Design and analysis of a novel two-speed line-start permanent magnet motor

A novel two-speed line-start permanent magnet motor (TSLSPMM) is proposed to replace the traditional pole-changing two-speed induction motor for energy saving. The proposed TSLSPMM, featured with pole-changing stator winding and a squirrel cage rotor with fixed permanent magnet poles, starts by a winding connection with higher pole number, and runs as an induction motor for a period of time, and after the pole-changing, the speed of the motor is increased to run in synchronous mode for long time operation. The higher efficiency of the synchronous mode can contribute to energy saving. In this paper, the topology and design characteristics of the motor are introduced in detail. Besides, the performances of the proposed motor under different operation modes are investigated through finite element simulation.