METHOD AND DEVICE FOR CONTROLLING THE OPERATION OF AN AC MOTOR

摘要

A method and device are presented for controlling the operation of an AC motor. The controlling consists in adjusting a frequency f of a driving voltage supplied to the motor. This is achieved by transforming an input harmonic voltage signal of a certain given frequency f0 into the driving voltage signal in the form of a periodic function with the period formed by two groups of opposite polarities, each of said groups including a desired number of pulses each shaped as a half-wave of the input voltage, and at least one of said groups including the at least two unipolar pulses. The frequency f of said periodic function is thus smaller than the frequency f0. by a predetermined factor defined by a number N of the pulses in the period of the driving voltage.