Fractional-Order Nonlinear PI Control for Tracking Wind Direction in Large Wind Energy Converters

In this work, the yaw control of large wind turbines is studied. The objective is to analyse how to maximise energy conversion by yawing the rotor in response to wind direction while minimising yaw activity. In order to improve the control performance, three algorithms are used and compared: the classic PI controller, the nonlinear PI controller, and the fractional-order nonlinear PI controller. An adaptive dead-zone and anti-windup procedure for amplitude- and rate-limited actuators are also considered, which helps to reach the main objective. Simulation experiments are carried out on a 20 MW reference wind turbine. The results are very promising, showing clear performance improvements.