STEPLESS SPEED REGULATION CIRCUIT AND METHOD FOR SINGLE-PHASE MOTOR

摘要

The present application provides a stepless speed regulation circuit and a stepless speed regulation method. The stepless speed regulation circuit for driving a motor comprises: a switch circuit (11) having an input end, a first output end and a second output end, wherein the input end receives a unidirectional fluctuating steamed-bread-shaped wave signal obtained by full-wave rectification of a sinusoidal AC signal, and the motor is coupled between the first output end and the second output end; a synchronizing signal generation circuit (12) which generates a synchronizing signal according to the sinusoidal AC signal; and a switch driving circuit (13) configured to select at least one switch in the switch circuit to perform chopping at a second frequency according to state of the synchronizing signal, and to form a sinusoidal envelope chopped signal between the first output end and the second output end, wherein the sinusoidal envelope chopped signal is synchronous with the waveform of the sinusoidal AC signal. The stepless speed regulation circuit and method for a motor in the present application lead to a small circuit size and relatively high power factor, and can greatly improve the efficiency of the motor at low speed.