双馈异步风力发电机气隙静偏心下电磁转矩特性分析

Analysis of Electromagnetic Torque Characteristics under SAGE in Doubly-fed Induction Generators

本文对双馈异步风力发电机气隙静偏心故障下的电磁转矩波动特性进行了综合分析。首先,推导正常和气隙静偏心工况下气隙磁密,然后得到正常和静态气隙偏心条件下电磁转矩的解析表达式,最后,对双馈异步发电机进行有限元计算。有限元计算结果与理论分析基本吻合。结果表明,气隙静偏心故障会使气隙磁密的空间阶次发生改变,但频率成分不会发生变化。此外,电磁转矩各谐波频率成分幅值也增大,其中,485Hz、585Hz和685Hz的高次谐波增幅最为明显。

This paper presents a comprehensive analysis of the fluctuation characteristics of electromagnetic torque under static air-gap eccentricity fault in doubly-fed induction wind generators.First,the magnetic flux density under normal and air-gap static eccentricity conditions is derived.Then the expressions for the electromagnetic torque is obtained.Finally,finite element calculations are performed for the doubly-fed induction generator.The finite element calculation results are basically consistent with the theoretical analysis.It is shown that the spatial orders of the air gap magnetic density will change due to the static air-gap eccentricity fault,but the frequency components will not change.In addition,the amplitude of each harmonic frequency component of the electromagnetic torque increases,with the most significant increase in the higher harmonics at 485Hz,585Hz and 685Hz.