Synchronous reluctance motor control device
First Claim
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1. A motor control apparatus of a synchronous reluctance motor comprising:
- a current detector that detects a motor current flowing in a stator winding of the synchronous reluctance motor;
a position and speed estimation unit that estimates an induced voltage of the synchronous reluctance motor from the detected value by the current detector and a voltage command which is a command to a voltage to be applied to the stator winding of the synchronous reluctance motor, and estimated rotor position and rotating speed of the synchronous reluctance motor on the basis of the estimated induced voltage;
a speed control unit that determines a current command which is a command to a current to be supplied to the stator winding of the synchronous reluctance motor so as to eliminate the error of the estimated rotating speed by the position and speed estimation unit and a target value of the rotating speed given from outside;
a distribution unit that distributes the current command from the speed control unit into a torque current command which is a torque current component of the current command and a field current command which is a field current component of the current command, on the basis of a predetermined current phase angle of the synchronous reluctance motor;
a torque current correction unit that corrects the torque current command on the basis of the torque current command from the distribution unit and the estimated rotating speed from the position and speed estimation unit, so that a load torque generated by a load element of the synchronous reluctance motor coincides with the output torque of the synchronous reluctance motor;
a current control unit that generates a voltage command so as to eliminate the error between the corrected torque current command from the torque current correction unit and the detected motor current from the current detector, and the error between the field current command from the distribution unit and the detected motor current obtained from the current detector; and
a conduction distribution unit that distributes conduction signals into driving elements in the synchronous reluctance motor on the basis of the voltage command.
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Abstract
A control apparatus of a synchronous reluctance motor includes a torque current correction unit (16) that generates a torque current command tracing a load torque so as to make the output torque of the motor coincide with the load torque. The control apparatus may further include a position and speed estimation unit (13) that estimates the position and speed based on three phase voltage equation to improve control performance in a voltage saturation state.
81 Citations
21 Claims
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1. A motor control apparatus of a synchronous reluctance motor comprising:
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a current detector that detects a motor current flowing in a stator winding of the synchronous reluctance motor;
a position and speed estimation unit that estimates an induced voltage of the synchronous reluctance motor from the detected value by the current detector and a voltage command which is a command to a voltage to be applied to the stator winding of the synchronous reluctance motor, and estimated rotor position and rotating speed of the synchronous reluctance motor on the basis of the estimated induced voltage;
a speed control unit that determines a current command which is a command to a current to be supplied to the stator winding of the synchronous reluctance motor so as to eliminate the error of the estimated rotating speed by the position and speed estimation unit and a target value of the rotating speed given from outside;
a distribution unit that distributes the current command from the speed control unit into a torque current command which is a torque current component of the current command and a field current command which is a field current component of the current command, on the basis of a predetermined current phase angle of the synchronous reluctance motor;
a torque current correction unit that corrects the torque current command on the basis of the torque current command from the distribution unit and the estimated rotating speed from the position and speed estimation unit, so that a load torque generated by a load element of the synchronous reluctance motor coincides with the output torque of the synchronous reluctance motor;
a current control unit that generates a voltage command so as to eliminate the error between the corrected torque current command from the torque current correction unit and the detected motor current from the current detector, and the error between the field current command from the distribution unit and the detected motor current obtained from the current detector; and
a conduction distribution unit that distributes conduction signals into driving elements in the synchronous reluctance motor on the basis of the voltage command. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21)
the average calculation unit has a grace period to change over conduct and non-conduct of the correction operation of the torque current command, and during the grace period changes it'"'"'s output gradually to be closer to the value obtained as the value after changeover. -
9. The motor control apparatus of a synchronous reluctance motor according to claim 1, wherein the current control unit performs a coordinate transformation from two-phase current command to three-phase current command about the torque current command or the corrected torque current command and the field current command to generate a voltage command so as to eliminate a current error of the three-phase current command and the detected motor current.
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10. The motor control apparatus of a synchronous reluctance motor according to claim 1, wherein the position and speed estimation unit includes an induced voltage estimation unit that estimates an induced voltage of the synchronous reluctance motor on the basis of the detected motor current from the current detector and the voltage command,
an induced voltage generating unit that has a motor model of the synchronous reluctance motor in its inside and generates an induced voltage from the motor model, and a position error correction unit that corrects the estimated induced value so as to eliminate the voltage error of the estimated induced voltage from the induced voltage estimation unit and the induced voltage from the induced voltage generating unit. -
11. The motor control apparatus of a synchronous reluctance motor according to claim 10, wherein the induced voltage estimation unit includes a motor constant compensation unit that compensates the motor constant of the synchronous reluctance motor by using the estimated rotating speed, the voltage command, and the detected motor current.
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12. The motor control apparatus of a synchronous reluctance motor according to claim 11, wherein the motor constant compensation unit compensates the motor constant when the estimated rotating speed is larger than a reference value.
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13. The motor control apparatus of a synchronous reluctance motor according to claim 12, wherein the motor constant compensation unit has a grace period to change over conduct and non-conduct of the compensation operation of the motor constant, and during the grace period changes the motor constant gradually to be closer to the value obtained as the value after changeover.
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14. The motor control apparatus of a synchronous reluctance motor according to claim 11, further comprising a torque fluctuation detecting unit that detects temporal fluctuation of the load torque generated by the load element,
wherein the motor constant compensation unit compensates the motor constant when the torque fluctuation from the torque fluctuation detecting unit is not larger than a reference value. -
15. The motor control apparatus of a synchronous reluctance motor according to claim 14, wherein the motor constant compensation unit has a grace period to change over conduct and non-conduct of the compensation operation of the motor constant, and during the grace period changes the motor constant gradually to be closer to the value obtained as the value after changeover.
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16. The motor control apparatus of a synchronous reluctance motor according to claim 1, further comprising a voltage saturation recognition unit that calculates a voltage saturation rate showing the degree of voltage saturation from the voltage command of the synchronous reluctance motor, and compares the voltage saturation rate with a predetermined value to output the comparison result,
wherein the speed control unit lowers the target value of the rotating speed given from outside when the voltage saturation rate is above the predetermined value on the basis of the output from the voltage saturation recognition unit, and determines the current command based on the lowered value. -
17. The motor control apparatus of a synchronous reluctance motor according to claim 1, further comprising:
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a DC voltage detector that detects a direct-current voltage which is an input voltage to an inverter for supplying an alternating-current voltage to drive the synchronous reluctance motor, a motor voltage correction unit that corrects the motor voltage command so as to cancel pulsations of the direct-current voltage, and a voltage saturation recognition unit that calculates the voltage saturation rate showing the degree of voltage saturation from the motor correction voltage command, compares the calculated voltage saturation rate with a predetermined value, and outputs the comparison result, wherein the voltage saturation recognition unit corrects the predetermined value based on the pulsations of the direct-current voltage detected by the DC voltage detector, and the speed control unit lowers the target value of the rotating speed given from outside when the calculated voltage saturation rate is above the predetermined value, on the basis of the output from the voltage saturation recognition unit, and determines the current command on the basis of the lowered value.
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18. The motor control apparatus of a synchronous reluctance motor according to claim 1, wherein the rotor of the synchronous reluctance motor includes a permanent magnet.
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19. The motor control apparatus of a synchronous reluctance motor according to claim 18, wherein the permanent magnet has only an amount of magnet of minimum limit required for canceling the brake torque at the rated load of the synchronous reluctance motor.
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20. The motor control apparatus of a synchronous reluctance motor according to claim 1, wherein the stator of the synchronous reluctance motor is a concentrated winding stator.
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21. The motor control apparatus of a synchronous reluctance motor according claim 1, wherein the load element of the synchronous reluctance motor is at least rotary compressor or scroll compressor.
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Specification