Analytical Modeling and Optimal Design of Slotted Axial Flux PM Motor With Equidirectional Toroidal Winding

This study presents a quasi-3D analytical model (AM) of a slotted axial flux permanent magnet motor (SAFPMM) with equidirectional toroidal winding (ETW), and based on this model, a two-stage optimization method for the motor is proposed. It not only reveals the influence mechanism of ETW on the air-gap magnetic field and electromagnetic performance of slotted motors in theory, but also provides a new method for the optimal design of ETW slotted motors. First, based on a simplified process, the AM for the magnetic field of the ETW SAFPMM is proposed, and the analytical expressions for the back electromotive force and torque of the motor are derived. Second, the size equations of the motor are determined. In addition, the electromagnetic performance of the motor’s initial design is analyzed by the proposed AM. Then, using the proposed two-stage optimization method, the optimal design of the motor is obtained and analyzed. Finally, the prototype of the optimal ETW SAFPMM is manufactured and tested, which not only verifies the accuracy of the AM and the initial design of the motor, but also validates the effectiveness of the proposed optimization method.