Split-Tooth Flux Reversal Motor Assisted With Yoke and Slot PMs

This article proposes a new flux reversal permanent magnet (FRPM) motor assisted with yoke and slot PMs. While the tooth PMs directly affect the air-gap flux density and contribute to torque production, the yoke and slot PMs significantly assist with torque ripple mitigation, lower core saturation as well as torque enhancement. A conventional FRPM is considered for comparison to explain the effectiveness of the added PMs. We use flux modulation theory (FMT) to analyze the working harmonics in both no-load and on-load conditions in torque production, back-EMF and cogging torque calculation. Also, the proposed and benchmark motors have been optimized using a genetic algorithm. Finite element analysis (FEA) results are carried out to verify the accuracy of the FMT modelling. Furthermore, different PM arrangements, including slot-tooth, yoke-slot, and yoke-tooth PM, are simulated with FEA and compared with the proposed motor. It is shown that the auxiliary PMs increase the torque of the proposed motor by 30% compared to the existing FRPM with 75% lower torque ripple. Among the compared structures, the proposed motor offers the highest torque density and efficiency. Finally, the proposed FRPM is prototyped and tested under no-load and on-load conditions to verify the simulations.