A robust adaptive control design for the rotor speed control of variable speed wind turbines

Producing electrical energy from wind power is a growing sector owing to efficient renewable energy characteristics and positive environmental impacts of these type of energy conversion systems. Recent researches have shown that the power efficiency of this production can be maximised via variable speed wind turbines (VSWTs). Controlling the rotor speed of VSWTs appropriately is one of the most feasible ways to reach this purpose. In this study, a novel full-state-feedback robust adaptive controller is designed to reach this purpose. This nonlinear control design is based on backstepping approach by considering the relevance of this approach to the structure of VSWTs. Using the adaptive structure of the designed controller, most of the uncertain parameters are adaptively compensated during the control process while the robust structure of the controller is protected by using constant best-guess estimates of remaining parameters. The stability of the closed-loop error dynamics is theoretically proven via Lyapunov-based arguments while the performance demonstration of the designed controller is realised via simulation studies. In the simulation studies, different cases about the designed controller and the controlled system are examined.