Cogging torque minimization of SMC motor with axially tapered stator tooth tip

In this paper, a novel stator structure with axially tapered stator tooth tip is proposed to mitigate cogging torque and reduce the machine back EMF harmonics. Furthermore, the stator tooth tips are specifically designed to provide balanced axial electromagnetic force. In order to realize continuous variation of stator tooth tip widths, the soft magnetic composite (SMC) material is used for the stator core. It is theoretically demonstrated that the cogging torque of the new structure can be reduced greatly compared with the conventional stator structure. Finally, the theoretical analysis results are confirmed by the finite-element analysis (FEA) results. A prototype has been designed and under manufactured.