A novel outer-rotor-permanent magnet flux-switching machine for in-wheel light traction

This paper proposes a novel outer-rotor-permanent-magnet flux-switching (ORPMFS) machine for in-wheel light traction applications. Firstly, the geometric topology is introduced. Then the stator and rotor pole combination is discussed, and the stator slot area equation and permanent-magnet (PM) size equation are derived. Further, two 48-stator-slot ORPMFS machines with 22- and 26-rotor-pole are optimized. Then, based on 2D finite element analysis (2D-FEA), a comprehensive comparison between a pair of 48-stator-slot ORPMFS machines with 22- and 26-rotor-pole, and a 12-stator-slot 22-rotor-pole (12s/22p) outer-rotor stator-PM flux-switching (OR-SPM-FS) machine is performed. The results reveal that the 48s/26p ORPMFS machine has significantly better torque capability and higher efficiency than the 48s/22p ORPMFS counterpart and the 12s/22p OR-SPM-FS machine.