Individual Pitch Control of Horizontal Axis Wind Turbines

An individual pitch controller (IPC) based on the multivariable Linear Quadratic Gaussian (LQG) concept is presented to reduce loads in megawatt-size wind turbines. Most turbines currently installed use collective pitch control to pitch the blades in order to limit the excess of wind power and to regulate the rotor speed above rated conditions. However, research has shown that IPC control is much more effective to reduce blade loads. Both collective and individual pitch control are implemented for the NREL 5 MW reference turbine. Simulation results are used to illustrate the advantage of the IPC approach, and its ability to reduce much of the flap-wise blade motion is demonstrated.