The control in full load operation, i.e., Region III, starts when the wind speed is stronger than the rated value. In such a case, the power has to be limited to its rated value. This control objective is reached for variable speed machines by pitching all blades simultaneously at the same angle (collective pitch control). For several reasons, for instance, inhomogeneous wind fields or mass imbalances in the rotor, loads appear in the blades, increasing fatigue. Such loads can be reduced by adjusting the pitch angles individually from the value provided by the collective pitch control, that is, the individual pitch control (IPC). Finally, blade pitching activities introduce disturbances in the forces, which, in turn, produce vibrations in the tower and on the blades. These vibrations can be attenuated by using active damping control. In this chapter, the most common control approaches for the Region III are studied.
