Line-start permanent-magnet motor synchronisation capability improvement using slotted solid rotor

This study presents a line-start permanent-magnet motor with high synchronisation capability using a slotted solid rotor. With slotted solid rotors, a much better magnetic flux and current penetration into the rotor is achieved. Moreover with additional magnetic flux penetration into rotor core, the motor slip decreases and electromagnetic torque near synchronous speed will increase. Consequently, the proposed motor can reach synchronous speed under higher load torques and inertias. Two-dimensional finite-element method has been implemented in order to confirm this new idea. Finally, a four-pole, 250 V, 1500 rpm, 1050 W, three-phase synchronous motor with slotted solid rotor is designed and prototyped to experimentally validate the capabilities of the proposed motor.