Quantitative study of the influence of switching period on brushless DC motor operation

Abstract

The existence of Pulse Width Modulation (PWM) switching period of a brushless dc motor (BLDCM) drive may cause commutation delay problem, especially when there are few switching periods (Tu) within one step. In this paper, this commutation delay problem was analyzed and calculated, the relationship between the number of Tu in one step and the instantaneous fluctuation magnitude of stator current was deduced. The simulation and experiment results verified the accuracy of the analysis. The results in this paper are useful for further understanding of BLDCM operating process and quantitatively choosing the optimal switching period of some BLDCM drive.