Multi-Objective Coordinated Control of Permanent Magnet Direct-Drive Wind Power System Under Asymmetrical Grid Fault

Low voltage ride-through (LVRT) control strategies for traditional wind turbine system under asymmetrical fault conditions typically consider only a single control objective, failing to coordinate and optimize multiple performance metrics. This paper focuses on the multi-objective coordinated LVRT control strategy for permanent magnet direct-drive wind turbine systems under asymmetric grid fault. First, based on the instantaneous power model under asymmetrical fault conditions, the mechanisms of current imbalance, active and reactive power double-frequency oscillations, and the resulting DC bus voltage fluctuations are analyzed. A unified reference current expression is established by the regulation coefficient k; A multi-objective optimization function is constructed, and the optimal regulation coefficient k is obtained through the artificial fish swarm algorithm. Compared to traditional LVRT control strategies, the proposed method achieves coordinated control under asymmetric faults, improving LVRT performance. Finally, the effectiveness of the proposed control strategy is validated through simulation.