Dynamics and Control of a Novel Wave-Augmented Floating Offshore Wind Turbine

This grant will fund research that enables innovation in the controlled use of combined aero- and hydrodynamic loading on floating offshore wind turbines to increase energy extraction and reduce platform mass -- resulting in a reduction in the levelized cost of electric power harvested for a key renewable energy generation technology -- thereby promoting the progress of science and advancing the national prosperity. To operate stably under extreme wind and wave conditions, floating offshore wind turbines are designed to be large and heavy. The floating platform alone occupies a significant portion of the overall capital expenditures. This project investigates a novel physical design and innovative control architecture that leverages the coupling between wind and wave power to allow stability requirements to be satisfied by a lighter floating platform, while also enhancing the energy-capturing efficiency. By integrating a wave-augmented control authority with the floating platform, the project aims to establish a foundational paradigm for leveraging wave power rather than mitigating its influence. An integrated outreach program for high school students and development of web-based resources on wind and wave energy for high school teachers aim to broaden participation in STEM, including to individuals from currently underrepresented groups. This research aims to develop the theoretical foundations for an innovative physical design and associated control logic that allows wave-driven pressure in closed-air chambers inside the foundation of a floating offshore wind turbine to both attenuate its motion and drive an auxiliary turbine. It accomplishes this outcome through a synergistic analytical, computational, and experimental study of the coupled hydro-, aero-, and thermodynamic behavior of the wave-augmented physical system, as well as the development of a control architecture rooted in sliding mode control, which ensures optimal performance also under environmental uncertainty. A robust aerodynamic time-domain load formulation is developed using a scaled-aeroelastic, boundary-layer wind-tunnel model of the turbine superstructure on a dynamic platform that simulates wave-induced base motion. System and control parameters are optimized concurrently using a stochastic search strategy. This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.