Comprehensive Comparison of Stator-PM and Rotor-PM Axial Field PM Machines

In this paper, an axial field rotor consequent pole permanent magnet (PM) (AFRCPPM) machine and an axial field flux-switching permanent magnet (AFFSPM) machine are comparatively investigated from comprehensive performance. First, the air gap field modulation principle is analyzed. Second, the torque equations are derived and the torque quality improvement principles are revealed. The influence mechanism of the key structural parameters on the torque quality is analyzed, which reflects the similarities and differences in parameter sensitivity between two machines. The optimization scheme is obtained and carried out. Then, the best design is determined. Finally, the comprehensive performances of two machines with same overall dimensions, material characteristics and operating speed are comparatively researched. The improvement in terms of power/torque density, PM utilization, space utilization, torque quality and overload capacity in the AFRCPPM machine is achieved, while inheriting the merits of the AFFSPM machine. Moreover, the superiority and rationality of the AFRCPPM machine are verified.