Direct adaptive control for individual blade pitch control of wind turbines for load reduction

In this article, a theory of adaptive disturbance rejection control is used to design an individual blade pitch controller to reduce the loading in a utility-scale wind turbine. The goal of the adaptive disturbance rejection control is to regulate the blade pitch angle individually to reduce the asymmetrical loading in blade due to vertical wind shear and also to reject the unnecessary disturbance introduced by the wind turbulence. The applicability of the theory is illustrated by implementing the controller in the National Renewable Energy Laboratory’s 5-MW nonlinear, high-fidelity wind turbine model and simulating it in MATLAB/Simulink.