Method for producing voltage waveforms in a PWM motor controller of a PM DC brushless motor

摘要

A method produces PWM voltage waveforms in a PWM motor controller of a three phase PM DC brushless motor, wherein the motor controller has first, second and third half H-bridge transistor pairs to generate the voltage waveforms to electronically commutate the motor. The first transistor pair is always assigned to the first phase for every commutation state requiring a voltage waveform from the first transistor pair. The second and third transistor pair are similarly assigned. The first method also includes always starting a voltage waveform generated by the first transistor pair substantially at the beginning of the PWM period when a commutation state requires a voltage waveform from the first transistor pair but delaying starting a voltage waveform generated by the second transistor pair by substantially 1/3 of the PWM period and delaying starting a voltage waveform generated by the third transistor pair by substantially 2/3 of the PWM period.