Individual pitch control for wind turbine load reduction including wake interaction

Individual pitch control (IPC) for wind turbine load reduction in Region 3 operation is improved when wake interaction is considered. The Larsen wake model is applied for composing the rotor wind profile for downstream turbines under wake interaction. The wind profile of the turbine wake was generated by modifying the NREL´s TurbSim codes. The state-space models of wind turbine were obtained via linearization of wind turbine model available in the NREL´s FAST. In particular, in order to obtain more accurate state-space models, equivalent circular wind profile was generated so as to better determine the local pitch reference. Based on such models, IPC controllers were designed following the disturbance accommodating control (DAC) and periodic control framework The simulation results showed that the turbine loads can be further reduced using the switching control scheme based on wake modeling, as compared with the generic DAC without wake consideration.