Alleviating solicitations on yaw actuators using individual pitch control for wake redirection in wind farm control

A wind turbine has become one of the solutions to create clean energy. Different strategies to optimize power production in a wind farm have been studied and investigated. Yaw misalignment is one of many promising strategies. Nevertheless, commercial wind turbines rely on yaw actuators to achieve yaw misalignment. Yaw actuators are subjected to fatigue loads and hence reduce the lifetime of the wind turbine. This master thesis investigates a free-yaw wind turbine where the yawing mechanism can be achieved by creating load imbalances in the blades of a wind turbine through a yaw controller. The study is done through a numerical simulation with an accurate LES Vortex Particle-Mesh solver. The free-yaw wind turbine is compared to a fix-yaw wind turbine with and without load-alleviating IPC. The study covers its power production, the wake that it produces, and the load acting on the wind turbine. Two different strategies are analyzed. First, the wind turbine is subjected to a static yaw input misalignment, and second, the wind turbine is subjected to a dynamic yaw input misalignment. In the end, the first strategy appears to be more promising to be implemented.