感应电机转子偏心故障下电磁转矩的研究

Calculation on Electromagnetic Torque of Induction Motor Under Mixed Eccentricity

为了分析转子偏心故障对感应电机电磁转矩影响,采用解析法分析了感应电机分别在静态偏心与动态偏心情况下的气隙磁导变化,并进一步推导了气隙磁场的畸变,运用虚位移法定性分析了转子偏心故障对电磁转矩的影响,利用有限元分析软件分别构建转子静态偏心与动态偏心有限元分析模型并进行相应仿真,采用傅里叶分析方法提取气隙磁密谐波分量与输出转矩谐波分量。研究表明,转子偏心故障会在气隙磁场中引入新的谐波成分,最终有效输出转矩降低,转矩波动增加,偏心度越大有效转矩降低越多,转矩波动越大,且静偏心比动偏心引起的效果更明显,为今后转子偏心故障对电磁转矩变化的研究提供理论基础。

In order to analyze the influence of rotor eccentricity on electromagnetic torque, analytical method was selected to analyze the air-gap permeance in both static and dynamic eccentricity conditions. The distor- tion of the air-gap flux density is deduced next. Virtual work method was applied to figuring out the effects of rotor on electromagnetic torque. Static and dynamic eccentricity models were established with finite element analysis software and the simulations were conducted later. Fast Fourier Transform was used to extract the harmonics of the air-gap flux density and the electromagnetic torque. The simulated results reveal that rotor eccentricity do introduce new harmonics both in the air-gap flux density and the electromagnetic torque. With the increase of the eccentricity, the fundamental torque decreases and the high frequency harmonics in- crease. It is more obvious in static eccentricity condition. It laid a fundamental for the study of the influence of rotor eccentricity on electromagnetic torque.