Maximum Ratio of Torque to Copper Loss Control for Hybrid Excited Flux-Switching Machine in Whole Speed Range

This paper proposes an optimized control strategy for hybrid excited flux-switching machine (HEFSM) in the whole speed range. First, the machine topology, operating principle, electromagnetic performance, and dynamic models of HEFSM are briefly introduced. Second, in the constant torque range, the optimized positive excitation is utilized to improve the load capacity, and minimize the copper loss, as well as achieve a faster response than the strategy of random combination of excitation and armature current and the zero excitation current control. In constant power range, there are several constraints like torque, current, voltage and speed. The optimized negative excitation current and d-axis current are not only used to achieve higher speed and produce reluctance torque, but also minimize the copper loss for a certain value of torque in the optimized strategy. Then, the maximum ratio of torque to copper loss is realized. Finally, other losses (such as iron loss, friction, and windage losses) and efficiency of HEFSM are analyzed. The feasibility and effectiveness of the proposed control strategy for the HEFSM drive system are confirmed by simulation and experiment.