Submerged Transmission in Wave Energy Converters: Full Scale In-Situ Experimental Measurements
2012 (English)Doctoral thesis, comprehensive summary (Other academic)
Different wave power technologies are in development around the world in different stages of prototype testing. So far only a few devices have been deployed offshore at full scale for extended periods of time. Little data is published about how these different devices perform.
This thesis presents results from experiments with the full-scale offshore wave energy converters at the Lysekil research site on the Swedish west coast. The theories, experiments, measurements, performance evaluations and developments of the submerged transmission in the direct driven permanent magnet linear generator are in focus. The reciprocating submerged transmission fulfills the purpose of transmitting the absorbed mechanical wave energy through the capsule wall into the generator, while preventing the seawater from entering the capsule and reducing the life time of the converter.
A measuring system with seven laser triangulation sensors has been developed to measure small relative displacements between piston rod and seal housing in the submerged transmission with excellent accuracy for the purpose of evaluating both functional behavior and successive wear in-situ. A method for calculating relative tilt angles, azimuth angles, differential tilt angles, and successive wear in the submerged transmission has been developed. Additional sensors systems have been installed in the converter enabling correlation and a thorough investigation into the operating conditions of the transmission and the converter. The thesis presents unique results from the measurements. A data acquisition system transmits the signals from the converter on the seabed to an onshore measuring station. Results are presented in time-, frequency- and the time-frequency domain.
The results have given important information for further development of the submerged transmission, which is important to the survivability of the system. The thesis describes the status of research, and is a step that may influence future designs of wave energy devices for reaching survivability and a cost-effective renewable energy system.
Place, publisher, year, edition, pages
Uppsala: Acta Universitatis Upsaliensis, 2012. , 214 p.
Digital Comprehensive Summaries of Uppsala Dissertations from the Faculty of Science and Technology, ISSN 1651-6214 ; 961
Wave energy converter, direct drive, submerged transmission, piston rod, seal housing, sealing system, laser triangulation sensor, offshore measurements, relative displacement, vibrations, tilt angle, tilting, wear estimation.
Energy Systems Marine Engineering Ocean and River Engineering Energy Engineering
Research subject Engineering Science with specialization in Science of Electricity
IdentifiersURN: urn:nbn:se:uu:diva-179740ISBN: 978-91-554-8440-8OAI: oai:DiVA.org:uu-179740DiVA: diva2:545975
2012-09-14, Polhemssalen, Ångströmlaboratoriet, Lägerhyddsvägen 1, Uppsala, 10:00 (English)
Aidanpää, Jan-Olov, Professor
Leijon, Mats, ProfessorBernhoff, Hans, Professor
ProjectsThe Lysekil Wave Power Project
Published is a preprint version of the full text and should be combined by the errata.2012-08-242012-08-212013-01-22Bibliographically approved
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