Cogging torque reduction in permanent magnet flux-switching machines by rotor teeth axial pairing

Cogging torque in permanent magnet flux-switching machines (PMFSM) is relatively high compared with other types of PM motors, because of their unique doubly salient structure. In this study, a new rotor teeth axial pairing (RTAP) technique is proposed. As verified with both 2-D and 3-D finite element analysis, as well as laboratory tests, the RTAP technique can effectively reduce the cogging torque, while its implementation is more flexible than the conventional rotor teeth circumferential pairing (RTCP) technique. Furthermore, the RTAP technique is also applicable to other types of machine with a salient iron rotor.