Incorporating mooring dynamics into the control design of a two-body wave energy converter
Date
2023
Authors
Funk, Spencer
Haider, Ali S.
Bubbar, Kush
Buckham, Bradley
Journal Title
Journal ISSN
Volume Title
Publisher
Journal of Marine Science and Engineering
Abstract
Mooring systems are a critical component of all floating wave energy converter (WEC) systems, yet the impact of amooring system on the WEC dynamics is often neglected during the initial assessment of candidate designs. The purpose of this study was to investigate how the inclusion of mooring dynamics in the early stages of the WEC design process influences decisions regarding hydrodynamic features and control strategies. The study was executed within a mechanical circuit framework to represent the WEC response in the frequency domain. Thevenin’s theorem was applied within this framework to transform a multi-body WEC into a single-body canonical form. This work specifically focused on self-reacting point absorbers and examined how four realistic mooring designs impact WEC intrinsic mechanical impedance across a range of common wave frequencies. We show how the mooring can easily be included in this framework, and a simple approach to identifying the mooring model parameters is described. It was observed that if mooring dynamics are considered within the WEC control design process, a 40% reduction in the required range of the controller physical variable can be achieved while yielding up to 16% more useful power. These results suggest that considering the mooring system early can enhance WEC design.
Description
Keywords
two-body wave energy converters, point absorber, mooring characterization, optimal control design, system identification, mathematical modeling, mechanical circuits, numerical simulation
Citation
Funk, S., Haider, A.S. Bubbar, K., & Buckham, B. Incorporating mooring dynamics into the control design of a two-body wave energy converter. J. Mar. Sci. Eng. 2023, 11, 2347. https:// doi.org/10.3390/jmse11122347