A Current Optimization Strategy for Torque Ripple Reduction of Brushless DC Motor with Nonideal Back Electromotive Force

Abstract

This paper presents a study of the torque component under the d-axis and q-axis of brushless DC motor with nonideal back electromotive force. Based on the improved torque harmonic expressions, the main ripple contributors can be found and are also used as the basis of designing the phase current. Then, a current optimization controller based on optimized proportional resonant control, which accounts for the influences of non-ideal back EMF and phase current lagging, is proposed to track the designed reference current in real time. Its effectiveness in minimizing low order torque harmonic component is validated and confirmed experimentally.