A METHOD TO REDUCE MIDRANGE RESONANCE DURING OPERATION OF A MULTI-PHASE STEP MOTOR

摘要

The frequency of the pulse width modulator within a step motor control circuit is increased above a base frequency under defined conditions to enable more accurate construction of the phase current waveform for preventing mid-range resonance. The PWM frequency is stepped between frequencies by a fixed amount above the base frequency, to prevent the excitation of system harmonics and prevent step motor operational instability.