Development of high-power PMASynRM using ferrite magnets for reducing rare-earth material use

Recently, the use of permanent magnet (PM) motors has expanded remarkably as a result of improvements in the performance of the rare-earth PM motor. However, it is desirable to reduce the use of rare-earth materials, which are an important aspect of the high-performance PM motor, 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, one which would not be easy to match without such materials. In this paper, we introduce novel structures for a high-power density PM-assisted synchronous reluctance motor (PMASynRM) that uses a ferrite PM. The performance of a PMASynRM is evaluated based on the 2-D finite element method and through an experiment using a prototype machine. The analysis results reveal that the proposed PMASynRM has the same power density and equivalent efficiency as conventional rare-earth PM synchronous motors for use in vehicle applications. The results of this study indicate that the proposed structure achieves both high-power and high-efficiency.