Optimization of outer-rotor hybrid excitation FSM for in-wheel direct drive electric vehicle

摘要

Research on flux switching machines (FSMs) hasbeen an attractive topic recently due to tremendous advantages ofrobust rotor structure, high torque, and high power capabilitythat suits for intense applications. However, most of theinvestigations are focusing on inner rotor structure whichincongruous for direct drive applications. In this paper, the designoptimization and performance analysis of 12Slot-14Pole hybridexcitation flux switching machine (HEFSM) with outer-rotorconfiguration are conducted for in-wheel direct drive electricvehicle (EV). Similar with conventional inner-rotor HEFSMs, twomagnetic flux sources of permanent magnet (PM) and fieldexcitation coil (FEC) have extra advantage of variable flux controlcapability, while the outer-rotor configuration has ability toprovide much higher torque and power density suitable for inwheelEV drives. Based on some design restriction andspecification, design refinements are conducted on the initialdesign machine by using deterministic optimization approach. Thefinal design machine has achieved maximum torque and powerdensity of 335.08Nm and 5.93kW/kg, respectively, slightly betterthan inner rotor HEFSM and interior permanent magnetsynchronous machine (IPMSM) design for EV.