Adaptive Control of a Utility-Scale Wind Turbine Operating in Region 3

Many challenges exist for the efficient and safe operation of wind turbines due to the difficulty in creating accurate models of their dynamic characteristics and the turbulent conditions in which they operate. A promising new area of wind turbine research is the application of adaptive control techniques, which are well suited to problems where the plant model is not well known and the plant operating conditions are unpredictable. In this paper, we design an adaptive collective pitch controller for a high-fidelity simulation of a utility scale, variable-speed horizontal axis wind turbine operating in Region 3. The objective of the adaptive pitch controller is to regulate generator speed and reject step disturbances, which model the uniform wind disturbance across the wind turbine rotor. The control objective is accomplished by collectively pitching the turbine blades. To improve controller performance, we use an extension of the Direct Model Reference Adaptive Control (DMRAC) approach to regulate turbine rotational speed and to accommodate step disturbances. The turbine simulation models the Controls Advanced Research Turbine (CART) of the National Renewable Energy Laboratory in Golden, Colorado. The CART is a utility-scale wind turbine that has a well-developed and extensively verified simulator. The adaptive collective pitch controller for Region 3 was compared in simulations with a baseline classical Proportional Integrator (PI) collective pitch controller. In the simulations, the adaptive pitch controller showed improved generator speed regulation in Region 3 when compared with the baseline PI pitch controller. The adaptive controller demonstrated robustness to modeling errors and changes in system parameters.