Self-Optimizing Control of Advanced Commutation Angle for Doubly Salient Electromagnetic Machine

Advanced angle commutation is an effective approach to suppress the commutation torque ripple for doubly salient electromagnetic machine (DSEM). In this paper, the commutation process under "three-phase three-state" conduction mode is analyzed in detail at first. On this base, a novel self-optimizing control strategy of advanced commutation angle for DSEM is proposed, it starts with setting an initial disturbance of advanced commutation angle, then according to the feedback of command current, the output of outer speed loop, the advanced commutation angle is continuously regulated with the aim of decreasing command current. Therefore, the output torque/current ratio is increased, DSEM is desired to operate at the steady state with the smallest current, so the output torque performance as well as system efficiency are enhanced. With no requirement for system parameters, this proposed method can be easily implemented in any other quasi-square current motor systems with outer speed and inner current loops control. Finally, the experiments on a 12/8-pole DSEM validate the correctness of the proposed methods.