Mastering the wind with blade pitch control for vertical-axis wind turbines

The large-scale implementation of vertical-axis wind turbines is limited by the turbines' lower efficiency and shorter lifetime, rooted in the high unsteadiness of the flow and blade loading. We address these limitations with blade-pitch angle control, which yields high controllability over the flow separation and dynamic stall development. The open-loop control of the pitch angle, optimized with Bayesian optimization, reorients the blades to alter the flow and reduce the detrimental effect of dynamic stall. The power production is increased by 219 %. In case of high winds, to remain within the generator rated power, the actuation can alternatively reduce the power production. The transient load fluctuations, which contributes to higher structural stresses and material fatigue, are reduced by 55 % and provide smootheroperating conditions and longer lifetime. Blade pitch control largely extends the efficiency and operational range of vertical-axis wind turbines, providing high incentive to support their widespread implementation.