Analysis of a Novel Hybrid-PM Variable-Flux Machine Using New Magnet Material CeFeB

Electric vehicle (EV) is a promising technology for saving fossil energy and reducing pollution. Hybrid-permanent-magnet (PM) variable-flux machine is a competitive candidate for EV propulsion since it has wide speed range and high efficiency at high-speed region. A novel hybrid-PM variable-flux machine with magnetic barriers is proposed in this paper, and a new magnet material CeFeB is used. The structure and operating principle are introduced, and different magnetization states of the machine are analyzed. The equivalent magnetic circuit model of the machine is established considering the influence of magnetic barriers, and the model is proven with good precision for the calculation of air gap flux density and PM operating point. The electromagnetic performances are analyzed, and compared with a traditional variable-flux machine. It is verified that the added magnetic barriers improve the distribution of air gap flux and load magnetization performance of the machine. The no-load back electromotive force, electromagnetic torque, speed range, and load magnetization ratio of the proposed scheme are all improved.