Some control aspects of a wind turbine

A wind turbine owned by Imperial College London is installed at Rutherford Appleton Laboratory (RAL) Wind Test Site in Oxfordshire. Some major improvements in the system have been proposed and are currently under way. One possible configuration of the new system is considered here and a system model is presented. A number of fixed and variable speed control strategies can be implemented on this system. Each control strategy requires at least two controllers. One controller for the below rated wind speed operation to optimize the energy capture and another controller for the above rated wind speed operation to keep power or torque constant. The correct model of such a stochastic and highly nonlinear system is difficult to determine, therefore both model based and model independent controllers are considered. The design procedure and some comparison in terms of response and implementation considerations for the different controller is presented