Robust H∞ control of variable-speed wind turbines in partial load

This paper describes a robust H^∞ control method of variable-speed wind turbines (VSWT) below the rated wind speed (in partial load) during wind energy conversion system (WECS) operations. Below rated wind speed, the objectives of the control are to maximize the captured energy and minimize the dynamic loads. The H^∞ control approach is based on a sector-boundary of nonlinearities for dealing with the noise affecting measurements of the rotor speed and aerodynamic disturbances. Simulation results show that the proposed H^∞ controller guarantees robust performance and reacts fast under the variations of the wind speed to track the optimal rotor speed. A peak efficiency can be obtained by continuously regulating the rotor speed and updating generator loading to maximize power. and reduce drive-train transient torque loads.