Method and apparatus for controlling synchronous motor

摘要

A method and apparatus of controlling a synchronous motor having a rotor, and a stator which produces a magnetic flux for rotating the rotor about an axis thereof, the method including the steps of detecting an angular position and a rotating speed of the rotor; estimating a phase difference between a voltage and an electric current of the synchronous motor, on the basis of the detected rotating speed of the rotor; and adjusting an advance angle of the rotor upon excitation of the synchronous motor, as a result of comparison of the detected rotating speed of the rotor with a target value, to thereby control the rotating speed and direction of the rotor.