发电机气隙静态偏心对电磁转矩的影响
Effect of Static Air-Gap Eccentricity on Electromagnetic Torque of Generator

针对发电机气隙静态偏心前后的电磁转矩特征进行了理论分析、仿真计算和动模实验验证。首先，对发电机气隙静态偏心前后的电磁转矩进行了理论推导，得到了两种运行状态下电磁转矩的具体表达式；然后，分别应用Matlab和有限元软件Ansoft针对实验室MJF 30 6型动模机组的具体参数进行了数值计算和建模仿真，并将所得结果与实验数据进行了对比，三者基本吻合。分析表明:气隙静偏心将引发电磁转矩产生二倍频波动，同时将使电磁转矩的平均值有所增大，但鉴于气隙偏心的数值较小，其增幅很小；随着静偏心程度的加剧，电磁转矩的二倍频波动程度将加剧，同时平均值增幅将扩大。本成果可在现有基础上丰富气隙静偏心故障的诊断判据，为该故障的监测与控制提供方便。
This paper analyzes the electromagnetic torque characteristics of generator before and after static air-gap eccentricity fault via theoretical deduction, simulating calculation,and experiment verification.First,the electromagnetic torque expressions under normal condition and air-gap eccentricity are deduced respectively. Then, the numerical calculation and finite element simulation are carried out on the MJF-30-6 fault simulating generator in Matlab Ansoft respectively. The results obtained from the calculation and simulations are generally in accordance with those of the practical experiments. It shows that the static air-gap eccentricity brings fluctuation whose frequency is twice of the fundamental value, and increases the mean value of the electromagnetic torque by a tiny amount. As the static air-gap eccentricity develops, the fluctuation intensity and increase of the mean value are greater. These findings can offer more convenience for the monitoring and control of this type of fault.