Design of a novel rotor structure for PM-assisted synchronous reluctance machines to improve torque characteristics

This paper proposes a novel rotor structure for PM-assisted synchronous reluctance machines (PMA-SynRMs) to improve torque characteristics. As opposed to the conventional designs, the proposed rotor structure for the PMA-SynRMs is designed to improve the torque by making the magnetic torque and reluctance torque obtain the maximum at the same current phase angle. To reveal this feature, the frozen permeability method is utilized to segregate the torque into its two torque components, based on a 2-D finite element method. The contribution of the proposed rotor to the machine performance is validated by comparing to a conventional PMA-SynRMs.