Torque Ripple Reduction in High Power BLDC Motors Utilizing an Auxiliary DC to DC Converter

Abstract

Brushless dc (BLDC) motors so far have generally been used for low power servo applications like printers, turntables, robotics etc. Of late they are seriously being considered for application as traction motors in low and medium power electric vehicles(EV) as they possess high torque to weight ratio, and have better operating efficiency. However, they suffer from high torque ripple which makes them unfavourable for such applications. In order to overcome the aforesaid limitation of high torque ripple, several techniques have been reported in the literature. However, the solutions reported in the literature are applicable for low power motors, and not suitable for high power BLDC motors. In this paper a simplified method to reduce the torque ripple of a high power BLDC motor drive utilizing a modified forward converter is proposed. The proposed scheme is able to operate the high power motor with a considerably reduced torque ripple. The efficacy of the proposed scheme is confirmed by performing detailed simulation studies.