A Mixed Hybrid Rare-Earth and Ferrite Magnet Asymmetric V-Shape IPMSM

This article proposes a novel mixed hybrid permanent magnet (HPM) asymmetric V-shape interior permanent magnet synchronous machine (IPMSM), which is compared with a rare-earth permanent magnet (REPM)-based symmetrical V-shape baseline. These machines are optimized for the same torque with a minimum volume of high-cost REPM at the same specification and size as a commercialized IPMSM, with due account for the mechanical von Mises stress at high speed. The results show that the proposed mixed HPM asymmetric V-shape IPMSM requires ~40% less REPM than that of the baseline. Meanwhile, the electromagnetic performance comparison shows how the synergies of magnetic field shifting effect and HPM utilization of the proposed mixed HPM asymmetric V-shape IPMSM improve the torque per REPM usage. As a result, assuming that the REPM is ten times more expensive than the ferrite magnet, the proposed HPM machine benefits from ~21% less cost of permanent magnets (PMs) than the baseline. In addition, the demagnetization analyses of REPM at high temperature and ferrite magnet at low temperature prove a high withstand capability of both PM types in the proposed HPM machine. A small size prototype is made and tested to verify the finite element analysis.