JP2009136035A - Motor controller - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a motor controller capable of efficiently improving the responsiveness and followability of a motor by performing non-interference control in which a delay in calculation time is compensated. <P>SOLUTION: The motor controller is provided with: PI calculation sections 51a, 52a for calculating PI calculation values V<SB>do</SB>, V<SB>qo</SB>; non-interference control amount calculation sections 51b, 52b for calculating non-interference control amounts D<SB>d</SB>, D<SB>q</SB>for non-interference control of the motor; first adding sections 51c, 52c for adding the PI calculation values V<SB>do</SB>, V<SB>qo</SB>to the non-interference control amounts D<SB>d</SB>, D<SB>q</SB>; correction value calculating sections 51e, 52e for calculating correction values ΔD<SB>d</SB>, ΔD<SB>q</SB>; and second adding sections for adding the correction values ΔD<SB>d</SB>, ΔD<SB>q</SB>to results of addition in the first adding sections 51c, 52c and outputting voltage command values V<SB>d</SB><SP>*</SP>, V<SB>q</SB><SP>*</SP>. The correction value calculating sections 51e, 52e obtain the difference in non-interference control amount between the present control cycle and the previous control cycle as correction values ΔD<SB>d</SB>, ΔD<SB>q</SB>. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a motor control device for driving a motor (particularly a brushless motor). The brushless motor is used, for example, as a source for generating a steering assist force in an electric power steering apparatus.

  A motor control device for a brushless motor includes a current detection unit that detects a current flowing through an armature winding of the motor, a rotation position detection unit that detects a rotor rotation position of the motor, a d-axis target current, and a q-axis target current A dq-axis target current calculation unit, a dq-axis current calculation unit that calculates a d-axis current and a q-axis current based on the detected armature winding current and rotor rotational position, a d-axis voltage command value calculation unit, And a q-axis 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 deviation 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 deviation 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 and the q-axis voltage command value obtained in this way and the detected rotor rotational position, the motor control device applies a voltage to the armature winding. Thereby, the rotational force of the rotor is generated.

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.
JP 2001-187578 A

The speed electromotive force generated inside the motor depends on the rotational angular speed and the current. Therefore, the non-interacting control amount for compensating for this also depends on the rotational angular velocity and the current. More specifically, the d-axis decoupling control amount depends on the rotation angular velocity and the q-axis current, and the q-axis decoupling control amount depends on the rotation angular velocity and the d-axis current.
However, after the current of the armature winding of each phase of the motor is detected, this is converted into the d-axis current and the q-axis current, and further, the d-axis voltage command value and the q-axis voltage command value are output. Calculation time for coordinate conversion and PI calculation is required. Further, after the rotor rotation angle is detected, a time for calculating the rotation angular velocity based on the rotor rotation angle is also required. Since the rotor also rotates during this time, the d-axis and q-axis rotate accordingly. As a result, when the d-axis voltage command value and the q-axis voltage command value are output, the directions of the d-axis and the q-axis are shifted from the directions of the d-axis and the q-axis when the motor current or the like is detected. Therefore, even if the non-interacting control amount corresponding to the d-axis and q-axis directions when detecting the motor current or the like is used, it is not always possible to output an appropriate voltage command value. In particular, this problem becomes apparent when the rotational angular velocity is large. For this reason, the non-interacting control does not necessarily produce an effect as expected, and the motor current may fluctuate, which may cause vibration and noise.

  SUMMARY OF THE INVENTION An object of the present invention is to provide a motor control device that can effectively improve the response and follow-up of a motor by performing non-interference control that compensates for a delay in calculation time.

  In order to achieve the above object, the invention as set forth in claim 1 includes basic drive value calculation means (51a, 52a) for calculating a basic drive value for driving the motor (1), and non-interference control of the motor. Non-interacting control amount computing means (51b, 52b) for computing a non-interacting control amount for the control, and a correction value for correcting the non-interacting control amount computed by the non-interacting control amount computing means Based on the correction value calculation means (51e, 52e) to be calculated, the decoupling control amount calculated by the non-interacting control amount calculation means, and the correction value calculated by the correction value calculation means, the basic drive Correction means (51c, 51d, 52c, 52d) for correcting the basic drive value calculated by the value calculation means to obtain a motor drive value, and a motor drive value obtained by the correction by the correction means. There are and a driving means (20,21,13) for driving the motor, a motor control device. In addition, the alphanumeric characters in parentheses represent corresponding components in the embodiments described later. The same applies hereinafter.

  According to this configuration, the motor drive value is obtained by correcting the basic drive value with the non-interacting control amount and the correction value. By appropriately determining the correction value, it is possible to compensate for an error of the non-interacting control amount caused by a delay for the calculation time. As a result, motor control with excellent responsiveness and follow-up capability is possible, and the original effects of non-interference control can be fully enjoyed.

  According to a second aspect of the present invention, the motor control device updates and outputs the motor drive value every predetermined calculation cycle, and the correction value calculation means performs the non-interference in the current calculation cycle. A value obtained by subtracting the non-interacting control amount calculated by the non-interacting control amount calculating unit in the previous calculation cycle from the non-interacting control amount calculated by the control amount calculating unit is calculated as the correction value. The motor control device according to claim 1.

  According to this configuration, the difference between the non-interacting control amount in the current calculation cycle and the non-interacting control amount in the previous calculation cycle is set as the correction value. In this case, the correction value corresponds to an error of the non-interacting control amount in the previous calculation cycle. It is considered that this error does not greatly differ between the previous calculation cycle and the current calculation cycle and between the current calculation cycle and the next calculation cycle. Therefore, in the present invention, the difference between the current and previous non-interacting control amounts is used as a correction value and used to compensate for the error of the current non-interacting control amount. As a result, an appropriate motor drive value that predicts a temporal change in the decoupling control amount in the delay time until the motor drive value is updated is obtained. That is, it is possible to perform non-interference control that is valid at the time when the motor drive value is updated. As a result, the delay due to the calculation time can be effectively compensated, so that the original effect of the non-interacting control can be achieved.

The invention according to claim 3 further includes motor current detection means (11, 17) for detecting a motor current flowing through the motor, wherein the correction value calculation means is an electric circuit including the motor from the motor driving value. 2. The motor control device according to claim 1, wherein a value obtained by subtracting a product of an electric resistance and a motor current detected by the motor current detecting means is calculated as the correction value.
It is.

  When a motor drive value (for example, a voltage command value) is output, the resulting motor current is detected. When the electric resistance of the electric circuit including the motor is multiplied by the motor current, the motor voltage actually applied to the motor is obtained. The difference between the motor voltage and the motor drive value becomes a control error. Therefore, in the present invention, the difference between the motor drive value and the motor voltage (the product of the electric resistance and the detected current) is set as a correction value for compensating for the error of the non-interacting control amount. This enables effective decoupling control.

  More specifically, when the motor control device updates and outputs the motor drive value every predetermined calculation cycle, the motor current detection means flows to the motor every calculation cycle. The motor current is detected, and the correction value calculation means is detected by the motor current detection means in the current calculation cycle and the electric resistance of the electric circuit including the motor from the motor drive value in the previous calculation cycle. A value obtained by subtracting the product of the motor current is preferably calculated as the correction value.

  When a motor drive value (for example, voltage command value) is output in the previous calculation cycle, the resulting motor current is detected in the current calculation cycle. When the electric resistance of the electric circuit including the motor is multiplied by the motor current, the motor voltage applied to the motor is obtained in the current calculation cycle. The difference between the motor voltage and the motor drive value output in the previous calculation cycle is a control error. This error is mainly caused by the decoupling control amount deviating from its appropriate value due to a delay of the calculation period. It is considered that this error does not greatly differ between the previous calculation cycle and the current calculation cycle and between the current calculation cycle and the next calculation cycle. Therefore, the difference between the previous motor drive value and the current motor voltage (product of electrical resistance and detected current) is used as a correction value for compensating for the error of the non-interacting control amount. As a result, an appropriate motor drive value that predicts a temporal change in the decoupling control amount in the delay time until the motor drive value is updated is obtained. That is, the non-interacting control that is valid at the time when the motor drive value is updated can be performed. As a result, the delay due to the calculation time can be effectively compensated, so that the original effect of the non-interacting control can be achieved.

Instead of the motor drive value output in the previous calculation cycle, the motor drive value in the current calculation cycle may be used.
According to a fourth aspect of the present invention, the motor control device updates and outputs the motor drive value at every predetermined calculation cycle, and detects a motor current flowing through the motor at each calculation cycle. Current correction means (11, 17), and the correction value calculation means calculates the product of the electric resistance of the electric circuit including the motor and the motor current detected by the motor current detection means from the motor drive value. The value obtained by subtracting and further subtracting the value obtained by multiplying the motor current change amount between the current calculation cycle and the previous calculation cycle by the inductance of the motor winding is calculated as the correction value. This is a motor control device.

  In this configuration, when determining the motor voltage, not only the product of the electric resistance and the detected current but also the product of the current and previous motor current variation and the inductance are taken into account. This product corresponds to the current derivative term. By adding this current differential term, the motor voltage can be determined more accurately, and accordingly, the error of the non-interacting control amount due to the delay in the calculation time can be compensated more effectively.

  The correction value calculation means subtracts the product of the electrical resistance and the motor current detected by the motor current detection means in the current calculation cycle from the motor drive value in the previous or current calculation cycle, and further It is preferable that a value obtained by subtracting a value obtained by multiplying the motor current change amount during the calculation period by the inductance of the motor winding is calculated as the correction value.

  The basic drive value calculation means may calculate a d-axis basic drive voltage and a q-axis basic drive voltage. In this case, the non-interacting control amount calculating means calculates a d-axis non-interacting control amount and a q-axis non-interacting control amount, and the correction value calculating means accordingly corresponds to the d-axis correction amount. The value and the q-axis correction value are preferably calculated.

Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying 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 DC motor.

The motor control device 10 includes a current detection unit 11, a microcomputer 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 (rotational position sensor) that detects the rotational position of the rotor in the motor 1.
The current detection unit 11 detects a current flowing through the armature winding of the motor 1. More specifically, the current detector 11 includes current detectors 11u, 11v, and 11w that detect phase currents in three-phase (U-phase, V-phase, and W-phase) armature windings, and a current detector 11u. , 11v, 11w have A / D converters 11u ′, 11v ′, 11w ′ for A / D (analog / digital) conversion of current detection signals.

  The microcomputer 12 includes a plurality of function processing units realized by program processing (software processing), and repeatedly executes processing at a predetermined calculation cycle. 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, a PWM (pulse width modulation) control unit 21, and a rotation angular velocity calculation unit 22 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 I _d ^* for generating a magnetic field in the d axis direction and a q axis target current I _q ^* 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 I _d and the q-axis current I _q by performing coordinate conversion on the phase currents Iu, Iv, and Iw based on the rotor rotational position 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 obtains a d-axis deviation δI _d between the d-axis target current I _d ^* and the d-axis current I _d . Similarly, the q-axis deviation calculating unit 18q obtains a q-axis deviation δI _q between the q-axis target current I _q ^* and the q-axis current I _q .
The dq-axis voltage command value calculation unit 19 obtains a d-axis voltage command value V _d ^* corresponding to the d-axis deviation δI _d and a q-axis voltage command value V _q ^* corresponding to the q-axis deviation δI _q .

The voltage command value coordinate conversion unit 20 performs coordinate conversion of the d-axis voltage command value V _d ^* and the q-axis voltage command value V _q ^* based on the rotor rotational position detected by the resolver 2, and performs U-phase armature winding. Applied voltage command values Vu ^* , Vv ^* , Vw ^* to be applied to the wire, the V-phase armature winding, and the W-phase armature winding are calculated. The calculation in the voltage command value coordinate conversion unit 20 may 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 V _d ^* and the q-axis voltage command value V _q ^* are applied from the drive circuit 13 to the armature windings of the respective phases, and the rotational force of the rotor is generated.
The rotation angular velocity calculation unit 22 calculates a rotation angular velocity ω (rad / sec) by calculating a temporal change (differentiation) of the rotor rotation position detected by the resolver 2. The rotational angular velocity ω is input to the dq axis voltage command value calculation unit 19.

FIG. 2 is a block diagram for explaining a detailed configuration of the dq-axis voltage command value calculation unit 19.
The dq-axis voltage command value calculation unit 19 includes a d-axis voltage command value calculation unit 51 and a q-axis voltage command value calculation unit 52. d-axis voltage command value computing part 51, so as to reduce the d-axis deviation .delta.I _d, PI calculation of the d-axis deviation (hereinafter, "d-axis PI calculation" hereinafter.) d-axis voltage command value based on such V _d ^* Ask for. q-axis voltage command value calculating unit 52, so as to reduce the q-axis deviation .delta.I _q, PI calculation of the q-axis deviation (hereinafter "q-axis PI calculation" hereinafter.) q-axis voltage command value based on such V _q ^* Ask for.

The d-axis voltage command value calculation unit 51 includes a d-axis PI calculation unit 51a, a d-axis decoupling control amount calculation unit 51b, a d-axis first addition unit 51c, a d-axis second addition unit 51d, and a d-axis correction value calculation. It has a part 51e.
The d-axis PI calculation unit 51a calculates the d-axis PI calculation value V _do by the PI calculation of the d-axis deviation, and outputs this d-axis PI calculation value V _do to the d-axis first addition unit 51c.

The d-axis non-interacting control amount calculation unit 51b is based on the rotational angular velocity ω obtained by the rotational angular velocity computing unit 22 and the q-axis current I _q obtained by the dq-axis current computing unit 17, and the d-axis non-interacting control amount. D _d (= −ωL _q I _q ) is obtained. L _q is the q-axis self-inductance of the armature winding of the motor 1 and is a constant measured in advance.
d-axis first adder 51c adds the d-axis non-interacting control amount D _d to the d-axis PI calculation value V _do.

The d-axis second addition unit 51d adds the d-axis correction value ΔD _d calculated by the d-axis correction value calculation unit 51e to the addition result (= V _do + D _d ) of the d-axis first addition unit 51c. , D-axis voltage command value V _d ^* (= V _do + D _d + ΔD _d ) is output.
The d-axis correction value calculation unit 51e calculates a d-axis correction value ΔD _d for correcting the d-axis decoupling control amount D _d . In this embodiment, the d-axis correction value calculation unit 51e performs the d-axis decoupling control amount D _d (n) (n = 1, 2, 3,...) In the current calculation cycle and the d-axis non-interference in the previous calculation cycle. A deviation calculating unit 51f that obtains a difference from the control amount D _d (n−1) as a d-axis correction value ΔD _d (= D _d (n) −D _d (n−1)). In the figure, Z ^-1 represents the previous value of the signal.

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 first addition unit 52c, a q-axis second addition unit 52d, and a q-axis correction value calculation. It has a part 52e.
The q-axis PI calculation unit 52a calculates the q-axis PI calculation value V _qo by the PI calculation of the q-axis deviation, and outputs the q-axis PI calculation value V _qo to the q-axis first addition unit 52c.

The q-axis non-interacting control amount calculation unit 52b is configured to determine the q-axis non-interacting control amount based on the rotational angular velocity ω obtained by the rotational angular velocity computing unit 22 and the d-axis current I _d obtained by the dq-axis current computing unit 17. D _q (= ωL _d I _d + ωΦ) is obtained. L _d 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 L _d is a constant that has been measured in advance.

The q-axis first addition unit 52c adds the q-axis _decoupling control amount D _q to the q-axis PI calculation value V _qo .
The q-axis second addition unit 52d adds the q-axis correction value ΔD _q calculated by the q-axis correction value calculation unit 52e to the addition result (= V _qo + D _q ) of the q-axis first addition unit 52c. , Q-axis voltage command value V _q ^* (= V _qo + D _q + ΔD _q ) is output.
The q-axis correction value calculation unit 52e calculates a q-axis correction value ΔD _q for correcting the q-axis decoupling control amount D _q . In this embodiment, the q-axis correction value calculation unit 52e includes the q-axis decoupling control amount D _q (n) in the current calculation cycle, and the q-axis decoupling control amount D _q (n−1) in the previous calculation cycle. Is provided as a deviation calculation unit 52f that obtains the difference between them as a q-axis correction value ΔD _q (= D _q (n) −D _q (n−1)). In the figure, Z ^-1 represents the previous value of the signal.

FIG. 3 is a diagram illustrating the relationship between the detection of the d-axis current and the q-axis current and the rotation of the dq coordinate axis. The speed electromotive force generated inside the motor 1 is expressed as −ωL _q I _q for the d axis and is expressed as ωL _d I _d + ωΦ for the q axis. Therefore, the d-axis decoupling control amount D _d that compensates for these is expressed as −ωL _q I _q, and the q-axis non-interacting control amount D _q is expressed as ωL _d I _d + ωΦ.
On the other hand, after the current is detected by the current detection unit 11, the d-axis voltage command value V _d ^* and the q-axis voltage command value V _q ^{*, which} are drive values corresponding to the detected current, are output. , Time for calculation of rotational angular velocity ω, coordinate conversion, PI calculation and other calculations are required. More specifically, the microcomputer 12 updates and outputs the d-axis voltage command value V _d ^* and the q-axis voltage command value V _q ^* every predetermined calculation cycle (for example, 0.001 second). Therefore, there is a delay from when the current is detected by the current detection unit 11 until the d-axis voltage command value V _d ^* and the q-axis voltage command value V _q ^* are updated to values corresponding to the detected current. Time arises. Since the rotor is rotating during this delay time, the d-axis and the q-axis are rotated accordingly.

As shown in FIG. 3, it is assumed that the d-axis 71 and the q-axis 72 rotate by the angle change amount θ during the delay time and rotate to the d-axis 71 ′ and the q-axis 72 ′. In this case, the non-interacting control amounts D _d and D _q are calculated based on the d-axis current I _d and the q-axis current I _q obtained corresponding to the d-axis 71 and the q-axis 72 before rotation. However, the calculated deinteracting control amounts D _d and D _q are applied when the dq coordinate axis is rotated to the positions of the d axis 71 ′ and the q axis 72 ′. Therefore, the non-interacting control amounts D _d and D _q are deviated from appropriate values. If this is applied as it is, the voltage command values V _d ^* and V _q ^* are also deviated from the appropriate values.

Therefore, in this embodiment, the d-axis decoupling control amount D _d is added to the d-axis PI calculation value V _do , and the addition result is corrected with the d-axis correction value ΔD _d to obtain the d-axis voltage command value V _d ^*. Have gained. Similarly, the q-axis voltage command value V _q ^* is obtained by adding the q-axis _decoupling control amount D _q to the q-axis PI calculation value V _qo and correcting the addition result with the q-axis correction value ΔD _q. ing.
FIG. 4 is an illustrative view illustrating each timing of current value acquisition and voltage command value update. The detected current value is acquired from the A / D converters 11u ′, 11v ′, 11w ′ and the rotor rotational position (motor angle) is acquired from the resolver 2 at a predetermined timing at the initial stage of the calculation cycle. The voltage command values V _d ^* and V _q ^* are updated at a predetermined timing in the latter half of the calculation cycle. The voltage command values V _d ^* and V _q ^* do not change until they are updated in the next calculation cycle.

As understood from FIG. 4, there is a delay of almost one cycle of the calculation cycle from the detection of the current and the rotor rotational position to the update timing of the voltage command values V _d ^* and V _q ^* . Accordingly, the non-interacting control amounts D _d and D _q ahead by one operation cycle are predicted, and the PI operation values V _do and V _qo are corrected based on the predicted non- _interacting control amounts D _d and D _q. If possible, the voltage command values V _d ^* and V _q ^* can have appropriate values at the update timing.

In this embodiment, it is assumed that the error of the non-interacting control amount in the previous calculation cycle (n−1) and the current calculation cycle (n) is substantially equal (not greatly different). That is, it is assumed that the following expressions (1) and (2) are satisfied.
D _d (n + 1) −D _d (n) ≈D _d (n) −D _d (n−1) = ΔD _d (n) (1)
D _q (n + 1) −D _q (n) ≈D _q (n) −D _q (n−1) = ΔD _q (n) (2)
The _{deinteracting} control amounts D _d (n) and D _q (n) PI calculated values V _do and V _qo are corrected by the _{predicted deinteracting} control amount errors ΔD _d (n) and ΔD _q (n). Thus, the voltage command values V _d ^* and V _q ^* can have appropriate values at the update timing. That is, the following expressions (3) and (4) are obtained, which is nothing but the outputs of the second adders 51d and 52d in the configuration of FIG.

V _d ^* = V _do + D _d (n) + ΔD _d (3)
V _q ^* = V _qo + D _q (n) + ΔD _q (4)
FIG. 5 is a flowchart for explaining a control procedure of the motor 1 by the motor control device 10. First, the microcomputer 12 reads detection values obtained by the torque sensor 7, the vehicle speed sensor 8, the current detectors 11u, 11v, 11w, and the resolver 2 (step S1). The basic target current calculation unit 15 calculates the target current I ^* based on the detected steering torque and vehicle speed (step S2). dq axis target current calculation unit 16 calculates and its target current d-axis target current corresponding to I ^* I _d ^* and q axis target current I _q ^* (step S3). The dq axis current calculation unit 17 calculates the d axis current I _d and the q axis current I _q corresponding to the detected phase currents Iu, Iv, Iw (step S4). From the d-axis target current I _d ^* and the d-axis current I _d , the d-axis deviation calculating unit 18d calculates the d-axis deviation δI _d , and from the q-axis target current I _q ^* and the q-axis current I _q , the q-axis in deviation calculation unit 18q, q-axis deviation .delta.I _q is computed (step S5). Further, the rotational angular velocity calculation unit 22 calculates the rotational angular velocity ω based on the rotor rotational position detected by the resolver 2 (step S6).

Next, the dq-axis voltage command value calculation unit 19 calculates the d-axis voltage command value V _d ^* and the q-axis voltage command value V _q ^* (step S7). Then, in the voltage command value coordinate conversion unit 20, a U-phase armature winding, a V-phase armature winding, and a W-phase armature winding corresponding to the d-axis voltage command value V _d ^* and the q-axis voltage command value V _q ^* . Applied voltage command values Vu ^* , Vv ^* , Vw ^{* to the line} are calculated (step S8). PWM control signals corresponding to these applied voltage command values Vu ^* , Vv ^* , Vw ^* are given from the PWM control unit 21 to the drive circuit 13. Thereby, the motor 1 is driven (step S9). Then, whether or not to end the control is determined by, for example, turning on or off the ignition switch (step S10). If not, the process returns to step S1.

FIG. 6 is a flowchart showing a calculation procedure of the d-axis voltage command value V _d ^* and the q-axis voltage command value V _q ^* . First, the d-axis PI calculation value V _do and the q-axis PI calculation value V _qo are respectively obtained by the d-axis PI calculation and the q-axis PI calculation (step S101). On the other hand, the d-axis decoupling control amount calculation unit 51b obtains the d-axis non-interacting control amount D _d (n) for the current calculation cycle (n), and the q-axis non-interacting control amount calculation unit 52b calculates the current calculation cycle The q-axis decoupling control amount D _q (n) of (n) is obtained (step S102). Further, the d-axis correction value calculation unit 51e, the d-axis non-interference control amount in kicking the calculation cycle (n) d-axis non-interference control amount D _d (n) and the previous calculation cycle (n-1) D _d A d-axis correction value ΔD _d which is a difference from (n−1) is obtained (step S103). Similarly, in the q-axis correction value calculation section 52e, calculation cycle (n) in the q-axis non-interacting control amount D _q (n) and the previous calculation cycle (n-1) in the q-axis non-interacting control amount D _q A q-axis correction value ΔD _q which is a difference from (n−1) is obtained (step S103). Then, the d-axis decoupling control amount D _d (n) is added to the d-axis PI calculation value V _do , and the d-axis correction value ΔD _d is added to the addition result to obtain the d-axis voltage command value V _d ^*. (Step S104). Similarly, q-axis _decoupling control amount D _q (n) is added to q-axis PI calculation value V _qo , and q-axis correction value ΔD _q is added to the addition result to obtain q-axis voltage command value V _q ^*. It is obtained (step S104). The d-axis voltage command value V _d ^* and the q-axis voltage command value V _q ^* thus obtained are output. Further, the non-interacting control amounts D _d (n) and D _q (n) in the current calculation cycle (n) are for calculating the correction values ΔD _d and ΔD _{q in} the next calculation cycle (n + 1) (step S103). Is stored in a memory (not shown) provided in the microcomputer 12 (step S105).

As described above, according to this embodiment, a change in the non-interacting control amounts D _d and D _q in the delay time from the detection time of the motor current or the like to the update time of the voltage command value is predicted, and this prediction corresponds to this prediction. Voltage command values V _d ^* and V _q ^* corrected with the correction values ΔD _d and ΔD _q are output. Therefore, these voltage command values V _d ^* and V _q ^* are values that reflect an appropriate non-interacting control amount when they are updated. As a result, responsiveness and followability can be improved by non-interacting control. In addition, as a result of setting appropriate voltage command values V _d ^* and V _q ^* , the motor current can be suppressed from fluctuating, so that control stability can be ensured. Thereby, since a dynamic characteristic can be improved, suppressing a vibration and abnormal noise, the steering feeling in an electric power steering device can be improved.

FIG. 7 is a block diagram for explaining the configuration of the motor control apparatus according to the second embodiment of the present invention. The dq-axis voltage command value calculation that can be used in place of the configuration shown in FIG. The structure of the part 19 is shown. In FIG. 7, the same functional parts as those shown in FIG. 2 are given the same reference numerals.
In this embodiment, the d-axis correction value calculation unit 51e includes the d-axis voltage command value V _d ^* (n−1) in the previous calculation cycle (n−1) and the d-axis current I _d detected in the current calculation cycle. The d-axis correction value C _d is calculated using (n) and the electric resistance R of the electric circuit including the motor 1 and the drive circuit 13. More specifically, the d-axis correction value calculation unit 51e includes a multiplication unit 51g that calculates the product of the d-axis current I _d (n) and the electric resistance R, the output of the multiplication unit 51g, and the d-axis voltage in the previous calculation cycle. A deviation calculating unit 51h that obtains a difference from the command value V _d ^* (n−1) as a d-axis correction value C _d (= V _d ^* (n−1) −R · I _d (n)). Yes. The d-axis correction value C _d obtained by the deviation calculation unit 51h is given to the d-axis subtraction unit 51d ′. In the figure, Z ^-1 represents the previous value of the signal.

Similarly, the q-axis correction value calculation unit 52e calculates the q-axis voltage command value V _q ^* (n−1) in the previous calculation cycle (n−1) and the q-axis current I _q (n) detected in the current calculation cycle. ) And the electric resistance R of the electric circuit including the motor 1 and the drive circuit 13, the q-axis correction value C _q is calculated. More specifically, the q-axis correction value calculation unit 52e includes a multiplication unit 52g that calculates the product of the q-axis current I _q (n) and the electric resistance R, the output of the multiplication unit 52g, and the q-axis voltage in the previous calculation cycle. A deviation calculating unit 52h for obtaining a difference from the command value V _q ^* (n−1) as a q-axis correction value C _q (= V _q ^* (n−1) −R · I _q (n)). Yes. The q-axis correction value C _q obtained by the deviation calculation unit 52h is given to the q-axis first subtraction unit 52d ′. In the figure, Z ^-1 represents the previous value of the signal.

The calculation results RI _d (n) and RI _q (n) of the multipliers 51g and 52g are the voltage command values V _d ^* (n−1) and V _q ^* (n−1) in the previous calculation cycle (n−1). Is generated at the voltage command value update timing and is generated at both ends of the electric circuit in the current calculation cycle (n). Therefore, the d-axis correction value C _d and the q-axis correction value C _q correspond to a voltage error caused by a difference between the detection timing of the motor current or the like and the voltage command value update timing. It is considered that this voltage error does not greatly differ between calculation periods adjacent on the time axis.

Therefore, in this embodiment, the PI calculation values V _do and V _qo are _corrected by the non- _interacting control amounts D _d (n) and D _q (n), and the d-axis correction value C _d and the q-axis correction value C are further corrected. Corrected by _q , the d-axis voltage command value V _d ^* (= V _do + D _d −C _d ) and the q-axis voltage command value V _q ^* (= V _qo + D _q −C _q ) are obtained. Yes. Therefore, these voltage command values V _d ^* and V _q ^* are appropriate values when they are updated. As a result, the motor current can be prevented from fluctuating, and the dynamic characteristics can be improved while suppressing vibration and abnormal noise.

FIG. 8 is a block diagram for explaining the configuration of the motor control apparatus according to the third embodiment of the present invention. The dq-axis voltage that can be used in place of the configuration shown in FIG. 2 or FIG. The configuration of the command value calculation unit 19 is shown. In FIG. 8, functional parts equivalent to those shown in FIG. 7 are given the same reference numerals.
In this embodiment, the d-axis correction value calculation unit 51e includes the d-axis voltage command value V _d ^* (n−1) in the previous calculation cycle (n−1) and the d-axis current I _d detected in the current calculation cycle. (n), the d-axis current I _d (n−1) detected in the previous calculation cycle, the electric resistance R of the electric circuit including the motor 1 and the drive circuit 13, and the d-axis inductance L _d of the motor 1. Using this, the d-axis correction value C _d is calculated. More specifically, the d-axis correction value calculation unit 51e includes a multiplication unit 51g that calculates the product of the d-axis current I _d (n) and the electrical resistance R, and a d-axis current change ΔI between the current calculation cycle and the previous calculation cycle. _d (= I _d (n) −I _d (n−1)) d-axis current change calculation unit 51i, and d-axis current change ΔI _d obtained by this d-axis current change calculation unit 51i to d-axis inductance L _The multiplication unit 51j that multiplies _d and the outputs of the multiplication units 51g and 51j are subtracted from the d-axis voltage command value V _d ^* (n-1) in the previous calculation cycle to obtain the d-axis correction value C _d (= V _d ^* (n −1) −R · I _d (n) −L _d · ΔI _d ). The d-axis correction value C _d obtained by the deviation calculation unit 51h is given to the d-axis subtraction unit 51d ′. In the figure, Z ^-1 represents the previous value of the signal.

Similarly, the q-axis correction value calculation unit 52e calculates the q-axis voltage command value V _q ^* (n−1) in the previous calculation cycle (n−1) and the q-axis current I _q (n) detected in the current calculation cycle. ), The q-axis current I _q (n−1) detected in the previous calculation cycle, the electric resistance R of the electric circuit including the motor 1 and the drive circuit 13, and the q-axis inductance L _q of the motor 1. Q-axis correction value C _q is calculated. More specifically, the q-axis correction value calculation unit 52e includes a multiplication unit 52g that calculates the product of the q-axis current I _q (n) and the electric resistance R, and a q-axis current change ΔI between the current calculation cycle and the previous calculation cycle. _q (= I _q (n) −I _q (n−1)) to obtain q-axis current change calculation unit 52i, and q-axis current change ΔI _q obtained by q-axis current change calculation unit 52i to q-axis inductance L _{The q} -axis correction value C _q (= V _q ^* (n) is obtained by subtracting the outputs of the multiplication unit 52j that multiplies _q and the outputs of the multiplication units 52g and 52j from the q-axis voltage command value V _q ^* (n-1) in the previous calculation cycle. −1) −R · I _q (n) −L _q · ΔI _q ). The q-axis correction value C _q obtained by the deviation calculation unit 52h is given to the q-axis subtraction unit 52d. In the figure, Z ^-1 represents the previous value of the signal.

The sum (R · I _d (n) + L _d · ΔI _d ) of the outputs of the multipliers 51g and 51j generates the d-axis voltage command value V _d ^* (n-1) in the previous calculation cycle (n-1). As a result of being output at the voltage command value update timing, it is a voltage generated at both ends of the electric circuit in the current calculation cycle (n). The second term is a current differential term, which is a term omitted in the second embodiment described above. Similarly, the sum (R · I _q (n) + L _q · ΔI _q ) of the outputs of the multipliers 52g and 52j is the q voltage command value V _q ^* (n-1) in the previous calculation period (n-1). Is generated at the voltage command value update timing and is generated at both ends of the electric circuit in the current calculation cycle (n). Again, the second term is a current differential term and is a term omitted in the second embodiment.

Therefore, as in the case of the second embodiment described above, the d-axis correction value C _d and the q-axis correction value C _q are caused by a difference between the detection timing of the motor current and the voltage command value update timing. Corresponds to voltage error. Therefore, as in the case of the second embodiment, the voltage command values V _d ^* and V _q ^* are appropriate values at the time when they are updated, so that the motor current can be prevented from fluctuating. The dynamic characteristics can be improved while suppressing vibration and abnormal noise. Furthermore, in this embodiment, since the current differential term is taken into consideration, more appropriate motor control can be performed.

Although three embodiments of the present invention have been described above, the present invention can be implemented in other forms. For example, in the above-described embodiment, the q-axis non-interacting control amount D _q obtained by the q-axis non-interacting control amount calculating unit 52b is set to ωL _d I _d + ωΦ, but instead of this, ωL _d I _{d is set} to The q-axis non-interacting control amount D _q may be used.
In the first embodiment described above, the PI calculation value is corrected with the non-interacting control amount, and the corrected value is corrected with the d-axis / q-axis correction value. The amount may be corrected with the d-axis / q-axis correction value, and the PI calculation value may be corrected with the non-interacting control amount after the correction.

In the second and third embodiments described above, the voltage command values V _d ^* (n−1) and V _q ^* (n−1) in the previous calculation period are used to obtain the correction values C _d and C _q. However, instead of these, voltage command values V _d ^* (n), V _q ^* (n) of the current calculation cycle may be used.
In the third embodiment, the current difference between the previous calculation cycle and the current calculation cycle is obtained as the current change amount. However, the current change amount may be obtained by another calculation method.

In the above-described embodiment, the rotor rotational position is detected by the resolver 2, but the rotor rotational position may be estimated by so-called sensorless control. The rotational angular velocity ω may be calculated based on the estimated rotor rotational position.
Further, instead of obtaining the rotational angular velocity ω based on the rotor rotational position, the rotational angular velocity ω may be obtained by using a motor equation shown in the following equations (5) and (6). However, in the following formulas (5) and (6), p represents a differential operator.

V _d − (R + pL _d ) I _d = ω (−L _q I _q ) (5)
V _q − (R + pL _q ) I _q = ω (Φ + L _d I _d ) (6)
More specifically, the rotational angular velocity ω can be obtained according to the following equation (7) or (8) with the differential term omitted.
ω = (V _d (n−1) −RI _d ) / (− L _q I _q ) (7)
ω = (V _q (n−1) −RI _q ) / (Φ + L _d I _d ) (8)
By calculating the rotational angular velocity ω by such calculation, it is possible to perform a rotational angular velocity calculation with a good response, so that the non-interacting control amount can be calculated more accurately.

Further, when the difference between L _d and L _q is small, such as an SPM (Surface Permanent Magnet) motor, the non-interacting control amount is calculated as L _d = L _q. Good.
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 the matters described in the claims.

1 is a block diagram for explaining an electrical configuration of an electric power steering device to which a motor control device according to an embodiment of the present invention is applied. FIG. It is a block diagram for demonstrating the detailed structure of a dq axis voltage command value calculating part. It is a figure which shows the relationship between the detection of d-axis current and q-axis current, and rotation of a dq coordinate axis. It is an illustration figure which illustrates each timing of electric current value acquisition and voltage command value update. It is a flowchart for demonstrating the control procedure of the motor by a motor control apparatus. It is a flowchart which shows the calculation procedure of d-axis voltage command value and q-axis voltage command value. It is a block diagram which shows the structure of the dq-axis voltage command value calculating part applied to the motor control apparatus which concerns on 2nd Embodiment of this invention. It is a block diagram which shows the structure of the dq axis voltage command value calculating part applied to the motor control apparatus which concerns on 3rd Embodiment of this invention.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 1 ... Motor, 2 ... Resolver, 10 ... Motor control apparatus, 11 ... Current detection part, 12 ... Microcomputer, 51 ... d-axis voltage command value calculating part, 51c ... d-axis 1st addition part, 51d ... d-axis 2nd Adder, 51d '... d-axis subtractor, 51e ... d-axis correction value calculator, 52 ... q-axis voltage command value calculator, 52c ... q-axis first adder, 52d ... q-axis second adder, 52d' ... q-axis subtraction unit, 52e ... q-axis correction value calculation unit

Claims (4)

Basic drive value calculating means for calculating a basic drive value for driving the motor;
A non-interacting control amount calculating means for calculating a non-interacting control amount for non-interacting control of the motor;
A correction value calculating means for calculating a correction value for correcting the non-interacting control amount calculated by the non-interacting control amount calculating means;
The basic driving value calculated by the basic driving value calculating means is corrected by the non-interacting control amount calculated by the non-interacting control amount calculating means and the correction value calculated by the correction value calculating means. Correction means for obtaining a motor drive value,
A motor control device including drive means for driving the motor based on a motor drive value obtained by correction by the correction means. The motor control device updates and outputs the motor driving value at every predetermined calculation cycle,
The correction value calculating means is decoupled calculated by the non-interacting control amount computing means in the previous computing cycle from the non-interacting control quantity computed by the non-interacting control amount computing means in the current computing cycle. The motor control device according to claim 1, wherein a value obtained by subtracting a control amount is calculated as the correction value. A motor current detecting means for detecting a motor current flowing through the motor;
The correction value calculation means calculates, as the correction value, a value obtained by subtracting a product of an electric resistance of an electric circuit including the motor and a motor current detected by the motor current detection means from the motor driving value. The motor control device according to claim 1. The motor control device updates and outputs the motor driving value at every predetermined calculation cycle,
A motor current detecting means for detecting a motor current flowing through the motor for each calculation cycle;
The correction value calculation means subtracts the product of the electric resistance of the electric circuit including the motor and the motor current detected by the motor current detection means from the motor drive value, and further calculates the current calculation cycle and the previous calculation. The motor control device according to claim 1, wherein a value obtained by subtracting a value obtained by multiplying an amount of change in the motor current with respect to the period by the inductance of the motor winding is calculated as the correction value.

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