ABSTRACT

Fault ride-through (FRT) capability of grid connected doubly fed induction generator (DFIG) for the wind energy system is an important feature. In this paper, FRT control technique of DFIG against the asymmetrical fault conditions is proposed. In which, the grid voltage unbalance is controlled with the help of sequence decomposition of rotor current, stator voltage and grid side current. The mathematical model of DFIG is presented in rotating synchronous reference frames using positive and negative sequence components of voltage and flux linkage. The main objectives of the proposed scheme are minimisation of electromagnetic torque oscillations, speed oscillations and DC link voltage oscillations. These objectives are achieved by using bandstop (Notch) filters. This technique also controls the rotor voltage of the converter by providing appropriate rotor current reference. The effectiveness of the proposed technique is proved by considering 2.6 MW grid-connected DFIG system in MATLAB Simulink environment.

摘要

风能系统的并网双馈感应发电机 (DFIG) 的故障穿越 (FRT) 能力是一个重要特征。本文提出了针对非对称故障条件的双馈FRT控制技术。其中，通过转子电流、定子电压和网侧电流的序列分解来控制电网电压不平衡。DFIG 的数学模型是在旋转同步参考系中使用电压和磁链的正序和负序分量呈现的。所提出方案的主要目标是最小化电磁转矩振荡、速度振荡和直流链路电压振荡。这些目标是通过使用带阻（陷波）滤波器来实现的。该技术还通过提供适当的转子电流参考来控制转换器的转子电压。通过在 MATLAB Simulink 环境中考虑 2.6 MW 并网双馈系统，证明了所提技术的有效性。