A Study on Design of Novel Asymmetrical Rotor Structures to Improve Torque Characteristics in Interior Permanent Magnet Synchronous Motors

Abstract

This paper presents a study on the torque improvement of interior permanent magnet synchronous motors (IPMSMs) by novel asymmetrical rotor structures. As opposed to the conventional design techniques, the asymmetrical rotor design is to improve torque characteristics by making the reluctance torque and the magnetic torque reach their maximum near or at the same current phase angle. Various IPMSMs where magnetic saliency exists are investigated with the proposed technique. In order to provide valuable insights to the contribution, the frozen permeability method (FPM) is utilized to separate the torque into the reluctance torque and magnetic torque based on a 2-D time stepping finite element method (FEM).