A Novel Partitioned-Stator Flux Reversal Machine With Two Sets of Permanent Magnet

Due to superior flux-weakening capability and easy thermal management for magnets, flux reversal permanent magnet machines (FRPMMs) have attracted extensive research interest. However, existing FRPMMs indicate some issues: The geometric conflict between magnetic excitation and electrical excitation restricts the torque density. In this article, a novel partitioned-stator FRPMM (PS-FRPMM) with two sets of PM is proposed to further improve torque density. It is a combination of two types of FRPMMs, i.e., one with magnets surfaced on the stator teeth, and the other one with magnets in the stator slots. Then, the magnets surfaced on the stator teeth are shifted from the original stator to the stator on the other rotor side, which alleviates the pressure of small electrical excitation and the risk of stator saturation. First, the topology and operation principle of the proposed PS-FRPMM are illustrated. Moreover, the contributions of dominant air gap flux density harmonics to back-electromotive force (back EMF) and electromagnetic torque are dissected from the perspective of air gap field modulation theory. Finally, the electromagnetic performances of the proposed PS-FRPMM with different rotor pole pair numbers are obtained and compared by the finite element method (FEM), including torque performance, overload capability, losses, and efficiency. The 13-rotor-pole proposed PS-FRPMM has more superior torque performance than the other three machines.