Analysis of torque ripple due to phase commutation in brushless DC machines

An original analytical study concerning the torque ripple due to phase commutation on brushless DC motors is developed. The results indicate that the relative ripple is independent of current, varies with speed, and may reach 50% of the average torque. The amplitude of the torque ripple and the duration of the commutation are analyzed, showing how this affects the torque-speed curve of the drive. Simulation as well as experimental results that validate the theoretical analysis are presented.< <ETX xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">&gt;</ETX>