Active vertical vane control for stabilizing platform roll motion of floating offshore turbines

摘要

For floating offshore wind turbines, control of the platform roll motion is important for performance, load, and structural stability. This paper proposes an active control strategy for stabilizing the platform roll motion of downwind wind turbine via a vertical vane installed underneath the nacelle bedplate. The aerodynamic lift induced by the vertical vane from the incoming wind renders a lateral force imposed on the tower top, which leads to a significant stabilizing torque on the platform via the tower height as moment arm. Such control authority can be manipulated by the vane pitch angle. The proposed idea is evaluated with a 5MW turbine model combined with the Hywind platform, using the Fatigue, Aerodynamics, Structures, and Turbulence software. The vane models are implemented based on slight modification of the tail furling module in Fatigue, Aerodynamics, Structures, and Turbulence. Simulation study is performed under different feedback measurements, vane areas, airfoil designs, wind speeds, wave heights, wind directions, and wave directions. The feedback of tower-top velocity feedback is shown to be more effective than the acceleration feedback. For all cases, the variance of platform roll angle shows reduction of approximately 73% to 95%, the damage equivalent load for the tower-base side-to-side bending moment can be reduced by 20% to 61%, and the power consumption of vane actuator is up to 0.075% of the turbine power generated during the simulated periods. The proposed actuation scheme promises a low-power and high-bandwidth solution to floating offshore wind turbines roll motion stabilization, more advantageous especially for higher winds when the structural stability is of greater concern.