DC-Biased Operation of a Double-Stator Hybrid Flux Switching Permanent-Magnet Machine

This article proposes the dc-biased operation of a new double-stator hybrid flux switching permanent-magnet (DSH-FSPM) machine. Through directly injecting the dc current into the armature windings, the dc-biased strategy contributes both the flux-enhancing (FE) and flux-weakening (FW) capabilities into the proposed machine design. First, the machine optimization is carried out to obtain the optimal dc-biased current, with the criteria of the torque performances. Then, when compared with the pure-armature-current and max-dc-current strategies, the optimal dc-biased operation increases the average steady torque by 41.3% and 65.5%, respectively. Moreover, the high torque–speed capability is analyzed with the cooperation of the FE and FW operating modes. With 2 A FW dc-biased current injection, the rotational speed is extended to two rated speed with the half-rate output torque. Under the max-dc-current FW operation, the speed can maximumly expand to six rated speed. Consequently, the wide speed range is realized with the integration of the FE and FW modes. Also, the loss and efficiency analysis are carried out based on the whole machine speed range. The simulations are performed to verify the feasibility of the proposed dc-biased DSH-FSPM machine.