Design and Characteristics Analysis of rotor skewed Single-Phase Line Start Permanent Magnet Motor

Abstract

The rotor of the single-phase Line start permanent magnet motors (LSPM) has both the permanent magnet and squirrel cage. Therefore it can start without inverter assistance; it shows the performance of the synchronous motor after synchronization [1]. The squirrel cage component contributes to accelerating the motor when it starts. But permanent magnet torque has a negative mean value, consequently it interferes with startup. So the squirrel cage torque plays very significant role in the stating of an LSPM. Most rotors of induction motor are commonly skewed in order to reduce noise, torque ripple, and high-frequency currents due to slotting harmonics [2]. However, in case of an LSPM, it is very difficult to have the core skewed because permanent magnet segment are buried straight wise in it. But through this study, it became possible to produce the dual structured rotor due to the development of new manufacturing technology of auto press die. Therefore, in this paper, the authors aim is twofold: to investigate the un-skewed rotor design by FEM and the rotor skewed structure is proposed and analyzed by 2D FEM applied slice technique [3]. Finally the skewed and the unskewed LSPM are manufactured and tested experimentally.