Analysis of torque ripple in a BDCM

In this paper, torque and torque ripple in a brushless direct-current motor drive are assessed. First, the cogging torque is determined using finite-element method. The torque ripple is then calculated for the motor drive with the controller. The simulation model allows a comparison between the motor design and the motor drive performance with respect to torque ripple. The analysis shows that although the machine is designed considering minimum cogging torque, the commutation process remains a major source of torque ripple. Its effect leads to a substantial ripple torque. Therefore, minimization techniques by controlling the excitation should be considered to improve motor dynamic performances. The simulation results are confirmed through experimental results.