Variable switching frequency PWM for torque ripple control of AC motors

Abstract

This paper presents a novel variable switching frequency PWM method for torque ripple control of three-phase AC motors. First, the switching torque ripple model is analyzed through the PWM current ripple in the motor. Based on the switching torque ripple prediction model, variable switching frequency PWM is developed to control the torque ripple maximum value. With this method, the switching losses and noise peak value can be reduced for the AC motor drive system, without impairing the torque ripple amplitude. Simulation and experimental results have been provided to support the conclusions.