JP7338136B2 - motor controller - Google Patents

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 so as to generate a voltage vector on the estimated d-axis in the rotational coordinates of vector control, as described in Patent Document 1, for example. The estimated d-axis is a control axis that is 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 called the estimated q-axis. The rotor position is estimated based on the q-axis current component, which is the current component flowing in the direction of the estimated q-axis when such power is supplied.

When the direction of the estimated d-axis is continuously changed under the condition that the brushless motor is supplied with power so that the 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 is brought closer to the direction of the actual d-axis, it can be determined that the direction of the q-axis current component is positive when the estimated q-axis high-frequency current Iqh has a positive value. The directions of the control axes (ie, the estimated d-axis and the estimated q-axis) are corrected to 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 negative. , the direction of the estimated d-axis is corrected. Then, when the estimated q-axis high-frequency current Iqh, that is, the magnitude of the q-axis current component becomes approximately "0", the phase difference Δθ between the direction of the actual d-axis and the direction of the estimated d-axis becomes approximately " 0°” or nearly “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 as to generate a voltage vector 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 near the phase difference Δθ of “+90°” and near the phase difference Δθ of “−90°”, noise components are superimposed q The direction of the axial current component becomes positive or negative. As a result, when correcting the direction of the control axis in the direction corresponding to the direction of the q-axis current component, the phase difference Δθ There is a risk that the correction will be completed in a state of a value.

A motor control device for solving the above-mentioned problems is a motor control device that, when vector-controlling a brushless motor, changes the direction of an estimated d-axis, which is a control axis that is estimated to be the d-axis of rotational coordinates in vector control, to the actual d-axis of rotational coordinates. It is a device that performs 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, this motor control device generates a voltage vector 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 direction of the estimated q-axis of the generated current vector; a magnitude of the q-axis current component acquired by the acquisition unit; and a correction section that corrects the estimated d-axis direction in accordance with the correction mode determined by the correction mode determination section.

According to the above configuration, the correction mode of the estimated d-axis direction is determined based on the comparison result between the magnitude of the acquired q-axis current component and a threshold value larger than "0". By correcting the direction of the estimated d-axis in the correction mode determined in this way, even if a 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 corrected. In a state where the phase difference is a value near “+90°” or a value near “−90°”, it becomes difficult to complete the correction of the direction of the control axis (that is, the estimated d-axis and the estimated q-axis). . That is, even if 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. easier.

When a correction direction determination threshold is set as the threshold, the correction mode determination unit estimates based on the result of comparison between the magnitude of the q-axis current component acquired by the acquisition unit and the correction direction determination threshold. A correction direction determination unit may be provided for determining the correction direction of the d-axis direction. Preferably, the correction section corrects the direction of the estimated d-axis to the correction direction determined by the correction direction determination section.

According to the above configuration, the correction direction of the estimated d-axis direction is determined based on the result of comparison between the magnitude of the acquired q-axis current component and the correction direction determination threshold value greater than "0". Then, the direction of the estimated d-axis is corrected to the corrected direction thus determined.

The correction direction determination unit may determine the correction direction of the estimated d-axis direction depending on whether or not the specified condition is satisfied. For example, when it is determined that the specified condition is established, the direction of the estimated d-axis is set as the first correction direction, and when it is determined that the specified condition is not established, the direction opposite to the first correction direction is used. The second correction direction, which is the direction, may be used as the correction direction of the direction of the estimated d-axis.

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 acquired by the acquisition unit is opposite to the specified direction. The prescribed direction 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 specified direction, the correction direction of the estimated d-axis direction can be set as the first correction direction regardless of the magnitude of the q-axis current component. can.

Further, the correction direction determination unit determines 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 less than the correction direction determination threshold value, the specified condition is preferably established. Thereby, the correction direction can be set as the first correction direction. On the other hand, when the direction of the q-axis current component acquired by the acquiring unit is in the specified direction and the magnitude of the q-axis current component is larger than the threshold value for determining the direction of correction, the correction direction determination unit determines that the specified condition It is preferable not to determine that Thereby, the correction direction can be set to the second direction.

According to the above configuration, the phase difference tends to deviate in the direction corresponding to the prescribed orientation with respect to the target value (“0°” or “180°”) at the end of the correction control.
Further, the motor control device may perform rotor rotation control for rotating the rotor of the brushless motor after the correction control is completed. The phase difference tends to change when the rotor starts rotating with the start of rotor rotation control. 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 specified direction in consideration of the direction of rotation of the rotor by the rotor rotation control, when the rotor is rotated by executing the rotor rotation control, the phase difference increases at the beginning of the rotation. can be suppressed.

By the way, a correction amount determination threshold may be 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 value for determining the amount of correction, the correction mode determining unit determines whether the magnitude of the q-axis current component is equal to or less than the threshold value for determining the amount of correction. A correction amount determination unit may be provided for determining the correction amount so that the correction amount when correcting the direction of the estimated d-axis is larger than the estimated d-axis direction. Then, it is preferable that the correction unit corrects the direction of the estimated d-axis 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, the larger the correction amount when correcting the direction of the estimated d-axis. As a result, compared to the case where the amount of correction is held at a constant value regardless of the magnitude of the q-axis current component, it becomes easier to bring the phase difference closer to "0°" or "180°".

Further, the correction amount determination threshold may include a first prescribed threshold and a second prescribed threshold. When the first specified threshold is set as the threshold for when it is determined that the specified condition is satisfied, and the second specified threshold is set as the threshold for when it is determined that the specified condition is not satisfied, the first It is preferable that the specified threshold is larger than the correction direction determination threshold. 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 predetermined 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 predetermined threshold when it is determined that the specified condition is satisfied. Then, it is preferable that the correction unit corrects the direction of the estimated d-axis based on the correction amount determined by the correction amount determination unit.

According to the above configuration, the first specified threshold is greater 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 amount of correction in the direction of the estimated d-axis can be determined depending on whether or not it is large.

Further, when the direction of the q-axis current component is in a specified direction, the correction of the direction of the estimated d-axis causes the phase difference to approach a value near “0°” or a value near “180°”, and the q-axis current When the magnitude of the q-axis current component shifts from the state where the magnitude of the component is greater than the first prescribed threshold to the state where the magnitude of the q-axis current component is equal to or less than the first prescribed threshold, the amount of correction can be reduced. In this way, by reducing the correction amount as the phase difference approaches the target phase difference ("0°" or "180°"), a value near the target phase difference can be obtained. It becomes easier to converge the phase difference.

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

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

Incidentally, it is assumed that the q-axis current component acquired by the acquisition unit includes a noise component. Therefore, it is preferable to set the threshold to a value equal to or greater than the size of the expected 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, when determining the correction mode, The magnitude of the noise component can be made less influential.

1 is a schematic configuration diagram showing a motor control device according to an embodiment and a brushless motor controlled by the motor control device; FIG. 5 is a graph showing how a voltage vector and a current vector deviate from each other when a voltage vector is generated on the estimated d-axis under the condition that the actual d-axis and the estimated d-axis are deviated from each other. 4 is a graph showing changes in estimated q-axis high-frequency current and signal value when the control axis in the rotational coordinates of vector control is continuously changed. 4 is a graph showing transition of an estimated q-axis high-frequency current superimposed with noise components; 4 is a flowchart for explaining a processing routine executed when the direction of the estimated d-axis approaches the direction of the actual d-axis; 7 is a graph showing changes in the estimated q-axis high-frequency current and the signal value when the control axis is continuously changed in the modified example;

An embodiment of the motor control device will be described below with reference to FIGS. 1 to 5. FIG.
FIG. 1 shows a motor control device 10 of this embodiment and a brushless motor 100 controlled by the motor control device 10 . Brushless motor 100 is used as a power source for discharging brake fluid in a vehicle-mounted brake device. Brushless motor 100 is a permanent magnet embedded 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 magnetized with one N pole and one S pole can be used.

The motor control device 10 drives the brushless motor 100 by vector control. Such a motor control device 10 has a command current calculator 11, a command voltage calculator 12, a 2-phase/3-phase converter 13, an inverter 14, a 3-phase/2-phase converter 15, and a rotor position estimator 16. ing.

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

The command voltage calculator 12 calculates the d-axis command voltage Vd* through 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 the current component in the estimated d-axis direction of the current vector generated on the rotating coordinates by the power supply to the coils 101 to 103 of the brushless motor 100 . The command voltage calculator 12 also calculates the q-axis command voltage Vq* through 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 the current component in the estimated q-axis direction of the current vector generated on the rotating coordinates by the power supply to each of the coils 101-103.

The estimated d-axis is an axis that is estimated to be the d-axis of vector control. The actual d-axis of the rotating coordinates is called the real d-axis. The actual q-axis of the rotating coordinates is called the actual q-axis, and the axis estimated to be the q-axis of the rotating coordinates is called the 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 the U-phase command voltage VU *, V-phase command voltage VV*, and W-phase command voltage VW*. The U-phase command voltage VU* is a command value for the voltage applied to the U-phase coil 101 . The V-phase command voltage VV* is a command value for the voltage applied to the V-phase coil 102 . The W-phase command voltage VW* is a command value for the voltage applied to the W-phase coil 103 .

The inverter 14 has a plurality of switching elements. Inverter 14 generates a U-phase signal based on U-phase command voltage VU* input from 2-phase/3-phase converter 13 and on/off operations of switching elements. The inverter 14 also generates a V-phase signal based on the input V-phase command voltage VV* and the ON/OFF operation of the switching element. The inverter 14 also generates a W-phase signal based on 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 three-phase/two-phase converter 15 is supplied with a U-phase current IU that flows through the U-phase coil 101 of the brushless motor 100, and receives a V-phase current IV that flows through the V-phase coil 102. A W-phase current IW, which is a current that is input and flows through the W-phase coil 103, is input. Based on the rotor rotation angle θ, the 3-phase/2-phase converter 15 converts the U-phase current IU, V-phase current IV, and W-phase current IW into d-axis current Id, which is a current component in the d-axis direction, and It is converted into a q-axis current Iq, which is a current component in the direction of the q-axis.

A rotor position estimator 16 estimates the rotor rotation angle θ. Such a rotor position estimating unit 16 reduces the phase difference Δθ between the direction of the actual d-axis and the direction of the estimated d-axis to approximately “0°” or Approximately 180°. The phase difference Δθ referred to 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 section 16 has an AC voltage generating section 161, an acquiring section 162, a signal value generating section 163, a correction mode determining section 164, and a correcting section 165 as functional sections for performing correction control.

The AC voltage generator 161 performs disturbance output processing to generate a disturbance voltage signal Vdh* that oscillates the voltage at a high frequency and output it to the first adder 17 . When the disturbance output process is executed 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 d-axis command voltage Vd* after the addition is obtained. is input to the two-phase/three-phase converter 13 .

The acquiring unit 162 acquires a q-axis current component, which is a current component in the direction of the estimated q-axis, among current vectors generated on the rotating coordinates. In the present embodiment, the obtaining unit 162 obtains the estimated q-axis high-frequency current Iqh, which is a numerical representation of 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 bandpass filter. .

Note that 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 and the direction of the actual d-axis are different, when the voltage vector is generated in the direction of the estimated d-axis, the current vector deviates toward the actual d-axis with respect to the voltage vector. occurs.

Specifically, as shown in FIG. 2, when the estimated d-axis deviates with respect to the actual d-axis, the rotation coordinate is In the above, a current vector is generated with a deviation angle toward the actual d-axis with respect to the estimated d-axis. Therefore, when the estimated d-axis deviates 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 representation 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 estimated q-axis direction. Also, the positive or negative of the estimated q-axis high-frequency current Iqh represents the direction of the current component in the estimated q-axis direction, that is, the positive direction or the negative direction.

On the other hand, when the direction of the estimated d-axis coincides with the direction of the actual d-axis, when power is supplied to the brushless motor 100 so as to generate a voltage vector in the direction of the estimated d-axis, the current vector generated on the rotational coordinate is No declination with respect to the estimated d-axis. Therefore, when the estimated d-axis is not tilted 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 transition of the estimated q-axis high-frequency current Iqh 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 the voltage vector is generated on the estimated d-axis. is shown in solid lines. As shown by the solid line in FIG. 3, the positive or negative of the estimated q-axis high-frequency current Iqh, that is, the direction of the current component in the direction of the estimated q-axis changes, or the estimated q-axis high-frequency current Iqh changes depending on the change in the phase difference Δθ. The absolute value, that is, the magnitude of the current component in the direction of the estimated q-axis may change.

Note that, as shown in FIG. 4 , a high-frequency noise component Iqn may be superimposed on the estimated q-axis high-frequency current Iqh acquired by the acquisition unit 162 . When the noise component Iqn is superimposed on the estimated q-axis high-frequency current Iqh in this way, if the direction of the estimated d-axis is continuously changed, the region near the phase difference Δθ of “+90°” and the phase difference Δθ The estimated q-axis high-frequency current Iqh oscillates around "0" in a region near "-90°". In this way, the estimated q-axis high-frequency current Iqh oscillates across "0" in the vicinity of the phase difference Δθ of "+90°", and the phase difference Δθ is estimated in the vicinity of "-90°". A region of the phase difference Δθ in which the q-axis high-frequency current Iqh oscillates across “0” is called a “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 through experiments, simulations, or 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 generates the thick solid line in FIG. generates a signal value Iqs as indicated by That is, the signal value generation unit 163 generates the signal value Iqs based on the result of comparison between the magnitude of the q-axis current component and the threshold when correction control is performed. Although the details will be described later, in this embodiment, the correction amount Δθq and the correction direction of the estimated d-axis direction are set based on the generated signal value Iqs.

In the present embodiment, the thresholds are a correction direction determination threshold IqhTh which is a threshold for determining whether the direction of the estimated d-axis is corrected to the advance side or the retardation side, and Thresholds IqhThA and IqhThB for determining the amount of correction are set. As shown in FIG. 3, the correction direction determination threshold IqhTh is set to a negative value. This is because the motor control device 10 performs rotor rotation control for rotating the rotor 105 in a direction that increases the rotor rotation angle θ after the correction control is completed. That is, the positive/negative of the correction direction determination threshold 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 the direction corresponding to the direction in which the rotor 105 is rotated by the rotor rotation control.

Also, the absolute value of the correction direction determination threshold IqhTh is set to be equal to or greater than the expected noise component Iqn. That is, as shown in FIG. 4, when the maximum absolute value of the estimated q-axis high-frequency current Iqh including the noise component Iqn that changes within the predetermined region RA is defined as the region maximum value IqhB, the correction The absolute value of the direction determination threshold IqhTh is greater than the absolute value of the intra-region maximum value IqhB.

In this embodiment, it is determined whether or not the specified condition is satisfied based on the result of comparison between the estimated q-axis high-frequency current Iqh acquired by the acquisition 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 value IqhTh, it is determined that the specified condition is established. On the other hand, when the estimated q-axis high-frequency current Iqh is smaller than the correction direction determination threshold value IqhTh, it is not determined that the specified condition is satisfied.

The correction direction determination threshold 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 direction of the estimated q-axis is positive, so 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 direction of the estimated q-axis is negative, the magnitude of the current component in the direction of the estimated q-axis is the correction direction determination threshold IqhTh. is equal to or less than the magnitude of , it is determined that the specified condition is established. 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 direction of the estimated q-axis is negative, the magnitude of the current component in the direction of the estimated q-axis is the corrected direction determination threshold IqhTh. is larger than the magnitude of , it is not determined that the specified condition is satisfied.

In this embodiment, the negative direction corresponds to the "prescribed direction". Therefore, based on whether or not the direction of the current component in the direction of the estimated q-axis is the specified direction, and the result of comparison between the magnitude of the current component in the direction of the estimated q-axis and the magnitude of the correction direction determination threshold IqhTh , a determination is made as to whether or not a specified condition is established.

Then, the signal value generator 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 determined that the specified condition is not satisfied. value.

In the present embodiment, the positive correction amount determination threshold IqhThA of the correction amount determination thresholds is an example of a "second specified threshold" that is a threshold for when it is determined that a specified condition is satisfied. be. Further, the negative side correction amount determination threshold IqhThB of the correction amount determination thresholds is an example of a "first specified threshold" which is a threshold for when it is not determined that the specified condition is satisfied.

The negative side correction amount determination threshold IqhThB is set to a negative value. That is, the positive/negative sign of the negative side correction amount determination threshold IqhThB is the same as the positive/negative sign of the correction direction determination threshold IqhTh. Also, the absolute value of the negative side correction amount determination threshold IqhThB is greater than the absolute value of the correction direction determination threshold IqhTh. Furthermore, the absolute value of the negative side correction amount determination threshold IqhThB is smaller than the absolute value of the estimated q-axis high-frequency current Iqh when the phase difference Δθ is "45°".

The positive side correction amount determination threshold IqhThA is set to a positive value. That is, the positive/negative sign of the positive correction amount determination threshold IqhThA is opposite to the positive/negative sign 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°". The absolute value of the positive side correction amount determination threshold IqhThA may be the same as or different from the absolute value of the negative side correction amount determination threshold IqhThB.

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

If it is determined that the specified condition is not satisfied and the estimated q-axis high-frequency current Iqh is equal to or greater than the negative side correction amount determination threshold value IqhThB, the signal value generation unit 163 generates the first negative side specified value A21 is set as the signal value Iqs. On the other hand, when it is determined that the specified condition is not 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 generates the second negative side A 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 negative specified value A22 is greater than the absolute value of the first negative specified value A21. Specifically, the absolute value of the second negative specified value A22 is greater 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 expressed by the thick solid line in FIG. It will change as shown.

Returning to FIG. 1, the correction mode determination unit 164 uses the signal value Iqs generated based on the comparison results between the estimated q-axis high-frequency current Iqh acquired by the acquisition unit 162 and the thresholds IqhTh, IqhThA, and IqhThB, and estimates Determine how the direction of the d-axis is corrected. The mode of correction of the direction of the estimated d-axis referred to in this embodiment includes the direction of correction of the direction of the estimated d-axis and the amount of correction Δθq of the direction of the estimated d-axis. That is, the correction mode determination unit 164 includes a correction direction determination unit 164a that determines the correction direction of the estimated d-axis direction, and a 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 value IqhTh and the positive/negative sign of the estimated q-axis high-frequency current Iqh. That is, the correction direction is determined based on the result of comparison between the current component in the estimated q-axis direction and the correction direction determination threshold IqhTh.

Specifically, the correction direction determination unit 164a determines the correction direction depending on whether or not the specified condition is satisfied. For example, as shown in FIG. 3, the correction direction determination unit 164a corrects the first direction C1 in the drawing, which is the direction in which the estimated d-axis is advanced, when it is determined that the specified condition is satisfied. 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 to retard the estimated d-axis, as the correction direction. The second direction C2 is 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 the result of comparison between the estimated q-axis high-frequency current Iqh and the positive side correction amount determination threshold 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 result of comparison between the estimated q-axis high-frequency current Iqh and the negative correction amount determination threshold IqhThB. do. That is, the correction amount Δθq is determined based on the result of comparison 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 this 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. FIG. When it is determined that the specified condition is established and the signal value Iqs is the second positive side specified value A12, the correction amount determination unit 164b sets the signal value Iqs to the first positive side specified value A11. The correction amount Δθq is made larger than when . That is, when it is determined that the prescribed condition is satisfied, and the estimated q-axis high-frequency current Iqh is greater than the positive-side correction amount determination threshold IqhThA, the estimated q-axis high-frequency current Iqh becomes the positive-side correction amount determination threshold. The correction amount Δθq becomes larger than when IqhThA or less.

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

Correction unit 165 executes correction processing for correcting the direction of the estimated d-axis in the correction mode determined by correction mode determination unit 164 when performing correction control. 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, with reference to FIG. 5, a processing routine executed by the rotor position estimator 16 to implement corrective control will be described. Execution of this processing routine is started when brushless motor 100 is started to be driven.

In this processing routine, in step S11, the AC voltage generator 161 starts executing disturbance output processing. Then, when the disturbance voltage signal Vdh* comes to be input to the first adder 17, the process proceeds to the next step S12. In step S12, the acquisition unit 162 acquires the estimated q-axis high-frequency current Iqh. Subsequently, in step S13, the signal value Iqs is generated by the signal value generator 163. FIG. Then, in the next step S14, the correction direction determining section 164a determines whether or not the specified condition is satisfied.

If it is determined that the specified condition is satisfied (S14: YES), the process proceeds to the next step S15. In step S15, the correction direction determination unit 164a sets the correction direction of the estimated d-axis as the first direction C1. After that, the process proceeds to step S17, which will be described later. On the other hand, in step S14, if it is determined that the prescribed condition is not satisfied (NO), the process proceeds to the next step S16. In step S16, the correction direction determining unit 164a sets the correction direction of the estimated d-axis as the second direction C2. After that, 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, correction processing is performed by the correction unit 165. FIG. Then, in the next step S19, it is determined whether or not the elapsed time from the start of execution of this processing routine has reached the end determination time TMTh. The end determination time TMTh is set to a time such that the phase difference Δθ can be set to a value near "0°" or "180°" by executing the correction process.

Then, 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 implementation of corrective control continues. 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 AC voltage generator 161 terminates the disturbance output process. When the disturbance voltage signal Vdh* is no longer input to the first adder 17, this processing routine ends. That is, the execution of correction control is terminated.

Next, the operation and effects of this embodiment will be described.
When correction control is started by an instruction to start driving brushless motor 100, signal value Iqs is generated based on the relationship between estimated q-axis high-frequency current Iqh and thresholds IqhTh, IqhThA, and IqhThB. Then, the direction of the estimated d-axis is corrected to the direction according 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. When the signal value Iqs is a positive value in this way, 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 in this way, the direction of the estimated d-axis is corrected to the second direction C2. As a result, the phase difference Δθ becomes smaller.

In this embodiment, the correction direction determination threshold 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 executed in a situation where the phase difference Δθ is a value near “+90°” or a value near “−90°”, the correction direction of the estimated d-axis direction is the first direction C1. or in the second direction C2. In this embodiment, the correction direction can be fixed to the first direction C1 when the phase difference Δθ is a value near “+90°” and when it is a value near “−90°”.

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

Further, in the correction processing in this embodiment, the direction of the estimated d-axis is corrected by a correction amount Δθq corresponding to the signal value Iqs. The signal value Iqs is a value calculated based on the result of comparison between the estimated q-axis high-frequency current Iqh and the correction amount determination threshold values IqhThA and IqhThB. That is, the larger 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, the larger the absolute value of the signal value Iqs. Then, the larger the absolute value of the signal value Iqs, the larger the correction amount Δθq. The correction amount Δθq can be increased as the absolute value of the estimated q-axis high-frequency current Iqh increases. As a result, compared with the case where the correction amount Δθq is a constant value regardless of the magnitude of the estimated q-axis high-frequency current Iqh, the phase difference Δθ It is possible to suppress the lengthening of the time required until it becomes.

Further, 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, it is possible to reduce the correction amount Δθq when correcting the direction of the estimated d-axis. Therefore, hunting of the phase difference Δθ that sandwiches the target convergence value can be suppressed. Therefore, it becomes easier to converge the phase difference Δθ to the target convergence value.

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

Further, after the correction control ends, rotor rotation control is performed to rotate the rotor 105 in a direction that increases the rotor rotation angle θ. At the start of rotation of the rotor 105 due to implementation of rotor rotation control, the change in the direction of the estimated d-axis is delayed with respect to the change in the direction of the actual d-axis, so the phase difference Δθ tends to become small. In this respect, 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 by the rotor rotation control after the correction control ends. Therefore, it is possible to converge the phase difference Δθ to a value slightly on the positive side of the target value (“0°” or “180°”) by performing correction control. As a result, it is possible to suppress an increase in the phase difference Δθ when the rotor 105 starts rotating due to the implementation of the rotor rotation control. Therefore, it is possible to improve the control performance of the motor control when the rotor 105 starts rotating.

The above embodiment can be implemented with the following modifications. The above embodiments and the following modifications can be combined with each other within a technically consistent range.
If the prescribed direction is negative and the correction direction determination threshold IqhTh is a negative value, the positive side correction amount determination threshold IqhThA may be set to a value smaller than "0" as shown in FIG. . In this case, it is preferable to set the absolute value of the positive side correction amount determination threshold IqhThA smaller than the absolute value of the correction direction determination threshold IqhTh. Furthermore, 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 IqhTh, the absolute value of the positive side correction amount determination threshold IqhThA is set to the assumed noise component Iqn. It may be less 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 is set to the positive-side correction amount when the estimated q-axis high-frequency current Iqh It may be made smaller than the signal value Iqs when it is equal to or greater than the decision threshold IqhThA. Then, the smaller the absolute value of the signal value Iqs, the larger the correction amount Δθq.

Even with such a configuration, even if the phase difference Δθ approaches the target convergence value from the positive side, the phase difference Δθ approaches the convergence value from the negative side. When the phase difference Δθ is positioned near the convergence value, the correction amount Δθq can be reduced. Therefore, hunting of the phase difference Δθ that sandwiches the convergence value can be suppressed. Therefore, it becomes easier to converge the phase difference Δθ to the target convergence value.

- After the correction control is finished, rotor rotation control may be performed to rotate the rotor 105 in a direction that decreases the rotor rotation angle θ. In this case, considering the direction in which the rotor 105 is rotated by the rotor rotation control, the specified direction may be the forward direction. In this case, the correction direction determination threshold IqhTh becomes a positive value.

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

When it is determined that the specified condition is not established, and the estimated q-axis high-frequency current Iqh is smaller than the negative-side correction amount determination threshold IqhThB, the estimated q-axis high-frequency current Iqh is the negative-side 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 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 correction amount determination threshold IqhThB, the signal value Iqs may be equal to the estimated q-axis high-frequency current Iqh.

If the positive side correction amount determination threshold IqhThA is provided, the negative side correction amount determination threshold IqhThB may not be provided. In this case, when the estimated q-axis high-frequency current Iqh is equal to or less 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 negative side correction amount determination threshold IqhThB is provided, the positive side correction amount determination threshold IqhThA need not be provided. In this case, when the estimated q-axis high-frequency current Iqh is greater 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 side correction amount determination threshold IqhThA and the negative side correction amount determination threshold IqhThB is provided, the correction direction determination threshold IqhTh may not be provided. In this case, the correction direction is determined depending on whether or not the estimated q-axis high-frequency current Iqh is a positive value.

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

If the correction direction determination threshold IqhTh is provided, both the positive side correction amount determination threshold IqhThA and the negative side correction amount determination threshold IqhThB need not be provided. In this case, when the estimated q-axis high-frequency current Iqh is greater than the correction direction determination threshold value IqhTh, the signal value Iqs may be held at a predetermined positive value larger than "0", or the signal value Iqs may be , 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 value IqhTh, the signal value Iqs may be held at a predetermined negative 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 is one of one or more processors that operate according to a computer program (software), dedicated hardware (application-specific integrated circuit: ASIC) that executes at least part of various types of processing, and the like. It can be configured as a circuit including the above dedicated hardware circuits or a combination thereof. A processor includes a CPU and memory, such as RAM and ROM, which stores program code or instructions configured to cause the CPU to perform processes. Memory or storage media 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 4-pole rotor instead of a 2-pole rotor.
- The brushless motor to which the motor control device 10 is applied may be a power source for an actuator other than the vehicle-mounted brake device.

DESCRIPTION OF SYMBOLS 10... Motor control apparatus 16... Rotor position estimation part 162... Acquisition part 164... Correction mode determination part 164a... Correction direction determination part 164b... Correction amount determination part 165... Correction part 100... Brushless motor 105 … the rotor.

Claims (8)

When vector-controlling a brushless motor, the direction of the estimated d-axis, which is the d-axis of the rotating coordinates of the vector control and the estimated control axis, is corrected to approach the direction of the actual d-axis, which is the actual d-axis of the rotating coordinates. In the control, among the current vectors generated in the rotating coordinates when the brushless motor is powered so that a voltage vector is generated in the direction of the estimated d-axis, the current vector is estimated to be the q-axis of the rotating coordinates. In a motor control device that performs correction control based on a q-axis current component that is a current component in the direction of an estimated q-axis that is a control axis ,
an acquisition unit that acquires the q -axis current component;
a correction mode determination 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 acquisition unit and a threshold having a magnitude greater than "0"; ,
and a correction section that corrects the direction of the estimated d-axis in the correction mode determined by the correction mode determination section. A correction direction determination threshold is set as the threshold,
The correction mode determination unit determines a correction direction for determining 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. has a part
The motor control device according to claim 1, wherein the correction section corrects the direction of the estimated d-axis to the correction direction determined by the correction direction determination section. The correction direction determination unit determines a correction direction of the estimated d-axis direction according to whether or not a prescribed condition is satisfied ,
The correction direction determination unit
The direction of the q-axis current component acquired by the acquisition unit is a prescribed direction that is one of a positive direction and a negative direction , and the magnitude of the q-axis current component determines the correction direction. When it is larger than the threshold for use, it is not determined that the specified condition is satisfied,
when the direction of the q-axis current component is in the specified direction and the magnitude of the q-axis current component is equal to or less than the correction direction determination threshold value, determining that the specified condition is satisfied;
3. 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. When starting to drive the brushless motor, the motor control device performs rotor rotation control for rotating the rotor of the brushless motor after the correction control ends,
4. The motor control device according to claim 3, wherein the specified direction when starting to drive the brushless motor is set based on the direction in which the rotor is rotated by the rotor rotation control. A correction amount determination threshold is set as the threshold,
When the magnitude of the q-axis current component acquired by the acquisition unit is greater than the threshold value for determining the amount of correction, the modification mode determination unit determines that the magnitude of the q-axis current component is equal to or less than the threshold value for determining the amount of correction. a correction amount determination 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 any one of claims 1 to 4, wherein the correction section corrects the direction of the estimated d-axis based on the correction amount determined by the correction amount determination section. A correction amount determination threshold including a first specified threshold and a second specified threshold is set as the threshold,
When the magnitude of the q-axis current component acquired by the acquisition unit is greater than the threshold value for determining the amount of correction, the modification mode determination unit determines that the magnitude of the q-axis current component is equal to or less than the threshold value for determining the amount of correction. a correction amount determination 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 greater than the correction direction determination threshold,
The correction amount determination unit
determining the amount of correction 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 established;
When it is determined that the specified condition is established, the correction amount is determined based on a comparison between the magnitude of the q-axis current component and the second specified threshold,
5. The motor control device according to claim 3, wherein the correction section corrects the direction of the estimated d-axis based on the correction amount determined by the correction amount determination section. The second prescribed threshold is smaller than the correction direction determination threshold,
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 less than the correction direction determination threshold 7. 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 greater than the expected magnitude of the noise component.

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