Abstract
Recently, the use of permanent magnet (PM) motors has increased remarkably because of improvements in the performance of the rare-earth PM motor. However, the use of rare-earth materials, which is an important aspect of the high-performance PM motor, should be reduced because of the high cost and the unpredictability involved in procuring such materials. The performance of motors that use rare-earth materials has reached a very high level, which will not be easy to match without such materials. In this paper, we propose a structure for a high-power-density PM-assisted synchronous reluctance motor involving the use of a ferrite PM. The structure prevents irreversible demagnetization of the PM even the presence of heavy flux-weakening excitation or an inverter fault. It is clarified that the proposed structure achieves high-power and high-efficiency performances.
