Floating offshore wind turbines allow wind energy to be harvested in deep
waters. However, additional dynamics and structural loads may result when the
floating platform is being excited by wind and waves. In this work, the
conventional wind turbine controller is complemented with a novel linear
feedforward controller based on wave measurements. The objective of the
feedforward controller is to attenuate rotor speed variations caused by wave
forcing. To design this controller, a linear model is developed that describes
the system response to incident waves. The performance of the
feedback-feedforward controller is assessed by a high-fidelity numerical tool
using the DTU 10MW turbine and the INNWIND.EU TripleSpar platform as
references. Simulations in the presence of irregular waves and turbulent wind
show that the feedforward controller effectively compensates the wave-induced
rotor oscillations. The novel controller is able to reduce the rotor speed
variance by 26%. As a result, the remaining rotor speed variance is only 4%
higher compared to operation in still water.Comment: Initial submission to the Science of Making Torque from Wind (TORQUE)
2020 conference, 10 pages, 7 figure