Comparison of partitioned stator machines with different PM excitation stator topologies

The partitioned stator (PS) machine adopts two stators to allocate coils and permanent magnets (PMs) separately, which can increase the space for PMs and coils to boost the electromagnetic torque and to improve the thermal condition of PMs which are on the stator. In this paper, the PS switched flux PM machine and PS flux reversal PM machine are proved to inherently share the same operating principle and the same machine topology but with interior PM (IPM) and surface-mounted PM (SPM) stators, respectively. Based on this concept, four PS machines with different PM excitation stator topologies are introduced and compared in terms of back-EMF, cogging torque, electromagnetic torque, torque per PM volume and flux-weakening capability. The results show that the spoke-IPM inner stator exhibits the maximum back-EMF and hence the largest average torque, while the IPM inner stator has the best flux-weakening capability and the V-shaped IPM (VIPM) produces the highest torque per PM volume.