Analysis of a High Torque Density Consequent-Pole Flux Reversal Permanent Magnet Machine with Dual-PM Excitation

This paper introduces a high torque density flux reversal permanent magnet (FRPM) machine that incorporates both stator and rotor permanent magnet (PM) excitation. In conventional FRPM machines, the stator PMs are typically placed on the teeth tips, which results in an increased length of the equivalent air gap and negatively impacts the performance. To solve this issue, the proposed machine utilizes stator PMs in the partial slot region while employing surface inset-type rotor PMs. The machine adopts a 12-slot/13-pole configuration with distributed winding. The flux modulation principle of this dual-PM FRPM machine is analyzed, and the contribution of the main harmonics to output torque is calculated using the Maxwell tensor method. Furthermore, the proposed machine undergoes optimization and is compared with three other consequent-pole dual-PM topologies that employ different stator-PM arrangements. The torque performance, back electromotive force, losses, and efficiency of the four FRPM machines, are evaluated through finite element analysis. The results of the analysis validate that the proposed machine surpasses the other mentioned dual-PM machines in torque density.