A self-adaptive fuzzy pitch control method for suppressing vibration of large-scale wind turbines under combined wind-seismic loading

Abstract For large-scale wind turbines subjected to sudden seismic excitation during operation, a self-adaptive fuzzy pitch (SFP) control method is proposed to mitigate the structural seismic response. The displacement and velocity of tower-top fore-aft (TTFA) are used as input variables for the fuzzy controller, and a self-adaptive proportional factor is established through an exponential function. The pitch angle adjustment is taken as the output variable, which is then superimposed on the pitch angle given by the baseline pitch controller to realize SFP control. Through co-simulation of OpenFAST and Simulink, the results demonstrate that compared with the traditional proportional–integral (PI) control, the proposed SFP strategy reduces the peak TTFA displacement and acceleration by approximately 25% and 31% on average, respectively, under various earthquake records. Seismic fragility analysis further shows that at a peak ground acceleration (PGA) of 1.0 g, SFP control reduces the failure probabilities corresponding to yield displacement and elastic limit displacement by 43.05% and 20.82%, respectively. These quantitative findings confirm that the proposed method significantly enhances the structural safety of wind turbines under combined wind-seismic loading, providing a practical and robust intelligent control solution for wind farms located in seismically active regions.