Novel switched-flux hybrid magnet memory motor

Based on the traditional switched-flux permanent magnet (PM) machine, a novel switched-flux hybrid magnet memory motor is developed, which has extra low coercive force (LCF) magnets and magnetization coils. By changing the magnetization stateof LCF magnets during operation, flux enhancing and weakening can be achieved without extra copper loss. The design considerations, such as stator/rotor pole combinations, cross-coupling effect and online magnetization strategy, are discussed. Meanwhile, the performances of a 6/5 stator/rotor pole model are investigated, such as open-circuit flux density, back-EMF, torque capability, magnetization capability as well as efficiency map. The results show that by changing the magnetization state, the back-EMF and average torque can be adjusted over a wide range, while the overall maximum efficiency region increases significantly.