Research on Control Strategy of Doubly-Fed Wind Turbine under Unbalanced Grid Voltage

The study investigates the operational challenges of doubly-fed induction generator (DFIG) wind turbines under unbalanced grid voltage conditions. A dynamic model of the DFIG system is developed, and a novel methodology combining quadrature signal processing with second-order generalized integrator (SOGI) is proposed to isolate the negative sequence components of the grid current accurately. The effectiveness of this approach is validated through MATLAB/Simulink simulations, demonstrating its capability to enhance grid-side current quality by suppressing dq-axis negative sequence currents. The proposed control strategy provides a robust solution for improving the adaptability of DFIG wind turbines in unbalanced grid scenarios.