Optimizing PM coverage ratio in flux concentrating axial flux machine

摘要

A two-stator, one-rotor axial motor is considered for bike applications. It has a 24 slot 20 pole structure, and concentrated pole windings. Two stator cores are made with the laminated sheets instead of the soft magnetic composite (SMC). PMs are magnetized to the circumferential direction for concentrating the PM flux. The air-gap field is analyzed based on a simplified 2D model, and is solved for optimal permanent magnet (PM) ratio. The optimum PM coverage ratio is determined based on 3D FEM results. A prototype motor was built, and back EMF was tested.