受平均斜率控制的 Crowbar 双馈异步电机低电压穿越

摘要

针对双馈感应电机低电压穿越提出一种新的撬棒电路。传统的Crowbar电路采用固定阻值的电阻已经很难满足抑制转子电流、缩短撬棒电路工作时间的要求，有些研究提出了Crowbar并联动态电阻的双馈风力发电机低电压穿越方案，但接入Crowbar电路的并联电阻只是给出一个上限值，不能在电网电压不同程度跌落情况下都能取得好的穿越效果。因此，提出一种基于电流变化率大小动态改变Crowbar电阻值的双馈感应电机低电压穿越方案。此方案与Crowbar并联动态电阻方案进行比较，Matlab／Simulink仿真结果表明上述方法效果更好。%This paper presents a new crowbar protection topology for low voltage ride through ( LVRT) of doubly-fed induction generator ( DFIG) based on wind turbines.Traditional DFIG crowbar used a fixed crowbar resistance is dif-ficult to meet the requirements of suppressing the rotor current and shortening the working time of crowbar at the same time.Parallel dynamic resistance are used in some papers, but only an upper limit be given that can’ t capable to all the dips during grid fault.From the discussion, a new LVRT of DFIG scheme, based on a crowbar resistance con-trolled by average slop of current, is proposed.In the case study, a comparison with a parallel dynamic resistance method based on RSC control is given.Matlab/Simulink simulation results show that the proposed method is advanta-geous for fault over-current protection.