【作者】 刘洋；

【导师】 唐贵基； 朱保伟；

【作者基本信息】 华北电力大学 ， 工程硕士（专业学位）， 2022， 硕士

【摘要】 双馈感应发电机是当前应用最为广泛的风力发电机之一,其安全稳定地运行对于推动风电行业发展具有重要意义。气隙偏心是风力发电机常见的机械故障之一,绕组振动磨损问题是目前国产风力发电机面临的共性问题。开展风力发电机气隙偏心故障下定子绕组电磁力的研究,对于探索绕组绝缘磨损破坏机理、保障风力发电机安全可靠运行具有重要意义。本文以YR180LA型(11 k W,两对极)双馈感应发电机模拟机组为分析对象,运用理论推导与仿真计算相结合的方法研究了正常状态下、气隙静偏心故障下、气隙动偏心故障下和气隙复合偏心故障下发电机定子绕组电磁力特性。首先通过理论推导得到正常和气隙偏心故障下的气隙磁密、定子绕组电磁力的表达式,然后利用有限元仿真进行验证,仿真计算与理论结果一致。本文研究结果表明:(1)正常状态下,发电机气隙磁密沿周向对称分布;气隙磁密时域波形近似余弦曲线,其幅值谱中主要是基波;定子绕组电磁力的时域波形也类似余弦曲线,幅值谱中包含直流分量和偶数倍频。(2)气隙静偏心故障下,气隙磁密沿周向分布不均匀,其不同位置处幅值大小的改变与对应位置的气隙长度的变化呈反比;定子绕组电磁力幅值大小也发生变化,幅值大小的改变也与绕组对应位置的气隙长度的变化呈反比。(3)气隙动偏心故障下,气隙磁密的幅值谱图中新增与转差率有关的频率成分;故障后定子绕组电磁力频谱图中也新增与转差率有关的倍频成分。(4)在复合偏心故障下,两个单故障下的气隙磁密与定子绕组电磁力特征都有表现,未发现其他明显特征信息。本文成果为双馈感应发电机气隙偏心故障的检测和诊断提供补充和借鉴,同时也为探索气隙偏心故障下定子绕组的绝缘磨损规律提供理论参考依据。更多还原

【Abstract】 Double-fed induction generator(DFIG)is one of the most widely used wind generators at present,and its safe and stable operation is of great significance to promote the development of wind power industry.Air gap eccentricity is one of the common mechanical faults of wind generators,and the wear problem caused by winding vibration is a common problem faced by domestic wind generators at present.It is of great significance to study the electromagnetic force(EMF)of the stator winding under the air gap eccentricity fault of the wind generators,which is important to explore the damage mechanism of the winding insulation wear and ensure the safe and reliable operation of the wind generators.This paper takes the YR180 LA type(11k W,two-pole)DFIG simulation unit as the analysis object.And the method of combining theoretical derivation and simulation calculation is used to study the electromagnetic force characteristics of generator stator windings under normal,static eccentricity,dynamic eccentricity and composite eccentricity conditions.Firstly,the expressions of air-gap magnetic flux density(MFD)and stator winding EMF under normal and eccentric faults are obtained through theoretical derivation.Then,the finite element simulation is used to verify,and the simulation calculation is consistent with the theoretical results.The results of this study show that:(1)Under normal conditions,the air gap MFD of the generator is symmetrically distributed along the circumferential direction.The time-domain waveform of MFD approximates a cosine curve,and the component in its amplitude spectrum is the fundamental wave.The time-domain waveform of the EMF of the stator winding is also similar to the cosine curve,and the amplitude spectrum contains DC components and even frequency multiplications.(2)Under the static eccentricity fault of the air gap,the air gap MFD is unevenly distributed along the circumferential direction,and the change of its amplitude at different positions is inversely proportional to the change of the air gap length at the corresponding positions.The magnitudes of the EMF amplitude of the stator windings also change,and the change of the magnitudes is also inversely proportional to the change of the air gap length at the corresponding position of the windings.(3)Under the dynamic eccentricity fault of the air gap,the frequency components related to the slip are newly added to the amplitude spectrum of the air gap MFD.The frequency doubling components related to the slip are also added to the frequency spectrum of the EMF of the stator windings after the fault.(4)Under the composite eccentricity fault,the characteristics of the air gap MFD and the stator winding EMF under the two single faults are all exhibited,and no other obvious characteristic information is found.The results of this paper provide supplements and references for the detection and diagnosis of DFIG air-gap eccentricity faults,and also provide a theoretical reference for exploring the insulation wear laws of stator windings under air-gap eccentricity faults.更多还原