Comparative analysis of end effect in partitioned stator flux reversal machines having surface-mounted and consequent pole permanent magnets

In this paper, the end effects of a partitioned stator flux reversal permanent magnet (PM) machine with a surface-mounted PM (SPM) inner stator and a consequent pole PM (CPM) inner stator are comparatively analyzed. It is found that due to higher saturated inner stator steel in a CPM machine, it suffers from larger end effect than the SPM machine. Influence of armature reaction on end effect is investigated by a finite-element (FE) analysis, together with that of aspect ratio, i.e., axial stack length to stator outer diameter. Furthermore, it is found that in the CPM machine, the optimal PM arcs for the highest average electromagnetic torque predicted by 2-D and 3-D FE are different due to the variation of end effect with PM arc. Prototypes with both SPM and CPM inner stators are built and tested to verify the FE analysis