Control analysis of PM brushless DC motor used in flywheel energy storage system

CHENG Wenxing, ZHU Changsheng
(College of Electrical Engineering，Zhejiang University, Hangzhou 310027,China)

Abstract: Aiming at reducing the current and the torque ripple appeared in flywheel energy storage system running in widerange speed, after the analysis of torque ripple in the commutation interval, the relation between the torque ripple and the speed was established. A hybrid method was presented that the PWMonPWM was chosen to control power devices during lowspeed range, while during highspeed range, the overlapping commutation with PWM was used. The control method were evaluated on the effect of reducing the current and the torque ripple during the commutation interval, the Matlab/Simulink model was built, and the running test in lowspeed range were tested. The experimental results show that the proposed method can eliminate diodes′ freewheeling phenomenon and reduce the torque ripple during the commutation interval, it adapts for brushless DC motor in wide speedrange.
Key words: flywheel energy storage system;PM brushless DC motor（PMBLDC）;  torque ripple; pulse width modulation(PWM);overlapping commutation