双馈风力发电机暂态自由响应近似解析解及其时间尺度分析

摘要

In this paper, the second-order differential equation of double-fed induction generator (DFIG) in complex field is established based on the fifth-order model of the DFIG, considering the stator and the rotor transients as well as the Thevenin equivalent circuit of the external system. Then, the approximate analytical solutions to the free responses of the flux and current and the corresponding approximate time constants formula are obtained. Furthermore, the verification approach for the proposed approximation is suggested, and the verification simulations are carried out. Moreover, the impacts of faults position and faults resistance on the time scales of the free responses are analyzed by simulations. The results show that the fault characteristics have great impacts on the time scale of the stator and rotor transients of DFIG. Therefore, the transient analyses with different faults require different models. Finally, the adaptability of the electromechanical transient model with or without the stator or rotor transient in the electromechanical transient analysis is discussed.%从计及定转子暂态的双馈风力发电机(DFIG)五阶详细模型出发,结合外网戴维南等效电路,推导双馈风力发电机的二阶复系数微分方程,获得了磁链、电流自由响应的近似解析解及其定转子暂态时间常数近似计算公式.进而,给出自由响应近似解析解的验证方法,并进行仿真证明.分析了故障位置及接地电阻对暂态时间尺度的影响,结果表明不同故障场景下DFIG定转子暂态时间尺度差异较大,相应地,不同故障场景下的暂态分析需采用不同的模型,即暂态时间尺度和分析模型与故障相关.分析了暂态分析中机电暂态模型忽略定子和转子暂态过程的适应性.