Modelling (IMM), the Technical University of Denmark (DTU). This thesis consists of two parts, i.e., adaptive extremum control and modelling and control of a wind turbine. The rst part of the thesis discusses design of adaptive extremum controllers for some processes which havethe behaviour that the process should have as high e ciency as possible. The main contribution is the development of an adaptive extremum control algorithm based on the parameter estimation for the processes with output nonlinearity. The second part of the thesis is concerned with modelling and control of a wind turbine. The investigation of control design is divided into below rated operation and above rated operation. The behaviour of wind turbines in below rated operation belongs to the process discussed in the rst part of the thesis, which can be considered as a connection between two parts. i ii Acknowledgements It is pleasure for me take the opportunity to express my gratefulness to everybody who enabled me to perform the work presented in this thesis. First, I wish to express my thanks to my supervisor Niels Kj stad Poulsen (IMM) and Henrik Bindner (Ris National Laboratory) for their willing to be my supervisors and their interests in the project. Further, I thank them for reading the rst version of the thesis and for giving helpful comments. Iwould also like to thank the sta at the IMM, my friends Anca Daniella Hansen for enjoyable daily company, and Lars Henrik Hansen who has always time and patience with my questions. Especially I wish to thank the librarian Finn Kuno Christensen for his help to nd literature sources. I greatly appreciate the support by my parents and my parents-in-law, who have helped me to take careofmy son during my study. I would also like to thank my son Johan Ziruo Ye for his understanding. iii iv Finally, A special acknowledge is to my husband Tao Ye, whom I can never thank enough for his support and encouragement
