Rotor structure for ultrahigh speed permanent magnet motor

CHENG Xin1, ZENG Guohui1, DU Guanghui2

(1.School of Electronics and Electrical Engineering, Shanghai University of Engineering Science,Shanghai 201600, China; 2.School of Electronic Information Engineering,Xian University of Technology, Xian 710021, China)

Abstract: Aiming at the problem that the permanent magnet is easily damaged by the centrifugal force when the ultrahigh speed permanent magnet motor rotates at high speed, the rotor structure which is suitable for the ultrahigh speed permanent magnet motor was studied. The finite element method was used to study the conventional rotor structure motor and solid permanent magnet rotor structure motor. The rotor eddy current loss of two structure motors under rated conditions were compared and analyzed, and the influence of sleeve thickness and speed on rotor strength was analyzed. Finally, the difference of temperature rise between the two structural motors were analyzed. The results indicate that the permanent magnet motor with solid rotor structure can achieve better rotor strength than the conventional permanent magnet motor with smaller rotor sleeve thickness under the premise of satisfying the electromagnetic performance. At the same time, the effective length of the motor with solid permanent magnet rotor is shorter, and the eddy current loss and temperature rise of the motor are lower than those of the conventional rotor structure motor.