Direct Torque Control Strategy for DC-Biased Vernier Reluctance Machines Capable of Zero-Sequence Current Regulation

This article proposes a direct torque control (DTC) strategy for dc-biased vernier reluctance machines (dc-biased-VRMs) capable of zero-sequence current regulation. The phase current waveform of the dc-biased-VRM is sinusoidal with dc bias. To regulate the dc bias current, the proposed method reserves the adjustment time in each switching period. Then, to achieve the maximum torque per ampere condition, the unique dc bias current needs to be distributed closely with respect to the reference torque and reference flux. In addition, a reference voltage distribution method is associated with the proposed DTC strategy to further reduce the procedure of rotating coordinate transformation. The proposed DTC strategy simplifies the control algorithm, and the torque reference can be directly responded. Finally, the effectiveness of the proposed method is verified experimentally.