基于有限元法的双馈风力发电机电磁场计算与分析

基于ANSYS有限元分析平台建立了新疆某风电场1.5 MW双馈风力发电机(double-fed induction generator,DFIG)的2维电磁场模型。基于有限元法对双馈发电机正常运行工况、单相接地短路、两相稳态短路时磁力线分布和气隙磁密分布进行了计算,分析了不对称短路故障对双馈发电机的影响。结果表明:在发生不对称短路故障时,双馈风力发电机的气隙磁场明显畸变,漏磁增多,其附加铁耗及定子表面铁耗显著增加;发生单相接地短路故障时的上述损耗均比两相短路故障时大;在发电机中感生的谐波电动势会引起发电机机械振动和噪声。

Finite Element Based Electromagnetic Field Simulation and Analysis of Doubly Fed Induction Generator

Based on finite element analysis platform ANSYS,a two-dimensional electromagnetic field model of doubly fed induction generator(DFIF),whose capacity is 1.5MW and is installed in a certain wind farm located in the Xinjiang Uygur Autonomous Region,is established.Using finite element analysis,the distribution of magnetic line of force in DFIG and the distribution of air-gap flux density under normal operation conditions,single-phase earth fault and two-phase short-circuit fault occurred in DFIG are calculated,and the influences of asymmetrical short-circuit on DFIG are analyzed.Analysis results show that asymmetrical short-circuit occurred in DFIG leads to evident distortion of its air-gap magnetic field and flux leakage increases,and its additional iron loss and surface iron loss of stator remarkably increase;above mentioned iron losses under single-phase earth fault is bigger than those under two-phase short-circuit fault;the harmonic emf induced in DFIG will lead to magnetic vibration and noise of induction generator.