JP2016096608A - Motor control device, electric power steering device using the same, and vehicle - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a motor control device that is able to continue driving control for en electric motor even if an abnormal state arises in output from the resolver of a motor.SOLUTION: A motor control device comprises: a steering torque detection part that detects steering torque by detecting input/output side rotation angle of a torsion bar inserted into a steering system; a motor rotation angle detection part including a resolver for detecting motor rotation angle of a multi-phase electric motor; a motor angle abnormality detection part that detects abnormality in the motor rotation angle detection part; a motor rotation angle estimation part that estimates motor rotation angle resulting from reverse electromotive voltage on the basis of motor current detection value and motor voltage detection value of the multi-phase electric motor, and on the basis of the output-side rotation angle of the torsion bar of the steering torque detection part; and a motor rotation angle selection part that, when abnormality in the motor rotation angle detection part is detected by a rotation angle detection part abnormality detecting part, selects a motor rotation angle estimated value of the motor rotation angle estimation part instead of a motor rotation angle detection value of the motor rotation angle detection part.SELECTED DRAWING: Figure 8

Description

  The present invention relates to a motor control device that drives and controls a multiphase electric motor, an electric power steering device using the same, and a vehicle.

Motor control devices that drive and control electric motors for electric power steering devices mounted on vehicles, electric motors for electric brake devices, electric motors for driving electric vehicles and hybrid vehicles, etc., even when an abnormality occurs in the motor control system It is desired that the drive of the electric motor can be continued.
In order to meet the above demand, for example, the multi-phase motor winding of the multi-phase electric motor is duplexed, and provided with a disconnection detecting means for detecting the disconnection state with respect to the duplexed multi-phase motor winding, and the motor according to the disconnection state. There has been proposed a motor control device and a vehicle steering device that include a control amount reducing means for reducing the control amount (see, for example, Patent Document 1).

Japanese Patent No. 4433856

By the way, in the motor control of the electric power steering apparatus, a resolver is provided in the motor in order to control the rotation angle of the motor with high accuracy in accordance with the steering angle, the steering speed, and the like of the steering. In the conventional example described in Patent Document 1 described above, the disconnection state of the power line of the motor is detected, the control amount of the motor is reduced by the disconnection state, and the heat generation of the motor at the time of disconnection of the power line is reduced. Although the motor continues to be driven, it does not deal with failures other than the motor power line, for example, resolver failures. For this reason, the above conventional example has an unsolved problem that it cannot cope with a case where the resolver attached to the motor fails and the rotation angle of the motor cannot be detected.
Therefore, the present invention has been made paying attention to the above-mentioned unsolved problems of the conventional example, and continues drive control of the electric motor even when a failure occurs in the resolver of the motor or when the output of the resolver is small. It is an object of the present invention to provide a motor control device that can be used, an electric power steering device using the motor control device, and a vehicle.

In order to solve the above-described object, an aspect of an electric power steering apparatus according to the present invention is a steering torque detector that detects a steering torque by detecting a rotation angle on the input / output side of a torsion bar inserted in a steering system. A motor rotation angle detection unit including a resolver that detects a motor rotation angle of the multiphase electric motor, a motor angle abnormality detection unit that detects abnormality of the motor rotation angle detection unit, and a motor current of the multiphase electric motor A motor rotation angle estimation unit that estimates a motor rotation angle by a back electromotive voltage based on a detection value, a motor voltage detection value, and an output side rotation angle of the torsion bar of the steering torque detection unit, and the rotation angle detection unit abnormality detection unit When an abnormality is detected in the motor rotation angle detection unit, the motor rotation angle estimation value of the motor rotation angle estimation unit is selected instead of the motor rotation angle detection value of the motor rotation angle detection unit. And a motor rotation angle selection unit for.
Further, in one aspect of the power steering device according to the present invention, the motor rotation angle estimation unit is configured such that when the estimated back electromotive force value using the motor current detection location and the motor voltage detection value is small, The motor rotation angle may be estimated based on the output side rotation angle.
Moreover, the one aspect | mode of the vehicle which concerns on this invention is equipped with the said electric power steering apparatus.

  According to the present invention, there is provided an electric power steering apparatus capable of accurately estimating a motor angle and continuing motor control even when it is difficult to detect the motor angle due to a motor resolver failure or the like. be able to.

1 is a system configuration diagram showing a first embodiment of an electric power steering apparatus according to the present invention. It is a schematic block diagram which shows a torque sensor. It is a circuit diagram which shows the specific structure of the motor control apparatus in 1st Embodiment. It is a block diagram which shows the specific structure of the control arithmetic unit of FIG. It is a characteristic diagram which shows the relationship between the steering torque at the time of normal time and abnormality, and a steering auxiliary current command value. FIG. 4 is a block diagram showing a specific configuration of the current detection circuit of FIG. 3. It is a schematic block diagram which shows the abnormality detection circuit in the inverter circuit of FIG. It is a block diagram which shows the other example of a motor rotation angle detection circuit. It is explanatory drawing which shows the calculation procedure of an absolute steering angle. It is a block diagram which shows an absolute steering angle calculation circuit.

Hereinafter, embodiments of the present invention will be described with reference to the drawings.
FIG. 1 is an overall configuration diagram showing a first embodiment when the motor control device of the present invention is applied to an electric power steering device mounted on a vehicle.
In the figure, reference numeral 1 denotes a steering wheel, and a steering force applied to the steering wheel 1 from a driver is transmitted to the steering shaft 2. The steering shaft 2 has an input shaft 2a and an output shaft 2b. One end of the input shaft 2 a is connected to the steering wheel 1, and the other end is connected to one end of the output shaft 2 b via the steering torque sensor 3.
The steering force transmitted to the output shaft 2 b is transmitted to the lower shaft 5 via the universal joint 4 and further transmitted to the pinion shaft 7 via the universal joint 6. The steering force transmitted to the pinion shaft 7 is transmitted to the tie rod 9 via the steering gear 8 and steers steered wheels (not shown). Here, the steering gear 8 is configured in a rack and pinion type having a pinion 8a connected to the pinion shaft 7 and a rack 8b meshing with the pinion 8a, and the rack 8b transmits the rotational motion transmitted to the pinion 8a. It has been converted to a straight motion in the width direction.

A steering assist mechanism 10 for transmitting a steering assist force to the output shaft 2b is connected to the output shaft 2b of the steering shaft 2. The steering assist mechanism 10 is an electric motor composed of, for example, a three-phase brushless motor that generates a steering assist force coupled to the reduction gear 11 and a reduction gear 11 composed of, for example, a worm gear mechanism coupled to the output shaft 2b. As a three-phase electric motor 12.
The steering torque sensor 3 detects the steering torque applied to the steering wheel 1 and transmitted to the input shaft 2a. For example, as shown in FIG. 2, the steering torque is transmitted between the input shaft 2a and the output shaft 2b. The twist angle displacement of the inserted torsion bar 3a is converted into an angular difference between the input side rotation angle sensor 3b arranged on the input shaft 2a side and the output side rotation angle sensor 3c arranged on the output shaft 2b side. It is configured to detect by conversion.

Furthermore, as shown in FIG. 3, the three-phase electric motor 12 includes a rotational position sensor 13a such as a resolver that detects the rotational position of the motor. The detection value from the rotation position sensor 13a is supplied to the motor rotation angle detection circuit 13, and the motor rotation angle detection circuit 13 detects the motor rotation angle θm.
The motor control device 20 receives the steering torque T detected by the steering torque sensor 3 and the vehicle speed Vs detected by the vehicle speed sensor 21 and the motor rotation angle θm output from the motor rotation angle detection circuit 13. Is done.
In addition, a direct current is input to the motor control device 20 from a battery 22 as a direct current voltage source.

Although not shown in FIG. 3, the control arithmetic unit 31 receives the steering torque T detected by the steering torque sensor 3 shown in FIG. 1 and the vehicle speed V detected by the vehicle speed sensor 21. As shown in FIG. 3, the motor rotation angle θm output from the motor rotation angle detection circuit 13 is input, and the multiphase motor windings La to Lc of the three-phase electric motor 12 output from a current detection circuit 39A described later. Motor currents Iad to Icd energizing the coils L1 to L3 of the respective phases are input.
As shown in FIG. 4, the control arithmetic unit 31 includes a steering auxiliary current command value calculation unit 34 for calculating a steering auxiliary current command value I *, and a steering auxiliary current command calculated by the steering auxiliary current command value calculation unit 34. A compensation control calculation unit 35 that performs compensation based on the angular velocity ωe and the angular acceleration α input to the value I *, and d based on the compensated torque command value I * ′ compensated by the compensation control calculation unit 35 A dq-axis current command value calculation unit 37 that calculates a -q-axis current command value and converts it into a three-phase current command value;

The steering assist current command value calculator 34 calculates a steering assist current command value I * that is a current command value with reference to the steering assist current command value calculation map shown in FIG. 5 based on the steering torque Ts and the vehicle speed Vs. . This steering assist current command value calculation map is a characteristic diagram represented by a parabolic curve with the steering torque Ts on the horizontal axis and the steering assist current command value I * on the vertical axis, as shown in FIG. It is configured.
When the motor drive circuit 32A is normal, the steering assist current command value I * is calculated with reference to the current command value calculation curve Lno shown in FIG. 5 which is preset based on the steering torque T and the vehicle speed V.

The compensation control calculation unit 35 compensates for a convergence compensation value for compensating the convergence of the yaw rate based on the motor angular velocity ωe, for example, and a torque equivalent generated by the inertia of the electric motor 12 based on the motor angular acceleration α. Alternatively, a torque compensation value for preventing deterioration of control responsiveness and a self-aligning torque compensation value for estimating and compensating for the self-aligning torque (SAT) are calculated, and these are added together to calculate a command value compensation value Icom.
Then, the compensation control calculation unit 35 adds the calculated command value compensation value Icom to the steering auxiliary current command value I * output from the steering auxiliary current command value calculation unit 34 by the adder 36, thereby obtaining a post-compensation current command value. I * ′ is calculated, and this compensated current command value I * ′ is output to the dq-axis current command value calculation unit 37.

The dq-axis current command value calculation unit 37 includes a d-axis target current calculation unit 37a, an induced voltage model calculation unit 37b, a q-axis target current calculation unit 37c, and a two-phase / three-phase conversion unit 37d.
The d-axis target current calculation unit 37a calculates the d-axis target current Id * based on the post-compensation steering assist current command value I * ′ and the motor angular velocity ωe.
The induced voltage model calculation unit 37b generates a d-axis EMF component ed (θ) and a q-axis EMF component eq (θ) of the dq-axis induced voltage model EMF (Electro Magnetic Force) based on the motor rotation angle θ and the motor angular velocity ωe. Is calculated.
The q-axis target current calculation unit 37c includes the d-axis EMF component ed (θ) and the q-axis EMF component eq (θ) output from the induced voltage model calculation unit 37b and the d-axis output from the d-axis target current calculation unit 37a. The q-axis target current Iq * is calculated based on the target current Id *, the post-compensation steering assist current command value I * ′, and the motor angular velocity ωe.
The two-phase / three-phase conversion unit 37d converts the d-axis target current Id * output from the d-axis target current calculation unit 37a and the q-axis target current Iq * output from the q-axis target current calculation unit 37c into a three-phase current. Convert to command values Ia *, Ib * and Ic *.

  Further, the control arithmetic unit 31 calculates the calculated A-phase current command value Ia *, B-phase current command value Ib * and C-phase current command value Ic *, and the current detection values Iad, Ibd and Icd detected by the current detection circuit 39A. Is provided with a voltage command value calculator 38 for calculating a voltage command value V1 * for the motor drive circuit 32A. The voltage command value calculation unit 38 subtracts the current detection values Iad, Ibd, and Icd from the A-phase current command value Ia *, the B-phase current command value Ib *, and the C-phase current command value Ic * to obtain current deviations ΔIa, ΔIb. And ΔIc are calculated, and for these current deviations ΔIa, ΔIb, and ΔIc, for example, PI control calculation or PID control calculation is performed to calculate a three-phase voltage command value V1 * for the motor drive circuit 32A, and the calculated three-phase voltage command The value V1 * is output to the motor drive circuit 32A.

Further, as shown in FIGS. 3 and 6, the control arithmetic unit 31 includes motor phase voltages V1ma detected by a motor voltage detection circuit 40A provided between the motor drive circuit 32A and the motor current cut-off unit 33A. V1mb and V1mc are input.
Further, as shown in FIG. 3, the control arithmetic unit 31 includes an upper current detection value IA1d output from a current detection circuit 39A1 that detects a direct current supplied to the inverter circuit 42A of the motor drive circuit 32A, and an inverter circuit. The lower current detection value IA2d output from the current detection circuit 39A2 that detects the direct current flowing from 42A to the ground is input.

  In the control arithmetic unit 31, the motor phase voltages Vm1a, Vm1b, Vm1c, the upper current detection value IA1d, and the lower current detection value IA2d are input to the A / D conversion unit 31c.

The motor drive circuit 32A receives a three-phase voltage command value V1 * output from the control arithmetic unit 31 to form a gate signal, and a gate signal output from the gate drive circuit 41A. Inverter circuit 42A.
When the voltage command value V1 * is input from the control arithmetic unit 31, the gate drive circuit 41A has six gate signals that are pulse width modulated (PWM) based on the voltage command value V1 * and the triangular wave carrier signal Sc. And outputs these gate signals to the inverter circuit 42A.
Note that six PWM gate signals may be commonly generated by the control arithmetic unit 31 and input to the inverter circuit 42A.

  The gate drive circuit 41A outputs three high-level gate signals to the motor current cut-off unit 33A when the abnormality detection signal SAa input from the control arithmetic unit 31 is a logical value “0” (normal). At the same time, a high-level gate signal is output to the power cutoff unit 44A. Further, the gate drive circuit 41A simultaneously outputs three low-level gate signals to the motor current cutoff unit 33A when the abnormality detection signal SAa is a logical value “1” (abnormal), thereby cutting off the motor current. Then, a low level gate signal is output to the power cutoff unit 44A to cut off the battery power.

In the first and second inverter circuits 42A, the battery current of the battery 22 is input via the noise filter 43, the power cutoff unit 44A, and the current detection circuit 39A1, and the smoothing electrolytic capacitors CA and CB are input to the input side. Is connected.
The first and second inverter circuits 42A have six field effect transistors (FETs) Q1 to Q6 as six switching elements, and three switching arms SWAa and SWAb in which two field effect transistors are connected in series. It has a configuration in which SWAc are connected in parallel.
In these first and second inverter circuits 42A, the gate signals output from the gate drive circuit 41A are input to the gates of the field effect transistors Q1 to Q6, whereby the field effects of the switching arms SWAa, SWAb, and SWAc are obtained. The A-phase current Ia, the B-phase current Ib, and the C-phase current Ic are supplied to the three-phase motor windings La, Lb, and Lc of the three-phase electric motor 12 through the motor current cut-off unit 33A from the connection point between the transistors.

The switching arms SWAa, SWAb, and SWAc of the inverter circuit 42A are grounded via the current detection circuit 39A2 with the sources of the field effect transistors Q2, Q4, and Q6 serving as the lower arms connected to each other. Thus, motor currents I1a to I1c are detected.
The current detection circuits 39A1 and 39A2 are configured as shown in FIG. That is, as shown in FIG. 7, the current detection circuit 39A1 includes a current detection shunt resistor 51A interposed between the power supply side of each switching arm SWAa to SWAc and the power supply cutoff unit 44A. As shown in FIG. 6 (a), the current detection circuit 39A1 mainly includes an operational amplifier 39a to which the voltage across the shunt resistor 51A is input via resistors R2 and R3, and an output signal from the operational amplifier 39a. It comprises a sample hold circuit 39s constituted by a filter.

Then, the current detection signal IA1d output from the sample hold circuit 39s is supplied to the A / D conversion unit 31c of the control arithmetic device 31.
Further, as shown in FIG. 7, the current detection circuit 39A2 includes a current detection shunt resistor 52A inserted between the ground side of each switching arm SWAa to SWAc and the ground. As shown in FIG. 6B, the current detection circuit 39A2 includes an operational amplifier 39a in which the voltage across the shunt resistor 52A is input via the resistors R2 and R3, and a noise filter to which the output signal of the operational amplifier 39a is supplied. The peak hold circuit 39p includes a sample hold circuit 39s mainly including a noise filter to which an output signal of the operational amplifier 39a is supplied.
Then, the current detection signal IA2d output from the sample hold circuit 39s is supplied to the A / D conversion unit 31c of the control arithmetic device 31.
Further, a peak hold signal IA3d of a current detection value output from the peak hold circuit 39p is supplied to the A / D converter 31c, an overcurrent cutoff circuit 70A and a current bypass circuit 80A, which will be described later.

The motor current cut-off unit 33A has 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 SWAa of the first inverter circuit 42A via the motor voltage detection circuit 40A, and the drain is the A phase motor winding of the three phase motor winding L1. It is connected to the line La.
The source of the field effect transistor QA2 is connected to the connection point of the transistors Q3 and Q4 of the switching arm SWAb of the first inverter circuit 42A via the motor voltage detection circuit 40A, and the drain is connected to the three-phase motor winding Lb. ing.
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 SWAc of the first inverter circuit 42A via the motor voltage detection circuit 40A, and the drain is connected to the three-phase motor winding Lc. ing.

The field effect transistors QA1 to QA3 and QB1 to QB3 of the motor current interrupter 33A are connected in the same direction with the anode of the parasitic diode D as the inverter circuit 42A side.
The power cutoff unit 44A is configured by a parallel circuit of one field effect transistor (FET) QC and QD and a parasitic diode, and the drain of the field effect transistor QC and QD is connected to the battery 22 via the noise filter 43. The source is connected to the inverter circuit 42A. In addition, these power supply interruption | blocking parts 44A are not restricted to the said structure, As shown in FIG. 7, you may make it connect two power supply interruption | blocking parts 44A and 44A 'in series so that a parasitic diode may become reverse direction.

Next, the operation of the above embodiment will be described.
When an ignition switch (not shown) is in an off state and the vehicle is stopped and the steering assist control process is also stopped, the control arithmetic unit 31 of the motor control device 20 is in an inoperative state. Yes. For this reason, the steering assist control process and the abnormality monitoring process executed by the control arithmetic device 31 are stopped. Accordingly, the operation of the electric motor 12 is stopped, and the output of the steering assist force to the steering assist mechanism 10 is stopped.
When the ignition switch is turned on from this operation stop state, the control arithmetic unit 31 enters the operation state, and the steering assist control process and the abnormality monitoring process are started. At this time, it is assumed that the field effect transistors Q1 to Q6 in the inverter circuit 42A of each motor drive circuit 32A are in a normal state in which no open failure and short-circuit failure have occurred. At this time, in the non-steering state in which the steering wheel 1 is not steered, the steering torque T is “0” and the vehicle speed V is “0” in the steering assist control process executed by the control arithmetic unit 31, so FIG. The steering assist current command value is calculated with reference to a normal current command value calculation curve Lno indicated by a solid line in the current command value calculation map of FIG.

Then, a d-axis current command value Id * and a q-axis current command value Iq * are calculated based on the calculated steering assist current command value I * and the motor electrical angle θe input from the motor rotation angle detection circuit 13; The calculated d-axis current command value Id * and q-axis current command value Iq * are subjected to a dq two-phase to three-phase conversion process to obtain an A-phase current command value Ia *, a B-phase current command value Ib *, and a C-phase current command value. Ic * is calculated.
Furthermore, each phase current command value Ia *, Ib * and Ic * and each phase current detection value Iad, Ibd calculated by calculation including the addition from each phase current detection value IA1d detected by the current detection circuit 39A and Current deviations ΔIa, ΔIb, and ΔIc from Ibc are calculated, and the target current command values Va *, Vb *, and Vc * are calculated by performing PI control processing or PID control processing on the calculated current deviations ΔIa, ΔIb, and ΔIc.

Then, the calculated target voltage command values Va *, Vb * and Vc * are output as voltage command values V1 * to the gate drive circuit 41A of the motor drive circuit 32A. Further, since the inverter circuit 42A is normal, the control arithmetic unit 31 outputs the abnormality detection signals SAa and SAb having the logical value “0” to the gate drive circuits 41A and 41B.
For this reason, the gate drive circuits 41A and 41B output three high-level gate signals to the motor current cutoff units 33A and 33B. Therefore, field effect transistors QA1 to QA3 and QB1 to QB3 of motor current interrupting portions 33A and 33B are turned on, and between inverter circuits 42A and 42B and three-phase motor windings L1 and L2 of three-phase electric motor 12 Becomes a conductive state, and the energization control for the three-phase electric motor 12 becomes possible.

At the same time, a high-level gate signal is output from the gate drive circuit 41A to the power cutoff unit 44A. Therefore, the field effect transistors QC and QD of the power cutoff unit 44A are turned on, and the direct current from the battery 22 is supplied to the inverter circuit 42A via the noise filter 43.
Further, the gate drive circuit 41A forms a gate signal by performing pulse width modulation based on the voltage command value V1 * input from the control arithmetic unit 31, and the formed gate signal is converted into each field effect transistor Q1 of the inverter circuit 42A. Supply to the gate of ~ Q6.
Therefore, when the vehicle is stopped and the steering wheel 1 is not steered, the steering torque Ts is “0”, so the steering assist current command value is also “0” and the electric motor 12 maintains the stopped state. To do.

However, when the steering wheel 1 is steered while the vehicle is stopped or the vehicle starts running, so-called stationary is performed, the steering torque Ts increases, so that a large steering assist current command value I is obtained with reference to FIG. * Is calculated, and a large voltage command value V1 * corresponding to this is supplied to the gate drive circuit 41A. Therefore, a gate signal having a duty ratio corresponding to the large voltage command value V1 * is output from the gate drive circuit 41A to the inverter circuit 42A.
Therefore, an A-phase current I1a, B-phase current I1b, C-phase currents I1c and I2a, I2b and I3c having a phase difference of 120 degrees corresponding to the steering assist current command value I * are output from the inverter circuit 42A. It is supplied to the three-phase motor windings La to Lc of the three-phase electric motor 12 through the field effect transistors QA1 to QA3 and QB1 to QB3 corresponding to each phase of the current interrupting unit 33A.

As a result, the electric motor 12 is rotationally driven to generate a large steering assist force corresponding to the target steering assist current value I * corresponding to the steering torque Ts, and this steering assist force is output via the reduction gear 11 to the output shaft 2b. Is transmitted to. For this reason, the steering wheel 1 can be steered with a light steering force.
Thereafter, when the vehicle speed Vs increases, the steering assist current command value calculated in accordance therewith decreases compared to the time of stationary, and the steering assist is decreased moderately by the electric motor 12 according to the steering torque Ts and the vehicle speed Vs. Generate power.
Thus, when the inverter circuit 42A is normal and the motor currents Ia, Ib and Ic supplied to the three-phase electric motor 12 are normal, the motor current optimum for the steering torque Ts and the vehicle speed Vs is three-phase electric. It is supplied to the motor 12.

  In the above embodiment, the case where the current detection circuit 39A detects the motor current using the two shunt resistors 51A and 52A in each inverter circuit has been described. However, the present invention is not limited to this. That is, in the present invention, the motor current of each phase is detected by inserting a shunt resistor individually on the ground side of each phase switching arm SWAa to SWAc of the motor drive circuit 32A, or one of the three shunt resistors is selected. The motor current of the omitted phase may be calculated by calculation.

In the above-described embodiment, the case where the control arithmetic unit 31 includes the A / D conversion unit 31c has been described. However, the present invention is not limited to this, and the A / D conversion unit 31c is connected to the output side of the current detection circuits 39A1 and 39A2. A / D converter may be provided.
In the above embodiment, the case where the motor rotation angle detection circuit 13 has a configuration using a resolver has been described. However, the motor rotation angle detection circuit 13 is subjected to backup control as shown in FIG. Yes.
That is, the specific configuration of the motor rotation angle detection circuit 13 includes a main motor rotation angle detection circuit 86, a sub motor rotation angle detection circuit 87, and the main motor rotation angle detection circuit 86 and sub motor rotation angle as shown in FIG. And a rotation angle selection unit 88 for selecting the motor rotation angles θm1 and θm2 output from the detection circuit 87.

The main motor rotation angle detection circuit 86 is based on a resolver 86A that detects the rotation angle of the three-phase electric motor 12, and a sin signal and a cos signal corresponding to the rotation angle of the three-phase electric motor 12 output from the resolver 86A. An angle calculation unit 86B that calculates the motor rotation angle θm and an abnormality detection unit 86C that detects an abnormality in the resolver 86A and the angle calculation unit 86B and outputs an abnormality detection signal SAr are provided.
The sub motor rotation angle detection circuit 87 receives the motor current detection value Im, the motor voltage detection value Vm, and the output shaft angle detection signal θos output from the output side rotation angle sensor 3c in FIG. .
The sub motor rotation angle detection circuit 87 calculates a back electromotive voltage EMF based on the motor current detection value Im and the motor voltage detection value Vm, and estimates a motor rotation angle θm based on the calculated back electromotive voltage EMF. Motor rotation angle estimation unit 87A, second motor rotation angle estimation unit 87B that estimates motor rotation angle θm based on output shaft angle detection signal θos, first motor rotation angle estimation unit 87A, and second motor rotation And a selection unit 87C that selects the estimated motor rotation angle values θme1 and θme2 of the angle estimation unit 87B.

Here, the selection unit 87C receives the back electromotive voltage EMF calculated by the first motor rotation angle estimation unit 87A, and the first motor rotation angle estimation unit 87A estimates when the back electromotive voltage EMF is equal to or greater than a predetermined threshold. The estimated motor rotation angle value θme1 is selected, and when the back electromotive force EMF is less than the predetermined threshold, the motor rotation angle estimation value θme2 estimated by the second motor rotation angle estimation unit 87B is selected and output as the motor rotation angle θm2. To do.
In addition, the rotation angle selection unit 88 has a main motor rotation angle detection circuit when the abnormality detection signal SAr output from the abnormality detection unit 86C of the main motor rotation angle detection circuit 86 is a logical value “0” indicating no abnormality. The motor rotation angle θm1 output from 86 is selected and output to the control arithmetic unit 31 as the motor rotation angle θm, and when the abnormality detection signal SAr is a logical value “1” indicating the presence of abnormality, the sub motor rotation angle The motor rotation angle θm2 output from the detection circuit 87 is selected and output to the control arithmetic unit 31 as the motor rotation angle θm.

  As described above, the motor rotation angle detection circuit 13 includes the main motor rotation angle detection circuit 86, the sub motor rotation angle detection circuit 87, and the rotation angle selection unit 88, so that the main motor rotation angle detection circuit 86 is normal. Sometimes, the high-precision motor rotation angle θm1 output from the main motor rotation angle detection circuit 86 is output to the control arithmetic unit 31 as the motor rotation angle θm. When an abnormality occurs in the main motor rotation angle detection circuit 86, the motor rotation angle estimated value θme1 or θme2 estimated by the sub motor rotation angle detection circuit 87 is output to the control arithmetic unit 31 as the motor rotation angle θm.

  Further, the sub motor rotation angle detection circuit 87 is based on the back electromotive voltage EMF in a state where the motor electromotive force EMF generated in the motor windings La to Lc of the three-phase electric motor 12 is higher than a predetermined threshold and the motor rotation speed is high. The motor rotation angle estimation value θme1 estimated by the first motor rotation angle estimation unit 87A for estimating the motor rotation angle is selected, and in the region where the motor rotation speed is low where the counter electromotive voltage EMF is less than a predetermined threshold, the counter electromotive voltage EMF is selected. Therefore, the estimation accuracy of the estimated motor rotation angle θme1 is reduced, so that the estimated motor rotation angle θme2 estimated based on the output shaft angle detection signal θos is selected by the second motor rotation angle estimation unit 87B.

Thus, when an abnormality occurs in the main motor rotation angle detection circuit 86, the motor rotation angle can be obtained while ensuring the minimum necessary accuracy by the sub motor rotation angle detection circuit 87.
In the above embodiment, since the steering torque sensor 3 includes the input side rotation angle sensor 3b and the output side rotation angle sensor 3c as shown in FIG. 2, the steering torque sensor 3 is steered toward the input shaft 2a as shown in FIG. By providing the angle sensor 91, the absolute steering angle θab can be detected based on the steering angle detection signal θs of the steering angle sensor 91 and the output shaft angle detection signal θos detected by the output side rotation angle sensor 3c. it can.

  That is, as shown in FIG. 9A, the steering angle sensor 91 outputs a steering angle detection signal θs that is a sawtooth wave with a 296 deg cycle of the steering wheel 1, and the output detected by the output side rotation angle sensor 3c. An output shaft angle detection signal θos composed of a sawtooth wave having a 40 deg cycle of the shaft 2b is output. The steering angle at which the steering angle detection signal θs and the output shaft angle detection signal θos coincide is 1480 deg. Then, as shown in FIG. 9B, the output shaft angle detection signal θos is absolute as shown in FIG. 9B by performing vernier calculation on which position (first to 37th) in the steering angle detection signal θs = 1480 deg. The steering angle θab can be obtained.

  For this purpose, as shown in FIG. 10, two systems of torque sensors 3A and 3B are arranged, and the input shaft rotation angle detection signal θis and the output shaft angle detection signal θos output from both torque sensors 3A and 3B are vernier. In addition to being supplied to the calculation unit 92, the steering angle detection signal θs detected by the steering angle sensor 91 is supplied to the vernier calculation unit 92, and the vernier calculation unit 92 performs a vernier calculation once immediately after the ignition switch is turned on. Then, the initial steering angle θinit is calculated. Further, the average value of the output shaft angle detection signal θos output from the torque sensors 3A and 3B is calculated by the averaging circuit 93, the change amount of the average value is integrated by the integrating circuit 94, and the integrated value is calculated and calculated. The absolute value steering angle θab is calculated by adding the integrated value to the initial steering angle θinit calculated by the vernier calculation unit 92.

Moreover, in the said embodiment, although the case where an electric motor was a three-phase electric motor was demonstrated, it is not limited to this, This invention is applicable also to a polyphase electric motor more than four phases. .
Further, in each of the above embodiments, the case where the motor control device according to the present invention is applied to an electric power steering device has been described. However, the present invention is not limited to this, and the electric brake device, the steer-by-wire system, and the vehicle driving device are used. The present invention can be applied to any system that uses an electric motor such as a motor drive device.

  DESCRIPTION OF SYMBOLS 1 ... Steering wheel, 2 ... Steering shaft, 3 ... Steering torque sensor, 3a ... Torsion bar, 3b ... Input side rotational angle sensor, 3c ... Output side rotational angle sensor, 8 ... Steering gear, 10 ... Steering assist mechanism, 12 ... Three-phase electric motor, La ... A phase motor winding, Lb ... B phase motor winding, Lc ... C phase motor winding, L1-L3 ... coil part, 20 ... motor control device, 21 ... vehicle speed sensor, 22 ... battery , 31 ... control arithmetic unit, 32A ... motor drive circuit, 33A ... motor current cutoff circuit, 34 ... steering assist current command value calculation unit, 35 ... compensation control calculation unit, 36 ... adder, 37 ... dq axis current command Value calculation unit 38 ... Voltage command value calculation unit 39A1, 39A2 ... Current detection circuit, 40A ... Voltage detection circuit, 41A ... Gate drive circuit, 42A ... Inverter circuit, 44A ... Source cut-off unit, 70A ... Overcurrent cut-off circuit, 80A ... Current bypass circuit, 86 ... Main motor rotation angle detection circuit, 87 ... Sub motor rotation angle detection circuit, 88 ... Angle selection unit, 91 ... Steering angle sensor, 92 ... Vernier calculation unit, 93 ... averaging circuit, 94 ... integration circuit

Claims (3)

(Claim 29)
A steering torque detector for detecting a steering torque by detecting a rotation angle of an input / output side of a torsion bar inserted in the steering system;
A motor rotation angle detector including a resolver for detecting a motor rotation angle of the multiphase electric motor;
Based on a motor angle abnormality detection unit that detects an abnormality of the motor rotation angle detection unit, a motor current detection value and a motor voltage detection value of the multiphase electric motor, and an output side rotation angle of the torsion bar of the steering torque detection unit A motor rotation angle estimation unit that estimates a motor rotation angle due to a back electromotive voltage, and when the abnormality of the motor rotation angle detection unit is detected by the rotation angle detection unit abnormality detection unit, the motor rotation angle of the motor rotation angle detection unit An electric power steering apparatus comprising: a motor rotation angle selection unit that selects a motor rotation angle estimation value of the motor rotation angle estimation unit instead of a detection value.   2. The motor rotation estimation unit estimates a motor rotation angle based on an output-side rotation angle of a torsion bar when a back electromotive force estimation value using the motor current detection location and the motor voltage detection value is small. The electric power steering device described in 1.   A vehicle comprising the electric power steering device according to claim 1.

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