JP2013063018A - Motor controller and electric power steering device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a motor controller capable of ensuring high output performance stably by smoothing motor rotation during two-phase driving incident to occurrence of energization failure, and to provide an electric power steering device.SOLUTION: A microcomputer detects each phase current value of a motor on the basis of the output signal from each current sensor acquired at a predetermined sampling period. At least the previous time detection value is held along with the this time detection value. If a predetermined rotation angle exists between the rotation angle of this time current detection and the rotation angle of previous time current detection during two-phase driving, the this time and previous time detection values thus held are corrected so as to have larger absolute values.

Description

  The present invention relates to a motor control device and an electric power steering device.

  Conventionally, many motor control devices used in an electric power steering device (EPS) or the like have any phase of the motor (any of U, V, and W) due to disconnection of a power supply line or a contact failure of a drive circuit. An abnormality detection means is provided that can detect the occurrence of the abnormality when a current-carrying failure occurs. And when generation | occurrence | production of the said abnormality is detected, the structure which stops motor control rapidly and aims at fail safe is common.

  However, in EPS, as the motor control stops, the steering characteristics change greatly. That is, in order for the driver to perform an appropriate steering operation, a larger steering force is required. Based on this point, conventionally, there is a motor control device that continues motor control using two phases other than the current-carrying failure phase as a current-carrying phase even when the occurrence of a current-carrying failure phase is detected as described above (for example, Patent Document 1). As a result, the application of assist force to the steering system can be continued, and an increase in the driver's burden associated with fail-safe can be avoided.

JP 200326020 A

  However, when the motor control is continued with two energization phases other than the energization failure phase at the time of occurrence of the energization failure phase as in the conventional example, for each energization phase as shown in FIG. In the configuration in which sine wave energization is performed (the example shown in the figure is when the U phase is abnormal and the V and W phases are energized), the steering feeling is inevitably deteriorated due to the occurrence of torque ripple.

  That is, as shown in FIG. 17, when the transition of the motor current during the conventional two-phase drive is expressed in the d / q coordinate system, the q-axis current command value that is the control target value of the motor torque is constant. Regardless, the actual q-axis current value changes sinusoidally. In other words, there is a problem that the assist force fluctuates greatly when the motor drive is continued in a state where the original output performance cannot be obtained because the motor current corresponding to the required torque is not generated. The room was left.

  The present invention has been made to solve the above-mentioned problems, and its purpose is to smooth the motor rotation at the time of two-phase driving accompanying the occurrence of an energization failure and to ensure stable high output performance. An object of the present invention is to provide a motor control device and an electric power steering device.

In order to solve the above problems, the invention according to claim 1 is a motor control signal output means for outputting a motor control signal, and a drive circuit for supplying three-phase drive power to the motor based on the motor control signal. And an abnormality detecting means capable of detecting an energization failure occurring in each phase of the motor, wherein the motor control signal output means generates the motor control signal by executing current control based on the rotation angle of the motor. In addition, when the energization failure occurs, in the motor control device that executes the output of the motor control signal using two phases other than the energization failure occurrence phase as the energization phase, the motor control signal output means In order to energize each energized phase with a phase current that changes into a secant curve or a cosecant curve with a predetermined rotation angle corresponding to the energization failure occurrence phase as an asymptotic line The current value of each phase is detected at a predetermined sampling period by the current detection means, and at least the previous detection value is held together with the current detection value, and the current detection means If the predetermined rotation angle corresponding to the asymptote is sandwiched between the rotation angle at the current detection time and the rotation angle at the previous current detection time, the held current detection value and the previous The gist is to correct the detected value so that the absolute value becomes a larger value.

  The invention according to claim 2 occurs in each phase of the motor, motor control signal output means for outputting a motor control signal, a drive circuit for supplying three-phase drive power to the motor based on the motor control signal, and An abnormality detection means capable of detecting a failure in energization, and the motor control signal output means generates the motor control signal by executing current control based on the rotation angle of the motor, and at the time of occurrence of the energization failure, In the motor control device that executes the output of the motor control signal with the two phases other than the energization failure occurrence phase as the energization phase, the motor control signal output means The current control is performed so as to energize a phase current that changes in a secant curve or a cosecant curve with a predetermined rotation angle corresponding to an energization failure occurrence phase as an asymptotic line. The current value is detected by a current detection unit at a predetermined sampling period, and the current detection unit detects the asymptotic value between a rotation angle at the current current detection and a rotation angle at the previous current detection. When the predetermined rotation angle corresponding to the line is sandwiched, the gist is to correct the current value detected this time so that the absolute value becomes a larger value.

  The invention according to claim 3 is generated in each phase of the motor, motor control signal output means for outputting a motor control signal, a drive circuit for supplying three-phase drive power to the motor based on the motor control signal. An abnormality detection means capable of detecting a failure in energization, and the motor control signal output means generates the motor control signal by executing current control based on the rotation angle of the motor, and at the time of occurrence of the energization failure, In the motor control device that executes the output of the motor control signal with the two phases other than the energization failure occurrence phase as the energization phase, the motor control signal output means The current control is performed so as to energize a phase current that changes in a secant curve or a cosecant curve with a predetermined rotation angle corresponding to an energization failure occurrence phase as an asymptotic line. The current value is detected at a predetermined sampling period by the current detection means, and includes an estimation means for estimating a rotation angle at the next current detection, and the current detection means is rotated at the current detection time. When it is estimated that a predetermined rotation angle corresponding to the asymptote is sandwiched between the angle and the rotation angle at the next current detection, the absolute value of the current value detected this time is a larger value. The gist is to make corrections as follows.

  According to each of the above configurations, the required torque except for a predetermined rotation angle corresponding to an asymptote (a current limiting range in the vicinity of the predetermined rotation angle when there is a limit to the phase current value energized in each phase) The motor current corresponding to the can be generated. As a result, even when a poorly energized phase is generated, the motor drive can be continued while ensuring high output performance without causing large torque ripple.

  Also, under a certain sampling period, the sampling angular interval (the angular interval for acquiring the output signal of the current sensor) increases as the rotational angular velocity increases. When compared with the normal three-phase sine wave drive in which the peak (absolute value) of each phase current is dispersed at 60 ° intervals, the peak of each phase current value is asymptotic in the two-phase drive as described above. Since it concentrates on a predetermined rotation angle corresponding to the line and its rising edge is steep, the increase in the sampling angle interval greatly affects the accuracy of current detection.

  That is, when the rotation angle at which the current is detected continuously deviates from the predetermined rotation angle corresponding to the asymptote, the continuous detection value indicates the peak value of the phase. Will not be. For example, when the motor temperature is estimated using these detected values, the calculation is performed in the form of rounding down the value in the vicinity of the predetermined rotation angle at which the energization amount to the motor increases most. As a result, the estimated motor temperature may be lower than the actual temperature.

  However, according to each of the above configurations, it is possible to reduce the amount of energization in the vicinity of the predetermined rotation angle, that is, the truncation of the range where the value increases most. As a result, for example, it is possible to enjoy great advantages such as more accurate estimation of the motor temperature.

The gist of the invention described in claim 4 is that the correction of the current value is performed by calculating an average value of the detected value and the maximum energizable value.
According to the above configuration, it is possible to execute the correction calculation efficiently and accurately while suppressing the calculation load.

The gist of the invention described in claim 5 is an electric power steering device provided with the motor control device according to any one of claims 1 to 4.
According to the above configuration, accurate current detection enables accurate estimation of the motor temperature, suppression of the overheating, and quick fail-safe control in the event of overheating, etc. In addition, the power assist control can be executed.

  ADVANTAGE OF THE INVENTION According to this invention, the motor control apparatus and electric power steering apparatus which can smooth | fasten motor rotation at the time of two-phase drive accompanying generation | occurrence | production of a conduction failure, and can ensure high output performance stably can be provided. .

The schematic block diagram of an electric power steering device (EPS). The block diagram which shows the electric constitution of EPS. The control block diagram of a microcomputer (motor control signal generation part). The flowchart which shows the process sequence of an electricity supply failure phase detection. Explanatory drawing which shows transition of each phase electric current at the time of two-phase drive (at the time of U-phase electricity failure). Explanatory drawing which shows transition of the q-axis current at the time of two-phase drive (at the time of U-phase conduction failure). The flowchart which shows the process sequence of abnormality determination and control mode switching. The flowchart which shows the process sequence of the motor control signal generation at the time of two-phase drive. The flowchart which shows the aspect of the electric current detection at the time of the two-phase drive in 1st Embodiment. The flowchart which shows the aspect of the electric current detection in 2nd Embodiment, and motor temperature estimation. Explanatory drawing which shows the aspect of the phase electric current value detected at the time of rotation angular velocity rise, and a phase electric current detection value correction | amendment calculation. The flowchart which shows the process sequence of a phase current detection value correction | amendment calculation. Explanatory drawing which shows the aspect of sampling period shortening of another example. The flowchart which shows the process sequence of the phase current detection value correction calculation of another example. Explanatory drawing which shows transition of the d-axis current and q-axis current at the time of the two-phase drive (at the time of U-phase conduction failure) of another example. Explanatory drawing which shows the aspect of the two-phase drive which uses the two phases other than the conventional energization failure generation phase as an energization phase. Explanatory drawing which shows transition of the d-axis current and q-axis current at the time of the conventional two-phase drive.

(First embodiment)
Hereinafter, a first embodiment in which the present invention is embodied in an electric power steering apparatus (EPS) will be described with reference to the drawings. Note that the first embodiment is described as a reference example.

  FIG. 1 is a schematic configuration diagram of the EPS 1 of the present embodiment. As shown in the figure, a steering shaft 3 to which a steering wheel (steering) 2 is fixed is connected to a rack 5 via a rack and pinion mechanism 4. It is converted into a reciprocating linear motion of the rack 5 by the and pinion mechanism 4. The rudder angle of the steered wheels 6 is changed by the reciprocating linear motion of the rack 5.

  Further, the EPS 1 includes an EPS actuator 10 as a steering force assisting device that applies an assist force for assisting a steering operation to the steering system, and an ECU 11 as a control unit that controls the operation of the EPS actuator 10. .

  The EPS actuator 10 of the present embodiment is a so-called rack-type EPS actuator in which a motor 12 that is a driving source thereof is arranged coaxially with the rack 5, and an assist torque generated by the motor 12 is a ball screw mechanism (not shown). Is transmitted to the rack 5 via. In addition, the motor 12 of this embodiment is a brushless motor, and rotates by receiving supply of three-phase (U, V, W) driving power from the ECU 11. And ECU11 as a motor control apparatus controls the assist force given to a steering system by controlling the assist torque which this motor 12 generate | occur | produces (power assist control).

  In the present embodiment, a torque sensor 14 and a vehicle speed sensor 15 are connected to the ECU 11. Then, the ECU 11 executes the operation of the EPS actuator 10, that is, power assist control, based on the steering torque τ and the vehicle speed V detected by the torque sensor 14 and the vehicle speed sensor 15, respectively.

Next, the electrical configuration of the EPS of this embodiment will be described.
FIG. 2 is a control block diagram of the EPS of this embodiment. As shown in the figure, the ECU 11 includes a microcomputer 17 as motor control signal output means for outputting a motor control signal, and a drive circuit 18 for supplying three-phase drive power to the motor 12 based on the motor control signal. ing.

  The drive circuit 18 of this embodiment is a known PWM inverter in which three arms corresponding to each phase are connected in parallel with a pair of switching elements connected in series as a basic unit (arm). The output of the motor control signal defines the on-duty ratio of each switching element constituting the drive circuit 18. Then, a motor control signal is applied to the gate terminal of each switching element, and each switching element is turned on / off in response to the motor control signal, so that the DC voltage of the in-vehicle power supply (not shown) becomes three-phase (U, V, W) is converted into drive power and supplied to the motor 12.

  More specifically, the ECU 11 detects the current sensors 19u, 19v, 19w for detecting the phase current values Iu, Iv, Iw energized to the motor 12, and the rotation angle (electrical angle) θ of the motor 12. A rotation angle sensor 20 is connected. The microcomputer 17 of the present embodiment includes a current detection unit 21 and a rotation angle detection unit 22, and outputs the output signals Su, Sv, Sw of the current sensors 19u, 19v, 19w acquired at a predetermined sampling period, and the rotation angle. Based on the output signal Sa of the sensor 20, the phase current values Iu, Iv, Iw and the rotation angle θ are detected. The microcomputer 17 outputs a motor control signal to the drive circuit 18 based on the detected phase current values Iu, Iv, Iw and the rotation angle θ, and the steering torque τ and the vehicle speed V.

  More specifically, the microcomputer 17 according to this embodiment determines an assist force (target assist force) to be applied to the steering system based on the steering torque τ and the vehicle speed V, and causes the motor 12 to generate the assist force. Therefore, the motor control signal is generated by executing current control based on the detected phase current values Iu, Iv, Iw and the rotation angle θ.

  Specifically, the microcomputer 17 includes a current command value calculation unit 23 as a current command value calculation unit that calculates a current command value as an assist force to be applied to the steering system, that is, a motor torque control target value, and a current command value calculation. And a motor control signal generation unit 24 as a motor control signal generation unit that generates a motor control signal based on the current command value calculated by the unit 23.

  Based on the steering torque τ and the vehicle speed V detected by the torque sensor 14 and the vehicle speed sensor 15, the current command value calculation unit 23 sets q in the d / q coordinate system as a current command value corresponding to the control target value of the motor torque. The shaft current command value Iq * is calculated and output to the motor control signal generator 24. On the other hand, the motor control signal generator 24 includes the q-axis current command value Iq * output from the current command value calculator 23 and the phase current values Iu, Iv, Iw detected by the current sensors 19u, 19v, 19w. , And the rotation angle θ detected by the rotation angle sensor 20 is input. Then, the motor control signal generation unit 24 executes current feedback control in the d / q coordinate system based on the phase current values Iu, Iv, Iw and the rotation angle θ (electrical angle), thereby performing the motor control signal. Is generated.

  More specifically, the motor control signal generation unit 24 of the present embodiment performs three-phase phase voltage command values Vu * and Vv by executing current feedback control (d / q axis current F / B) in the d / q coordinate system. A first current control unit 24a for calculating * and Vw * is provided. At normal times, a motor control signal is generated based on the phase voltage command values Vu *, Vv *, and Vw * calculated by the first current control unit 24a.

  As shown in FIG. 3, each phase current value Iu, Iv, Iw input to the first current control unit 24a is input to the three-phase / two-phase conversion unit 25 together with the rotation angle θ, and the three-phase / 2-phase The converter 25 converts the d / q coordinate system into a d-axis current value Id and a q-axis current value Iq. The q-axis current value Iq is input to the subtractor 26q together with the q-axis current command value Iq * input from the current command value calculation unit 23, and the d-axis current value Id is the d-axis current command value Id * (Id). * = 0) and input to the subtractor 26d.

  The d-axis current deviation ΔId and q-axis current deviation ΔIq calculated in the subtracters 26d and 26q are input to the corresponding F / B control units 27d and 27q, respectively. In each of the F / B control units 27d and 27q, the d-axis current command value Id * and the q-axis current command value Iq * output from the current command value calculation unit 23 are the d-axis current value Id and the actual current value. Feedback control is performed to follow the q-axis current value Iq.

  That is, the F / B control units 27d and 27q multiply the inputted d-axis current deviation ΔId and q-axis current deviation ΔIq by a predetermined F / B gain (PI gain), thereby obtaining a d-axis voltage command value Vd * and The q-axis voltage command value Vq * is calculated. The calculated d-axis voltage command value Vd * and q-axis voltage command value Vq * are input to the two-phase / three-phase conversion unit 28 together with the rotation angle θ, and the two-phase / three-phase conversion unit 28 outputs three-phase signals. Converted to phase voltage command values Vu *, Vv *, Vw *. Then, the first current control unit 24 a outputs the phase voltage command values Vu *, Vv *, and Vw * to the PWM conversion unit 30.

  The PWM converter 30 generates duty command values αu, αv, αw based on the input phase voltage command values Vu *, Vv *, Vw *, and further indicates the duty command values αu, αv, αw. A motor control signal having an on-duty ratio is generated. Then, as shown in FIG. 2, the microcomputer 17 outputs the motor control signal generated by the motor control signal generator 24 to each switching element (the gate terminal thereof) constituting the drive circuit 18, thereby The operation of the drive circuit 18, that is, the supply of drive power to the motor 12 is controlled.

[Control mode when an abnormality occurs]
As shown in FIG. 2, in the ECU 11 of the present embodiment, the microcomputer 17 is provided with an abnormality determination unit 31 for identifying the abnormality mode when any abnormality occurs in the EPS 1. Then, the ECU 11 (microcomputer 17) changes the control mode of the motor 12 according to the abnormality mode specified (determined) by the abnormality determination unit 31.

  More specifically, an abnormality signal S_tr for detecting an abnormality in the mechanical system of the EPS actuator 10 is input to the abnormality determination unit 31, and the abnormality determination unit 31 receives the input abnormality signal. Based on S_tr, an abnormality in the mechanical system in EPS 1 is detected. The abnormality determination unit 31 includes the detected phase current values Iu, Iv, Iw, the rotational angular velocity ω, and the q-axis current deviation calculated in the motor control signal generation unit 24 (first current control unit 24a). ΔIq and duty command values αu, αv, αw, etc. for each phase are input. And the abnormality determination part 31 detects generation | occurrence | production of abnormality in a control system based on each of these state quantities.

  Specifically, the abnormality determination unit 31 of the present embodiment monitors the q-axis current deviation ΔIq in order to detect the occurrence of an abnormality related to the entire control system, such as a failure of the torque sensor 14 or a failure of the drive circuit 18. That is, the q-axis current deviation ΔIq is compared with a predetermined threshold value, and if the q-axis current deviation ΔIq is equal to or greater than the threshold value (continuous for a predetermined time), it is determined that an abnormality has occurred in the control system. To do.

  Further, the abnormality determination unit 31 disconnects or drives a power line (including a motor coil) based on the phase current values Iu, Iv, Iw, the rotational angular velocity ω, and the duty command values αu, αv, αw of each phase. The occurrence of an energization failure phase caused by a contact failure of the circuit 18 is detected. The detection of the occurrence of a poorly energized phase is performed by detecting the phase current value Ix of the X phase (X = U, V, W) below the predetermined value Ith (| Ix | ≦ Ith) and the rotational angular velocity ω within the target range for disconnection determination ( When | ω | ≦ ω0), the state in which the duty command value αx corresponding to the phase is not in the predetermined range (αLo ≦ αx ≦ αHi) corresponding to the predetermined value Ith and the threshold value ω0 defining the determination target range continues. Depending on whether or not.

  In this case, the predetermined value Ith serving as the threshold value of the phase current value Ix is set to a value near “0”, and the threshold value ω0 of the rotational angular velocity ω is set to a value corresponding to the maximum rotational speed of the motor. . The threshold values (αLo, αHi) relating to the duty command value αx are set to a value smaller than a lower limit value that can be taken by the duty command value αx and a value larger than the upper limit value in normal control.

  That is, as shown in the flowchart of FIG. 4, the abnormality determination unit 31 determines whether or not the detected phase current value Ix (absolute value thereof) is equal to or less than a predetermined value Ith (step 101), and the predetermined value Ith If it is below (| Ix | ≦ Ith, Step 101: YES), it is subsequently determined whether or not the rotational angular velocity ω (the absolute value thereof) is not more than a predetermined threshold value ω0 (Step 102). If the rotational angular velocity ω is equal to or less than the predetermined threshold ω0 (| ω | ≦ ω0, step 102: YES), whether the duty command value αx is within the predetermined range (αLo ≦ αx ≦ αHi). If it is not within the predetermined range (step 103: NO), it is determined that an energization failure has occurred in the X phase (step 104).

  When the phase current value Ix is larger than the predetermined value Ith (| Ix |> Ith, step 101: NO), when the rotational angular velocity ω is larger than the threshold ω0 (| ω |> ω0, step 102: NO), Alternatively, if the duty command value αx is within the predetermined range (αLo ≦ αx ≦ αHi, step 103: YES), it is determined that no energization failure has occurred in the X phase (normal X phase, step 105).

  That is, when an energization failure (disconnection) occurs in the X phase (any one of the U, V, and W phases), the phase current value Ix of the phase is “0”. Here, in the case where the X-phase phase current value Ix is “0” or “a value close to 0”, there may be the following two cases in addition to the occurrence of such disconnection.

− When the rotational angular velocity of the motor reaches the maximum number of rotations − When the current command itself is substantially “0” Based on this point, in the present embodiment, first, the X-phase phase current value Ix to be determined is set to a predetermined value. By comparing with the value Ith, it is determined whether or not the phase current value Ix is “0”. Then, it is determined whether or not the two cases where the phase current value Ix is “0” or “a value close to 0” except when the wire is disconnected. It is determined that a disconnection has occurred.

  That is, if the extreme duty command value αx is output even though the rotational angular velocity ω is not such that the phase current value Ix is equal to or less than the predetermined value Ith in the vicinity of “0”, the energization failure of the X phase is poor. Can be determined to have occurred. And in this embodiment, it has the structure which specifies the phase in which the conduction failure generate | occur | produced by performing the said determination sequentially about each phase of U, V, and W. FIG.

  Although not shown in the flowchart of FIG. 4 for convenience of explanation, the above determination is made on the assumption that the power supply voltage is equal to or higher than a specified voltage necessary for driving the motor 12. Then, the final abnormality detection determination is made based on whether or not the state in which it is determined that the energization failure has occurred in the predetermined step 104 has continued for a predetermined time or more.

  In the present embodiment, the ECU 11 (microcomputer 17) switches the control mode of the motor 12 based on the result of the abnormality determination in the abnormality determination unit 31. Specifically, the abnormality determination unit 31 outputs the result of abnormality determination including the above-described failure of energization as an abnormality detection signal S_tm, and the current command value calculation unit 23 and the motor control signal generation unit 24 receive the input. The calculation of the current command value according to the abnormality detection signal S_tm to be performed and the generation of the motor control signal are executed. As a result, the control mode of the motor 12 in the microcomputer 17 can be switched.

  More specifically, the ECU 11 of the present embodiment is a “normal control mode” that is a normal control mode, and a “assist stop mode” that is a control mode when an abnormality that should stop driving the motor 12 occurs. , And “two-phase drive mode” which is a control mode in the case where energization failure occurs in any of the phases of the motor 12, and the above three broad control modes. When the abnormality detection signal S_tm output from the abnormality determination unit 31 corresponds to the “normal control mode”, the current command value calculation unit 23 and the motor control signal generation unit 24 respectively Calculation of the current command value and generation of the motor control signal are executed.

  On the other hand, when the abnormality detection signal S_tm output from the abnormality determination unit 31 is in the “assist stop mode”, the current command value calculation unit 23 and the motor control signal generation unit 24 respectively stop driving the motor 12. Calculation of the current command value and generation of the motor control signal are executed. The “assist stop mode” is selected not only when an abnormality occurs in the mechanical system or the torque sensor 14, but when an abnormality occurs in the power supply system, an overcurrent may occur. Can be mentioned. In addition, in the “assist stop mode”, there is a case where the output of the motor 12 is gradually reduced, that is, the assist force is gradually reduced and then stopped after the drive of the motor 12 is stopped immediately. The motor control signal generator 24 gradually reduces the value (absolute value) of the q-axis current command value Iq * output as the current command value. Then, after the motor 12 is stopped, the microcomputer 17 is configured to open each switching element constituting the drive circuit 18 and open a power relay (not shown).

  Further, the abnormality detection signal S_tm corresponding to the “two-phase drive mode” includes information for specifying the energization failure occurrence phase. When the abnormality detection signal S_tm output from the abnormality determination unit 31 corresponds to this “two-phase drive mode”, the motor control signal generation unit 24 sets two phases other than the current-carrying failure occurrence phase as current-carrying phases. In order to continue motor driving, the motor control signal is generated.

  More specifically, as shown in FIG. 2, the motor control signal generator 24 of this embodiment obtains the phase voltage command values Vu *, Vv *, Vw * by executing current feedback control in the d / q coordinate system. In addition to the first current control unit 24a that calculates, a second current control unit 24b that calculates the phase voltage command values Vu **, Vv **, and Vw ** by executing phase current feedback control is provided. When the abnormality detection signal S_tm input from the abnormality determination unit 31 corresponds to the “two-phase drive mode”, each phase voltage command value Vu * calculated by the second current control unit 24b. *, Vv ** and Vw ** are used to output motor control signals.

  More specifically, as shown in FIG. 3, the second current control unit 24 b of the present embodiment selects a control phase that selects one of the remaining two phases other than the detected conduction failure phase as a control phase. And a phase current command value calculation unit 33 for calculating a phase current command value Ix * (X = U, V, or W) for the phase selected as the control phase. Then, by executing the phase current feedback control based on the deviation between the phase current value Ix selected as the control phase and the phase current command value Ix * (Ix **), two phases other than the conduction failure occurrence phase are transferred to the conduction phase. Each phase voltage command value Vu **, Vv **, Vw ** is calculated to execute the motor drive.

  Specifically, the phase current command value Ix * output from the phase current command value calculation unit 33 is input to the guard processing unit 34. The phase current command value Ix ** after the guard process is input to the subtractor 35 together with the phase current value Ix of the phase selected as the control phase by the control phase selection unit 32. The subtractor 35 calculates the phase current deviation ΔIx by subtracting the phase current value Ix from the phase current command value Ix *, and outputs the calculated phase current deviation ΔIx to the F / B control unit 36. Then, the F / B control unit 36 calculates the phase voltage command value Vx * for the control phase by multiplying the input phase current deviation ΔIx by the F / B gain.

  The phase voltage command value Vx * calculated by the F / B control unit 36 is input to the phase voltage command value calculation unit 37. And the phase voltage command value calculating part 37 calculates each phase voltage command value Vu **, Vv **, Vw ** based on the phase voltage command value Vx * about the control phase.

  That is, the energization failure occurrence phase cannot be energized, and the phase of each energized phase during two-phase driving is shifted by π / 2 (180 °). Accordingly, the phase voltage command value of the phase where the power failure has occurred is “0”, and the phase voltage command value of the other current phase can be calculated by inverting the sign of the phase voltage command value Vx * related to the control phase. The second current control unit 24b of the present embodiment is configured to output the phase voltage command values Vu **, Vv **, and Vw ** calculated in this way to the PWM conversion unit 30. ing.

  Here, the phase current command value calculation unit 33 according to the present embodiment, when performing two-phase driving, excludes a predetermined rotation angle corresponding to the phase where the energization failure occurs, and the control target value (q-axis) of the required torque, that is, the motor torque. A phase current command value Ix * is calculated such that a motor current (q-axis current value Iq) corresponding to the current command value Iq *) is generated.

  Specifically, the phase current command value calculation unit 33 is a phase current command value of one of the remaining two phases based on the following formulas (1) to (3) according to the energization failure occurrence phase. Calculate Ix *.

That is, according to the above formulas (1) to (3), the secant curve (reciprocal of cos θ (secant: sec θ)) or cosecant curve with predetermined rotation angles θA and θB corresponding to the energization failure occurrence phase as asymptotic lines. A phase current command value Ix * that changes in the form (reciprocal of sin θ (cosecant: cosec θ)) is calculated (see FIG. 5). Then, by executing the phase current feedback control based on the phase current command value Ix * that changes into such a secant curve or a cosecant curve, theoretically, predetermined rotation angles θA, θB corresponding to the asymptotic lines are obtained. Except for the motor current (q-axis current value Iq) corresponding to the required torque (q-axis current command value Iq *) can be generated (see FIG. 6).

  5 and 6 are examples in which the U phase is an energized defective phase and the two phases of the V and W phases are energized phases, and among the two rotation angles corresponding to the above asymptotic lines, In the electrical angle range of 0 ° to 360 °, when the smaller value is the rotation angle θA and the larger value is the rotation angle θB, the rotation angles θA and θB are “90 °” and “270 °, respectively. " The predetermined rotation angles θA and θB when the V phase is a current-carrying failure occurrence phase are “30 °” and “210 °”, respectively, and the predetermined rotation angles θA and θA when the W-phase is a current conduction failure occurrence phase. θB is “150 °” and “330 °”, respectively (not shown).

  In practice, since there is an upper limit to the current (absolute value) that can be passed through the motor coils 12u, 12v, 12w of each phase, in the present embodiment, the guard processing unit 34 calculates the phase current command value. A guard process for limiting the phase current command value Ix * output from the unit 33 to within a predetermined range (−Ix_max ≦ Ix * ≦ Ix_max) is executed. Note that “Ix_max” is the maximum value of current that can be passed through the X phase (U, V, W phase), and this maximum value is defined by the rated current of each switching element constituting the drive circuit 18. The Therefore, in the range where the guard process is performed (current limiting range: θ1 <θ <θ2, θ3 <θ <θ4), the phase current command value Ix ** after the guard process is the upper limit value ( Ix_max) or the lower limit (−Ix_max).

  That is, the microcomputer 17 of the present embodiment performs the phase current feedback control so as to energize each energized phase with a secant curve or a cosecant curve during two-phase driving, Except for current limiting ranges (θ1 <θ <θ2, θ3 <θ <θ4) set in the vicinity of predetermined rotation angles θA and θB corresponding to asymptotes, a motor current corresponding to the required torque is generated. As a result, even when an energization failure phase occurs, the assist force is continuously applied while maintaining a good steering feeling without causing a large torque ripple.

Next, the abnormality determination and control mode switching by the microcomputer and the motor control signal generation processing procedure during two-phase driving will be described.
As shown in the flowchart of FIG. 7, the microcomputer 17 first determines whether or not any abnormality has occurred (step 201). If it is determined that an abnormality has occurred (step 201: YES), then It is determined whether the abnormality is a control system abnormality (step 202). Next, when it is determined in step 202 that a control abnormality has occurred (step 202: YES), it is determined whether or not the current control mode is the two-phase drive mode (step 203), and the two-phase drive mode is determined. If not (step 203: NO), it is determined whether or not the abnormality of the control system is the occurrence of a poorly energized phase (step 204). If it is determined that a current-carrying failure phase has occurred (step 204: YES), a motor control signal is output that uses the remaining two phases other than the current-carrying failure phase as a current-carrying phase (two-phase drive mode, step). 205).

  As described above, the output of the motor control signal in the two-phase drive mode is a phase current command that changes into a secant curve or a remainder curve with predetermined rotation angles θA and θB corresponding to the energization failure occurrence phase as asymptotic lines. This is performed by calculating a value and executing phase current feedback control based on the phase current command value.

  That is, as shown in the flowchart of FIG. 8, the microcomputer 17 first determines whether or not the current-carrying failure occurrence phase is the U phase (step 301), and if it is the U phase (step 301: YES). In step S302, the phase current command value Iv * for the V phase is calculated based on the equation (1). Next, the microcomputer 17 executes a guard process calculation for the phase current command value Iv *, and limits the phase current command value Iv ** after the guard process within a predetermined range (step 303). Then, by executing phase current feedback control based on the phase current command value Iv ** after the guard processing, a phase voltage command value Vv * for the V phase is calculated (step 304), and based on the phase voltage command value Vv *. Thus, phase voltage command values Vu **, Vv **, and Vw ** for each phase are calculated (Vu ** = 0, Vv ** = Vv *, Vw ** =-Vv *, step 305).

  On the other hand, if it is determined in step 301 that the energization failure occurrence phase is not the U phase (step 301: NO), the microcomputer 17 determines whether the energization failure occurrence phase is the V phase (step 306). When the defect occurrence phase is the V phase (step 306: YES), the phase current command value Iu * for the U phase is calculated based on the above equation (2) (step 307). Next, the microcomputer 17 executes a guard process calculation for the phase current command value Iu *, and limits the phase current command value Iu ** after the guard process within a predetermined range (step 308). Then, phase current feedback control based on the phase current command value Iv ** after the guard processing is executed (step 309), and each phase voltage command value Vu * calculated by the execution of the phase current feedback control is The phase voltage command values Vu **, Vv **, and Vw ** for the phases are calculated (Vu ** = Vu *, Vv ** = 0, Vw ** = − Vu *, step 310).

  If it is determined in step 306 that the energization failure occurrence phase is not the V phase (step 306: NO), the microcomputer 17 determines the phase current command value Iv * for the V phase based on the above equation (3). Is calculated (step 311), and then the guard process calculation is executed to limit the phase current command value Iv ** after the guard process within a predetermined range (step 312). Then, the phase current feedback control based on the phase current command value Iv ** after the guard processing is executed (step 313), and the remaining based on the phase voltage command value Vv * calculated by the execution of the phase current feedback control. Two-phase (V, W phase) phase voltage command values Vu ** and Vw ** are calculated (Vu ** = − Vv *, Vv ** = Vv *, Vw ** = 0, step 314).

The microcomputer 17 generates a motor control signal based on the phase voltage command values Vu **, Vv **, and Vw ** calculated in step 305, step 310, or step 314, and outputs the motor control signal to the drive circuit 18. (Step 315).

  If it is determined in step 201 that there is no abnormality (step 201: NO), as described above, the microcomputer 17 executes the current feedback control in the d / q coordinate system to execute the motor control signal. The output is executed (normal control mode, step 206). Further, when it is determined in step 202 that an abnormality other than the control system has occurred (step 202: NO), when it is determined in step 203 that the two-phase drive mode has already been established (step 203: YES), or the above If it is determined in step 203 that an abnormality other than the occurrence of a poorly energized phase has occurred (step 203: NO), the microcomputer 17 shifts to the assist stop mode (step 207). And the output of the motor control signal for stopping the drive of the motor 12, opening of the power relay, etc. are executed.

[Current detection during two-phase drive]
Next, the mode of current detection during two-phase driving in this embodiment will be described.
As described above, the microcomputer 17 of the present embodiment is based on the output signals Su, Sv, Sw of the current sensors 19u, 19v, 19w and the output signal Sa of the rotation angle sensor 20 acquired at a predetermined sampling period. The phase current values Iu, Iv, Iw and the rotation angle θ of the motor 12 are detected. Then, the microcomputer 17 controls the rotation of the motor 12 based on the detected phase current values Iu, Iv, Iw and the rotation angle θ, and executes the abnormality determination and the like.

  Moreover, the microcomputer 17 of this embodiment performs the temperature estimation of the motor 12 based on each phase current value Iu, Iv, Iw as part of the abnormality detection. That is, it is known that the temperature of the motor 12 rises according to the amount of current that flows through the motor 12. In this embodiment, the temperature estimation is performed by calculating the sum of squares of the current values of the respective phases, and the temperature of the motor 12 is constantly monitored, so that the overheating can be suppressed and the fail safe can be performed quickly in the event of overheating. It is the structure which aims at execution of control.

  Here, during the two-phase driving, the microcomputer 17 of the present embodiment energizes each energized phase with a phase current that changes in the form of a secant curve or a remainder curve. Accordingly, each phase current value Ix increases to an upper limit value (Ix_max) or a lower limit value (−Ix_max) that can be energized in the vicinity of the predetermined rotation angles θA and θB corresponding to the asymptote (FIG. 5). reference). That is, during two-phase driving, the motor 12 is operated in a state where overheating is more likely to occur than during normal control. Therefore, monitoring of the motor temperature as described above, that is, accurate estimation of the motor temperature is extremely important.

  However, during such two-phase driving, the fluctuation of each phase current value Ix is extremely large, and the peak of the absolute value becomes a predetermined rotation angle θA, θB corresponding to the asymptote for each energized phase. For this reason, when the rotational angular velocity ω of the motor 12 increases, the motor temperature estimated based on the detected phase current value Ix tends to be lower than the actual temperature. There may be a delay in the start timing.

  That is, under a certain sampling period, the angular interval (electrical angle) at which the microcomputer 17 obtains the output signals Su, Sv, Sw of the current sensors 19u, 19v, 19w increases as the rotational angular velocity ω increases. When compared with the normal three-phase sine wave drive in which the peak (absolute value) of each phase current value Iu, Iv, Iw is dispersed at 60 ° intervals, the peak of each phase current value Ix in the two-phase drive. Are concentrated on the predetermined rotation angles θA and θB and their rising edges are steep, so that the increase of the acquisition angle interval of each output signal Su, Sv, Sw greatly affects the accuracy of current detection. Become.

  That is, at the time of two-phase driving of the present embodiment, the range of the rotation angle (electrical angle) that can acquire the peak value (or a value close to it) of each phase current value Ix is narrow. As the acquisition angle interval of each output signal Su, Sv, Sw increases, the detection frequency of the peak value decreases. For this reason, the energization current amount to the motor 12 calculated based on the output signals Su, Sv, Sw of the respective current sensors 19u, 19v, 19w (the square sum of the phase current values Ix corresponds to this) As a result, the motor temperature may be estimated to be lower than the actual temperature.

  Here, in order to cope with such an increase in the acquisition angle interval accompanying the increase in the rotational angular velocity ω, the sampling period of the output signals Su, Sv, Sw of the current sensors 19u, 19v, 19w can be shortened. Conceivable. However, in this case, as a contradiction, it is inevitable that the microcomputer 17 has a higher performance and a corresponding increase in cost in order to respond to an increase in calculation load accompanying the execution of high-speed sampling.

  In consideration of this point, in the present embodiment, the microcomputer 17 as the current detection unit shortens the sampling cycle in accordance with the detected rotational angular velocity ω. Specifically, as shown in FIG. 9, the microcomputer 17 determines whether or not the detected rotational angular velocity ω (absolute value thereof) exceeds a predetermined threshold ω0 (step 401), and the rotational angular velocity ω is If the predetermined threshold value ω0 is exceeded (| ω |> ω0, step 401: YES), high-speed sampling with a reduced sampling period is executed (step 402). When the rotational angular velocity ω is equal to or less than a predetermined threshold value ω0 (| ω | ≦ ω0, step 401: NO), the output signals Su, Sv, Sw is acquired (step 403).

  That is, the microcomputer 17 according to the present embodiment has the current sensors 19u and 19v only in the high-speed rotation region where the detected rotational angular velocity ω affects the temperature estimation based on the sum of squares of the phase current values Ix. , 19w of the output signals Su, Sv, and Sw, high-speed sampling is performed by shortening the sampling period. As a result, the temperature can be estimated with high accuracy while suppressing an increase in the calculation load.

(Second Embodiment)
Hereinafter, a second embodiment in which the present invention is embodied in an electric power steering device (EPS) will be described with reference to the drawings.

  The main difference between the present embodiment and the first embodiment is only the mode of current detection during two-phase driving. For this reason, for convenience of explanation, the same parts as those in the first embodiment are denoted by the same reference numerals, and the explanation thereof is omitted.

  As described above, it is known that the temperature of the motor 12 rises according to the amount of current that flows through the motor 12. Also in the present embodiment, the microcomputer 17 executes the temperature estimation of the motor 12 by calculating the sum of squares of the current values of the phases using this relationship.

  Specifically, in the present embodiment, each phase current value Ix continuously detected by the microcomputer 17 is stored in a memory (not shown) up to the latest four detected values (the latest four values). It has become. Then, the microcomputer 17 reads the latest four values stored (held) in the memory as needed, and multiplies the square sum by a predetermined gain to execute the temperature estimation of the motor 12.

  That is, as shown in the flowchart of FIG. 10, when the microcomputer 17 detects each phase current value Ix (step 501), the microcomputer 17 stores the detected value (detected value) in the memory (step 502). In the present embodiment, the oldest value stored in the memory is updated by storing the detected value, so that the latest four values are held for the phase.

  Next, the microcomputer 17 according to the present embodiment executes a phase current detection value correction calculation to be described later for the detection value stored in the memory (step 503). Then, the latest four values of each phase stored in the memory are read (step 504), and the temperature of the motor 12 is estimated by calculating the sum of squares (step 505).

  As described above, during two-phase driving, the angular interval (electrical angle) at which the microcomputer 17 obtains the output signals Su, Sv, Sw of the current sensors 19u, 19v, 19w increases as the rotational angular velocity ω increases. As a result, the detection frequency of the peak value of each phase current value Ix (or a value close thereto) decreases. For this reason, the energization current amount to the motor 12 indicated by the sum of squares of the phase current values Ix is smaller than the actual energization current amount, and as a result, a motor temperature lower than the actual current is estimated. is there.

  That is, for example, as shown in FIG. 11, when current detection is performed four times within an electrical angle of 360 °, all the rotation angles θp1, θp2, θp3, and θp4 at the time of the four detections are If the predetermined rotational angles θA and θB corresponding to the asymptote are deviated, the latest four detected values I1, I2, I3, and I4 stored in the memory all indicate the peak value of the phase. There will be no. That is, the estimation of the motor temperature based on these detected values I1, I2, I3, and I4 is performed by rounding down the value in the vicinity of the predetermined rotation angles θA and θB and the portion where the amount of current supplied to the motor 12 increases most. The operation will be executed. As a result, the estimated motor temperature may be lower than the actual temperature.

  In consideration of this point, in this case, the microcomputer 17 according to the present embodiment performs the phase current detection value correction calculation to perform the latest two detection values among the latest four detection values held by storage in the memory. The detected value is corrected.

  Specifically, when the microcomputer 17 detects the latest phase current value Ix, the microcomputer 17 corresponds to the asymptotic line between the rotation angle (electrical angle) θcu at the current detection and the rotation angle θbf at the previous detection. When the predetermined rotation angles θA and θB are sandwiched, the current detection value Icu and the previous detection value Ibf stored in the memory are corrected so that their absolute values become larger.

  For example, in the example shown in FIG. 11, when “I2” is detected as the latest phase current value Ix, the rotation angle θcu at the current detection, that is, the rotation angle θp2 (120 °), and the phase current value Ix A predetermined rotation angle θA (90 °) corresponding to an asymptotic line is sandwiched between the rotation angle θbf at the time of the previous detection when “I1” was detected as the previous value, that is, the rotation angle θp1 (0 °). Similarly, when “I4” is detected as the latest phase current value Ix, the rotation angle θcu at the current detection, that is, the rotation angle θp4 (360 °), and “I3” as the phase current value Ix are detected. A predetermined rotation angle θB corresponding to an asymptote is sandwiched between the rotation angle θbf at the previous detection, that is, the rotation angle θp3 (240 °).

  In such a case, the microcomputer 17 according to the present embodiment, for each of the current detection value Icu and the previous detection value Ibf stored (held) in the memory, the maximum energizable value Imax (the upper limit in the guard process). An average value between the value (Ix_max) and the lower limit value (−Ix_max)) is calculated. And the correction which increases the absolute value is performed by making the average value into new detection value Icu ', Ibf'.

  That is, as shown in the flowchart of FIG. 12, the microcomputer 17 of the present embodiment first determines a predetermined rotation angle corresponding to the asymptote between the rotation angle θcu at the current detection and the rotation angle θbf at the previous detection. It is determined whether or not θA and θB are sandwiched (step 601).

  If it is determined in step 601 that the predetermined rotation angles θA and θB are sandwiched (step 601: YES), the microcomputer 17 next calculates an average value of the current detection value Icu and the energizable maximum value Imax. The current detection value Icu is calculated and updated by updating the current detection value Icu (Icu ′ = (Icu + Imax) / 2, step 602). Further, the average value of the previous detection value Ibf and the maximum energizable value Imax is calculated, and the previous detection value Ibf stored in the memory is updated to correct the detection value Ibf ( Ibf ′ = (Ibf + Imax) / 2, step 602).

  That is, when the predetermined rotation angles θA and θB are sandwiched between the rotation angle θcu at the current detection and the rotation angle θbf at the previous detection, the absolute values of the current detection value Icu and the previous detection value Ibf Is corrected so as to have a larger value, it is possible to reduce the amount of energization in the vicinity of the predetermined rotation angles θA and θB, that is, the truncation of the range in which the value increases most. Further, in the present embodiment, the calculation load due to the execution of the correction calculation is taken into account, and the average value of the detected values Icu and Ibf to be corrected and the maximum value Imax that can be energized is used, thereby efficiently and accurately. Often, the phase current detection value correction calculation is executed. And the motor temperature is estimated more accurately by using the latest four detected values (see FIG. 11, I1 ′, I2 ′, I3 ′, I4 ′) after being corrected by the phase current detection value correction calculation. It is possible to do this.

In addition, you may change each said embodiment as follows.
In each of the above embodiments, the ECU 11 as the motor control device is roughly divided into three control modes of “normal control mode”, “assist stop mode”, and “two-phase drive mode”. However, the mode of motor control when an abnormality occurs is not limited to these modes. In other words, any configuration may be applied as long as the motor control is executed by using two phases other than the energization failure phase as the energization phase when the energization failure phase occurs. Also, the method of abnormality detection (determination) is not limited to the configuration of the present embodiment.

  In each of the above embodiments, the current command value calculation unit 23 outputs a phase current command value for one of the two phases other than the energization failure occurrence phase during two-phase driving, and the motor control signal generation unit 24 After calculating the phase voltage command value for the phase, the phase voltage command value for the other phase is calculated based on the calculated phase voltage command value. However, the present invention is not limited to this, and the current command value calculation unit 23 may output phase current command values for both two phases other than the energization failure occurrence phase.

  In each of the above embodiments, based on the above equations (1) to (3), when the U phase or W phase is abnormal, the V phase phase current command value Iv * is calculated, and when the V phase is abnormal, The U-phase phase current command value Iu * is calculated. However, not limited to this, the W-phase current command value (Iw *) is calculated when the U-phase or V-phase is abnormal, and the U-phase current command value (Iu *) is calculated when the W-phase is abnormal. It is good also as a structure of carrying out. In addition, each phase current command value in this case can be calculated by reversing the signs of the above formulas (1) to (3).

  Furthermore, the phase current command value at the time of energization failure does not necessarily have to be completely the same as that calculated by the above formulas (1) to (3). That is, even if a phase current command value that changes to a substantially secant curve or a substantially cosecant curve with an asymptotic line as a predetermined rotation angle, or changes in an approximate manner, is similar to each of the above embodiments. An effect can be obtained. However, when the phase current command value is calculated based on the above equations (1) to (3), it is possible to generate a motor current closest to the required torque, and the phase current command calculated based on each equation Needless to say, a method that calculates a value close to a value provides a more remarkable effect.

  In the first embodiment, when the detected rotational angular velocity ω (the absolute value thereof) exceeds the predetermined threshold value ω0, the microcomputer 17 executes high-speed sampling with a shortened sampling cycle ( (See FIG. 9). However, the present invention is not limited to this. For example, the sampling cycle may be shortened continuously according to the increase in the rotational angular velocity ω as shown in FIG. Alternatively, the sampling cycle may be shortened in a plurality of stages based on the rotational angular velocity ω.

  In the second embodiment, each detected phase current value Ix is held (stored in the memory) up to the latest four detected values (the latest four values), and the microcomputer 17 is held. The latest four values are read as needed to estimate the motor temperature. However, the present invention is not limited to this, and the present invention can be applied to any configuration as long as at least the previous detection value Ibf is held together with the current detection value Icu. Further, the use of each detection value held is not necessarily limited to temperature estimation.

  Furthermore, in the second embodiment, the detected value stored in the memory is read out and used for estimating the motor temperature. However, the present invention is not limited to this, and the phase current detection value correction calculation that increases the absolute value of the detected value Idt may be executed for a configuration that uses the detected phase current value Ix as needed.

Specifically, one or both of the following two correction calculations may be executed.
-If a predetermined rotation angle corresponding to the asymptote is sandwiched between the rotation angle at the current detection and the rotation angle at the previous current detection, the absolute value of the current value detected this time is Correct to a larger value.

  − Estimate the rotation angle at the next current detection. If it is estimated that a predetermined rotation angle corresponding to the asymptote is sandwiched between the rotation angle at the current detection time and the rotation angle at the next current detection time, the current value detected this time The absolute value is corrected so as to be a larger value. The rotation angle at the next current detection may be estimated from the rotation angular velocity ω of the motor or the transition of the rotation angle at the past current detection.

  More specifically, for example, as shown in the flowchart of FIG. 14, first, predetermined rotation angles θA and θB corresponding to the asymptote between the rotation angle at the current detection time and the rotation angle at the previous detection time. It is determined whether or not a clip is inserted (step 701). If it is determined in step 701 that the predetermined rotation angles θA and θB are sandwiched (step 701: YES), the detected phase current value Ix (detected value Idt) and the maximum energizable value Imax Then, the detected value Idt is corrected by calculating the average value (Idt ′ = (Idt + Imax) / 2, step 702).

  On the other hand, if it is determined in step 701 that the predetermined rotation angles θA and θB are not sandwiched between the rotation angle at the current detection and the rotation angle at the previous detection (step 701: NO), Thus, the rotation angle at the next detection is estimated (step 703). Then, it is determined whether or not it is estimated that predetermined rotation angles θA and θB corresponding to the asymptote are sandwiched between the rotation angle at the current detection time and the rotation angle at the next detection time (step 704). When it is estimated that the predetermined rotation angles θA and θB are sandwiched (step 704: YES), the detected value Idt is corrected by executing step 702.

  As described above, by executing Steps 701 to 704, the same effects as those of the second embodiment can be obtained. In addition, about the estimation means which performs estimation of the rotation angle at the time of next detection, the microcomputer 17 may be sufficient and the form which comprises this other than the microcomputer 17 may be sufficient.

  Furthermore, as a form of current control, the phase current feedback control in the three-phase AC coordinates (U, V, W) as in the above embodiments is not necessarily required. For example, according to the following equations (4) to (6), a d-axis current command value Id * that changes into a tangent curve (tangent) with predetermined rotation angles θA and θB corresponding to the energization failure occurrence phase as asymptotic lines. Is calculated. Then, the present invention may be applied to a configuration in which a motor control signal is generated by executing current feedback control in the d / q coordinate system based on the d-axis current command value Id * (see FIG. Example). In this case, the F / B gain variable control may be performed in the current feedback control in the d / q coordinate system.

In each of the above embodiments, the present invention is embodied in a rack assist type EPS, but may be applied to other types of EPS such as a so-called column assist type. Moreover, you may actualize in the motor control apparatus used for uses other than EPS.

  DESCRIPTION OF SYMBOLS 1 ... Electric power steering apparatus (EPS), 10 ... EPS actuator, 11 ... ECU, 12 ... Motor, 12u, 12v, 12w ... Motor coil, 17 ... Microcomputer, 18 ... Drive circuit, 19u, 19v, 19w ... Current sensor, DESCRIPTION OF SYMBOLS 21 ... Current detection part, 23 ... Current command value calculating part, 24 ... Motor control signal production | generation part, 24a ... 1st current control part, 24b ... 2nd current control part, 31 ... Abnormality determination part, 33 ... Phase current command value Calculation unit 34 ... Guard processing unit 36 ... F / B control unit 37 ... Phase voltage command value calculation unit Ix *, Iu *, Iv *, Iw * ... Phase current command value, Ix, Iu, Iv, Iw ... phase current values, I1, I1 ', I2, I2', I3, I3 ', I4, I4', Icu, Icu ', Ibf, Ibf', Idt, Idt '... detected value, Imax ... maximum value, Vx * , Vu *, Vv *, Vw *, Vu **, Vv **, Vw ** ... Phase voltage command value, Id ... Axis current value, Iq ... q-axis current value, Id * ... d-axis current command value, Iq * ... q-axis current command value, θ, θA, θB, θp1, θp2, θp3, θp4, θcu, θbf ... rotation angle, ω: rotational angular velocity, ω0: threshold, Su, Sv, Sw: output signal.

Claims (5)

Motor control signal output means for outputting a motor control signal; a drive circuit for supplying three-phase drive power to the motor based on the motor control signal; The motor control signal output means generates the motor control signal by executing current control based on the rotation angle of the motor, and when the energization failure occurs, two phases other than the energization failure occurrence phase are generated. In the motor control device that executes the output of the motor control signal with the current passing phase as
The motor control signal output means is a phase that changes into a secant curve or a remainder curve with a predetermined rotation angle corresponding to the energization failure occurrence phase as an asymptotic line for each energization phase when the energization failure occurs. While performing the current control to energize the current,
The current value of each phase is detected at a predetermined sampling period by the current detection means, and at least the previous detection value is held together with the current detection value,
When the current detection means sandwiches a predetermined rotation angle corresponding to the asymptote between the rotation angle at the current detection and the rotation angle at the previous current detection, the current detection is held. A motor control device that corrects the value and the previous detection value so that the absolute value becomes a larger value. Motor control signal output means for outputting a motor control signal; a drive circuit for supplying three-phase drive power to the motor based on the motor control signal; The motor control signal output means generates the motor control signal by executing current control based on the rotation angle of the motor, and when the energization failure occurs, two phases other than the energization failure occurrence phase are generated. In the motor control device that executes the output of the motor control signal with the current passing phase as
The motor control signal output means is a phase that changes into a secant curve or a remainder curve with a predetermined rotation angle corresponding to the energization failure occurrence phase as an asymptotic line for each energization phase when the energization failure occurs. While performing the current control to energize the current,
The current value of each phase is detected at a predetermined sampling period by the current detection means,
When the current detection means sandwiches a predetermined rotation angle corresponding to the asymptote between the rotation angle at the current detection and the rotation angle at the previous current detection, the current detection means , Correct that absolute value to a larger value,
A motor control device. Motor control signal output means for outputting a motor control signal; a drive circuit for supplying three-phase drive power to the motor based on the motor control signal; The motor control signal output means generates the motor control signal by executing current control based on the rotation angle of the motor, and when the energization failure occurs, two phases other than the energization failure occurrence phase are generated. In the motor control device that executes the output of the motor control signal with the current passing phase as
The motor control signal output means is a phase that changes into a secant curve or a remainder curve with a predetermined rotation angle corresponding to the energization failure occurrence phase as an asymptotic line for each energization phase when the energization failure occurs. While performing the current control to energize the current,
The current value of each phase is detected at a predetermined sampling period by the current detection means,
An estimation means for estimating the rotation angle at the next current detection is provided
The current detection means is detected this time when it is estimated that a predetermined rotation angle corresponding to the asymptote is sandwiched between the rotation angle at the current detection time and the rotation angle at the next current detection time. Correct the current value so that the absolute value becomes a larger value,
A motor control device. In the motor control device according to any one of claims 1 to 3,
The motor control device characterized in that the correction of the current value is performed by calculating an average value of the detected value and a maximum value that can be energized.   An electric power steering device comprising the motor control device according to any one of claims 1 to 4.