Switching method and apparatus for increasing efficiency of an inductive load and switching means supplying the load

摘要

A switching method and apparatus for increasing the efficiency of an inductive motor. A switching device connects, according to a PWM process, a D.C. voltage (E) to an inductive motor creating a low-frequency contribution UmLF rising from 0V to the peak voltage at the beginning of each half period T/2. The peak voltage is maintained for at least one sixth of a period T/6 creating a plateau and, then, the switching device connects, according to the PWM process, the D.C. voltage (E) to the inductive motor for the remainder of the half period T/2 creating a low frequency contribution UmLF declining from the peak voltage to 0V. With this arrangement, motor vibration is reduced and efficiency is increased.