Three-phase variable flux outer-rotor switched flux permanent magnet machine

High torque density and robust rotor structure outer-rotor switched flux permanent magnet (SFPM) machine with DC excitation is proposed for emerging candidates to replace conventional electric motor of direct drive electric vehicle (EV). The extraordinary of DC excitation coil provides higher generated flux and flux control capability that suitable for various operating conditions. With the concept of motor housing inside the wheel, mechanical transmission as conventionally applied in centralized drive can be eliminated. In this paper, the proposed machine operating principle, predicted back electromagnetic force, cogging torque and torque production based on 2D-FEA are validated experimentally on the developed prototype. The results obtained show that there is good agreement between 2D-FEA and experiments.