Three-part hybrid rotor PM machine with variable magnetization state

This paper proposes a novel three-part hybrid rotor design for a permanent magnet synchronous machine (PMSM). The hybrid rotor can be designed to achieve key desired parameters and obtain extended speed operation by combining simple PM and reluctance rotor designs. An additional degree of freedom in the proposed three-part hybrid rotor is the flexibility to align the magnetizing axis of the reluctance rotor in order to produce torque without imposing demagnetizing flux on the magnets. The three-part hybrid rotor machine can generate wide constant speed power range by utilizing low coercive force PM material and implementing variable PM material magnetization state concept. This article provides an analytical model and finite element characterization of the hybrid rotor variable magnetization state PM machine.