Motor control apparatus and magnetic-pole position estimating method
A motor control apparatus according to an embodiment includes a power conversion unit and a control unit. The power conversion unit supplies power to a motor having salient pole characteristic. The control unit performs proportional-integral control on the deviation between a current reference and a current flowing into the motor to generate a voltage reference, and controls the power conversion unit on the basis of the voltage reference. The control unit estimates the magnetic-pole position of a rotor of the motor on the basis of a high-frequency current flowing into the motor by controlling the power conversion unit, and corrects the estimated magnetic-pole position on the basis of an integrated value of the proportional-integral control.
1. A motor control apparatus comprising:
a power conversion unit that supplies power to a motor having salient pole characteristic; and
a control unit that performs proportional-integral control to generate a voltage reference, and controls the power conversion unit on the basis of the voltage reference, the control unit being connected to the power conversion unit and including:
a current controller that performs the proportional-integral control on a deviation for a component of a q-axis orthogonal to a d-axis to generate a q-axis voltage reference; and
a determining unit that determines a polarity of a magnetic-pole position of a rotor of the motor on the basis of a positive/negative polarity of a q-axis integrated value of the proportional-integral control, the determining unit being connected to the current controller, wherein
the control unit estimates the magnetic-pole position of the rotor of the motor on the basis of a high-frequency current flowing into the motor by controlling the power conversion unit,
the control unit corrects the estimated magnetic-pole position on the basis of the polarity of the q-axis integrated value of the proportional-integral control, and
the control unit controls the power conversion on the basis of the q-axis voltage reference.
2. The motor control apparatus according to claim 1 , wherein the control unit includes:
an adder that adds a high-frequency signal to a voltage reference of a d-axis parallel to a magnetic flux of the motor; and
an extractor that extracts a high-frequency current corresponding to the high-frequency signal from the current flowing into the motor, wherein
the current controller performs proportional-integral control on the deviation between the current reference and the current flowing into the motor for a component of the d-axis to generate a d-axis current reference, wherein the control unit also includes
an estimator that estimates the magnetic-pole position of the rotor on the basis of the high-frequency current extracted by the extractor, and correcting the estimated magnetic-pole position on the basis of the positive/negative polarity of the q-axis integrated value of the current controller.
3. The motor control apparatus according to claim 2 , wherein the estimator includes:
a speed estimator that determines a speed estimated value of the rotor on the basis of the high-frequency current extracted by the extractor;
an integrator that integrates the speed estimated value output from the speed estimator to determine a first position estimated value that is an estimated value of the magnetic-pole position; and
a corrector that corrects the first position estimated value on the basis of the polarity determined by the determining unit to determine a second estimated value.
4. The motor control apparatus according to claim 2 , wherein the estimator corrects the estimated magnetic-pole position on the basis of the positive/negative polarity of the q-axis integrated value of the current controller when the q-axis integrated value of the current controller exceeds a certain threshold.
5. The motor control apparatus according to claim 3 , wherein the estimator corrects the estimated magnetic-pole position on the basis of the positive/negative polarity of the q-axis integrated value of the current controller when the q-axis integrated value of the current controller exceeds a certain threshold.
6. The motor control apparatus according to claim 2 , further comprising a high-frequency signal generator that generates the high-frequency signal, wherein
the high-frequency signal generator determines an amplitude value of the high-frequency signal on the basis of the set speed, an induced voltage constant, a d-axis inductance, and a q-axis inductance when an electrical angular speed of the rotor is equal to or lower then a set speed.
7. The motor control apparatus according to claim 3 , further comprising a high-frequency signal generator that generates the high-frequency signal, wherein
the high-frequency signal generator determines an amplitude value of the high-frequency signal on the basis of the set speed, an induced voltage constant, a d-axis inductance, and a q-axis inductance when an electrical angular speed of the rotor is equal to or lower than a set speed.
8. The motor control apparatus according to claim 4 , further comprising a high-frequency signal generator that generates the high-frequency signal, wherein
the high-frequency signal generator determines an amplitude value of the high-frequency signal on the basis of the set speed, an induced voltage constant, a d-axis inductance, and a q-axis inductance when an electrical angular speed of the rotor is equal to or lower than a set speed.
9. The motor control apparatus according to claim 5 , further comprising a high-frequency signal generator that generates the high-frequency signal, wherein
the high-frequency signal generator determines an amplitude value of the high-frequency signal on the basis of the set speed, an induced voltage constant, a d-axis inductance, and a q-axis inductance when an electrical angular speed of the rotor is equal to or lower than a set speed.
10. A motor control apparatus comprising:
means for performing proportional-integral control on a deviation between a current flowing into a motor having salient pole characteristic and a current reference to generate a voltage reference; the means for performing proportional-integral control including;
current control means for performing proportional-integral control on a deviation for a component of a q-axis orthogonal to a d-axis to generate a q-axis voltage reference; and
means for determining a polarity of the magnetic-pole position of a rotor of the motor on the basis of a positive/negative polarity of a q-axis integrated value of the proportional-integral control, the means for determining being connected to the current control means;
means for estimating the magnetic-pole position of the rotor of the motor on the basis of a high-frequency current to the motor; and
means for correcting the estimated magnetic-pole position on the basis of the polarity of the q-axis integrated value of the proportional-integral control, wherein
the means for performing proportional-integral control controls power conversion on the basis of the q-axis voltage reference.
11. A magnetic-pole position estimating method comprising:
performing proportional-integral control, with a current controller, on a deviation between a q-axis current reference and a current flowing in the motor to generate a q-axis voltage reference;
determining, with a determining unit connected to the current controller, a polarity of a magnetic-pole position of a rotor of a motor on the basis of a positive/negative polarity of a q-axis intergrated value of the proportional-integral control;
estimating the magnetic-pole position of the rotor of the motor having salient pole characteristic on the basis of a high-frequency current applied from a power-conversion unit to the motor; and
correcting the estimated magnetic-pole position on the basis of the polarity of the q-axis integrated value of the proportional integral control of the current controller.