CONTROL APPARATUS AND METHOD FOR AC MOTOR

摘要

PROBLEM TO BE SOLVED: To provide a control apparatus for an AC motor capable of realizing highly accurate variable speed driving even at a high carrier frequency, in a drive without use of a means of directly detecting the rotor position and rotational speed of the AC motor as well as its phase current.

SOLUTION: In detecting an electric current from a DC power supply of an inverter for driving the motor, a value near the middle time of each conduction interval is sampled for a current which intermittently passes in a pulse shape. On the basis of the sampled value, applied voltage or frequency to the motor is controlled.

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