larger than 2), and the configuration is 8 poles and 12 slots.

Then, in the slot SL of the stator 22S, the first three-phase motor winding L1 and the second three-phase motor winding L1 which are the same phase with respect to the rotor magnet in the two systems shown in FIG. Two three-phase motor windings L2 are wound. In the first three-phase motor winding L1, one end of the U-phase coil L1u, V-phase coil L1v, and W-phase coil L1w is connected to each other to form a star connection, and the other end of each phase coil L1u, L1v, and L1w is the motor. The motor drive currents I1u, I1v, and I1w are individually connected to the control device 25.
Two coil portions L1ua, L1ub, L1va, L1vb and L1wa, L1wb are formed in each phase coil L1u, L1v, and L1w, respectively. These coil portions L1ua, L1va, and L1wa are wound around the teeth Te1, Te2, and Te3 in the clockwise direction by concentrated winding. In addition, the coil portions L1ub, L1vb, and L1wb are wound around the teeth Te1, Te2, Te3 and the clockwise teeth Te7, Te8, and Te9 that are opposite to the teeth Te1, Te2, and Te3 in a concentrated manner.

The second three-phase motor winding L2 has a star connection with one end of the U-phase coil L2u, V-phase coil L2v, and W-phase coil L2w, and the other end of each phase coil L2u, L2v, and L2w. Are connected to the motor control device 25, and motor drive currents I2u, I2v and I2w are individually supplied.
Two coil portions L2ua, L2ub, L2va, L2vb and L2wa, L2wb are formed in each phase coil L2u, L2v, and L2w, respectively. These coil portions L2ua, L2va and L2wa are wound around the teeth Te4, Te5 and Te6 in the clockwise direction by concentrated winding. The coil portions L1ub, L1vb, and L1wb are wound around the teeth Te4, Te5, and Te6 on the counterclockwise teeth Te10, Te11, and Te12 diagonally across the rotor 22R with concentrated winding.

The coil portions L1ua, L1ub, L1va, L1vb and L1wa, L1wb of each phase coil L1u-L1w and the coil portions L2ua, L2ub, L2va, L2vb and L2wa, L2wb of each phase coil L2u-L2w sandwich the teeth Te. It is wound around the SL so that the direction of the energization current is the same.
Thus, the coil portions L1ua, L1ub, L1va, L1vb and L1wa, L1wb of the phase coils L1u to L1w of the first three-phase motor winding L1 and the phase coils L2u to L2wa of the second three-phase motor winding L2 The coil portions L2ua, L2ub, L2va, L2vb and L2wa, L2wb of L2w are wound around 12 different teeth. That is, the phase coils L1ua, L1va, L1wa, which are the first system, are sequentially wound around the 12 teeth Te in the same winding direction in the clockwise direction, and then the phase coils L2ua, L2va, which are the second system, L2wa is wound in the same winding direction in the clockwise direction, and the phase coils L1ub, L1vb, L1wb which are the first system are wound in the same winding direction in the clockwise direction, and finally the second system The phase coils L2ub, L2vb and L2wb are wound in the same winding direction in the clockwise direction. For this reason, the in-phase coil portions of the first multiphase motor winding L1 and the second motor winding L2 do not interlink simultaneously with the same magnetic flux formed by the permanent magnet PM of each magnetic pole of the rotor 22R. It is wound like so. Therefore, each coil part of the first three-phase motor winding L1 and each coil part of the second three-phase motor winding L2 constitute a magnetic circuit that minimizes mutual magnetic interference. .

Furthermore, as shown in FIG. 5, the three-phase electric motor 22 includes a rotational position sensor 23a configured from a resolver that detects the rotational position of the rotor. The detection value from the rotational position sensor 23a is supplied to the motor electrical angle detection circuit 23, and the motor electrical angle detection circuit 23 detects the motor electrical angle θm. The rotational position sensor 23a is not limited to the resolver, and may be composed of other sensors such as a rotary encoder. Further, the rotational position sensor 23a may be hereinafter referred to as “resolver 23a”.
The motor control device 25 receives the steering torque T detected by the torque sensor 13 and the vehicle speed Vs detected by the vehicle speed sensor 26 and the motor electrical angle θm output from the motor electrical angle detection circuit 23. The

In addition, a direct current is input to the motor control device 25 from a battery 27 as a direct current source. Here, the negative electrode of the battery 27 is grounded, and the positive electrode thereof is connected to the motor control device 25 via an ignition switch 28 (hereinafter sometimes referred to as “IGN switch 28”) for starting the engine, and IGN. It is directly connected to the motor control device 25 without going through the switch 28.
The specific configuration of the motor control device 25 is configured as shown in FIG. That is, the motor control device 25 includes a control calculation device 31 for calculating a motor current command value, and first and second motor drive circuits 32A to which motor current command values output from the control calculation device 31 are individually input. And 32B, and the first and second three-phase motor windings L1 and L2 of the three-phase electric motor 22 and the first and second motor drive circuits 32A and 32B. 1 and second motor current cut-off circuits 33A and 33B.

  Although not shown in FIG. 5, the control arithmetic unit 31 receives the steering torque T detected by the torque sensor 13 and the vehicle speed Vs detected by the vehicle speed sensor 26 shown in FIG. As shown, the motor electrical angle θm output from the motor electrical angle detection circuit 23 is input. Further, the motor current I1m (output from the coils of the respective phases of the first multiphase motor winding L1 and the second multiphase motor winding L2 of the three-phase electric motor 22 output from the current detection circuits 34A and 34B ( I1mu, I1mv, I1mw) and I2m (I2mu, I2mv, I2mw) are input.

Hereinafter, when there is no need to distinguish between the motor currents I1m and I2m, the detected value may be described as “motor current detected value Im (Imu, Imv, Imw)”.
In addition, as shown in FIG. 5, the control arithmetic unit 31 includes a voltage provided between the first and second motor drive circuits 32A and 32B and the first and second motor current cutoff circuits 33A and 33B. Motor phase voltages V1m (V1mu, V1mv, V1mw) and V2m (V2mu, V2mv, V2mw) detected by the detection circuits 40A and 40B are input.
Hereinafter, when there is no need to distinguish between the motor phase voltages V1m and V2m, the detected value may be described as “motor voltage detected value Vm (Vmu, Vmv, Vmw)”.

In the control arithmetic unit 31, when the first and second motor drive circuits 32A and 32B are normal, refer to the normal-time steering auxiliary current command value calculation map shown in FIG. 6 set in advance based on the steering torque T and the vehicle speed Vs. Then, steering assist current command values I1 ^* and I2 ^* are calculated. Further, in the control arithmetic unit 31, when the first and second motor drive circuits 32A or 32B are abnormal, the abnormal-time steering auxiliary current command value calculation map shown in FIG. 7 preset based on the steering torque T and the vehicle speed Vs is shown. , Steering assist current command values I1 ^* and I2 ^* are calculated.
Further, in the control arithmetic unit 31, the target d-axis current command value Id ^* and the target q-axis current command value in the dq coordinate system based on the calculated steering assist current command values I1 ^* and I2 ^* and the motor electrical angle θm. Iq ^* is calculated. In addition, the control arithmetic unit 31 converts the calculated d-axis current command value Id ^* and q-axis current command value Iq ^* into dq-phase to three-phase, thereby converting the U-phase current command value Iu ^* , the V-phase current command value Iv ^*, and W-phase current command value Iw ^* is calculated. The control arithmetic unit 31 then calculates the U-phase current command value Iu ^* , the V-phase current command value Iv ^{*, the} W-phase current command value Iw ^*, and the current detection values detected by the current detection circuits 34A and 34B for each phase. Current deviations ΔIu, ΔIv, and ΔIw from the added value are calculated. Still further, the control arithmetic unit 31 performs, for example, a PI control calculation or a PID control calculation on the calculated current deviations ΔIu, ΔIb, and ΔIw, and performs a three-phase voltage command value V1 for the first and second motor drive circuits 32A and 32B. ^{* And} V2 ^* are calculated, and the calculated three-phase voltage command values V1 ^* and V2 ^* are output to the first and second motor drive circuits 32A and 32B.

Further, the control arithmetic device 31 is provided between the first and second motor current cutoff circuits 33A and 33B and the first and second three-phase motor windings L1 and L2 of the three-phase electric motor 22. Motor current detection values I1mu, I1mv, I1mw and I2mu, I2mv, I2mw detected by the first and second abnormality detection circuits 35A and 35B are input.
Then, the control arithmetic unit 31 compares the input motor current detection values I1mu to I1mw and I2mu to I2mw with the phase current command values Iu ^* , Iv ^* and Iw ^* calculated by the control arithmetic unit 31 in the first and later described. An abnormality detection unit 31a that detects open failure and short-circuit failure of field effect transistors (FETs) Q1 to Q6 as switching elements constituting the second inverter circuits 42A and 42B is provided.

In the abnormality detection unit 31a, the first and second motors that have detected an abnormality when an open failure or a short failure of the field effect transistors (FETs) constituting the first and second inverter circuits 42A and 42B are detected. An abnormality detection signal SAa or SAb having a logical value “1” is output to the gate drive circuit 41A or 41B of the drive circuit 32A or 32B.
Each of the first and second motor drive circuits 32A and 32B receives the three-phase voltage command values V1 ^* and V2 ^* output from the control arithmetic unit 31 to form a gate signal, and performs current control during abnormality. Gate drive circuits 41A and 41B having a section 41a, and first and second inverter circuits 42A and 42B to which gate signals output from the gate drive circuits 41A and 41B are input.

When the voltage command values V1 ^* and V2 ^* are input from the control arithmetic unit 31, each of the gate drive circuits 41A and 41B performs a pulse based on the voltage command values V1 ^* and V2 ^* and the triangular carrier signal Sc. Six gate signals subjected to width modulation (PWM) are formed, and these gate signals are output to the first and second inverter circuits 42A and 42B.
Further, when the abnormality detection signal SAa input from the control arithmetic unit 31 is a logical value “0” (normal), the gate drive circuit 41A has three gates with a high level relative to the first motor current cutoff circuit 33A. In addition to outputting a signal, two high-level gate signals are output to the first power cutoff circuit 44A. Furthermore, when the abnormality detection signal SAa is a logical value “1” (abnormal), the gate drive circuit 41A is configured to provide three low-level gates with respect to the first motor current cutoff circuit 33A by the abnormal current control unit 41a. Signals are simultaneously output to cut off the motor current, and at the same time, two low-level gate signals are output to the first power cut-off circuit 44A to cut off the battery power.

  Similarly, when the abnormality detection signal SAb input from the control arithmetic unit 31 is a logical value “0” (normal), the gate drive circuit 41B has three high levels with respect to the second motor current cutoff circuit 33B. While outputting a gate signal, it outputs two high-level gate signals to the second power shutoff circuit 44B. Further, when the abnormality detection signal SAb is a logical value “1” (abnormal), the gate drive circuit 41B has three low-level gates with respect to the second motor current cutoff circuit 33B in the abnormal current control unit 41a. A signal is simultaneously output to cut off the motor current, and at the same time, two low level gate signals are outputted to the second power cut-off circuit 44B to cut off the battery power.

In each of the first and second inverter circuits 42A and 42B, the battery current of the battery 27 is input via the noise filter 43 and the first and second power shut-off circuits 44A and 44B, and smoothing electrolysis is performed on the input side. Capacitors CA and CB are connected.
These first and second inverter circuits 42A and 42B have six field effect transistors (FETs) Q1 to Q6 as six switching elements, and three switching arms SAu in which two field effect transistors are connected in series, It has a configuration in which SAv and SAw are connected in parallel. The gate signals output from the gate drive circuits 41A and 41B are input to the gates of the field effect transistors Q1 to Q6, so that the U-phase current Iu, between the field effect transistors of the switching arms SAu, SAv, and SAw The V-phase current Iv and the W-phase current Iw are output to the first and second three-phase motor windings L1 and L2 of the three-phase electric motor 22 via the first and second motor current cutoff circuits 33A and 33B. .

Although not shown, the voltage across the shunt resistor inserted between the switching arms SAu, SAv and SAw of the first and second inverter circuits 42A and 42B and the ground is input to the current detection circuits 34A and 34B. These current detection circuits 34A and 34B detect motor currents I1m (I1mu to I1mw) and I2m (I2mu to I2mw).
The first motor current cut-off circuit 33A includes three current cut-off field effect transistors QA1, QA2, and QA3. The source of the field effect transistor QA1 is connected to the connection point of the transistors Q1 and Q2 of the switching arm SAu of the first inverter circuit 42A, and the drain is connected to the first three-phase motor winding L1 via the first abnormality detection circuit 35A. Connected to the U-phase coil L1u. The source of the field effect transistor QA2 is connected to the connection point between the transistors Q3 and Q4 of the switching arm SAv of the first inverter circuit 42A, and the drain is connected to the first three-phase motor winding via the first abnormality detection circuit 35A. It is connected to the V-phase coil L1v of the line L1. Further, the source of the field effect transistor QA3 is connected to the connection point of the transistors Q5 and Q6 of the switching arm SAw of the first inverter circuit 42A, and the drain is connected to the first three-phase motor winding via the first abnormality detection circuit 35A. It is connected to the W-phase coil L1w of the line L1.

  The second motor current cut-off circuit 33B has three current cut-off field effect transistors QB1, QB2, and QB3. The source of the field effect transistor QB1 is connected to the connection point of the transistors Q1 and Q2 of the switching arm SBu of the second inverter circuit 42B, and the drain is connected to the second three-phase motor winding L2 via the second abnormality detection circuit 35B. Connected to the U-phase coil L2u. The source of the field effect transistor QB2 is connected to the connection point of the transistors Q3 and Q4 of the switching arm SBv of the second inverter circuit 42B, and the drain is connected to the second three-phase motor winding via the first abnormality detection circuit 35A. It is connected to the V-phase coil L2v of the line L2. Further, the source of the field effect transistor QB3 is connected to the connection point of the transistors Q5 and Q6 of the switching arm SBw of the second inverter circuit 42B, and the drain is connected to the second three-phase motor winding via the first abnormality detection circuit 35A. It is connected to the W-phase coil L2w of the line L2.

The field effect transistors QA1 to QA3 and QB1 to QB3 of the first and second motor current cut-off circuits 33A and 33B have the cathodes of the respective parasitic diodes D as the first and second inverter circuits 42A and 42B, respectively. Connected in the same direction.
Each of the first and second power cutoff circuits 44A and 44B has a series circuit configuration in which two field effect transistors (FETs) QC1, QC2 and QD1, QD2 connect the drains and the parasitic diodes are reversed. Have The sources of the field effect transistors QC1 and QD1 are connected to each other and connected to the output side of the noise filter 43, and the sources of the field effect transistors QC2 and QD2 are the field effect transistors of the first and second inverter circuits 42A and 42B. Connected to the sources of Q1, Q2 and Q3.

(Motor electrical angle detection circuit 23)
Next, a specific configuration of the motor electrical angle detection circuit 23 according to the first embodiment will be described.
As shown in FIG. 8, the motor electrical angle detection circuit 23 of the first embodiment includes a main motor electrical angle detection circuit 23b, a sub motor electrical angle detection circuit 23c, an electrical angle selection unit 23d, a RAM 50, and a ROM 51. I have.
The main motor electrical angle detection circuit 23 b includes an angle calculation unit 60 and a resolver abnormality diagnosis unit 61.
The angle calculation unit 60 calculates the first motor electrical angle θm1 based on the sin signal and the cos signal corresponding to the rotation angle of the three-phase electric motor 22 output from the resolver 23a. Then, the calculated first motor electrical angle θm1 is output to the electrical angle selector 23d.

The resolver abnormality diagnosis unit 61 detects an abnormality in the resolver 23a and the angle calculation unit 60 and outputs an abnormality detection signal SAr.
Although not shown in FIG. 5, the sub-motor electrical angle detection circuit 23c outputs the output shaft rotation angle θos output from the output side rotation angle sensor 13c, the steering torque T, and the IGN switch 28. An ignition signal IGN indicating ON / OFF of the ignition is input. In addition, the first motor electrical angle θm1 from the angle calculation unit 60, the abnormality detection signal SAr from the resolver abnormality diagnosis unit 61, the motor current detection value Im from the current detection circuits 34A and 34B, and the voltage detection circuit 40A And the motor voltage detection value Vm from 40B is input.

The sub motor electrical angle detection circuit 23 c includes a relative offset amount estimation unit 62, a motor electrical angle estimation unit 63, and a first estimated angle correction unit 64.
The relative offset amount estimation unit 62 estimates the relative offset amount θoff between the origin θmd of the motor electrical angle θm (hereinafter sometimes referred to as “motor electrical angle origin θmd”) and the reference value θosr of the output shaft rotation angle θos. To do. Then, the estimated relative offset amount θoff is output to the motor electrical angle estimation unit 63.
The motor electrical angle estimator 63 detects the output shaft rotation angle detection value θos detected by the output side rotation angle sensor 13c, the reduction ratio RGr of the reduction gear 21 stored in advance in the ROM 51, and the rotor 22R of the three-phase electric motor 22. Based on the number P of pole pairs and the relative offset amount θoff estimated by the relative offset amount estimation unit 62, the motor electrical angle estimated value θme is calculated. Then, the calculated motor electrical angle estimated value θme is output to the first estimated angle correction unit 64.

Specifically, the motor electrical angle estimation unit 63 calculates the motor electrical angle estimated value θme according to the following equation (1).
θme = θos × RGr × P + θoff (1)
That is, the motor electrical angle estimated value θme is calculated by multiplying the output shaft rotation angle detection value θos by the reduction ratio RGr and the pole pair number P, and adding the relative offset amount θoff to the multiplication result.
The first estimated angle correction unit 64 corrects the motor electrical angle estimated value θme based on the back electromotive voltage EMF of the three-phase electric motor 22. Then, the corrected motor electrical angle estimated value is output to the electrical angle selector 23d as the second motor electrical angle θm2.

  When the abnormality detection signal SAr output from the resolver abnormality diagnosis unit 61 of the main motor electrical angle detection circuit 23b is the logical value “0” indicating no abnormality, the electrical angle selection unit 23d is configured to detect the main motor electrical angle detection circuit 23b. The first motor electrical angle θm1 output from is selected and output to the control arithmetic unit 31 as the motor electrical angle θm. On the other hand, when the abnormality detection signal SAr is a logical value “1” indicating that there is an abnormality, the second motor electrical angle θm2 output from the sub motor electrical angle detection circuit 23c is selected to be used as the motor electrical angle θm. To 31.

(Relative offset amount estimation unit 62)
Next, a specific configuration of the relative offset amount estimation unit 62 according to the first embodiment will be described.
As shown in FIG. 9, the relative offset amount estimation unit 62 of the first embodiment includes a first relative offset amount estimation unit 70, a second relative offset amount estimation unit 71, and a relative offset amount selection unit 72. Yes.
The first relative offset amount estimation unit 70 is detected by the output shaft rotation angle detection value θos detected by the output side rotation angle sensor 13c and the main motor electrical angle detection circuit 23b when the resolver 23a and the angle calculation unit 60 are normal. The first relative offset amount θoff1 is estimated based on the detected motor electrical angle detected value θm1. Then, the estimated first relative offset amount θoff1 is stored in the RAM 50.

Here, when the resolver 23a and the angle calculation unit 60 are normal, the motor electrical angle origin θmd is known, so that it is possible to easily estimate the relative offset amount with respect to the reference value θosr of the output shaft rotation angle detection value.
The reference value θosr is an output shaft rotation angle detection value when the system is started (when the IGN switch 28 is turned from OFF to ON).
In order to supplement the motor electrical angle θm with the output shaft rotation angle θos, it is necessary to make the motor electrical angle origin θmd coincide with the reference value θosr of the output shaft rotation angle. For example, as shown in FIG. 10, when the reference value θosr and the origin θmd do not coincide with each other, the output is made with respect to the motor electrical angle θm indicated by the solid line in the figure, as indicated by the one-dot chain line in the figure. Since the shaft rotation angle θos (the amount of displacement from the reference value θosr) first reaches 360 degrees and the count returns to 0, a large deviation from the actual motor electrical angle θm occurs thereafter.

Therefore, how much the reference value θosr of the output shaft rotation angle is deviated from the motor electrical angle origin θmd is obtained as a relative offset amount, and when the motor electrical angle is estimated, the relative offset amount is added (relative offset amount). Need to be corrected).
The second relative offset amount estimation unit 71 receives the abnormality detection signal SAr in the initial diagnosis by the resolver abnormality diagnosis unit 61 when the system is restarted after the system stop when the ignition switch is turned off and the IGN switch 28 is turned on again. When the value indicates that there is an abnormality, the second relative offset amount θoff2 is estimated. Then, the estimated second relative offset amount θoff2 is stored in the RAM 50.

Here, for example, when the resolver 23a has failed at the time of the previous system startup, or when the resolver 23a has failed during the system stop, for example, an abnormality is diagnosed by the initial diagnosis at the time of the current system startup. In this case, all the angle data and the like obtained at the previous system startup are lost. Further, the driver may operate the steering wheel 11 while the system is stopped.
Accordingly, when an abnormality is diagnosed when the system is restarted, it is necessary to estimate the motor electrical angle origin θmd and to estimate the second relative offset amount θoff2 based on the estimated motor electrical angle origin θmd.
The second relative offset amount estimation unit 71 of the first embodiment first stores the current steering torque T detected by the torque sensor 13 at the time of system restart in the RAM 50 as the torque offset amount Toff.

Next, assuming that the current motor electrical angle θm is X degrees, a current output command Ioi (information on the assumed angle X degrees) is input so that a step-wave motor driving current corresponding to X degrees is input to the three-phase electric motor 22. Is output to the control arithmetic unit 31.
The control arithmetic unit 31 of the first embodiment inputs a step-wave motor driving current corresponding to the assumed angle X degrees to the three-phase electric motor 22 in response to the input of the current output command Ioi from the sub motor electrical angle detection circuit 23c. Is configured to do.
The second relative offset amount estimation unit 71 acquires the steering torque T detected by the torque sensor 13 in accordance with the input of the step-wave motor driving current to the three-phase electric motor 22.

Subsequently, the second relative offset amount estimation unit 71 subtracts the torque offset amount Toff from the acquired steering torque T.
Here, at the time of starting the system, there is a possibility that the steering torque T is offset when the driver is applying force to the steering wheel 11 when turning on the IGN switch 28, or due to the influence of other load, weight, etc. is there. In the first embodiment, this offset amount is stored in advance as a torque offset amount Toff and subtracted from the actual steering torque T.

Subsequently, the second relative offset amount estimation unit 71 determines the symmetry of the torque waveform composed of the steering torque Tc after subtracting the torque offset amount Toff. In the first embodiment, it is determined whether the amplitudes are positive and negative and are equal. When it is determined that the amplitude is positive and negative, the motor electrical angle θm at that time can be estimated to be the assumed X degree.
For example, when a torque waveform having positive and negative amplitudes as shown in FIG. 11B is obtained with respect to the stepped torque command value (motor drive current) as shown in FIG. The motor electrical angle θm at that time can be estimated to be the assumed X degree. That is, when the assumed angle X and the current motor electrical angle θm of the three-phase electric motor 22 match, an output according to the torque command value is obtained.

On the other hand, if it is determined that the amplitude of the torque waveform composed of the steering torque Tc after subtraction is positive and negative and not equivalent (not output as the torque command), the motor electrical angle θm at that time is not the assumed X degree. judge.
For example, when torque waveforms shown in FIG. 11C are obtained with different positive and negative amplitudes with respect to the torque command shown in FIG. 11A, the motor electrical angle θm at that time is assumed to be X degrees. It can be determined that it is not.
In this case, the second relative offset amount estimator 71 shifts the current initial position from either the 0 degree side or the 360 degree side with respect to the assumed angle X degree from the shape of the torque waveform having positive and negative amplitudes. Judge whether there is. Since this deviation direction is understood from the waveform shape (asymmetry), the assumed angle X degrees is updated to a value that reduces the deviation, and then the stepped motor drive current corresponding to the updated assumed angle X degrees is obtained. A current output command Ioi is output to the control arithmetic unit 31 so as to be input to the three-phase electric motor 22. Such processing is repeatedly executed until it is determined that the amplitude of the torque waveform is positive and negative and equal.

  The relative offset amount selection unit 72 selects the first relative offset amount θoff1 when the abnormality detection signal SAr becomes a value indicating that there is an abnormality during the system startup, and the abnormality detection signal is detected in the initial diagnosis after the system is restarted. When SAr becomes a value indicating that there is an abnormality, the second relative offset amount θoff2 is selected. Then, the selected one of the first relative offset amount θoff1 and the second relative offset amount θoff2 is read from the RAM 50, and is output to the motor electrical angle estimator 63 as the relative offset amount θoff.

(First estimated angle correction unit 64)
As shown in FIG. 12, the first estimated angle correction unit 64 includes a back electromotive voltage calculation unit 80, a zero cross timing detection unit 81, an angle error calculation unit 82, and a first correction unit 83.
Here, mechanical elements such as a reduction gear (worm gear) 21 are interposed between the output side rotation angle sensor 13 c and the three-phase electric motor 22. For example, a reduction gear (worm gear) 21 due to backlash and material reasons.
Compliance has non-linear characteristics. In addition, this characteristic changes due to aging, moisture absorption, and temperature change. Due to this characteristic, the motor electrical angle θm does not have a one-to-one correspondence with the output shaft rotation angle θos, and the error between the electrical angle estimated value θme and the actual motor electrical angle θm increases as the motor output increases. For example, the compliance characteristic of the worm gear has nonlinearity and hysteresis as shown in FIG. In FIG. 13, the X-axis is load torque (motor output torque), and the Y-axis is the deformation amount Δθ of the motor electrical angle θm.

When such compliance characteristics are not taken into account, a deviation occurs between the actual motor electrical angle θm and the estimated motor electrical angle θme depending on the driving state of the three-phase electric motor 22. Therefore, in the first embodiment, the first estimated angle correction unit 64 corrects the estimated motor electrical angle θme based on the back electromotive force EMF that is uniquely determined by the motor electrical angle θm and the motor rotation speed.
In the first embodiment, the counter electromotive voltage calculation unit 80 is based on the motor current detection value Im (Imu, Imv, Imw) and the motor voltage detection value Vm (Vmu, Vmv, Vmw). EMFuv, EMFvw, EMFwu) are calculated. Then, the calculated interphase counter electromotive voltage EMF is output to the zero cross timing detector 81.

The back electromotive force voltage EMF between the UV phase is the back electromotive voltage EMFuv between the U phase and the V phase, the back electromotive force voltage EMFvw between the V phase and the W phase, and the WU between the W phase and the U phase. It consists of a phase back electromotive voltage EMFwu and appears as a positive or negative value with 0 as a reference. Specifically, for example, a sine wave having a phase difference of 120 degrees as shown in the lower diagram of FIG. 14 is obtained. In the lower diagram of FIG. 14, the solid line indicates the UV phase counter electromotive voltage EMFuv, the broken line indicates the VW phase counter electromotive voltage EMFvw, and the alternate long and short dash line indicates the WU phase counter electromotive voltage EMFwu.
The zero-cross timing detector 81 detects a zero-cross timing that is a timing at which the UV-phase back electromotive voltage EMFuv, the VW phase back-electromotive voltage EMFvw, and the WU-phase back electromotive voltage EMFwu become zero. Specifically, the point at which the vertical line extending from the end of the upper rhombus in the lower diagram of FIG. 14 intersects the horizontal axis where the vertical axis is 0 is the zero cross point.

Specifically, the zero-cross timing detection unit 81 of the first embodiment performs timing when the signs of the VW phase counter electromotive voltage EMFvw, the VW phase counter electromotive voltage EMFvw, and the WU phase counter electromotive voltage EMFwu change from negative to positive or from positive to negative. Detect as zero cross timing. Then, the motor electrical angle θmz corresponding to the detected zero cross timing (zero cross point) is read from the ROM 51, and the read motor electrical angle θmz is output to the angle error calculation unit 82.
That is, in the first embodiment, the motor electrical angle at the zero cross point of the VW phase counter electromotive voltage EMFvw, the VW phase counter electromotive voltage EMFvw, and the WU phase counter electromotive voltage EMFwu is a known value, and therefore the motor corresponding to each zero cross point. The electrical angle θmz is stored in the ROM 51 in advance.

The angle error calculation unit 82 calculates a difference between the motor electrical angle θmz corresponding to the zero cross point input from the zero cross timing detection unit 81 and the motor electrical angle estimation value θme input from the motor electrical angle estimation unit 63, The calculated difference is stored in the RAM 50 as the angle error θerr.
The angle error calculation unit 82 updates the angle error θerr stored in the RAM 50 every time zero cross timing is detected. As shown in the lower diagram of FIG. 14, the zero cross timing appears six times per one cycle (360 degrees) of the motor electrical angle θm. Accordingly, it is possible to update the angle error θerr with a period of 60 electrical angles.

The first correction unit 83 corrects the motor electrical angle estimation value θme input from the motor electrical angle estimation unit 63 with the angle error θerr stored in the RAM 50, and sets the corrected motor electrical angle estimation value to the second value. The motor electrical angle θm2 is output to the electrical angle selector 23d.
For example, as shown in the upper diagram of FIG. 14, the estimated motor electrical angle value θme having an error surrounded by a dotted circle corresponding to the zero cross point shown in the lower diagram of FIG. 14 is converted into a known motor electrical angle θm corresponding to the zero cross point. Is corrected by the angle error θerr. Until the next zero cross point is detected, the motor electrical angle estimated value θme is corrected by the angle error θerr at each correction timing. That is, the first correction unit 83 performs correction using the angle error θerr currently stored in the RAM 50 until the next zero cross timing is detected.

(Operation)
Next, the operation of the first embodiment will be described.
When the IGN switch 28 is off and the vehicle 1 is stopped and the steering assist control process is also stopped, the control arithmetic unit 31 and the motor electrical angle detection circuit 23 of the motor control device 25 are stopped. Is inactive.
For this reason, the various processes performed by the control arithmetic unit 31 and the motor electrical angle detection circuit 23 are stopped. In this state, the operation of the three-phase electric motor 22 is stopped, and the output of the steering assist force to the steering mechanism is stopped.

When the IGN switch 28 is turned on from this operation stop state, the control arithmetic unit 31 and the motor electrical angle detection circuit 23 are activated, and various processes such as a motor electrical angle θm detection process and a steering assist control process are started. At this time, it is assumed that the resolver 23a and the angle calculation unit 60 are normal.
At this time, the abnormality detection signal SAr becomes a value indicating that there is no abnormality, and the electrical angle selection unit 23d outputs the first motor electrical angle θm1 calculated by the angle calculation unit 60 to the control arithmetic unit 31 as the motor electrical angle θm.

The control arithmetic unit 31 calculates the d-axis current command value Id ^* and the q-axis current command value Iq ^* based on the motor electrical angle θm. Then, based on the d-axis current command value Id ^* and the q-axis current command value Iq ^* , three-phase voltage command values V1 ^* and V2 ^* for the first and second motor drive circuits 32A and 32B are calculated, and the calculated 3 The phase voltage command values V1 ^* and V2 ^* are output to the first and second motor drive circuits 32A and 32B. Thus, the first and second inverter circuits 42A and 42B are driven and controlled by the first and second motor drive circuits 32A and 32B, and the three-phase electric motor 22 is driven (commutation controlled).

On the other hand, when the resolver 23a and the angle calculation unit 60 are normal, the relative offset amount estimation unit 62 of the sub motor electrical angle detection circuit 23c performs the process of estimating the first relative offset amount θoff1. That is, based on the output shaft rotation angle detection value θos detected by the normal output side rotation angle sensor 13c and the motor electrical angle θm output from the main motor electrical angle detection circuit 23b, the first relative offset amount θoff1 is calculated. The estimated first relative offset amount θoff1 is stored in the RAM 50.
Then, the relative offset amount estimation unit 62 of the present embodiment provides the motor electrical angle estimation unit 63 with the first relative offset amount θoff1 stored in the RAM 50 as the relative offset amount θoff when the resolver 23a and the angle calculation unit 60 are normal. Output.

When the resolver 23a and the angle calculation unit 60 are normal, the motor electrical angle estimation unit 63 outputs the output shaft rotation angle detection value θos detected by the output side rotation angle sensor 13c, the first relative offset amount θoff1, and the reduction ratio. A motor electrical angle estimated value θme is calculated from RGr (for example, 20.5) and a magnetic pole pair (for example, 4). Then, the motor electrical angle estimated value θme is output to the first estimated angle correction unit 64.
The first estimated angle correction unit 64 calculates the interphase counter electromotive force EMF (EMFuv, EMFvw, EMFwu) from the motor current detection value Im and the motor voltage detection value Vm, and detects the zero cross timing. Then, the motor electrical angle θmz at the zero cross point is acquired from the ROM 51, and the angle error θerr is calculated from the difference between the motor electrical angle estimated value θme and the motor electrical angle θmz. Then, the calculated angle error θerr is overwritten and stored in the RAM 50. Further, the first estimated angle correction unit 64 corrects the estimated motor electrical angle value θme using the angle error θerr stored in the RAM 50, and outputs the corrected value to the electrical angle selection unit 23d as the second motor electrical angle θm2.

Thereafter, when a failure occurs in at least one of the resolver 23a and the angle calculation unit 60 during the system startup, and the abnormality detection signal SAr becomes a value indicating that there is an abnormality, the electrical angle selection unit 23d receives a signal from the sub motor electrical angle detection circuit 23c. The input second motor electrical angle θm2 is output to the control arithmetic unit 31 as the motor electrical angle θm.
Thereby, in the control arithmetic unit 31, the three-phase electric motor 22 is driven and controlled (commutation control) based on the second motor electrical angle θm2 estimated by the sub motor electrical angle detection circuit 23c.
Subsequently, it is assumed that the IGN switch 28 is once turned off to stop the system, and then the IGN switch 28 is turned on again to restart the system.

In this case, the abnormality detection signal SAr becomes a value indicating that there is an abnormality by the initial diagnosis by the resolver abnormality diagnosis unit 61 after the system is restarted, and the relative offset amount estimation unit 62 performs the estimation process of the second relative offset amount θoff2. The
Specifically, the relative offset amount estimation unit 62 first acquires the steering torque T after the initial diagnosis and stores it in the RAM 50 as the torque offset amount Toff. Subsequently, the initial value of the assumed angle X is set to 180 degrees here, and a current output command Ioi is output to the control arithmetic unit 31 so that a step-wave motor driving current corresponding to 180 degrees is input to the three-phase electric motor 22. . As a result, a step-wave motor driving current corresponding to 180 degrees flows through the three-phase electric motor 22.

Subsequently, the steering torque T detected by the torque sensor 13 is acquired in response to the input of the step-wave motor driving current, the torque offset amount Toff is subtracted from the steering torque T, and the torque waveform of the steering torque Tc after the subtraction is obtained. Determine symmetry. Here, it is assumed that it is determined to be asymmetric. In this case, the second relative offset amount estimation unit 71 determines the deviation direction from the shape of the asymmetric torque waveform, and updates the assumed angle X in a direction in which the deviation becomes smaller.
For example, when the actual motor electrical angle θm is 0 degree, the response waveform of 180 degrees is shifted in the direction of 360 degrees with respect to 0 degrees. Update to the intermediate value of 90 degrees. Then, a step-wave motor driving current corresponding to 90 degrees is input to the three-phase electric motor 22, and the symmetry of the torque waveform is determined again from the response torque. In this case, since the 90-degree response waveform is shifted in the direction of 360 degrees with respect to 0 degrees, the process of updating the assumed angle X to 45 degrees, which is an intermediate value between 0 degrees and 90 degrees, is performed. Repeat until the positive and negative amplitudes of the torque waveforms are equal.

Then, the assumed angle X when they are equal is the motor electrical angle origin θmd. It is not limited to the case where the amplitudes are completely the same. For example, it may be determined that the amplitudes are equal when the difference between the positive and negative amplitudes is within a preset error range.
The relative offset amount estimation unit 62 calculates the second relative offset amount θoff2 from the estimated motor electrical angle origin θmd and the reference value θosr of the output shaft rotation angle detection value acquired when the system is restarted. Then, the calculated second relative offset amount θoff2 is stored in the RAM 50.

Further, the relative offset amount estimation unit 62 reads the second relative offset amount θoff2 from the RAM 50 because the abnormality detection signal SAr has a value indicating that there is an abnormality at the time of system restart, and the read second relative offset amount. θoff2 is output to the motor electrical angle estimation unit 63 as a relative offset amount θoff.
As a result, the motor electrical angle estimation unit 63 outputs the output shaft rotation angle detection value θos detected by the output side rotation angle sensor 13c, the second relative offset amount θoff2, and the reduction ratio RGr (for example, 20.5). Then, the motor electrical angle estimated value θme is calculated from the magnetic pole pair (for example, 4). Then, the calculated motor electrical angle estimated value θme is output to the first estimated angle correction unit 64.

The first estimated angle correction unit 64 corrects the motor electrical angle estimated value θme with the angle error θerr similarly to the case where the first relative offset amount θoff1 is used, and the corrected motor electrical angle estimated value is set to the second value. Is output to the electrical angle selector 23d as the motor electrical angle θm2.
Since the abnormality detection signal SAr has a value indicating that there is an abnormality, the electrical angle selection unit 23d sets the second motor electrical angle θm2 input from the sub motor electrical angle detection circuit 23c as the motor electrical angle θm to the control arithmetic device 31. Output.
Thereby, in the control arithmetic unit 31, the three-phase electric motor 22 is driven and controlled (commutation control) based on the second motor electrical angle θm2 estimated by the sub motor electrical angle detection circuit 23c.

Here, the motor electrical angle estimation unit 63 corresponds to the motor electrical angle estimation unit, and the control arithmetic device 31 and the motor electrical angle detection circuit 23 correspond to the motor drive control unit.
The torque sensor 13 corresponds to a torque detector, the output side rotation angle sensor 13c corresponds to a steering angle detector, the three-phase electric motor 22 corresponds to a multiphase electric motor, the resolver 23a and the angle calculator 60. Corresponds to the motor electrical angle detector.
The first and second inverter circuits 42A and 42B correspond to the motor drive circuit, the control arithmetic device 31 corresponds to the control arithmetic device, the resolver abnormality diagnosis unit 61 corresponds to the abnormality diagnosis unit, and the first estimation The angle correction unit 64 corresponds to the motor electrical angle correction unit, and the zero cross timing detection unit 81 corresponds to the cross timing detection unit.

(Effect of 1st Embodiment)
(1) In the motor control device 25 according to the first embodiment, the motor electrical angle estimation unit 63 detects the output shaft rotation detected by the output side rotation angle sensor 13c that detects the steering angle (output shaft rotation angle θos) of the steering. The motor electrical angle θm is estimated based on the angle θos. The control arithmetic unit 31 and the motor electrical angle detection circuit 23 drive-control the three-phase electric motor 22 based on the first motor electrical angle θm1 detected by the resolver 23a and the angle calculation unit 60 when they are normal. On the other hand, when the resolver 23a and the angle calculator 60 are abnormal, the three-phase electric motor 22 is based on the second motor electrical angle θm2 (the value corrected by the first estimated angle corrector 64) estimated by the motor electrical angle estimator 63. Is controlled.
With this configuration, it is possible to estimate the motor electrical angle θm based on the output shaft rotation angle θos detected by the output side rotation angle sensor 13c. When at least one of the resolver 23a and the angle calculator 60 is abnormal, it is possible to drive and control the multiphase electric motor based on the estimated motor electrical angle θm2.
As a result, even when at least one of the resolver 23a and the angle calculation unit 60 is abnormal, the three-phase electric motor 22 can be continuously driven.

(2) In the motor control device 25 according to the first embodiment, the torque sensor 13 detects the steering torque T transmitted to the steering mechanism. The output side rotation angle sensor 13c detects the steering angle (output shaft rotation angle θos) of the steering. A three-phase electric motor 22 generates a steering assist force. The resolver 23 a and the angle calculation unit 60 detect the motor electrical angle θm of the three-phase electric motor 22. The first and second inverter circuits 42 </ b> A and 42 </ b> B supply drive current to the three-phase electric motor 22. The control arithmetic device 31 drives and controls the first and second inverter circuits 42A and 42B based on the steering torque T detected by the torque sensor 13 and the motor electrical angle θm detected by the resolver 23a and the angle calculator 60. The resolver abnormality diagnosis unit 61 diagnoses abnormality of the resolver 23a and the angle calculation unit 60. The motor electrical angle estimation unit 63 estimates the motor electrical angle θm based on the output shaft rotation angle θos detected by the output side rotation angle sensor 13c. When the resolver abnormality diagnosis unit 61 diagnoses that at least one of the resolver 23 a and the angle calculation unit 60 is abnormal, the control arithmetic unit 31 estimates the steering torque T detected by the torque sensor 13 and the motor electrical angle estimation unit 63. The first and second inverter circuits 42A and 42B are driven and controlled based on the second motor electrical angle θm2 (the value corrected by the first estimated angle correction unit 64).
With this configuration, it is possible to estimate the motor electrical angle θm based on the output shaft rotation angle θos detected by the output side rotation angle sensor 13c. When at least one of the resolver 23a and the angle calculator 60 is abnormal, it is possible to drive and control the multiphase electric motor based on the estimated motor electrical angle θm2.
As a result, even when at least one of the resolver 23a and the angle calculation unit 60 is abnormal, the three-phase electric motor 22 can be continuously driven.

(3) In the motor control device 25 according to the first embodiment, the first estimated angle correction unit 64 corrects the motor electrical angle estimated value θme based on the back electromotive voltage EMF of the three-phase electric motor 22.
With this configuration, it is possible to correct the estimated motor electrical angle based on the back electromotive force EMF that is uniquely determined by the motor electrical angle and the motor rotation speed. Thereby, it is possible to reduce errors due to deformation of mechanical elements such as the reduction gear 21 interposed between the output side rotation angle sensor 13c and the three-phase electric motor 22.

(4) In the motor control device 25 according to the first embodiment, the zero cross timing detector 81 detects the timing at which the back electromotive voltage waveform of each phase of the three-phase electric motor 22 zero-crosses. When the first estimated angle correction unit 64 detects the timing at which the zero cross timing detection unit 81 performs zero crossing, the motor electrical angle estimated value θme is corrected based on the motor electrical angle information corresponding to the zero cross point.
With this configuration, it is possible to detect the zero cross point of the counter electromotive voltage waveform whose motor electric angle is known, and to correct the estimated motor electric angle based on the motor electric angle information corresponding to the detected zero cross point. . As a result, it is possible to accurately reduce errors due to deformation of mechanical elements such as the reduction gear 21 interposed between the output side rotation angle sensor 13c and the three-phase electric motor 22.

(5) The electric power steering device 3 according to the first embodiment includes a motor control device 25.
With this configuration, the same operation and effect as the motor control device 25 described in the above (1) to (4) can be obtained, and the steering assist control can be continued even when the resolver 23a and the angle calculation unit 60 are out of order. Therefore, the reliability of the electric power steering device 3 can be improved.

(6) The vehicle 1 according to the first embodiment includes the electric power steering device 3 including the motor control device 25.
With this configuration, the same operation and effect as the motor control device 25 described in (1) to (4) above can be obtained, and the steering assist control can be continued even when the resolver 23a fails. The reliability of the vehicle 1 can be improved.

(Second Embodiment)
Next, a second embodiment of the present invention will be described.
(Constitution)
The second embodiment is different in that a second estimated angle correction unit 65 is provided in place of the first estimated angle correction unit 64 in the sub motor electrical angle detection circuit 23c of the first embodiment, and the other points are the same as those in the first embodiment. This is the same as the embodiment.
Hereinafter, the same components as those in the first embodiment are denoted by the same reference numerals, description thereof will be omitted as appropriate, and different portions will be described in detail.

(Second estimated angle correction unit 65)
As shown in FIG. 15, the second estimated angle correction unit 65 of the second embodiment includes a back electromotive voltage calculation unit 80, a switching timing detection unit 84, an angle error calculation unit 82, and a first correction unit 83. I have. That is, the first estimated angle correction unit 64 of the first embodiment except that a switching timing detection unit 84 is provided instead of the zero cross timing detection unit 81 in the first estimated angle correction unit 64 of the first embodiment. It becomes the same composition as.
The switching timing detection unit 84 has a set of a magnitude relationship between the amplitude (absolute value) of each phase back electromotive voltage waveform and a sign relationship between each phase back electromotive voltage value when the three-phase electric motor 22 rotates in the positive and negative directions. Timing of switching to another set of magnitude relationship and code relationship is detected.

Here, as shown in FIGS. 16B and 16D, the interphase counter electromotive voltage waveforms shown in FIGS. 16A and 16C have large and small amplitudes in a certain angle range (30 degree range). The relation and the sign relation are constant. In FIGS. 16A and 16C, the solid line indicates the UV-phase counter electromotive voltage EMFuv, the broken line indicates the VW inter-phase counter electromotive voltage EMFvw, and the alternate long and short dash line indicates the WU-phase counter electromotive voltage EMFwu.
For example, in the range of the motor electrical angle of 0 to 30 degrees when rotating in the forward direction, the UV phase back electromotive voltage EMFuv becomes the largest (“large” in FIG. 16B), and the VW phase back electromotive voltage EMFvw is It becomes the second largest (“middle” in FIG. 16B), and the WU-phase counter electromotive voltage EMFwu becomes the smallest (“small” in FIG. 16B).

However, in the range of the motor electrical angle 180 to 210 degrees when rotating in the positive direction, the magnitude relationship is the same as the range of the motor electrical angle 0 to 30 degrees. That is, the same magnitude relationship appears twice in the motor electrical angle range of 0 to 360 degrees. This is the same for other magnitude relationships, and the same magnitude relationship appears twice when the motor rotation direction is negative.
On the other hand, paying attention to the sign, in the range of the motor electrical angle of 0 to 30 degrees when rotating in the forward direction, the UV phase counter electromotive voltage EMFuv is “+”, the VW phase counter electromotive voltage EMFvw is “−”, and the WU phase counter electromotive force is The voltage EMFwu becomes “+”.

Further, in the range of the motor electrical angle of 180 to 210 degrees when rotating in the forward direction, the UV phase counter electromotive voltage EMFuv is “−”, the VW phase counter electromotive voltage EMFvw is “+”, and the WU phase counter electromotive voltage EMFwu is “−”. "
That is, even if the magnitude relationship is the same, the sign relationship is different. The same applies to other magnitude relationships, and the same applies when the motor rotation direction is negative.
From the above, it is possible to uniquely determine the angle range from the set of the magnitude relationship of the amplitude (absolute value) of each phase back electromotive voltage waveform and the sign relationship of each phase back electromotive voltage value.

Based on this, in the second embodiment, the motor electrical angle at the boundary position at the moment when the current magnitude relation and sign relation set is switched to another magnitude relation and sign relation set is the current motor electrical angle θm. The motor electrical angle estimation value θme is corrected using the motor electrical angle θ.
For example, when switching from a set of magnitude relationship and sign relationship corresponding to an angle range of 60 degrees to 90 degrees to a set of magnitude relationship and sign relationship corresponding to an angle range of 90 degrees to 120 degrees, the current motor electrical The angle θ is 90 degrees. In addition, for example, when switching from a set of magnitude relation and sign relation corresponding to an angle range of 120 degrees to 150 degrees to a magnitude relation and sign relation set corresponding to an angle range of 90 degrees to 120 degrees, The motor electrical angle θ is 120 degrees.

In the second embodiment, map data of a set of amplitude relations of interphase counter electromotive voltage waveforms and sign relations of interphase counter electromotive voltage values shown in FIGS. 16B and 16D is stored in the ROM 51 in advance. Has been.
Then, the switching timing detection unit 84 calculates the motor electrical angle θm (hereinafter sometimes referred to as “motor electrical angle θmc”) corresponding to the motor rotation direction and the set of magnitude relationship and sign relationship before and after the switching timing. Read from the ROM 51 and output the read motor electrical angle θmc to the angle error calculator 82.

The angle error calculation unit 82 of the second embodiment includes a motor electrical angle θmc corresponding to the switching point input from the switching timing detection unit 84 and a motor electrical angle estimation value θme input from the motor electrical angle estimation unit 63. The difference is calculated, and the calculated difference is stored in the RAM 50 as the angle error θerr.
Note that the angle error calculation unit 82 of the second embodiment updates the angle error θerr stored in the RAM 50 every time the switching timing is detected. As shown in FIG. 17, the switching timing is as shown at the switching point which is the intersection of the straight line extending from the end of the upper rhombus and the lower round in FIG. It appears 12 times per cycle (360 degrees) of the electrical angle θm. Accordingly, it is possible to update the angle error θerr with a period of 30 electrical degrees.

In addition, the first correction unit 83 of the second embodiment performs correction using the angular error θerr stored in the RAM 50 at the previous switching timing for each correction timing until the next switching timing is detected.
Here, the motor electrical angle estimation unit 63 corresponds to the motor electrical angle estimation unit, and the control arithmetic device 31 and the motor electrical angle detection circuit 23 correspond to the motor drive control unit.
The torque sensor 13 corresponds to a torque detector, the output side rotation angle sensor 13c corresponds to a steering angle detector, the three-phase electric motor 22 corresponds to a multiphase electric motor, the resolver 23a and the angle calculator 60. Corresponds to the motor electrical angle detector.
Further, the first and second inverter circuits 42A and 42B correspond to the motor drive circuit, the control arithmetic device 31 corresponds to the control arithmetic device, the resolver abnormality diagnosis unit 61 corresponds to the abnormality diagnosis unit, and the second estimation The angle correction unit 65 corresponds to the motor electrical angle correction unit, and the switching timing detection unit 84 corresponds to the switching timing detection unit.

(Effect of 2nd Embodiment)
The second embodiment has the following effects in addition to the effects of the first embodiment.
(1) The switching timing detection unit 84 detects the timing at which the magnitude relation and sign relation set of the back electromotive voltage waveform of each phase of the three-phase electric motor 22 is switched to another magnitude relation and sign relation set. When the second estimated angle correction unit 65 switches and the timing detection unit 84 detects the switching timing, the motor electrical angle estimated value θme is corrected based on the motor electrical angle information (motor electrical angle θmc) corresponding to the switching point.
With this configuration, it is possible to detect the switching point of the back electromotive voltage waveform where the motor electrical angle is known, and to correct the estimated motor electrical angle based on the motor electrical angle information corresponding to the detected switching point. . As a result, it is possible to accurately reduce errors due to deformation of mechanical elements such as the reduction gear 21 interposed between the output side rotation angle sensor 13c and the three-phase electric motor 22.

(Third embodiment)
Next, a third embodiment of the present invention will be described.
(Constitution)
The third embodiment is different in that a third estimated angle correction unit 66 is provided instead of the first estimated angle correction unit 64 in the sub motor electrical angle detection circuit 23c of the first embodiment, and the other points are the same as those of the first embodiment. This is the same as the embodiment.
Hereinafter, the same components as those in the first embodiment are denoted by the same reference numerals, description thereof will be omitted as appropriate, and different portions will be described in detail.

(Third estimated angle correction unit 66)
As shown in FIG. 18, the third estimated angle correction unit 66 of the third embodiment includes a first counter electromotive voltage calculation unit 90, a second counter electromotive voltage calculation unit 91, an EMF comparison unit 92, and a second correction. Part 93.
The first counter electromotive voltage calculation unit 90 receives the motor current detection value Im from the current detection circuits 34A and 34B and the motor voltage detection value Vm from the voltage detection circuits 40A and 40B.

The first counter electromotive voltage calculation unit 90 calculates the first counter electromotive voltage EMF1 based on the input motor current detection value Im and the motor voltage detection value Vm. Note that the interphase counter electromotive voltage may be calculated in the same manner as the counter electromotive voltage calculation unit 80 of the first embodiment. The first counter electromotive voltage calculation unit 90 outputs the calculated first counter electromotive voltage EMF1 to the EMF comparison unit 92.
The second counter electromotive voltage calculation unit 91 calculates a second counter electromotive voltage EMF2 corresponding to the first counter electromotive voltage EMF1 based on the motor electric angle estimation value θme estimated by the motor electric angle estimation unit 63. That is, when the first counter electromotive voltage EMF1 is the interphase counter electromotive voltage, the interphase counter electromotive voltage is calculated. The second counter electromotive voltage calculation unit 91 outputs the calculated second counter electromotive voltage EMF2 to the EMF comparison unit 92.

The EMF comparison unit 92 calculates an amplitude difference between the first counter electromotive voltage EMF1 and the second counter electromotive voltage EMF2, and calculates a phase difference between the first counter electromotive voltage EMF1 and the second counter electromotive voltage EMF2 based on the amplitude difference. calculate.
For example, as shown in FIG. 19, the first counter electromotive voltage EMF1 and the second counter electromotive voltage EMF2 are indicated by the waveform of the first counter electromotive voltage EMF1 indicated by the solid line in FIG. It is assumed that the relationship with the waveform of the second counter electromotive voltage EMF2 is obtained.
For example, as shown in FIG. 19, the EMF comparator 92 calculates the amplitude difference Wd at the correction timing tc, and the first counter electromotive voltage EMF1 and the second counter electromotive voltage EMF2 draw a sine wave. A phase difference between the first counter electromotive voltage EMF1 and the second counter electromotive voltage EMF2 is calculated using the function. The phase difference is output to the second correction unit 93 as an angle error θerr.

The second corrector 93 corrects the estimated motor electrical angle θme estimated by the motor electrical angle estimator 63 with the angular error θerr input from the EMF comparator 92. Then, the corrected motor electrical angle estimated value is output to the electrical angle selector 23d as the second motor electrical angle θm2.
Note that the third estimated angle correction unit 66 of the third embodiment calculates the first counter electromotive voltage EMF1 and the second counter electromotive voltage EMF2 every time the correction timing, and the first counter electromotive voltage EMF1 and the second counter electromotive force. An angle error θerr is calculated based on the voltage EMF2. Then, correction is performed using the angle error θerr calculated at each correction timing.

Here, the motor electrical angle estimation unit 63 corresponds to the motor electrical angle estimation unit, and the control arithmetic device 31 and the motor electrical angle detection circuit 23 correspond to the motor drive control unit.
The torque sensor 13 corresponds to a torque detector, the output side rotation angle sensor 13c corresponds to a steering angle detector, the three-phase electric motor 22 corresponds to a multiphase electric motor, the resolver 23a and the angle calculator 60. Corresponds to the motor electrical angle detector.
Further, the first and second inverter circuits 42A and 42B correspond to the motor drive circuit, the control arithmetic device 31 corresponds to the control arithmetic device, the resolver abnormality diagnosis unit 61 corresponds to the abnormality diagnosis unit, and the third estimation The angle correction unit 66 corresponds to a motor electrical angle correction unit.

(Effect of the third embodiment)
The third embodiment has the following effects in addition to the effects of the first embodiment.
(1) In the motor control device 25 according to the third embodiment, the third estimated angle correction unit 66 calculates the first counter electromotive voltage EMF1 calculated based on the detected motor voltage Vm and the detected motor current Im of the three-phase electric motor 22. And the motor electrical angle estimated value θme based on the phase difference or amplitude difference between the second counter electromotive voltage EMF2 calculated based on the motor electrical angle estimated value θme.
With this configuration, it is possible to perform correction every time correction timing, so that it is possible to obtain a more accurate motor electrical angle estimated value θme.

(Fourth embodiment)
Next, a fourth embodiment of the present invention will be described.
(Constitution)
The fourth embodiment is different in that a fourth estimated angle correction unit 67 is provided instead of the first estimated angle correction unit 64 in the sub motor electrical angle detection circuit 23c of the first embodiment, and the other points are the same as those of the first embodiment. This is the same as the embodiment.
Hereinafter, the same components as those in the first embodiment are denoted by the same reference numerals, description thereof will be omitted as appropriate, and different portions will be described in detail.

(Fourth estimated angle correction unit 67)
As shown in FIG. 20, the fourth estimated angle correction unit 67 of the fourth embodiment includes a deviation amount measurement unit 100, a map generation unit 101, and a third correction unit 102.
When the resolver 23a and the angle calculation unit 60 are normal, that is, when the abnormality detection signal SAr is a value indicating no abnormality, the deviation amount measurement unit 100 calculates the motor electrical angle θm and the motor electrical angle calculated by the angle calculation unit 60. An angle error θerr that is a deviation from the estimated motor electrical angle value θme estimated by the estimation unit 63 is measured.

Specifically, the deviation amount measuring unit 100 of the fourth embodiment includes the q-axis current command value Iq ^* , which is a value related to the output torque of the three-phase electric motor 22, and the first motor electrical value calculated by the angle calculating unit 60. The relationship between the angle θm1 and the amount of deviation between the motor electrical angle estimation value θme estimated by the motor electrical angle estimation unit 63 is measured.
As described in the first embodiment, this shift amount is a shift amount caused by deformation of a mechanical element such as the reduction gear 21 interposed between the output side rotation angle sensor 13c and the three-phase electric motor 22 or the like. .

That is, the deviation measuring unit 100 estimates the q-axis current command value Iq ^* and the motor electrical angle θm and the motor electrical angle estimation used to calculate the q-axis current command value Iq ^* when the resolver 23a and the angle calculation unit 60 are normal. A difference from the value θme is calculated as a deviation amount (angle error θerr). The q-axis current command value Iq ^* and the calculated angle error θerr are output to the map generation unit 101.
Note that the measurement timing is set to a timing suitable for measurement, such as a timing when the driver stops the steering wheel 11.

The map generation unit 101 sorts a set of the q-axis current command value Iq ^* input from the deviation amount measurement unit 100 and the angle error θerr corresponding to the q-axis current command value Iq ^* in an order suitable for reference. While stored in the RAM 50, a shift amount map is generated.
The third correction unit 102 receives an angle corresponding to the q-axis current command value Iq ^* input from the deviation map stored in the RAM 50 in response to the input of the motor electrical angle estimated value θme and the q-axis current command value Iq ^*. Read error θerr. Then, the motor electrical angle estimated value θme is corrected using the read angle error θerr, and is output to the electrical angle selector 23d as the second motor electrical angle θm2.

The deviation amount map is stored in the RAM 50 until the next map update.
Here, the motor electrical angle estimation unit 63 corresponds to the motor electrical angle estimation unit, and the control arithmetic device 31 and the motor electrical angle detection circuit 23 correspond to the motor drive control unit.
The torque sensor 13 corresponds to a torque detector, the output side rotation angle sensor 13c corresponds to a steering angle detector, the three-phase electric motor 22 corresponds to a multiphase electric motor, the resolver 23a and the angle calculator 60. Corresponds to the motor electrical angle detector.
The first and second inverter circuits 42A and 42B correspond to the motor drive circuit, the control arithmetic device 31 corresponds to the control arithmetic device, and the resolver abnormality diagnosis unit 61 corresponds to the abnormality diagnosis unit.
Further, the deviation amount measuring unit 100 corresponds to the deviation amount measuring unit, the map generation unit 101 corresponds to the deviation amount storage unit, and the third correction unit 102 corresponds to the motor electrical angle correction unit.

(Effect of 4th Embodiment)
The fourth embodiment has the following effects in addition to the effects of the first embodiment.
(1) In the motor control device 25 according to the fourth embodiment, the deviation measuring unit 100 determines that the value relating to the output torque of the three-phase electric motor 22 (q-axis current command value) when the resolver 23a and the angle calculating unit 60 are normal. Iq ^* ) and the deviation between the motor electrical angle θm detected by the main motor electrical angle detection circuit 23b by the mechanical element interposed between the output side rotation angle sensor 13c and the three-phase electric motor 22 and the estimated motor electrical angle θme The relationship with the quantity (angle error θerr) is measured. The map generation unit 101 stores the relationship between the value related to the output torque measured by the deviation amount measuring unit 100 and the deviation amount. The third correction unit 102 corrects the estimated motor electrical angle θme based on the amount of deviation stored in the RAM 50 and corresponding to the value related to the output torque when estimating the estimated motor electrical angle θme.
With this configuration, the relationship between the value related to the output torque in the normal state and the deviation amount can be stored in advance, so that an accurate angle error can be obtained, and more accurate motor electrical angle estimation is possible. The value θme can be obtained. In particular, by periodically updating the relationship between the value related to the output torque and the deviation amount, it is possible to cope with characteristics that change due to secular change or the like.

(Modification)
(1) In the above-described embodiment, the motor electrical angle is estimated based on the output shaft rotation angle θos detected by the output-side rotation angle sensor 13c constituting the torque sensor 13, but the present invention is not limited to this configuration. For example, other sensors can be used as long as they detect the rotation angle of the shaft that rotates in accordance with the operation of the steering wheel 11, such as estimating the motor electrical angle based on the input shaft rotation angle θis detected by the input side rotation angle sensor 13b. The motor electrical angle may be estimated on the basis of the rotation angle detected in (1).
(2) In the fourth embodiment, the q-axis current command value Iq ^* has been described as an example of the value relating to the output torque of the three-phase electric motor 22. However, the present invention is not limited to this configuration. Any other value may be used as long as it is a value that does not depend on the resolver 23a and the angle calculation unit 60, such as a related value.

(3) In the above embodiment, in the steering assist control process of the control arithmetic unit 31, the d-axis current command value Id ^* and the q-axis current command value Iq ^* are calculated based on the steering assist current command value, and these are calculated as dq. Phase-to-phase conversion is performed to calculate a U-phase current command value Iu ^* , a V-phase current command value Iv ^*, and a W-phase current command value Iw ^* , and a current deviation ΔIu between these and an added value for each phase of the current detection value , ΔIv and ΔIw have been described. Not limited to this configuration, the addition value for each phase of the current detection value is dq-axis converted, and deviations ΔId and ΔIq between these values and the d-axis current command value Id ^* and the q-axis current command value Iq ^* are calculated, and the deviation ΔId And ΔIq may be converted into dq phase to 3 phase.
(4) In the above embodiment, an example in which the present invention is applied to a column assist type electric power steering apparatus has been described. However, the present invention is not limited to this configuration. For example, the present invention is applied to a rack assist type or pinion assist type electric power steering apparatus. It is good also as composition to apply.

  DESCRIPTION OF SYMBOLS 1 ... Vehicle, 3 ... Electric power steering apparatus, 11 ... Steering wheel, 12 ... Steering shaft, 12b ... Output shaft, 13 ... Torque sensor, 13c ... Output side rotation angle sensor, 18 ... Steering gear, 20 ... Steering assist mechanism, 22 ... three-phase electric motor, 23 ... motor electrical angle detection circuit, 23a ... resolver, 23b ... main motor electrical angle detection circuit, 23c ... sub motor electrical angle detection circuit, 23d ... electrical angle selection unit, 25 ... motor control device, 26 ... Vehicle speed sensor, 27 ... Battery, 28 ... IGN switch, 31 ... Control arithmetic unit, 32A ... First motor drive circuit, 32B ... Second motor drive circuit, 33A ... First motor current cutoff circuit, 33B ... First 2 motor current cut-off circuit, 34A, 34B ... current detection circuit, 35A ... first abnormality detection circuit, 35B ... second Normal detection circuit, 41A, 41B ... gate drive circuit, 42A ... first inverter circuit, 42B ... second inverter circuit, 43 ... noise filter, 44A ... first power cut-off circuit, 44B ... second power cut-off circuit , 60 ... Angle calculation unit, 61 ... Resolver abnormality diagnosis unit, 62 ... Relative offset amount estimation unit, 63 ... Motor electrical angle estimation unit, 64 to 67 ... First to fourth estimation angle correction units, 81 ... Zero cross timing detection unit , 84 ... switching timing detection unit, 100 ... deviation amount measurement unit, 101 ... map generation unit, 102 ... third correction unit

Claims (9)

A motor electrical angle estimator that estimates a motor electrical angle of a multiphase electric motor that generates a steering assist force based on a steering angle detected by a steering rudder angle detector that detects a steering angle of the steering;
When the motor electrical angle detection unit for detecting the motor electrical angle is normal, the multiphase electric motor is driven and controlled based on the motor electrical angle detected by the motor electrical angle detection unit, and when the motor electrical angle detection unit is abnormal And a motor drive control unit configured to drive and control the multiphase electric motor based on the estimated motor electrical angle estimated by the motor electrical angle estimation unit. A torque detector for detecting torque transmitted to the steering mechanism;
A steering angle detector that detects the steering angle of the steering;
A multiphase electric motor that generates steering assist force;
A motor electrical angle detector for detecting a motor electrical angle of the multiphase electric motor;
A motor drive circuit for supplying a drive current to the multiphase electric motor;
A control arithmetic device that drives and controls the motor drive circuit based on the torque detected by the torque detector and the motor electrical angle detected by the motor electrical angle detector;
An abnormality detection unit for detecting an abnormality of the motor electrical angle detection unit;
A motor electrical angle estimator that estimates the motor electrical angle based on the steering angle detected by the steering rudder angle detector;
When the abnormality detection unit detects an abnormality in the motor electrical angle detection unit, the control arithmetic device uses the torque detected by the torque detection unit and the estimated motor electrical angle estimated by the motor electrical angle estimation unit. A motor control device for driving and controlling the motor drive circuit based on the motor control circuit.   The motor control device according to claim 1, further comprising a motor electrical angle correction unit that corrects the estimated motor electrical angle based on a back electromotive voltage of the multiphase electric motor. A cross timing detector for detecting the timing at which the back electromotive force waveform of each phase of the multiphase electric motor crosses zero;
The motor control according to claim 3, wherein the motor electrical angle correction unit corrects the motor electrical angle estimation value based on motor electrical angle information corresponding to a zero cross point when the cross timing detection unit detects the timing of the zero crossing. apparatus. A switching timing detector for detecting a timing at which a set of magnitude relation and sign relation of the back electromotive voltage waveform of each phase of the multiphase electric motor is switched to another magnitude relation and sign relation set;
The motor control device according to claim 3, wherein the motor electrical angle correction unit corrects the motor electrical angle estimation value based on motor electrical angle information corresponding to a switching point when the switching timing detection unit detects the switching timing. .   The motor electrical angle correction unit includes a phase difference or amplitude between a back electromotive voltage calculated based on a detected motor voltage value and a detected motor current value of the multiphase electric motor and a back electromotive voltage calculated based on the estimated motor electrical angle value. The motor control device according to claim 3, wherein the estimated motor electrical angle value is corrected based on the difference. When the motor electrical angle detection unit is normal, the motor electrical angle detection unit includes a value related to the output torque of the multiphase electric motor and a mechanical element interposed between the steering rudder angle detection unit and the multiphase electric motor. A deviation amount measuring unit that measures the relationship between the motor electrical angle detected in step 1 and the deviation amount of the motor electrical angle estimated value;
A deviation amount storage unit for storing a relationship between a value related to the output torque measured by the deviation amount measurement unit and the deviation amount;
A motor electrical angle correction unit that corrects the estimated motor electrical angle based on the amount of deviation stored in the displacement amount storage unit and corresponding to the value related to the output torque when the estimated motor electrical angle is estimated; The motor control device according to claim 1 or 2.   An electric power steering device comprising the motor control device according to any one of claims 1 to 7.   A vehicle comprising the electric power steering device according to claim 8.

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