Maximization utilization of DC‐link voltage in variable flux reluctance machine with field winding driven by single‐leg converter

Abstract In order to improve the torque/speed characteristics of the variable flux reluctance machines (VFRMs), an optimal voltage distribution method is proposed to maximize the utilization of the DC‐link voltage. According to the investigation of operating range VFRM driven by single‐leg converter, the optimal armature voltage and the zero‐sequence voltage can be obtained to generate adjustable zero‐sequence current. Thus, the DC‐link voltage utilization and output capacity of VFRM can be significantly improved by optimizing the zero‐sequence current. For verification, the test results on a prototype 6/4 VFRM with single‐leg excitation are presented. The experimental results indicate that, compared with the constant zero‐sequence current control, the DC‐link voltage utilization of the VFRM with proposed method increases by 11.13% together with 36.67% higher output torque at rated speed.