JP2020048251A - Motor controller - Google Patents

Abstract

To provide a motor controller that easily makes a phase difference approach "0°" or "180°" by executing a correction control.SOLUTION: A motor controller 10 comprises: an acquisition unit 162 for acquiring a q-axis current component as a current component in an estimation q-axis direction out of a current vector generated in a rotation coordinate when power is supplied to a brushless motor 100 in such a manner that a voltage vector is generated in an estimation d-axis direction; a correction mode determination unit 164 for determining a correction mode in the estimation d-axis direction on the basis of a comparison result of a magnitude of the q-axis current component acquired by the acquisition unit 162 with a threshold value larger than "0"; and a correction unit 165 for correcting the estimation d-axis direction with the correction mode determined by the correction mode determination unit 164.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a motor control device for controlling a brushless motor having saliency.

  When estimating the rotor position of the brushless motor, power is supplied to the brushless motor such that a voltage vector is generated on an estimated d-axis in rotational coordinates of vector control, as described in Patent Document 1, for example. The estimated d-axis is a control axis estimated to be the d-axis of the rotational coordinates, and the control axis orthogonal to the estimated d-axis in the rotational coordinates is referred to as the estimated q-axis. The rotor position is estimated based on a q-axis current component that is a current component flowing in the estimated q-axis direction when such power supply is performed.

  When the direction of the estimated d-axis is continuously changed under the condition that the brushless motor is supplied with power so that a voltage vector is generated on the estimated d-axis, the value indicating the q-axis current component as shown in FIG. The estimated q-axis high-frequency current Iqh changes. Therefore, when the direction of the estimated d-axis approaches the direction of the actual d-axis, and when the estimated q-axis high-frequency current Iqh is a positive value, it can be determined that the direction of the q-axis current component is a positive direction. The directions of the control axes (that is, the estimated d-axis and the estimated q-axis) are corrected in the first direction C1. On the other hand, when the estimated q-axis high-frequency current Iqh is a negative value, it can be determined that the direction of the q-axis current component is a negative direction, and thus the second direction C2 which is the opposite direction to the first direction C1 in FIG. The direction of the estimated d-axis is corrected. When the magnitude of the estimated q-axis high-frequency current Iqh, that is, the magnitude of the q-axis current component becomes substantially “0”, the phase difference Δθ between the direction of the actual d-axis, which is the actual d-axis, and the direction of the estimated d-axis is substantially “ Since the angle is “0 °” or almost “180 °”, the correction of the direction of the control axis is terminated.

JP 2014-50121 A

  When power is supplied to the brushless motor so that a voltage vector is generated on the estimated d-axis, a high-frequency noise component is superimposed on the obtained estimated q-axis high-frequency current Iqh as shown in FIG. There is. In this case, when the direction of the control axis is changed when the phase difference Δθ is near “+ 90 °” and when the phase difference Δθ is near “−90 °”, the noise component q The direction of the axial current component may be positive or negative. As a result, when correcting the direction of the control axis to a direction corresponding to the direction of the q-axis current component, the phase difference Δθ is a value near “+ 90 °” or the phase difference Δθ is a value near “−90 °”. When the value is a value, the correction may be completed.

  A motor control device for solving the above-mentioned problem, when performing vector control of a brushless motor, changes the direction of an estimated d-axis, which is a control axis estimated as the d-axis of the rotational coordinate of the vector control, to the actual d-axis of the rotational coordinate. This is a device for performing correction control to approach the direction of the real d-axis. When the control axis estimated to be the q-axis of the rotational coordinate is the estimated q-axis, the motor control device uses the rotational coordinate when supplying power to the brushless motor so that a voltage vector is generated in the direction of the estimated d-axis. An acquisition unit that acquires a q-axis current component that is a current component in the estimated q-axis direction of the generated current vector, a magnitude of the q-axis current component acquired by the acquisition unit, and a threshold that is larger than “0”. And a correction unit that corrects the estimated d-axis direction with the correction mode determined by the correction mode determination unit based on the comparison result.

  According to the above configuration, the correction mode of the estimated d-axis direction is determined based on the comparison result between the acquired magnitude of the q-axis current component and the threshold value greater than “0”. By correcting the direction of the estimated d-axis in the correction mode determined in this way, even when the noise component is superimposed on the q-axis current component, the direction of the actual d-axis and the direction of the estimated d-axis can be changed. Is less likely to be completely corrected in the direction of the control axes (that is, the estimated d-axis and the estimated q-axis) in a state where the phase difference is near “+ 90 °” or near “−90 °”. . That is, even when the noise component is superimposed on the q-axis current component acquired during the execution of the correction control, the phase difference is brought closer to “0 °” or “180 °” by the execution of the correction control. It will be easier.

  Note that when a correction direction determination threshold is set as the threshold, the correction mode determination unit estimates based on a comparison result between the magnitude of the q-axis current component acquired by the acquisition unit and the correction direction determination threshold. You may make it have the correction direction determination part which determines the correction direction of the direction of a d-axis. Then, the correction unit preferably corrects the direction of the estimated d-axis to the correction direction determined by the correction direction determination unit.

  According to the above configuration, the correction direction of the estimated d-axis direction is determined based on the comparison result between the acquired magnitude of the q-axis current component and the correction direction determination threshold value larger than “0”. Then, the direction of the estimated d-axis is corrected to the correction direction determined in this way.

  The correction direction determining unit may determine the correction direction of the estimated d-axis direction according to whether a prescribed condition is satisfied. For example, when it is determined that the specified condition is satisfied, the first correction direction is the correction direction of the estimated d-axis direction, and when it is not determined that the specified condition is satisfied, the first correction direction is opposite to the first correction direction. The second correction direction, which is the direction, may be the correction direction of the estimated d-axis direction.

  In this case, it is preferable that the correction direction determination unit determines that the specified condition is satisfied when the direction of the q-axis current component obtained by the obtaining unit is opposite to the specified direction. The prescribed direction referred to here is one of the positive direction and the negative direction. In this case, when the direction of the q-axis current component is opposite to the prescribed direction, the correction direction of the estimated d-axis direction may be the first correction direction regardless of the magnitude of the q-axis current component. it can.

  In addition, the correction direction determination unit determines that the direction of the q-axis current component acquired by the acquisition unit is the prescribed direction and that the magnitude of the q-axis current component is equal to or less than the modification direction determination threshold. Is preferably determined to hold. This allows the correction direction to be the first correction direction. On the other hand, when the direction of the q-axis current component obtained by the obtaining unit is the specified direction and the magnitude of the q-axis current component is larger than the correction direction determining threshold, the correction direction determination unit Is preferably not determined to hold. Thereby, the correction direction can be set to the second direction.

According to the above configuration, at the end of the correction control, the phase difference easily shifts from the target value (“0 °” or “180 °”) in a direction corresponding to the specified direction.
Further, the motor control device may execute a rotor rotation control for rotating the rotor of the brushless motor after the correction control is completed. At the start of the rotation of the rotor accompanying the start of the rotor rotation control, the phase difference tends to change. Therefore, it is preferable to set the prescribed direction based on the direction in which the rotor is rotated by the rotor rotation control.

  According to the above configuration, by setting the prescribed direction in consideration of the rotation direction of the rotor by the rotor rotation control, when the rotor is rotated by the execution of the rotor rotation control, the phase difference is enlarged at the initial stage of the rotation. This can be suppressed.

  In some cases, a threshold for determining the amount of correction is set as the threshold. In this case, when the magnitude of the q-axis current component acquired by the acquisition unit is greater than the threshold for determining the amount of correction, the correction mode determining unit determines that the size of the q-axis current component is equal to or less than the threshold for determining the amount of correction. A correction amount determination unit that determines the correction amount may be provided so that the correction amount when correcting the direction of the estimated d-axis is larger than that. Then, the correction unit preferably corrects the estimated d-axis direction based on the correction amount determined by the correction amount determination unit.

  According to the above configuration, the larger the magnitude of the q-axis current component is, the larger the correction amount when correcting the estimated d-axis direction can be. As a result, the phase difference becomes easier to approach “0 °” or “180 °” as compared with the case where the correction amount is maintained at a constant value regardless of the magnitude of the q-axis current component.

  Further, the correction amount determination threshold may include a first specified threshold and a second specified threshold. When the first prescribed threshold value is a threshold value when it is determined that the prescribed condition is satisfied, and the second prescribed threshold value is a threshold value when it is not determined that the prescribed condition is fulfilled, the first It is preferable that the prescribed threshold value is larger than the correction direction determination threshold value. In this case, the correction amount determination unit may determine the correction amount based on a comparison between the magnitude of the q-axis current component and the first specified threshold when it is not determined that the specified condition is satisfied. . The correction amount determination unit may determine the correction amount based on a comparison between the magnitude of the q-axis current component and the second specified threshold when it is determined that the specified condition is satisfied. Then, the correction unit preferably corrects the estimated d-axis direction based on the correction amount determined by the correction amount determination unit.

  According to the above configuration, the first specified threshold is larger than the correction direction determination threshold. Therefore, when the direction of the q-axis current component is the prescribed direction and the magnitude of the q-axis current component is greater than the correction direction determination threshold, the magnitude of the q-axis current component is greater than the first prescribed threshold. The correction amount in the direction of the estimated d-axis can be determined depending on whether it is large or not.

  Further, when the direction of the q-axis current component is the prescribed direction, the phase difference approaches a value near “0 °” or a value near “180 °” by correcting the direction of the estimated d-axis. When the magnitude of the component shifts from a state in which the magnitude of the component is larger than the first prescribed threshold to a state in which the magnitude of the q-axis current component is equal to or less than the first prescribed threshold, the correction amount can be reduced. As described above, the correction amount is reduced in accordance with the approach of the target phase difference, which is the target phase difference (“0 °” or “180 °”), so that the value near the target phase difference can be reduced. It becomes easy to converge the phase difference.

  Note that the second specified threshold may be smaller than the correction direction determination threshold. In this case, the correction amount determination unit determines that the direction of the q-axis current component acquired by the acquisition unit is the prescribed direction and that the magnitude of the q-axis current component is equal to or smaller than the correction direction determination threshold. The correction amount may be determined based on a comparison result between the magnitude of the q-axis current component and the second specified threshold.

  According to the above configuration, when the magnitude of the q-axis current component is equal to or smaller than the correction direction determination threshold value even when the direction of the q-axis current component is the prescribed direction, the magnitude of the q-axis current component becomes the second prescribed magnitude. The amount of correction in the direction of the estimated d-axis can be determined depending on whether or not it is larger than the threshold value. Therefore, the phase difference approaches a value near “0 °” or a value near “180 °” by correcting the estimated d-axis direction, and the magnitude of the q-axis current component is larger than the second specified threshold. When the state shifts to a state where the magnitude of the q-axis current component is equal to or smaller than the second specified threshold, the correction amount can be reduced. In this case, it becomes easy to converge the phase difference to a value near the target phase difference that is the target phase difference (“0 °” or “180 °”).

  Incidentally, it is assumed that the q-axis current component obtained by the obtaining unit includes a noise component. Therefore, it is preferable to set the threshold to a value equal to or larger than the size of the assumed noise component.

  According to the above configuration, even when the phase difference becomes a value near “+ 90 °” or the phase difference becomes a value near “−90 °” during the execution of the correction control, the correction mode is determined. The influence of the magnitude of the noise component can be reduced.

FIG. 1 is a schematic configuration diagram illustrating a motor control device of an embodiment and a brushless motor controlled by the motor control device. 9 is a graph showing a state in which the voltage vector and the current vector are shifted when a voltage vector is generated on the estimated d-axis in a situation where the actual d-axis and the estimated d-axis are shifted. 9 is a graph showing changes in estimated q-axis high-frequency current and signal values when the control axis in the rotation coordinates of vector control is continuously changed. 9 is a graph showing a transition of an estimated q-axis high-frequency current on which a noise component is superimposed. 9 is a flowchart illustrating a processing routine that is executed when the estimated d-axis direction approaches the actual d-axis direction. 13 is a graph showing changes in estimated q-axis high-frequency current and signal values when the control axis is continuously changed in a modified example.

Hereinafter, an embodiment of a motor control device will be described with reference to FIGS.
FIG. 1 illustrates a motor control device 10 of the present embodiment and a brushless motor 100 controlled by the motor control device 10. The brushless motor 100 is used as a power source for discharging brake fluid in a vehicle-mounted brake device. The brushless motor 100 is a permanent magnet embedded type synchronous motor. The brushless motor 100 includes coils 101, 102, and 103 of a plurality of phases (U-phase, V-phase, and W-phase), and a rotor 105 having saliency. As the rotor 105, for example, a two-pole rotor in which a north pole and a south pole are magnetized one by one can be cited.

  The motor control device 10 drives the brushless motor 100 by vector control. Such a motor control device 10 includes a command current calculation unit 11, a command voltage calculation unit 12, a two-phase / 3-phase conversion unit 13, an inverter 14, a 3-phase / 2-phase conversion unit 15, and a rotor position estimation unit 16. ing.

  Command current calculator 11 calculates d-axis command current Id * and q-axis command current Iq * based on required torque TR * for brushless motor 100. The d-axis command current Id * is a command value of a current component in the direction of the d-axis in the rotational coordinates of the vector control. The q-axis command current Iq * is a command value of a current component in the q-axis direction on the rotating coordinates. The d axis and the q axis are orthogonal to each other on the rotational coordinates.

  The command voltage calculator 12 calculates the d-axis command voltage Vd * by feedback control based on the d-axis command current Id * and the d-axis current Id. The d-axis current Id is a value indicating a current component in the direction of the estimated d-axis in the current vector generated on the rotating coordinates by the power supply to each of the coils 101 to 103 of the brushless motor 100. The command voltage calculator 12 calculates the q-axis command voltage Vq * by feedback control based on the q-axis command current Iq * and the q-axis current Iq. The q-axis current Iq is a value indicating a current component in the direction of the estimated q-axis in a current vector generated on the rotating coordinates by power supply to each of the coils 101 to 103.

  Note that the estimated d-axis is an axis that is estimated as the d-axis of the vector control. The actual d-axis of the rotation coordinates is called the actual d-axis. In addition, the actual q axis of the rotation coordinates is called an actual q axis, and the axis estimated as the q axis of the rotation coordinates is called an estimated q axis.

  The two-phase / three-phase converter 13 converts the d-axis command voltage Vd * and the q-axis command voltage Vq * into a U-phase command voltage VU based on the rotor rotation angle θ that is the position (that is, the rotation angle) of the rotor 105. *, V-phase command voltage VV *, and W-phase command voltage VW *. U-phase command voltage VU * is a command value of a voltage applied to U-phase coil 101. V-phase command voltage VV * is a command value of a voltage applied to V-phase coil 102. W-phase command voltage VW * is a command value of a voltage applied to W-phase coil 103.

  The inverter 14 has a plurality of switching elements. The inverter 14 generates a U-phase signal by the U-phase command voltage VU * input from the two-phase / three-phase converter 13 and the on / off operation of the switching element. The inverter 14 generates a V-phase signal by the input V-phase command voltage VV * and the ON / OFF operation of the switching element. The inverter 14 generates a W-phase signal by the input W-phase command voltage VW * and the on / off operation of the switching element. Then, the U-phase signal is input to the U-phase coil 101 of the brushless motor 100, the V-phase signal is input to the V-phase coil 102, and the W-phase signal is input to the W-phase coil 103.

  The U-phase current IU, which is the current flowing through the U-phase coil 101 of the brushless motor 100, is input to the three-phase / two-phase conversion unit 15, and the V-phase current IV, which is the current flowing through the V-phase coil 102, is input. A W-phase current IW, which is a current flowing through the W-phase coil 103, is input. The three-phase / two-phase converter 15 converts the U-phase current IU, the V-phase current IV, and the W-phase current IW based on the rotor rotation angle θ into d-axis currents Id and d-axis current components. It is converted into a q-axis current Iq which is a current component in the q-axis direction.

  The rotor position estimating unit 16 estimates the rotor rotation angle θ. The rotor position estimating unit 16 sets the phase difference Δθ between the direction of the actual d-axis and the direction of the estimated d-axis to approximately “0 °” or “0 °” by performing the correction control that brings the direction of the estimated d-axis closer to the direction of the actual d-axis. It is almost “180 °”. The phase difference Δθ here is a value obtained by subtracting the direction of the actual d-axis from the direction of the estimated d-axis. The rotor position estimating unit 16 includes an AC voltage generating unit 161, an obtaining unit 162, a signal value generating unit 163, a correction mode determining unit 164, and a correcting unit 165 as functional units for performing the correction control.

  The AC voltage generation unit 161 performs a disturbance output process of generating a disturbance voltage signal Vdh * for oscillating a voltage at a high frequency and outputting the generated disturbance voltage signal Vdh * to the first adder 17. When the disturbance output process is being performed by the AC voltage generator 161, the disturbance voltage signal Vdh * is added to the d-axis command voltage Vd * calculated by the command voltage calculator 12, and the added d-axis command voltage Vd * Is input to the two-phase / three-phase converter 13.

  The acquisition unit 162 acquires a q-axis current component, which is a current component in the estimated q-axis direction, among the current vectors generated on the rotating coordinates. In the present embodiment, the acquisition unit 162 acquires the estimated q-axis high-frequency current Iqh obtained by digitizing the q-axis current component. That is, the acquisition unit 162 acquires the estimated q-axis high-frequency current Iqh, which is the high-frequency component of the q-axis current Iq, by passing the q-axis current Iq input from the three-phase / two-phase conversion unit 15 through a band-pass filter. .

  Since the rotor 105 of the brushless motor 100 has saliency, the inductance in the q-axis direction may be larger than the inductance in the d-axis direction. In this case, if the direction of the estimated d-axis is different from the direction of the actual d-axis, when the voltage vector is generated in the direction of the estimated d-axis, the current vector deviated toward the actual d-axis with respect to the voltage vector Occurs.

  Specifically, as shown in FIG. 2, when the estimated d-axis is deviated from the actual d-axis, power is supplied to the brushless motor 100 such that a voltage vector is generated in the direction of the estimated d-axis. Above, a current vector is generated with a declination with respect to the estimated d-axis toward the actual d-axis. Therefore, when the estimated d-axis is deviated from the actual d-axis, an estimated q-axis high-frequency current Iqh, which is a current component in the direction of the estimated q-axis, is generated. The estimated q-axis high-frequency current Iqh is a numerical value of a current vector generated in the direction of the estimated q-axis. That is, the absolute value of the estimated q-axis high-frequency current Iqh corresponds to the magnitude of the current component in the direction of the estimated q-axis. The sign of the estimated q-axis high-frequency current Iqh indicates the direction of the current component in the direction of the estimated q-axis, that is, the positive or negative direction.

  On the other hand, when the direction of the estimated d-axis matches the direction of the actual d-axis, when power is supplied to the brushless motor 100 so that a voltage vector is generated in the direction of the estimated d-axis, the current vector generated on the rotating coordinates becomes Does not deviate from the estimated d-axis. Therefore, when the estimated d-axis is not inclined with respect to the actual d-axis, no current flows in the direction of the estimated q-axis. That is, the magnitude of the estimated q-axis high-frequency current Iqh becomes “0”.

  FIG. 3 shows the transition of the estimated q-axis high-frequency current Iqh when the phase difference Δθ between the estimated d-axis direction and the actual d-axis direction is continuously changed while generating a voltage vector on the estimated d-axis. Are shown by solid lines. As shown by the solid line in FIG. 3, the sign of the estimated q-axis high-frequency current Iqh, that is, the direction of the current component in the estimated q-axis direction changes, or the estimated q-axis high-frequency current Iqh The absolute value, that is, the magnitude of the current component in the direction of the estimated q-axis changes.

  As illustrated in FIG. 4, a high-frequency noise component Iqn may be superimposed on the estimated q-axis high-frequency current Iqh obtained by the obtaining unit 162. When the noise component Iqn is superimposed on the estimated q-axis high-frequency current Iqh in this manner, when the direction of the estimated d-axis is continuously changed, the region where the phase difference Δθ is near “+ 90 °” and the phase difference Δθ In the region near “−90 °”, the estimated q-axis high-frequency current Iqh vibrates across “0”. As described above, the estimated q-axis high-frequency current Iqh is oscillated around “0” when the phase difference Δθ is near “+ 90 °”, and is estimated when the phase difference Δθ is near “−90 °”. The region of the phase difference Δθ in which the q-axis high-frequency current Iqh vibrates across “0” is referred to as “predetermined region RA”.

  The magnitude of the noise component Iqn superimposed on the estimated q-axis high-frequency current Iqh and the width of the predetermined area RA can be predicted in advance by experiments, simulations, and the like. The width of the predetermined area RA is the difference between the phase difference Δθa that is the lower limit of the predetermined area RA and the phase difference Δθb that is the upper limit of the predetermined area RA.

  Returning to FIG. 1, the signal value generation unit 163 uses the estimated q-axis high-frequency current Iqh acquired by the acquisition unit 162 and a threshold value set to a value different from “0” based on the thick solid line in FIG. A signal value Iqs as shown by is generated. That is, the signal value generation unit 163 generates the signal value Iqs based on the comparison result between the magnitude of the q-axis current component and the threshold when the correction control is performed. Although details will be described later, in the present embodiment, the correction amount Δθq and the correction direction of the estimated d-axis are set based on the generated signal value Iqs.

  In the present embodiment, as a threshold, a correction direction determination threshold IqhTh, which is a threshold for determining which direction of the estimated d-axis is to be corrected to the advance side or the retard side, and the estimated d-axis direction Correction amount determination thresholds IqhThA and IqhThB for determining the correction amount are set. As shown in FIG. 3, the correction direction determination threshold value IqhTh is set to a negative value. This is because the rotor control for rotating the rotor 105 in the direction of increasing the rotor rotation angle θ, that is, in the direction of increasing the estimated direction of the d-axis, is performed by the motor control device 10 after the completion of the execution of the correction control. . That is, the positive / negative of the correction direction determination threshold value IqhTh is set based on the direction in which the rotor 105 is rotated by the rotor rotation control. Note that the rotation direction X in FIG. 3 is a direction corresponding to the direction in which the rotor 105 is rotated by the rotor rotation control.

  Further, the absolute value of the correction direction determination threshold value IqhTh is set to be equal to or larger than the assumed noise component Iqn. That is, as shown in FIG. 4, when the value having the maximum absolute value among the estimated q-axis high-frequency currents Iqh including the noise component Iqn that changes in the predetermined area RA is the area maximum value IqhB, The absolute value of the direction determination threshold value IqhTh is larger than the absolute value of the maximum value IqhB in the area.

  In the present embodiment, it is determined whether the specified condition is satisfied based on a comparison result between the estimated q-axis high-frequency current Iqh obtained by the obtaining unit 162 and the correction direction determination threshold IqhTh. Specifically, when the estimated q-axis high-frequency current Iqh is equal to or greater than the correction direction determination threshold IqhTh, it is determined that the specified condition is satisfied. On the other hand, when the estimated q-axis high-frequency current Iqh is smaller than the correction direction determination threshold IqhTh, it is not determined that the specified condition is satisfied.

  The correction direction determination threshold value IqhTh is a negative value. Therefore, when the estimated q-axis high-frequency current Iqh is a positive value, the direction of the current component in the estimated q-axis direction is positive, and it is determined that the specified condition is satisfied. Further, when the estimated q-axis high-frequency current Iqh is a negative value and the direction of the current component in the estimated q-axis direction is negative, the magnitude of the current component in the estimated q-axis direction becomes the correction direction determination threshold value IqhTh. Is smaller than or equal to, it is determined that the specified condition is satisfied. On the other hand, when the estimated q-axis high-frequency current Iqh is a negative value and the direction of the current component in the estimated q-axis direction is negative, the magnitude of the current component in the estimated q-axis direction becomes the correction direction determination threshold value IqhTh. When it is larger than the size of, it is not determined that the specified condition is satisfied.

  In the present embodiment, the negative direction corresponds to the “prescribed direction”. Therefore, based on whether or not the direction of the current component in the estimated q-axis direction is the prescribed direction, and based on the comparison result between the magnitude of the current component in the estimated q-axis direction and the magnitude of the correction direction determination threshold IqhTh. It is determined whether or not the prescribed condition is satisfied.

  The signal value generation unit 163 sets the signal value Iqs to a positive value when it is determined that the specified condition is satisfied, and sets the signal value Iqs to a negative value when it is not determined that the specified condition is satisfied. Value.

  In the present embodiment, the positive-side correction amount determination threshold IqhThA of the correction amount determination thresholds is an example of a “second specified threshold” that is a threshold when it is determined that the specified condition is satisfied. is there. The negative correction amount determination threshold IqhThB of the correction amount determination thresholds is an example of a “first specified threshold” which is a threshold for a case where it is not determined that the specified condition is satisfied.

  The threshold value IqhThB for determining the negative correction amount is set to a negative value. That is, the positive and negative signs of the negative correction amount determination threshold IqhThB are the same as the positive and negative signs of the correction direction determination threshold IqhTh. Further, the absolute value of the threshold value IqhThB for determining the negative side correction amount is larger than the absolute value of the threshold value IqhTh for determining the correction direction. Further, the absolute value of the negative side correction amount determination threshold value IqhThB is smaller than the absolute value of the estimated q-axis high-frequency current Iqh when the phase difference Δθ is “45 °”.

  The threshold value for positive side correction amount determination IqhThA is set to a positive value. In other words, the positive and negative signs of the positive side correction amount determination threshold IqhThA are opposite to the positive and negative signs of the correction direction determination threshold IqhTh. The positive-side correction amount determination threshold IqhThA is smaller than the estimated q-axis high-frequency current Iqh when the phase difference Δθ is “−45 °”. Note that the absolute value of the positive correction amount determination threshold IqhThA may be the same as or different from the absolute value of the negative correction amount determination threshold IqhThB.

  Then, the signal value generation unit 163 determines that the specified condition is satisfied and that the estimated q-axis high-frequency current Iqh is equal to or less than the positive correction amount determination threshold IqhThA, The value A11 is set as the signal value Iqs. On the other hand, if it is determined that the specified condition is satisfied and the estimated q-axis high-frequency current Iqh is larger than the positive side correction amount determination threshold IqhThA, the signal value generation unit 163 sets the second positive side specified value. The value A12 is set as the signal value Iqs. The first positive specified value A11 and the second positive specified value A12 are values larger than “0”. Then, the second positive specified value A12 is larger than the first positive specified value A11. Specifically, the second positive specified value A12 is larger than the positive correction amount determination threshold IqhThA, and is larger than the estimated q-axis high-frequency current Iqh when the phase difference Δθ is “−45 °”. large. On the other hand, the first positive specified value A11 is smaller than the positive correction amount determination threshold IqhThA.

  The signal value generation unit 163 determines that the first negative specified value is satisfied when it is not determined that the specified condition is satisfied and the estimated q-axis high-frequency current Iqh is equal to or more than the negative correction amount determination threshold IqhThB. A21 is set as the signal value Iqs. On the other hand, if it is not determined that the specified condition is satisfied and the estimated q-axis high-frequency current Iqh is smaller than the negative-side correction amount determination threshold IqhThB, the signal value generation unit 163 sets the second negative side The specified value A22 is set as the signal value Iqs. Each of the first negative specified value A21 and the second negative specified value A22 is a value smaller than “0”. The absolute value of the second specified negative value A22 is larger than the absolute value of the first specified negative value A21. Specifically, the absolute value of the second negative specified value A22 is larger than the absolute value of the negative correction amount determination threshold IqhThB, and the estimated q-axis when the phase difference Δθ is “45 °”. It is larger than the absolute value of the high frequency current Iqh. On the other hand, the absolute value of the first negative specified value A21 is smaller than the absolute value of the negative correction amount determination threshold IqhThB.

  Therefore, when the phase difference Δθ between the direction of the estimated d-axis and the direction of the actual d-axis is continuously changed while generating the voltage vector on the estimated d-axis, the signal value Iqs is represented by a thick solid line in FIG. It will change as shown.

  Returning to FIG. 1, the correction mode determination unit 164 estimates and uses the signal value Iqs generated based on the comparison result between the estimated q-axis high-frequency current Iqh acquired by the acquisition unit 162 and the thresholds IqhTh, IqhThA, IqhThB. The correction mode of the direction of the d-axis is determined. The correction mode of the estimated d-axis direction in the present embodiment includes the correction direction of the estimated d-axis direction and the correction amount Δθq of the estimated d-axis direction. That is, the correction mode determination unit 164 includes the correction direction determination unit 164a that determines the correction direction of the estimated d-axis direction, and the correction amount determination unit 164b that determines the correction amount Δθq of the estimated d-axis direction. .

  The correction direction determination unit 164a determines the correction direction based on the comparison result between the estimated q-axis high-frequency current Iqh and the correction direction determination threshold IqhTh, and the sign of the estimated q-axis high-frequency current Iqh. That is, the correction direction is determined based on the comparison result between the estimated q-axis direction current component and the correction direction determination threshold value IqhTh.

  Specifically, the correction direction determining unit 164a determines a correction direction according to whether a specified condition is satisfied. For example, as shown in FIG. 3, when it is determined that the specified condition is satisfied, the correction direction determination unit 164a corrects the first direction C1 in the figure, which is the direction in which the estimated d-axis is advanced. Direction. On the other hand, when it is not determined that the specified condition is satisfied, the correction direction determination unit 164a sets the second direction C2 in the drawing, which is the direction in which the estimated d-axis is retarded, as the correction direction. The second direction C2 is a direction opposite to the first direction C1.

  When it is determined that the specified condition is satisfied, the correction amount determination unit 164b determines the correction amount Δθq based on a comparison result between the estimated q-axis high-frequency current Iqh and the positive-side correction amount determination threshold value IqhThA. On the other hand, when it is not determined that the specified condition is satisfied, the correction amount determination unit 164b determines the correction amount Δθq based on the comparison result between the estimated q-axis high-frequency current Iqh and the negative-side correction amount determination threshold IqhThB. I do. That is, the correction amount Δθq is determined based on a comparison result between the magnitude of the current component in the estimated q-axis direction and the magnitudes of the correction amount determination thresholds IqhThA and IqhThB.

  In the present embodiment, the correction amount determination unit 164b determines the correction amount Δθq based on the signal value Iqs generated by the signal value generation unit 163. When it is determined that the specified condition is satisfied and the signal value Iqs is the second specified positive value A12, the correction amount determination unit 164b sets the signal value Iqs to the first specified positive value A11. The correction amount Δθq is made larger than when. That is, when it is determined that the prescribed condition is satisfied, and when the estimated q-axis high-frequency current Iqh is larger than the positive-side correction amount determination threshold value IqhThA, the estimated q-axis high-frequency current Iqh becomes the positive-side correction amount determination threshold value. The correction amount Δθq is larger than when it is equal to or less than IqhThA.

  On the other hand, when it is not determined that the specified condition is satisfied and the signal value Iqs is the second specified negative value A22, the correction amount determination unit 164b sets the signal value Iqs to the first specified negative value. The correction amount Δθq is made larger than when the value is the specified value A21. That is, when it is not determined that the prescribed condition is satisfied, and when the estimated q-axis high-frequency current Iqh is smaller than the negative correction amount determination threshold IqhThB, the estimated q-axis high-frequency current Iqh is set to the negative correction amount determination threshold. The correction amount Δθq is larger than when it is equal to or greater than IqhThB.

  When performing the correction control, the correction unit 165 executes a correction process of correcting the direction of the estimated d-axis in the correction mode determined by the correction mode determination unit 164. That is, in the correction process, the correction unit 165 corrects the estimated d-axis direction to the correction direction determined by the correction direction determination unit 164a by the correction amount Δθq determined by the correction amount determination unit 164b.

  Next, a processing routine executed by the rotor position estimating unit 16 to perform the correction control will be described with reference to FIG. Note that the execution of this processing routine is started at the start of driving of the brushless motor 100.

  In this processing routine, in step S11, the execution of the disturbance output processing by the AC voltage generation unit 161 is started. Then, when the disturbance voltage signal Vdh * is input to the first adder 17, the process proceeds to the next step S12. In step S12, the obtaining unit 162 obtains the estimated q-axis high-frequency current Iqh. Subsequently, in step S13, the signal value generation unit 163 generates a signal value Iqs. Then, in the next step S14, the correction direction determination unit 164a determines whether the specified condition is satisfied.

  If it is determined that the prescribed condition is satisfied (S14: YES), the process proceeds to the next step S15. In step S15, the correction direction determining unit 164a sets the correction direction of the estimated d-axis direction to the first direction C1. Thereafter, the process proceeds to step S17 described below. On the other hand, if it is not determined in step S14 that the prescribed condition is satisfied (NO), the process proceeds to the next step S16. In step S16, the correction direction of the estimated d-axis is set to the second direction C2 by the correction direction determination unit 164a. Then, the process proceeds to the next step S17.

  In step S17, the correction amount Δθq is determined by the correction amount determination unit 164b based on the signal value Iqs generated in step S13. Subsequently, in step S18, a correction process is executed by the correction unit 165. Then, in the next step S19, it is determined whether or not the elapsed time from the start of the execution of this processing routine has reached the end determination time TMTh. The end determination time TMTh is set to such a time that the phase difference Δθ can be set to a value near “0 °” or “180 °” by executing the correction processing.

  If the elapsed time has not yet reached the end determination time TMTh (S19: NO), the process proceeds to step S12 described above. That is, the execution of the correction control is continued. On the other hand, if the elapsed time has already reached the end determination time TMTh (S19: YES), the process proceeds to the next step S20. In step S20, the execution of the disturbance output processing by the AC voltage generation unit 161 is terminated. When the disturbance voltage signal Vdh * is no longer input to the first adder 17, the processing routine ends. That is, the execution of the correction control ends.

Next, the operation and effect of the present embodiment will be described.
When the correction control is started in response to an instruction to start driving the brushless motor 100, a signal value Iqs is generated based on the relationship between the estimated q-axis high-frequency current Iqh and each of the thresholds IqhTh, IqhThA, and IqhThB. Then, the direction of the estimated d-axis is corrected to a direction corresponding to the signal value Iqs. Specifically, when it is determined that the specified condition is satisfied, the signal value Iqs is set to a positive value. Thus, when the signal value Iqs is a positive value, the direction of the estimated d-axis is corrected to the first direction C1. As a result, the phase difference Δθ increases. On the other hand, when it is not determined that the specified condition is satisfied, the signal value Iqs is set to a negative value. When the signal value Iqs is a negative value, the direction of the estimated d-axis is corrected to the second direction C2. As a result, the phase difference Δθ decreases.

  In the present embodiment, the correction direction determination threshold value IqhTh is set based on a predicted value of the magnitude of the noise component Iqn superimposed on the estimated q-axis high-frequency current Iqh. Therefore, when the correction process is performed under the situation where the phase difference Δθ is a value near “+ 90 °” or a value near “−90 °”, the correction direction of the direction of the estimated d-axis is the first direction C1. Or in the second direction C2. In the present embodiment, when the phase difference Δθ is a value near “+ 90 °” and when the phase difference Δθ is near “−90 °”, the correction direction can be fixed to the first direction C1.

  As a result, it is possible to prevent the correction control from ending when the phase difference Δθ is a value near “+ 90 °” or a value near “−90 °”. That is, by performing the correction control, the phase difference Δθ can be set to a value near “0 °” or a value near “180 °”.

  In the correction processing according to the present embodiment, the direction of the estimated d-axis is corrected by the correction amount Δθq corresponding to the signal value Iqs. The signal value Iqs is a value calculated based on a comparison result between the estimated q-axis high-frequency current Iqh and the correction amount determination thresholds IqhThA and IqhThB. That is, as the absolute value of the estimated q-axis high-frequency current Iqh, that is, the magnitude of the current component in the direction of the estimated q-axis, increases, the absolute value of the signal value Iqs increases. Then, the correction amount Δθq increases as the absolute value of the signal value Iqs increases. The larger the absolute value of the estimated q-axis high-frequency current Iqh, the larger the correction amount Δθq can be. As a result, the phase difference Δθ is set to a value near “0 °” or a value near “180 °” in comparison with the case where the correction amount Δθq is set to a constant value regardless of the magnitude of the estimated q-axis high-frequency current Iqh. It is possible to suppress an increase in the time required until the above.

  When the phase difference Δθ approaches “0 °” or “180 °” and the absolute value of the estimated q-axis high-frequency current Iqh decreases, the absolute value of the signal value Iqs also decreases. As a result, the correction amount Δθq for correcting the direction of the estimated d-axis can be reduced. Therefore, hunting of the phase difference Δθ across the target convergence value can be suppressed. Therefore, it becomes easy to converge the phase difference Δθ to a target convergence value.

  At the end of the correction control, the phase difference Δθ converges at a value near the estimated q-axis high-frequency current Iqh becomes the correction direction determination threshold value IqhTh. That is, the phase difference Δθ easily shifts to the direction corresponding to the prescribed direction, that is, the positive side with respect to the target value (“0 °” or “180 °”).

  Further, after the end of the correction control, a rotor rotation control for rotating the rotor 105 in a direction to increase the rotor rotation angle θ, that is, a direction to increase the direction of the actual d-axis is performed. At the start of the rotation of the rotor 105 due to the execution of the rotor rotation control, the change in the estimated d-axis direction is delayed with respect to the change in the actual d-axis direction, so that the phase difference Δθ tends to be small. In this regard, in the present embodiment, the correction direction determination threshold IqhTh is set to a negative value in consideration of the direction in which the rotor 105 is rotated in the rotor rotation control after the end of the correction control. Therefore, by performing the correction control, the phase difference Δθ can be made to converge to a value slightly more positive than the target value (“0 °” or “180 °”). As a result, it is possible to suppress the phase difference Δθ from increasing at the start of the rotation of the rotor 105 due to the execution of the rotor rotation control. Therefore, it is possible to improve the control performance of the motor control when the rotation of the rotor 105 starts.

The above embodiment can be implemented with the following modifications. The above embodiment and the following modified examples can be implemented in combination with each other within a technically consistent range.
When the prescribed direction is negative and the correction direction determination threshold value IqhTh is a negative value, the positive correction amount determination threshold value IqhThA may be set to a value smaller than “0” as shown in FIG. . In this case, it is preferable that the absolute value of the threshold value IqhThA for determining the correction amount on the positive side be smaller than the absolute value of the threshold value IqhTh for determining the correction direction. Further, if the absolute value of the positive-side correction amount determination threshold IqhThA is smaller than the absolute value of the correction-direction determination threshold IqhThA, the absolute value of the positive-side correction amount determination threshold IqhThA is calculated using the assumed noise component Iqn. It may be smaller than the size.

  When it is determined that the specified condition is satisfied, the signal value Iqs when the estimated q-axis high-frequency current Iqh is smaller than the positive-side correction amount determination threshold IqhThA, and the estimated q-axis high-frequency current Iqh is the positive-side correction amount The signal value Iqs when the value is equal to or more than the determination threshold value IqhThA may be set to be smaller. Then, the smaller the absolute value of the signal value Iqs, the larger the correction amount Δθq.

  Even with such a configuration, even when the phase difference Δθ approaches the target convergence value from the positive side, or when the phase difference Δθ approaches the target convergence value from the negative side, When the phase difference Δθ is located near the convergence value, the correction amount Δθq can be reduced. Therefore, hunting of the phase difference Δθ across the convergence value can be suppressed. Therefore, it becomes easy to converge the phase difference Δθ to a target convergence value.

  After completion of the correction control, the rotor rotation control for rotating the rotor 105 in a direction in which the rotor rotation angle θ is reduced, that is, in a direction in which the direction of the actual d-axis is reduced may be performed. In this case, the prescribed direction may be set to the forward direction in consideration of the direction in which the rotor 105 is rotated by the rotor rotation control. In this case, the correction direction determination threshold IqhTh is a positive value.

  When it is determined that the specified condition is satisfied, and when the estimated q-axis high-frequency current Iqh is larger than the positive-side correction amount determination threshold IqhThA, the estimated q-axis high-frequency current Iqh is set to the positive-side correction amount determination threshold IqhThA. As long as the signal value Iqs can be made larger than in the following cases, the signal value Iqs may be determined by a method different from the method described in the above embodiment. For example, when the estimated q-axis high-frequency current Iqh is equal to or smaller than the positive side correction amount determination threshold IqhThA, the signal value Iqs may be equal to the positive side correction amount determination threshold IqhThA, or the positive side correction amount determination threshold It may be a positive value smaller than IqhThA. On the other hand, when the estimated q-axis high-frequency current Iqh is larger than the positive correction amount determination threshold IqhThA, the signal value Iqs may be set to a value equal to the estimated q-axis high-frequency current Iqh.

  When the specified condition is not determined to be satisfied, and when the estimated q-axis high-frequency current Iqh is smaller than the negative correction amount determination threshold IqhThB, the estimated q-axis high-frequency current Iqh is reduced to the negative correction amount determination threshold IqhThB. If the signal value Iqs can be made smaller than in the above case, the signal value Iqs may be determined by a method different from the method described in the above embodiment. For example, when the estimated q-axis high-frequency current Iqh is equal to or greater than the negative correction amount determination threshold IqhThB, the signal value Iqs may be equal to the negative correction amount determination threshold IqhThB, or the negative correction amount determination threshold may be set. It may be a negative value larger than IqhThB. On the other hand, when the estimated q-axis high-frequency current Iqh is smaller than the negative side correction amount determination threshold IqhThB, the signal value Iqs may be set to a value equal to the estimated q-axis high-frequency current Iqh.

  If the threshold value IqhThA for determining the positive correction amount is provided, the threshold value IqhThB for determining the negative correction amount may not be provided. In this case, when the estimated q-axis high-frequency current Iqh is equal to or smaller than the correction direction determination threshold IqhTh, the correction amount Δθq is held at a constant value regardless of the magnitude of the estimated q-axis high-frequency current Iqh.

  If the threshold value IqhThB for determining the negative correction amount is provided, the threshold value IqhThA for determining the positive correction amount may not be provided. In this case, when the estimated q-axis high-frequency current Iqh is larger than the correction direction determination threshold IqhTh, the correction amount Δθq is held at a constant value regardless of the magnitude of the estimated q-axis high-frequency current Iqh.

  When at least one of the positive correction amount determination threshold value IqhThA and the negative correction amount determination threshold value IqhThB is provided, the correction direction determination threshold value IqhTh may not be provided. In this case, the correction direction is determined by whether or not the estimated q-axis high-frequency current Iqh has a positive value.

  When at least one of the positive correction amount determination threshold value IqhThA and the negative correction amount determination threshold value IqhThB is provided, the absolute value of the correction direction determination threshold value IqhTh is smaller than the assumed noise component Iqn. May be.

  If the correction direction determination threshold value IqhTh is provided, both the positive correction amount determination threshold value IqhThA and the negative correction amount determination threshold value IqhThB need not be provided. In this case, when the estimated q-axis high-frequency current Iqh is larger than the correction direction determination threshold IqhTh, the signal value Iqs may be held at a positive predetermined value larger than “0”, or the signal value Iqs may be held. , May be a positive value corresponding to the magnitude of the estimated q-axis high-frequency current Iqh. On the other hand, when the estimated q-axis high-frequency current Iqh is equal to or less than the correction direction determination threshold IqhTh, the signal value Iqs may be held at a negative predetermined value smaller than “0”, or the signal value Iqs may be It may be a negative value according to the magnitude of the estimated q-axis high-frequency current Iqh.

  The motor control device 10 includes one or more processors that operate according to a computer program (software) and one or more dedicated hardware (application-specific integrated circuit: ASIC) that executes at least a part of various processes. The above-described dedicated hardware circuit or a circuit including a combination thereof can be configured. The processor includes a CPU and a memory such as a RAM and a ROM, and the memory stores a program code or a command configured to cause the CPU to execute a process. Memory, or storage medium, includes any available media that can be accessed by a general purpose or special purpose computer.

The rotor 105 applied to the brushless motor 100 may be a four-pole rotor instead of a two-pole rotor.
The brushless motor to which the motor control device 10 is applied may be a power source of an actuator different from the on-vehicle brake device.

  Reference Signs List 10: motor control device, 16: rotor position estimation unit, 162: acquisition unit, 164: correction mode determination unit, 164a: correction direction determination unit, 164b: correction amount determination unit, 165: correction unit, 100: brushless motor, 105 ... the rotor.

Claims (8)

When performing vector control of the brushless motor, a correction is made such that the direction of the estimated d-axis, which is the control axis estimated as the d-axis of the rotational coordinate of the vector control, approaches the direction of the actual d-axis, which is the actual d-axis of the rotational coordinate. In a motor control device that performs control,
When the control axis estimated to be the q-axis of the rotational coordinate is the estimated q-axis, the voltage is generated at the rotational coordinate when power is supplied to the brushless motor so that a voltage vector is generated in the direction of the estimated d-axis. An acquisition unit that acquires a q-axis current component, which is a current component in the estimated q-axis direction, of the current vector;
A correction mode determining unit that determines a correction mode of the estimated d-axis direction based on a comparison result between the magnitude of the q-axis current component acquired by the acquiring unit and a threshold value greater than “0”;
A correction unit configured to correct the direction of the estimated d-axis in the correction mode determined by the correction mode determination unit. As the threshold, a correction direction determination threshold is set,
The correction mode determination unit is configured to determine a correction direction of the estimated d-axis direction based on a comparison result between the magnitude of the q-axis current component acquired by the acquisition unit and the correction direction determination threshold. Part
The motor control device according to claim 1, wherein the correction unit corrects the direction of the estimated d-axis to the correction direction determined by the correction direction determination unit. The correction direction determination unit is configured to determine a correction direction of the estimated d-axis direction depending on whether a prescribed condition is satisfied,
If one of the positive direction and the negative direction is the specified direction,
The correction direction determination unit,
When the direction of the q-axis current component obtained by the obtaining unit is the specified direction and the magnitude of the q-axis current component is larger than the correction direction determination threshold, the specified condition is satisfied. Without determining that
When the direction of the q-axis current component is the specified direction and the magnitude of the q-axis current component is equal to or smaller than the correction direction determination threshold, it is determined that the specified condition is satisfied;
The motor control device according to claim 2, wherein when the direction of the q-axis current component is opposite to the specified direction, it is determined that the specified condition is satisfied. The motor control device, after the end of the correction control, implements a rotor rotation control to rotate the rotor of the brushless motor,
The motor control device according to claim 3, wherein the prescribed direction is set based on a direction in which the rotor is rotated by the rotor rotation control. As the threshold, a correction amount determination threshold is set,
When the magnitude of the q-axis current component acquired by the acquiring unit is larger than the threshold for correction amount determination, the magnitude of the q-axis current component is equal to or less than the threshold for correction amount determination. A correction amount determining unit that determines the correction amount so that the correction amount when correcting the direction of the estimated d-axis is larger than when
The motor control device according to claim 1, wherein the correction unit corrects the direction of the estimated d-axis based on the correction amount determined by the correction amount determination unit. As the threshold, a correction amount determination threshold including a first specified threshold and a second specified threshold is set,
When the magnitude of the q-axis current component acquired by the acquiring unit is larger than the threshold for correction amount determination, the magnitude of the q-axis current component is equal to or less than the threshold for correction amount determination. A correction amount determining unit that determines the correction amount so that the correction amount when correcting the direction of the estimated d-axis is larger than when
The first prescribed threshold is larger than the correction direction determination threshold,
The correction amount determination unit,
When it is not determined that the specified condition is satisfied, the correction amount is determined based on a comparison between the magnitude of the q-axis current component and the first specified threshold,
When it is determined that the specified condition is satisfied, the correction amount is determined based on a comparison between the magnitude of the q-axis current component and the second specified threshold,
The motor control device according to claim 3, wherein the correction unit corrects the direction of the estimated d-axis based on the correction amount determined by the correction amount determination unit. The second prescribed threshold is smaller than the correction direction determination threshold,
The correction amount determination unit is configured such that when the direction of the q-axis current component acquired by the acquisition unit is the specified direction and the magnitude of the q-axis current component is equal to or smaller than the correction direction determination threshold. The motor control device according to claim 6, wherein the correction amount is determined based on a comparison result between the magnitude of the q-axis current component and the second prescribed threshold. It is assumed that the q-axis current component acquired by the acquisition unit includes a noise component,
The motor control device according to claim 1, wherein the threshold value is set to a value equal to or larger than the magnitude of the assumed noise component.

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