JP2012235647A - Motor controller - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a motor controller with a stable control operation without deteriorating responsiveness and followability even if a voltage command value is restricted.SOLUTION: The motor controller includes: a PI control section for operating a PI operation value; a decoupling control amount operation section for operating a decoupling control amount for decoupling control of a motor; an addition section for adding the PI operation value operated by the PI control means and a decoupling control amount operated by the decoupling control amount operation section; a limiter limiting an addition result of the addition section and outputting the limited control amount as a motor voltage command value; and a gain operation section for operating a voltage command value gain from the motor voltage command value and the PI operation value operated by the PI control section. The voltage command value gain operated by the gain operation section or a current limit gain obtained from a dq-axis gain map is multiplied by a dq-axis target current, and the dq-axis target current of the motor is limited.

Description

  The present invention relates to a motor control device for driving a motor (particularly a brushless motor).

  The motor control device for driving the brushless motor includes a current detection unit that detects a current flowing through the armature winding of the motor, a rotation position detection unit that detects a rotation position of the rotor of the motor, a d-axis target current and q A dq-axis target current calculation unit that calculates an axis target current, a dq-axis current calculation unit that calculates a d-axis current and a q-axis current based on the detected current and rotational position, a d-axis voltage command value calculation unit, q And a shaft voltage command value calculation unit. The d-axis voltage command value calculation unit obtains a d-axis voltage command value based on the PI calculation of the d-axis current so as to reduce the d-axis deviation between the d-axis target current and the d-axis current. The q-axis voltage command value calculation unit obtains the q-axis voltage command value based on the PI calculation of the q-axis current so as to reduce the q-axis deviation between the q-axis target current and the q-axis current. Based on the d-axis voltage command value, the q-axis voltage command value, and the detected rotational position thus obtained, the motor control device applies a voltage to the armature winding. Thereby, the rotational force of a rotor generate | occur | produces (refer patent document 1).

JP 2001-187578 A

When the voltage command value for the dq axis is obtained based on the PI calculation value, it is necessary to provide a limiter for limiting the voltage command value. The limiter limits the voltage command value so that the voltage command value applied to the armature winding does not exceed the set maximum value. Thereby, the waveform showing the change of the applied voltage to the armature winding with respect to the change of the rotational position of the rotor can be prevented from becoming discontinuous.
If the limiter is not provided, the PI calculation value continues to increase when a situation occurs in which the deviation between the target current and the detected current does not decrease. Then, even if the deviation decreases, it takes time for the voltage command value corresponding to the PI calculation value to be an appropriate value. In addition, since the maximum voltage that can be applied to the armature winding is specified according to the performance of the power supply, etc., if the voltage command value becomes excessive, the change in the voltage applied to the armature winding with respect to the change in the rotational position of the rotor The waveform representing is discontinuous. For example, the waveform is shaped like a clip near the top of a sine wave, causing abnormal noise and vibration.

Generally, the limiter is provided as a part of the PI control unit, and a PI operation value limited by the limiter is generated from the PI control unit.
On the other hand, non-interference control is known in which a non-interference control amount is added to a PI calculation value (see Patent Document 1). The non-interacting control is control for determining a voltage command value so as to compensate for speed electromotive force generated inside the motor as the rotor rotates. By performing the non-interacting control, it is expected that a decrease in response and tracking performance due to speed electromotive force can be effectively suppressed.

  However, if the non-interacting control amount is added to the PI calculation value output from the PI control unit provided with the limiter, the rotational speed and current value of the motor become variable, and the operation becomes unstable. More specifically, when the motor voltage command value is determined by adding the non-interacting control amount to the PI calculation value limited by the limiter, the motor voltage command value exceeds the limit value for sine wave driving. There is a fear. The problem is small when the PI calculation value is small, but when the PI voltage value is large and the motor voltage command value after adding the decoupling control amount exceeds the limit value, the oscillation state occurs and the response performance becomes unstable. Become.

  The present invention has been made to solve the above-described problems, and an object of the present invention is to provide a motor control device that is stable in control operation without deteriorating responsiveness and follow-up performance even when the voltage command value is limited. It is to provide.

  In order to solve the above-mentioned problems, the invention according to claim 1 is based on target current calculation means for calculating a current command value which is a current to be supplied to the motor, and current command value calculated by the target current calculation means. , Dq-axis target current calculation means for calculating a dq-axis current command value in the d / q coordinate system, and a voltage applied to the motor based on the dq-axis current command value calculated by the dq-axis target current calculation means And a voltage control means for controlling the motor based on the motor voltage command value calculated by the voltage control means, wherein the voltage control means includes the dq-axis current command value and the dq-axis current. And a PI control means for calculating a PI control amount on the basis of the deviation and a non-interacting control amount for performing the non-interacting control on the motor on the basis of the rotational angular velocity of the motor. A non-interacting control amount computing means, an adding means for adding the PI control amount computed by the PI control means, and the non-interacting control amount computed by the non-interacting control amount computing means; Limit value calculating means for calculating the limit value of the motor voltage command value, and the addition result of the adding means is limited to the limit value calculated by the limit value calculating means, and the limited control amount is the motor Limiting means for outputting as a voltage command value; gain calculating means for calculating a gain from the motor voltage command value and the PI control amount calculated by the PI control means; and the dq-axis target current calculating means, The gist is to correct the dq-axis current command value by multiplying the dq-axis current command value by the gain calculated by the gain calculation means.

According to the above configuration, after the non-interacting control amount calculated by the non-interacting control amount calculating unit is added to the PI control amount calculated by the PI control unit, the added value is limited by the limiting unit. It has come to be added. Thereby, since the motor voltage command value output from the limiting means is appropriately limited, it is possible to reliably avoid the oscillation state and obtain stable response performance.
Further, it is calculated based on the deviation between the PI control amount calculated by the PI control means and the motor voltage command value restricted by the limiting means, or the ratio between the motor voltage command value and the PI control amount. The dq-axis target current calculation means multiplies the gain by the dq-axis current command value to correct the dq-axis command current value of the motor. As a result, when the motor voltage command value is limited, the motor current value limited according to the gain can be commanded, so that the responsiveness and follow-up performance of the motor output torque is improved and the stability of the system is improved. Can do well.

  Even if the voltage command value is limited, it is possible to provide a motor control device with stable control operation without deteriorating responsiveness and followability.

The block diagram for demonstrating the electric constitution of the electric power steering apparatus to which the motor control apparatus which concerns on this invention is applied. The block diagram for demonstrating the detailed structure of a dq axis voltage command value calculating part. The flowchart for demonstrating the control procedure of an electric power steering apparatus. The flowchart for demonstrating the control procedure of the motor by a motor control apparatus. The flowchart for demonstrating the calculation procedure of a dq axis voltage command value. The flowchart for demonstrating the calculation procedure of the dq-axis target current of FIG. 4 based on the 1st Embodiment of this invention. The flowchart for demonstrating the calculation procedure of the dq-axis target current of FIG. 4 based on the 2nd Embodiment of this invention.

Hereinafter, embodiments of the present invention will be specifically described with reference to the drawings.
FIG. 1 is a block diagram for explaining an electrical configuration of an electric power steering apparatus to which a motor control apparatus according to an embodiment of the present invention is applied. This electric power steering apparatus includes a torque sensor 7 that detects a steering torque applied to a steering wheel of a vehicle, a vehicle speed sensor 8 that detects the speed of the vehicle, a motor 1 that applies a steering assist force to the steering mechanism 3 of the vehicle, And a motor control device 10 for driving and controlling the motor 1. The motor control device 10 drives the motor 1 in accordance with the steering torque detected by the torque sensor 7 and the vehicle speed detected by the vehicle speed sensor 8, thereby realizing appropriate steering assistance according to the steering situation. The motor 1 is, for example, a three-phase brushless motor.

The motor control device 10 includes a current detection unit 11, a microcomputer (hereinafter referred to as a CPU) 12 as a signal processing unit, and a drive circuit 13. The above-described torque sensor 7 and vehicle speed sensor 8 are connected to the motor control device 10 together with the resolver 2 that detects the rotational position θ of the rotor in the motor 1.
The current detection unit 11 detects a current flowing through the armature winding of the motor 1. The current detection unit 11 according to the present embodiment converts current detection signals from the current detectors 11u, 11v, and 11w that detect the phase currents in the three-phase armature windings and the current detectors 11u, 11v, and 11w into A / D. A / D converters 11u ', 11v', 11w 'for converting (analog / digital).

  The CPU 12 includes a plurality of function processing units realized by program processing (software processing). The plurality of function processing units include a basic target current calculation unit 15, a dq axis target current calculation unit 16, a dq axis current calculation unit 17, a d axis deviation calculation unit 18d, a q axis deviation calculation unit 18q, and a dq axis voltage command. A value calculation unit 19, a voltage command value coordinate conversion unit 20, and a PWM (pulse width modulation) control unit 21 are included.

The drive circuit 13 is composed of an inverter circuit and is controlled by the PWM control unit 21 to supply power from a power source such as an in-vehicle battery to the U-phase, V-phase, and W-phase armature windings of the motor 1. A phase current flowing between the drive circuit 13 and the armature winding of each phase of the motor 1 is detected by current detectors 11u, 11v, and 11w.
The basic target current calculation unit 15 calculates the basic target current I * of the motor 1 based on the steering torque detected by the torque sensor 7 and the vehicle speed detected by the vehicle speed sensor 8. For example, the basic target current I * is determined so as to increase as the steering torque increases and increase as the vehicle speed decreases.

  The basic target current I * calculated by the basic target current calculation unit 15 is input to the dq-axis target current calculation unit 16. The dq-axis target current calculation unit 16 calculates a d-axis target current Id * for generating a magnetic field in the d-axis direction and a q-axis target current Iq * for generating a magnetic field in the q-axis direction. The d-axis is an axis along the magnetic flux direction of the field of the rotor of the motor 1, and the q-axis is an axis orthogonal to the d-axis and the rotor rotation axis. The calculation in the dq-axis target current calculation unit 16 can be performed using a known calculation formula.

  The phase currents Iu, Iv, Iw output from the current detection unit 11 are input to the dq axis current calculation unit 17. The dq-axis current calculation unit 17 calculates the d-axis current Id and the q-axis current Iq by transforming the phase currents Iu, Iv, and Iw based on the rotor rotational position θ detected by the resolver 2. The calculation in the dq axis current calculation unit 17 can be performed using a known calculation formula.

The d-axis deviation calculating unit 18d calculates a d-axis deviation ΔId between the d-axis target current Id * and the d-axis current Id. Similarly, the q-axis deviation calculating unit 18q obtains a q-axis deviation ΔIq between the q-axis target current Iq * and the q-axis current Iq.
The dq-axis voltage command value calculation unit 19 obtains a d-axis voltage command value Vd * corresponding to the d-axis deviation ΔId and a q-axis voltage command value Vq * corresponding to the q-axis deviation ΔIq. Further, the d-axis voltage command value gain αd and the q-axis voltage command value gain αq are obtained and output to the dq-axis target current calculation unit 16. These dq-axis voltage command value gains αd and αq are used to calculate the d-axis target current Id * and the q-axis target current Iq * of the motor 1.

  The voltage command value coordinate conversion unit 20 performs coordinate conversion of the d-axis voltage command value Vd * and the q-axis voltage command value Vq * based on the rotor rotational position θ of the motor 1 detected by the resolver 2, and the U-phase electric machine Applied voltage command values Vu *, Vv *, and Vw * to be applied to the child winding, the V-phase armature winding, and the W-phase armature winding are calculated. The calculation in the voltage command value coordinate conversion unit 20 can be performed using a known calculation formula.

  The PWM control unit 21 generates a PWM control signal for each phase, which is a pulse signal having a duty ratio corresponding to the applied voltage command values Vu *, Vv *, and Vw *. As a result, voltages corresponding to the d-axis voltage command value Vd * and the q-axis voltage command value Vq * are applied from the drive circuit 13 to the armature windings of the respective phases of the motor 1 to generate the rotational force of the rotor.

  FIG. 2 is a block diagram for explaining a detailed configuration of the dq-axis voltage command value calculation unit 19. Referring to FIG. 1, dq-axis voltage command value calculator 19 includes d-axis voltage command value calculator 51, q-axis voltage command value calculator 52, dq-axis limit value calculator 50, and angular velocity calculator 59. . The d-axis voltage command value calculation unit 51 obtains a d-axis voltage command value Vd * based on a PI calculation of the d-axis current (hereinafter referred to as d-axis PI calculation) or the like so as to reduce the d-axis deviation ΔId. The q-axis voltage command value calculation unit 52 obtains the q-axis voltage command value Vq * based on the PI calculation of the q-axis current (hereinafter referred to as q-axis PI calculation) or the like so as to reduce the q-axis deviation ΔIq.

  The dq axis limit value calculation unit 50 sets the d axis limit values VLd and q so that the applied voltage command values Vu *, Vv *, Vw * to the armature winding of the motor 1 do not exceed the set maximum value Vmax. Determine the axis limit value VLq. The set maximum value Vmax is a sine wave drive in which the waveform representing a change in the voltage applied to the armature winding with respect to a change in the rotor rotational position θ of the motor 1 does not become discontinuous, and the waveform is a sine wave. It is a limit value for. The angular velocity calculation unit 59 obtains the rotational speed ω (rad / sec) of the rotor based on the rotor rotational position θ of the motor 1 detected by the resolver 2.

The d-axis voltage command value calculation unit 51 includes a d-axis PI control unit 51a, a d-axis decoupling control amount calculation unit 51b, a d-axis addition unit 51c, a d-axis limiter 51d, a d-axis subtraction unit 51e, and a d-axis gain calculation. It has a part 51f.
The d-axis PI control unit 51a calculates the d-axis PI calculation value Vd0 by the d-axis PI calculation, and outputs the d-axis PI calculation value Vd0 to the d-axis addition unit 51c.

  The d-axis non-interacting control amount calculation unit 51b calculates the d-axis non-interacting control amount −ωLqIq based on the q-axis current Iq calculated by the dq-axis current calculation unit 17. ω is the rotational speed of the rotor of the motor 1, and Lq is the q-axis self-inductance of the armature winding of the motor 1. The rotational speed ω of the rotor is obtained from the changing speed of the detected rotational position θ by the resolver 2 by the angle calculator 59. The q-axis self-inductance Lq is a constant that has been measured in advance.

The d-axis addition unit 51c adds the d-axis decoupling control amount −ωLqIq to the d-axis PI calculation value Vd0.
The d-axis limiter 51d limits the absolute value of the value obtained by adding the d-axis decoupling control amount −ωLqIq to the d-axis PI calculation value Vd0 to the d-axis limit value VLd or less. The output value of the d-axis limiter 51d becomes the d-axis voltage command value Vd *. Thereby, the d-axis voltage command value Vd * is obtained by limiting the value obtained by correcting the d-axis PI calculation value Vd0 by the d-axis non-interacting control amount −ωLqIq.

  The previous value of the d-axis voltage command value Vd * is fed back for PI calculation in the d-axis PI calculation unit 51a. However, in the d-axis subtraction unit 51e, the non-interacting control amount −ωLqIq is subtracted from the d-axis voltage command value Vd * (in other words, the inversion value obtained by inverting the sign of the non-interacting control amount −ωLqIq is + ωLqIq). The previous value after the calculation is used for the PI calculation in the d-axis PI calculation unit 51a.

  The d-axis gain calculation unit 51f calculates the deviation between the d-axis PI calculation value Vd0 and the output value of the d-axis limiter 51d, or the d-axis voltage command value Vd * and the d-axis PI. The d-axis voltage command value gain αd is obtained based on the ratio with the value Vd0.

The q-axis voltage command value calculation unit 52 includes a q-axis PI calculation unit 52a, a q-axis decoupling control amount calculation unit 52b, a q-axis addition unit 52c, a q-axis limiter 52d, a q-axis subtraction unit 52e, and a q-axis gain calculation. It has a portion 52f.
The q-axis PI calculation unit 52a calculates the q-axis PI calculation value Vq0 by the PI calculation of the q-axis current, and outputs the q-axis PI calculation value Vq0 to the q-axis addition unit 52c.

The q-axis non-interacting control amount calculation unit 52b calculates the q-axis non-interacting control amount ωLdId + ωΦ based on the d-axis current Id calculated by the dq-axis current calculation unit 17. Ld is the d-axis self-inductance of the armature winding of the motor 1, and Φ is (3/2) ^1/2 times the maximum value of the number of armature winding linkage magnetic fluxes in the rotor field. The d-axis self-inductance Ld is a constant measured in advance. ω is the rotational speed of the rotor.

The d-axis addition unit 52c adds the q-axis decoupling control amount ωLdId + ωΦ to the q-axis PI calculation value Vq0.
The q-axis limiter 52d limits the absolute value of the value obtained by adding the q-axis decoupling control amount ωLdId + ωΦ to the q-axis PI calculation value Vq0 to the q-axis limit value VLq or less. The output value of the q-axis limiter 52d becomes the q-axis voltage command value Vq *. Thereby, the q-axis voltage command value Vq * is obtained by limiting the value obtained by correcting the q-axis PI calculation value Vq0 by the q-axis decoupling control amount ωLdId + ωΦ.

  The previous value of the q-axis voltage command value Vq * is fed back for PI calculation in the q-axis PI calculation unit 52a. However, the q-axis subtraction unit 52e subtracts the non-interacting control amount ωLdId + ωΦ from the q-axis voltage command value Vq * (in other words, −ωLdId−ωΦ, which is an inverted value obtained by inverting the sign of the non-interacting control amount ωLdId + ωΦ. The previous value after the calculation is used for the PI calculation in the q-axis PI calculation unit 52a.

  The q-axis gain calculation unit 52f calculates the deviation between the q-axis PI calculation value Vq0 and the output value of the q-axis limiter 52d, or the q-axis voltage command value Vq * and the q-axis PI calculation. The q-axis voltage command value gain αq is obtained based on the ratio to the value Vq0.

  FIG. 3 is a flowchart for explaining a control procedure of the electric power steering apparatus. Referring to FIGS. 1 and 2, CPU 12 reads detection values obtained by torque sensor 7, vehicle speed sensor 8, current detectors 11 u, 11 v and 11 w, and resolver 2 (step S <b> 301). Next, the basic target current calculation unit 15 executes basic assist control calculation and various compensation control calculations, and adds the calculated control amount (step S302). Subsequently, the basic target current I * is calculated based on the added value, the d-axis target current Id * and the q-axis target current Iq * are obtained based on the basic target current I *, and current feedback control is executed. Thereby, the applied voltage command values Vu *, Vv *, Vw * to the motor 1 are calculated, and the motor 1 is driven (step S303).

  FIG. 4 is a flowchart for explaining a control procedure of the motor 1 by the motor control device 10. With reference to FIGS. 1 and 2, first, the CPU 12 reads detection values obtained by the torque sensor 7, the vehicle speed sensor 8, the current detectors 11u, 11v, and 11w, and the resolver 2 (step S401). The basic target current calculation unit 15 calculates the basic target current I * based on the detected steering torque and vehicle speed (step S402). The dq-axis target current calculation unit 16 calculates the d-axis target current Id * and the q-axis target current Iq * corresponding to the basic target current I * (step S403). The dq axis current calculation unit 17 calculates the d axis current Id and the q axis current Iq corresponding to the detected phase currents Iu, Iv, Iw (step S404). From the d-axis target current Id * and the d-axis current Id, the d-axis deviation calculator 18d calculates the d-axis deviation ΔId, and from the q-axis target current Iq * and the q-axis current Iq, the q-axis deviation calculator 18q. In step S405, the q-axis deviation ΔIq is calculated.

  Next, the dq-axis voltage command value calculation unit 19 calculates the d-axis voltage command value Vd * and the q-axis voltage command value Vq * (step S406). Then, in the voltage command value coordinate conversion unit 20, to the U-phase armature winding, V-phase armature winding, and W-phase armature winding corresponding to the d-axis voltage command value Vd * and the q-axis voltage command value Vq *. Applied voltage command values Vu *, Vv *, Vw * are calculated (step S407). PWM control signals corresponding to these applied voltage command values Vu *, Vv *, and Vw * are given from the PWM control unit 21 to the drive circuit 13. Thereby, the motor 1 is driven (step S408). Then, whether or not to end the control is determined by, for example, turning on or off the ignition switch (step S409). If not, the process returns to step S401.

  FIG. 5 is a flowchart showing the calculation procedure of the d-axis voltage command value Vd * and the q-axis voltage command value Vq *. First, the d-axis PI calculation value Vd0 and the q-axis PI calculation value Vq0 are obtained by the d-axis PI calculation and the q-axis PI calculation of the CPU 12 (step S501). On the other hand, the d-axis non-interacting control amount calculation unit 51b calculates the d-axis non-interacting control amount −ωLqIq, and the q-axis non-interacting control amount calculation unit 52b calculates the q-axis non-interacting control amount ωLdId + ωΦ (step S502). Then, the d-axis decoupling control amount −ωLqIq is added to the d-axis PI calculation value Vd0, and the q-axis decoupling control amount ωLdId + ωΦ is added to the q-axis PI calculation value Vq0 (step S503). Further, the dq axis limit value calculation unit 50 calculates the d axis limit value VLd and the q axis limit value VLq (step S504).

Next, the absolute value of Vd0−ωLqIq, which is a value obtained by correcting the d-axis PI calculation value with the d-axis decoupling control amount, is limited to the d-axis limit value VLd or less by the d-axis limiter 51d (d-axis limiter). processing). Similarly, the absolute value of Vq0 + ωLdId + ωΦ, which is a value obtained by correcting the q-axis PI calculation value by the q-axis decoupling control amount, is limited to the q-axis limit value VLq or less by the q-axis limiter 52d (q-axis limiter processing). . That is, the d-axis limiter 51d determines whether or not the absolute value of Vd0−ωLqIq is equal to or less than VLd (step S505). ) If not less than VLd, it is determined whether or not Vd0−ωLqIq is positive (step S507). If positive, VLd is output as the d-axis voltage command value Vd ^* (step S508). Is output as the d-axis voltage command value Vd * (step S509). Further, the q-axis limiter 52d determines whether or not the absolute value of Vq0 + ωLdId + ωΦ is equal to or less than VLq (step S510). If not, it is determined whether or not Vq0 + ωLdId + ωΦ is positive (step S512). If positive, VLq is output as the q-axis voltage command value Vq * (step S513). If not positive, −VLq is the q-axis voltage command value. It outputs as Vq * (step S514).

  The d-axis subtracting unit 51e subtracts the d-axis decoupling control amount −ωLqIq from the d-axis voltage command value Vd * (step S515). This subtraction result is stored in the memory for use as the previous value of the next d-axis PI calculation. Similarly, the q-axis subtraction unit 52e subtracts the q-axis decoupling control amount ωLdId + ωΦ from the q-axis voltage command value Vq * (step S516). This subtraction result is stored in the memory for use as the previous value of the next q-axis PI calculation.

  Next, the d-axis gain calculation unit 51f calculates the deviation between the d-axis PI calculation value Vd0 and the output value of the d-axis limiter 51d or the d-axis voltage command value Vd * or the d-axis voltage command value Vd * and d. The d-axis voltage command value gain αd is obtained based on the ratio to the axis PI calculation value Vd0. Similarly, the q-axis gain calculation unit 52f calculates the deviation between the q-axis PI calculation value Vq0 and the output value of the q-axis limiter 52d between the q-axis voltage command value Vq * or the q-axis voltage command value Vq * and q A q-axis voltage command value gain αq is obtained based on the ratio with the axis PI calculation value Vq0 (step S517). After this process, the process returns to the main routine (see FIG. 4).

  FIG. 6 is a flowchart for explaining a calculation procedure of the dq-axis target currents Id * and Iq * of FIG. 4 according to the first embodiment of the present invention. First, in the dq-axis target current calculation process shown in FIG. 6, the CPU 12 multiplies the basic target current I * by 0 (zero) to calculate the d-axis target current Id * (step S601). Next, the d-axis voltage command value gain αd obtained in step S517 is multiplied by the d-axis target current Id * (step S602). Subsequently, the basic target current I * is multiplied by 1, and the q-axis target current Iq * is calculated (step S603). Next, the q-axis voltage command value gain αq obtained in step S517 is multiplied by the q-axis target current Iq * (step S604). After this process, the process returns to the main routine (see FIG. 4).

  FIG. 7 is a flowchart for explaining a calculation procedure of the dq-axis target currents Id * and Iq * in FIG. 4 according to the second embodiment of the present invention. In the dq-axis target current calculation process shown in FIG. 7, the CPU 12 first multiplies the basic target current I * by 0 (zero) to calculate the d-axis target current Id * (step S701). Next, a d-axis current limiting gain βd corresponding to the d-axis voltage command value gain αd obtained in step S517 is obtained based on the d-axis gain map (step S702). Subsequently, the d-axis current limiting gain βd is multiplied by the d-axis target current Id * (step S703). Similarly, the basic target current I * is multiplied by 1 to calculate the q-axis target current Iq * (step S704). Next, a q-axis current limiting gain βq corresponding to the q-axis voltage command value gain αq obtained in step S517 is obtained based on the q-axis gain map (step S705). Subsequently, the q-axis current limit gain βq is multiplied by the q-axis target current Iq * (step S706). After this process, the process returns to the main routine (see FIG. 4). Here, for example, the dq-axis gain map has a value that gradually decreases from a constant value as the input increases.

  As described above, according to the present embodiment, the d-axis voltage command value Vd * is obtained by performing the d-axis limiter process on the value obtained by correcting the d-axis PI calculation value Vd0 by the d-axis decoupling control amount −ωLqIq. Looking for. The q-axis voltage command value Vq * is obtained by performing q-axis limiter processing on the value obtained by correcting the q-axis PI calculation value Vq0 by the q-axis decoupling control amount ωLdId + ωΦ. Further, based on the dq-axis PI calculation values Vq0 and Vd0 and the dq-axis voltage command values Vd * and Vq *, the dq-axis gain based on the dq-axis voltage command value gains αd and αq or the dq-axis voltage command value gains αd and αq The command current value is limited by multiplying the dq axis target currents Id * and Iq * by the dq axis current limit gains βd and βq obtained from the map, respectively, and the d axis target current Id * and the q axis target current Iq * are Seeking.

  Thus, the dq axis voltage command values Vd * and Vq * are limited by the dq axis limiters 51d and 52d, while the dq axis voltage command values Vd * and Vq * are set to values within the limit value range, and the dq axis target value is set. By limiting the currents Id * and Iq *, it is possible to improve the responsiveness and followability of the current control of the motor 1. Moreover, since overshoot and undershoot can be greatly reduced, control stability can be ensured. As a result, the dynamic characteristics can be improved while suppressing vibrations and noises, and thus the steering feeling in the electric power steering apparatus can be improved. Moreover, since overshoot and undershoot can be significantly reduced as described above, it is possible to suppress the assumed maximum load when designing the strength of the transmission system that transmits torque from the motor 1 to the steering mechanism 3. Thereby, cost reduction can be aimed at.

  On the other hand, the previous value used for the d-axis PI calculation is obtained by adding an inverted value obtained by inverting the sign of the d-axis decoupling control amount to the d-axis voltage command value Vd *. Similarly, the previous value used for the q-axis PI calculation is obtained by adding an inverted value obtained by inverting the sign of the q-axis decoupling control amount to the q-axis voltage command value Vq *. Thereby, since the influence of the non-interacting control does not affect the PI calculation, an appropriate PI calculation can be performed.

Although one embodiment according to the present invention has been described above, the present invention can also be implemented in other forms.
In the present embodiment, the countermeasure including the non-interacting control is described as a countermeasure for generating the interference component. However, the present invention can be applied without the non-interacting control calculation process.
In the above-described embodiment, the example in which the present invention is applied to the motor as the drive source of the electric power steering apparatus has been described. However, the present invention is also applicable to the control of a motor for applications other than the electric power steering apparatus. Applicable. In particular, it is effective when applied to motor torque control in applications where responsiveness and followability are required in a servo system.
In addition, various design changes can be made within the scope of matters described in the claims.

1: motor, 10: motor control device, 12: CPU, 16: dq-axis target current calculation unit,
19: dq-axis voltage command value calculation unit, 50: dq-axis limit value calculation unit,
51a, 52a: dq axis PI control unit, 51b, 52b: dq axis non-interacting control amount calculation unit,
51c, 52c: dq axis adder, 51d, 52d: dq axis limiter,
51e, 52e: dq axis subtraction unit, 51f, 52f: dq axis gain calculation unit,
59: Angular velocity calculation unit,
Id, Iq: dq axis current, I *: basic target current, Id *, Iq *: dq axis target current,
ΔId, ΔIq: dq axis deviation, Vd *, Vq *: dq axis voltage command value,
Vd0, Vq0: dq axis PI calculation value, VLd, VLq: dq axis limit value,
αd, αq: dq axis voltage command value gain, βd, βq: dq axis current limit gain,
θ: Motor rotation angle, ω: Motor rotation angular velocity

Claims (1)

Target current calculation means for calculating a current command value which is a current to be given to the motor;
Dq-axis target current calculation means for calculating a dq-axis current command value of the d / q coordinate system based on the current command value calculated by the target current calculation means;
Voltage control means for controlling the voltage applied to the motor based on the dq axis current command value calculated by the dq axis target current calculation means,
In the motor control device that controls the motor based on the motor voltage command value calculated by the voltage control means,
The voltage control means includes
PI control means for calculating a PI control amount based on a deviation between the dq axis current command value and the dq axis current;
A non-interacting control amount calculating means for calculating a non-interacting control amount for performing non-interacting control of the motor based on the rotational angular velocity of the motor;
Adding means for adding the PI control amount calculated by the PI control means and the non-interacting control amount calculated by the non-interacting control amount calculating means;
Limit value calculating means for calculating a limit value of the motor voltage command value;
Limiting means for limiting the addition result of the adding means to the limit value calculated by the limit value calculating means, and outputting the limited control amount as the motor voltage command value;
Gain calculating means for calculating a gain from the motor voltage command value and the PI control amount calculated by the PI control means;
The dq axis target current calculation means corrects the dq axis current command value by multiplying the dq axis current command value by the gain calculated by the gain calculation means. .

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