This study presents a nonlinear controller with a wind speed estimator for a variable speed wind turbine at below-rated wind speed. A nonlinear controller is designed to address the rapid variations in wind and uncertainties in the wind system. The objective of nonlinear controller is to maximize the energy that can be extracted from wind with a reduction on mechanical loads. The synergetic and terminal synergetic controllers are proposed for improving energy capture and load mitigation. Also, the stability of the controllers is analysed by Lyapunov stability. The proposed controllers were validated using the FAST (Fatigue, aerodynamics, structures and turbulence) numerical model. Finally, a comparative study has been made between the controllers for different wind speed profiles.

本研究提出了一种带有风速估算器的非线性控制器，适用于低于额定风速的变速风力涡轮机。非线性控制器旨在解决风系统中风的快速变化和不确定性。非线性控制器的目标是最大化可从风中提取的能量，同时减少机械负载。提出了协同和终端协同控制器，以改善能量捕获和负载缓解。此外，控制器的稳定性由 Lyapunov 稳定性分析。所提出的控制器使用 FAST（疲劳、空气动力学、结构和湍流）数值模型进行了验证。最后，对不同风速剖面的控制器进行了比较研究。