Electromagnetic Performance Analysis of Less Rare-Earth Double-Stator Permanent Magnet Machine

A less rare-earth double-stator flux-switching permanent magnet (LR-DSFSPM) motor is proposed in this paper, in which the permanent magnets (PMs) and windings are all located in the inner and outer stator, resulting in a simple and robust rotor structure. By adopting V-shaped ferrite PMs in the outer stator, an enhanced flux-focusing effect can be obtained in the outer motor, contributing to obtaining a relatively high torque capability without rare-earth PMs. Meanwhile, since the two types of PMs are embedded in the inner stator, the inner motor can still maintain a desirable torque capability for general operation. And the middle rotor of the motor is designed with different pole numbers in its inner and outer sides, thus the requirements of multiple driving cycles can be obtained successfully. Moreover, by using the finite element analysis (FEA) method, the no-load characteristics and torque performances are investigated in details. The corresponding results reveal that the proposed motor can not only offer a relatively high torque capability with extremely less rare-earth PMs, but also provide a enrich operation modes in motor operation, indicating a potential application in electric vehicles.