Asymmetric Fault Ride-Through Optimal Control of Direct-Drive Wind Turbine Based on the APLL

As wind power continues to integrate into the grid, its ability to withstand faults increasingly impacts the safe and stable operation of the power grid. To address concerns such as direct-driven wind turbines experiencing multiple entries and exits from the fault ride-through process during asymmetric grid faults and off-grid incidents, as well as over-voltage occurrences due to insufficient dynamic response speed during the recovery process, this paper introduces an optimal control strategy based on the amplitude-phase-locked-loop (APLL). The proposed strategy aims to achieve a swift balancing of active power at the busbar and provide reactive power compensation to enhance grid voltage through the active support role of APLL. The paper concludes with simulations conducted on the MATLAB/Simulink platform, demonstrating the effectiveness of the control strategy in enhancing the asymmetric fault ride-through capability and operational stability of the direct-drive wind power system.