Individual pitch control using LIDAR measurements

Abstract

In this work the problem of individual pitch control of a variable-speed variable-pitch wind turbine in the full load region is considered. Model predictive control (MPC) is used to solve the problem. However as the plant is nonlinear and time varying, a new approach is proposed to simplify the optimization problem. Nonlinear dynamics of the wind turbine is derived by combining blade element momentum (BEM) theory and first principle modeling of the flexible structure. Then the nonlinear model of the system is linearized using Taylor series expansion around its operating points and a family of linear models are obtained. The operating points are determined by LIDAR measurements both for the current and predicted future operating points. The obtained controller is applied on a full complexity, high fidelity wind turbine model. Finally simulation results show improved load reduction on out-of-plane blade root bending moments and a better transient response compared to a benchmark PI individual pitch controller.