电网电压不对称暂降下考虑Chopper动作的双馈风机转子电流分析  

Analysis of DFIG Rotor Current Considering Chopper Protection under Asymmetrical Grid Voltage Sags

作　　者：林瑞星 马晓阳[2] 常晓青 徐琳 丁理杰 杨洪耕[2] LIN Ruixing;MA Xiaoyang;CHANG Xiaoqing;XU Lin;DING Lijie;YANG Honggeng(Electric Power Research Institute,State Grid Sichuan Electric Power Company,Chengdu 610072,China;College of Electrical Engineering and Information Technology,Sichuan University,Chengdu 610065,China)

机构地区：[1]国网四川省电力公司电力科学研究院,成都610072 [2]四川大学电气信息学院,成都610065

出　　处：《电力系统及其自动化学报》2019年第4期106-112,117,共8页Proceedings of the CSU-EPSA

基　　金：四川省电力公司科技资助项目(521997150019)

摘　　要：针对电网电压不对称暂降下双馈感应发电机直流侧卸荷Chopper电路的投入,分析了其动作后双馈感应发电机的转子三相不对称电流,双馈感应发电机在机端电压不对称故障时表现出极为复杂的电磁暂态特性。首先建立了正反向旋转坐标系下双馈感应发电机的正序、负序模型,然后基于序分量叠加法把不对称故障时复杂电磁暂态过程中出现的暂态量等效分解为正序、负序和自由分量,推导了不对称故障下Chopper投入后转子暂态短路电流精确解析表达式。利用Matlab/Simulink仿真软件对所提方法进行验证,仿真结果验证了机端电压不对称跌落过程中双馈感应发电机转子不对称短路电流变化特性。Considering the DC Chopper circuit of doubly-fed induction generator(DFIG)triggered by unbalanced grid voltage sags,the DFIG rotor’s asymmetrical three-phase current after the switching of Chopper circuit is analyzed. The DFIG will present complex electromagnetic transient characteristics under asymmetrical fault of generator-side voltage. First,positive- and negative-sequence models of DFIG are established in forward and reverse rotating reference frames. Then,based on the sequence component superposition method,the transient component generated in the complex electromagnetic transient process is decomposed into positive-sequence,negative-sequence and free components under asymmetrical fault. Moreover,the accurate analytical expressions of the rotor’s transient short-circuit current under asymmetrical fault and after Chopper protection are deduced. Through simulations using Matlab/Simulink,the asymmetrical short-circuit current characteristics of DFIG rotor under asymmetrical voltage sags are verified.

关 键 词：双馈感应发电机 Chopper保护 不对称故障 转子电流 

分 类 号：TM46[电气工程—电器]