Novel rotor structure of permanent magnet synchronous motor with rare earth and ferrite magnets

Rare earth magnets are used for permanent magnet synchronous motors (PMSMs), and they are expensive. Therefore, we have tried to design a PMSM that can reduce the rare earth magnet. A basic model and two developed models are shown in this paper. The basic model uses only rare earth magnet in the rotor. The developed models use rare earth and also ferrite magnets to reduce the rare earth magnet by more than 50 %, and have three-dimensional structures. The analysis is carried out by the simulation software using a finite element method. As a result, one of the developed models shows the torque of 96.3 % for the basic model.