Dynamic Stability Analysis of the Weak Grid-Connected DFIG-based Wind Turbines under Severe Symmetrical Faults

In this paper, the small signal state space model of the DFIG system taking into account the phase-locked loop (PLL) under the weak grid fault is established. Based on the small signal model, the dynamic behavior of the DFIG-based wind turbines during LVRT is investigated. Moreover, the impacts of voltage dips degree, operating conditions, bandwidth of the PLL and control parameters of the RSC etc. on the dynamic behavior of the DFIG-based wind turbines under weak grid symmetrical faults are revealed in detail. Finally, the simulation for the DFIG-based wind turbine system is carried out using Matlab/Simulink, and the simulation results are presented to verify the correctness of the theoretical analysis.