Line-Start Permanent-Magnet Motors: Significant Improvements in Starting Torque, Synchronization, and Steady-State Performance

Abstract

We present a new scheme to improve the starting torque and synchronization capability of line-start permanent-magnet motors based on pole changing winding. Pole changing at start-up neutralizes the magnetic influence of permanent magnets and, therefore, leads to the elimination of braking and pulsating torques, and enhances the starting torque. Our scheme also solves the synchronization problem. We used finite-element analysis to validate the scheme. The simulation results show that the method leads to a high starting torque, good synchronization, and excellent steady-state performance.