EP1633040A2

Control device for alternating-current motor

Abstract

In one coordinate system of arbitrary rectangular coordinate systems including a coordinate system in which the position of a stator is fixed, a coordinate system in which the position of a rotor is fixed, and a coordinate system which rotates at a rotational frequency which is n times (n is an integer which is not 0 or 1) that of the rotor, a filter on any other coordinate system is defined. Further, driving of a motor is controlled by utilizing this filter. As a result, a coordinate transformation operation need not be individually performed with respect to control variables.

EP1633040A2, drawing sheet 1
Sheet 1 of 40

Term

Term ended

Projected expiry passed 5 September 2025, 1.1 years ago.

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6 claims: 3 independent, 3 dependent

  1. 1
    A control device for an alternating-current motor including a rotor and a stator, wherein in one coordinate system of arbitrary rectangular coordinate systems including a coordinate system fixed to the stator, a coordinate system fixed to the rotor and a coordinate system which rotates at a rotational frequency which is n times (n is an integer which is not 0 or 1) that of the rotor, a filter on any other coordinate system is defined, and driving of the motor is controlled by utilizing the filter.
  2. 2
    A control device for an alternating-current motor including a rotor and a stator, the control device comprising:a fundamental wave current control circuit which obtains a current control output which controls a fundamental wave component of a motor current in an axis coordinate system which rotates in synchronization with the rotor with respect to a d axis current which is mainly an exciting current component of a phase current of the alternating-current motor and a q axis current which is mainly a torque current component of the same;a higher harmonic current control circuit which controls an e axis current and an f axis current, the e axis current and the f axis current have a frequency which is an integer multiple of a frequency of the fundamental wave component of the alternating motor, the higher harmonic current control circuit realizing the e and f axes current controls on the d axis current control and the q axis current control;an addition circuit which adds an output from the fundamental wave current control circuit and an output from the higher harmonic current control circuit;and an inverter circuit which receives an output from the addition circuit and outputs a motor driving current, wherein PI control in the higher harmonic current control circuit is also executed as current control on the d and q axes.
  3. 6
    A current control circuit which separates an α phase current and a β phase current as current components of axes which are fixed to a stator and orthogonal to each other with respect to an alternating-current motor including a rotor and the stator, and controls the respective phase currents based on an α phase current error and a β phase current error which are errors from command values of motor currents of the α phase current and the β phase current, the current control circuit comprising:an α phase proportional unit which multiplies the α phase current error by a predetermined proportional coefficient to obtain an α phase proportional control component;an α phase integrator which integrates a difference value between the α phase current error and a coefficient multiple based on a rotational frequency of the rotor as an output from a β phase integrator;a β phase integrator which integrates an added value of the β phase current error and a coefficient multiple based on a rotational frequency as an output from the α phase integrator;an α phase voltage command unit which adds an α phase integration control component obtained by multiplying an output from the α phase integrator by a predetermined proportional coefficient and an α phase proportional control component as an output from the α phase proportional unit, and outputs an α phase voltage command;a β phase voltage command unit which adds a β phase integration control component obtained by multiplying an output from the β phase integrator by a predetermined proportional coefficient and a β phase proportional control component as an output from the β phase proportional unit, and outputs a β phase voltage command;and an inverter circuit which drives the alternating-current motor based on the α phase voltage command and the β phase voltage command from the α phase voltage command unit and the β phase voltage command unit.