Comparative Study of Novel Dual Winding Dual Magnet Flux-Modulated Machines With Different Stator/Rotor Pole Combinations

This article presents a comparative investigation of the various performances of dual winding dual magnet flux-modulated machine (DWDM) with different stator/rotor pole combinations, including winding configuration, no-load performance, and electromagnetic performance. As an illustrative case, the study example employs a consistent configuration consisting of a five-phase and ten-pole stator structure for the purpose of comparison. Four combinations with an 8-pole rotor (10s8r), a 9-pole rotor (10s9r), a 12-pole rotor (10s12r), and a 14-pole rotor (10s14r) are proposed and modeled by finite element method (FEM). Then, the flux distribution, back-electromotive force (EMF), torque performance, overload capability, efficiency, power factor, and flux weakening capability are analyzed and discussed one by one. It is found that the 10s9r-DWDM exhibits the largest average torque and the lowest torque ripple due to the close-pole combination. The torque density of the 10s9r-DWDM reaches close to 40 kNm/m(3) at lower current densities. In contrast, the 10s14r-DWDM exhibits more harmonics in the back EMF and the lowest average torque, due to the far-pole combination. Moreover, the 10s12r-DWDM has a more balanced performance in terms of torque density, overload capacity, and power factor. Finally, a 10s12r-DWDM prototype is manufactured and tested to verify the analyses.