The researchers took a 1:70 model of an offshore wind turbine and tested features of its computer-controlled system called the Reference OpenSource Controller (ROSCO). Features such as “peak shaving” and “floating feedback” help smoothen the turbines in strong wind conditions, and “tuned mass dampers” can reduce the impact of certain vibrations. The results show both positive and negative effects of these load-mitigation measures.
This work is imperative in further developing floating offshore wind turbines in Maine and the United States. Governor Janet Mills signed into law LD 1895 for Maine to procure 3,000 MW of offshore wind energy to advance Maine’s goal of moving to 100% renewable energy by 2040. The U.S. White House Administration aims to deploy 15 gigawatts of floating offshore wind by 2035.
Experimental investigation of advanced turbine control strategies and load-mitigation measures with a model-scale floating offshore wind turbine system
Lu Wang, Roger Bergua, Amy Robertson, Alan Wright, Daniel Zalkind, Matthew Fowler, Eben Lenfest, Anthony Viselli, Andrew Goupee, and Richard Kimball
To advance the control co-design of offshore wind energy systems, the authors perform basin-scale experiments with a fully instrumented and actuated floating offshore wind turbine model. The model consists of a 1:70 scale performance-matched model of the International Energy Agency Wind Technology Collaboration Programme 15-MW reference turbine atop the VolturnUS-S semisubmersible platform. The Reference OpenSource Controller provides real-time blade pitch and generator torque control. We aim to develop an open data set for the validation of numerical models in predicting the influence of turbine control and load-mitigation measures. For this purpose, we measure the effects of advanced turbine control features, including peak shaving and floating feedback as well as hull-based control using tuned mass dampers on the system. Overall, the results demonstrate measurable and consistent influences from the control and load-mitigation measures, thus confirming the usefulness as a validation data set. Peak shaving attenuates the response to wind turbulence at near-rated wind speed. Floating feedback reduces the load and platform pitch motion associated with the negative damping induced by blade pitch control. The tuned mass dampers also attenuate the system response near the targeted frequencies under suitable conditions. We also identify detrimental side effects of each load-mitigation measure.