Rotor strength analysis of high speed permanent magnet machine

LI Zhenping1, ZHAN Yan2

(1.Beijing Power Machinery Institute, Beijing 100074, China; 2.ThyssenKrupp
BulkTec (China) Ltd., Beijing 100020, China)

Abstract: Aiming at the structural design and strength of highspeed permanent magnet synchronous motor rotor, the selections of rotor structure and permanent material, determination of rotor shaft’s dimensions, the interference fit between protective sleeve and permanent magnets, and analysis method of rotor strength were investigated. After the theoretical analysis of interference between protective sleeve and permanent magnets, the calculation formula for dynamic interference was established by analytical method,a method was presented to check the structural strength of rotor. Based on the theoretical analysis, combined with a 10 kW highspeed permanent magnet synchronous motor with maximum speed of 72 000 r/min, heatstructural coupling analysis of rotor was carried out by ANSYS workbench software. The results indicate that the strength of the rotor is determined by the dynamic interference, and the optimal value of interference is 0.03 mm~0.05 mm for the rotor,the design is reasonable and meets the design requirements; the finite element simulation method can easily analyze the structural strength of the embedded rotor, provide the basis for the optimization design of the rotor.

Key words: permanent magnet synchronous motor; rotor; protective sleeve; strength analysis; magnitude of interference; thermalstructural coupling analysis