Digital robust control of a variable speed pitch regulated wind turbine for above rated wind speeds

This paper presents the design of a robust RR–SS–TT controller of a variable speed pitch regulated wind turbine (VSPRWT) for above rated wind speeds (ARWS). An introduction of the subject and a state of the art review for controllers in ARWS are carried out. Afterwards, the studied VSPRWT and its validated model are presented. Then, the operating zone and control scheme are described. This system is non-linear and its linearising allows for the analysis of its behaviour, thereby obtaining the discrete-time control model as well as defining the controller's concrete objectives. The digital controller, which is designed following the pole assignment with sensitivity function shaping method, provides satisfactory simulation trial results.