Optimal Slot/Pole Combination of Axial-Field Flux-Modulated Machines With Split Teeth

In this paper, a novel axial-field permanent magnet (AFPM) motor is presented and the optimal stator-slot/rotor-pole combination is explored for great performance. This machine contains two stators with split teeth and an inner rotor with consequent-pole (CP) PMs. The stator configuration achieves a harmonious balance between a high winding factor and an elevated torque amplification capability, while the rotor structure enhances PM utilization. The investigation into the slot/pole combination is primarily driven by two considerations: winding configuration and the number of ferromagnetic pole pieces attached to each main tooth. The introduced CP PM brings about direct component (DC) bias and even-number harmonics in the flux linkage of each winding, which must be eliminated by selecting appropriate winding configurations. Additionally, the number of ferromagnetic pole pieces has a significant influence on the magnetic gearing effect and iron saturation. In this way, the torque characteristics and power factor are compared using the finite element method. A 12-slot/24-flux-modulation-pole (FMP) /19-rotor-pole AFPM machine is fabricated and experimented to confirm the effectiveness.