摘要
双馈感应风力发电机(doubly-fed induction generator,DFIG)在电网发生对称故障后,因其定子侧直接与电网相连,且转子电阻阻值通常较小,电网电压对称故障将导致DFIG转子电流快速抬升,严重影响风电机组的并网稳定性.对于当电网发生故障后变流器无法直接快速准确获取暂态量来补偿转子电压以达到抑制转子过电流的问题,提出了一种基于转子暂态电流的转子电压动态补偿方案,并分析了该补偿方案对定子暂态磁链衰减的影响.首先对DFIG进行故障电路分析,得到转子绕组等效电路以及转子电流在电网电压对称跌落时的动态过程,并基于转子侧变流器的电流内环调节得到在同步旋转坐标系下的转子电流表达式.然后通过坐标变换与转子绕组等效电路参数,得到转子暂态感应电动势,将其通过前馈控制补偿转子侧变流器的输出电压,以此削弱转子过电流.仿真结果表明,基于转子暂态电流的转子电压动态补偿方案对转子过电流抑制有良好效果,所提的控制方案提高了DFIG在故障状态下的并网能力.
Since the stator side of the doubly-fed induction generator(DFIG)is directly connected to the power grid and the rotor resistance value is usually small,the grid voltage symmetry fault leads to the rapid rise of DFIG rotor current,seriously affecting the grid-connected stability of wind turbines.Hence,this paper proposes a dynamic compensation scheme of rotor voltage based on the rotor transient current and analyzes the influence of the compensation scheme on the stator transient flux attenuation to address the problem that the converter cannot obtain the transient value directly and accurately compensate the rotor voltage for suppressing the rotor overcurrent when the power grid fails.The proposed method involves analyzing the fault circuit of the DFIG to derive the equivalent circuit of rotor winding and study the dynamic process of rotor current when the grid voltage drops symmetrically.Subsequently,the rotor overcurrent expression in the synchronous rotating coordinate system is obtained based on the current inner loop adjustment of the rotor side converter.Then,the rotor transient electromotive force(EMF)is obtained using coordinate transformation and equivalent circuit parameters of the rotor winding.This EMF is used by feedforward control to compensate the output voltage of the rotor-side converter,aiming to weaken the rotor overcurrent.Simulation results demonstrate that the dynamic compensation scheme based on transient rotor current for rotor voltage effectively suppresses rotor overcurrent,and the proposed control scheme enhances the grid connection capability of DFIG during power grid fault conditions.
作者
白望望
张中丹
张耀忠
赵伟阳
付媛
BAI Wangwang;ZHANG Zhongdan;ZHANG Yaozhong;ZHAO Weiyang;FU Yuan(Institute of Economic Technology,State Grid Gansu Electric Power Company,Lanzhou 730050,China;Hebei Key Laboratory of Distributed Energy Storage and Micro-Grid,North China Electric Power University,Baoding 071003,China)
出处
《河北大学学报(自然科学版)》
北大核心
2025年第1期20-33,共14页
Journal of Hebei University(Natural Science Edition)
基金
国网甘肃省电力科技项目(522730230006)。
关键词
双馈感应风力发电机
电网电压对称跌落
转子过电流
转子电压补偿
定子磁链衰减
doubly-fed induction generator
grid voltage symmetrical drop
rotor overcurrent
rotor voltage compensation
stator flux attenuation
