ABSTRACT
Wind turbines are complex systems with large and flexible structures that work under unpredictable environmental conditions and a variable electrical grid. This chapter provides a case study that presents the design of a pitch control system to regulate the rotor speed of a variable-speed pitch-controlled wind turbine, while attenuating simultaneously the tower and blades vibration. The machine is composed of a gearless drive-train, a multi-pole synchronous generator, and a full-power converter. The case study pursues four objectives: to control the rotor speed by pitching simultaneously the angles of the turbine blades - also called collective pitch; to reject the effect of unpredictable wind disturbances; to minimize the tower fore-aft oscillations; and to attenuate the blades flap-wise vibrations. It accomplishes five simultaneous control objectives: stability; tracking and regulation of the rotor speed by pitching the angle of the blades; rejection of unpredictable wind disturbances; minimization of the tower fore-aft oscillations; and attenuation of the blades flap-wise vibrations.
