Abstract
Control of blade pitch angle (BPA) based on the platform-pitching motions (floating platform vibration control; FVC) can suppress the platform-pitching vibrations of floating offshore wind turbines (FOWTs) generated by the variable speed control (VSC). However, FVC increases cumulative moving distances of BPA and fatigue loads of blade pitch actuators comparing with those without FVC. This study proposes a new control method to reduce loads of blade pitch actuators; in this method, the blade pitch angle demand is generated using feedforward control (FFC) based on operational characteristics of BPA, and the input of the feedforward control is wind speed detected by the wind speed sensor placed at the top of nacelle of the downwind turbine. Simulations and demonstrations using a utility-scale five-megawatt advanced-spar type FOWT are performed and the results show that the proposed method can reduce loads of blade pitch actuators.
