Robust nonlinear fractional-order state feedback control for variable-speed wind turbines using PSO algorithm

Abstract This paper designs a robust nonlinear fractional-order state feedback control (NFOSFC) method for variable-speed wind turbines. This method’s control law is constructed from the fractional-order two-mass model. The use of the fractional-order two-mass model is justified by its improved flexibility in modeling the complex dynamics of the wind turbine, especially for handling flexible modes induced by low shaft stiffness at low speeds. To ensure the best performance of the NFOSFC, the Particle Swarm Optimization (PSO) algorithm is used to extract the optimal control parameters. Comparative studies with some existing control strategies demonstrate that the proposed NFOSFC scheme significantly improves the system performance, offering smoother transient responses and improved power capture and load mitigation efficiency.