永磁体与护套分段结构的高速电机转子强度及动力学研究

Study on axial segment strength and dynamics of high speed permanent magnet motor rotor

针对护套和永磁体轴向分段设计导致的强度和动力学方面的问题,以一台额定功率150 kW、额定转速30000 r/min的高速永磁电机为研究对象,基于厚壁圆筒理论建立强度仿真模型,采用解析法和有限元法对护套轴向分段结构的转子应力分布规律和护套分段数对转子强度的影响规律进行研究,并以厚壁圆筒理论验证规律的合理性;建立转子系统动力学仿真模型,以有限元法研究永磁体和护套分段数对临界转速、不平衡响应的影响规律。结果表明,护套轴向分段提高了永磁体局部最大轴向应力和切向应力。永磁体轴向分段降低了转子各阶临界转速,尤其对采用刚度等级较高轴承的转子影响较大,同时升高了转子振幅。为高速永磁电机护套和永磁体轴向分段设计提供了强度和动力学方面的参考。

Aiming at strength and dynamics issues caused by the axial segmentation design of sheaths and permanent magnets,a high-speed permanent magnet motor with rated power of 150 kW and rated speed of 30000 r/min was taken as the research object.Based on the thick wall cylinder theory,a strength simulation model was established.The distribution law of the rotor stress of the sheath axial segmented structure and the influence law of the number of sheath segments on the rotor strength were studied by analytical method and finite element method.Rationality of the law is verified by the thick wall cylinder theory.The dynamic simulation model of rotor system was established,and the influence of the number of permanent magnet and sheath segments on the critical speed and unbalance response was studied by finite element method.The results show that the axial segmentation of the sheath increases the local maximum axial stress and tangential stress of the permanent magnet.The axial segmentation of the permanent magnet reduces the critical speed of each stage of the rotor,especially for the rotor with high rigidity,and increases the rotor amplitude.It provides strength and dynamics reference for the design of high-speed permanent magnet motor sheath and permanent magnet axial segment.