Study of a novel permanent magnet synchronous motor with composite-rotor

This paper provides a novel permanent magnet motor with composite-rotor for flux weakening. The rotor consists of two segments with different permanent magnet materials. One kind of permanent magnet material has very high coercive force and high remanence, thus a strong air gap magnetic field could form; the other has low coercive force, thus d-axis current pulse could demagnetize it easily. The structure and operation action are proposed and the magnetization process is analyzed. Simulation by finite element method expresses the results at different flux weakening state, showing effectiveness of the magnetization models.