Experimental Results of a Load-Controlled Vertical Axis Marine Current Energy Converter
2015 (English)Licentiate thesis, comprehensive summary (Other academic)
This thesis investigates the load control of a marine current energy converter using a vertical axis turbine mounted on a permanent magnet synchronous generator. The purpose of this thesis is to show the work done in the so far relatively uncharted territory of control systems for hydro kinetic energy conversion. The work is in its early stage and is meant to serve as a guide forfuture development of the control system.
An experimental power station has been deployed and the first results are presented.
A comparison between three load control methods has been made; a fixedAC load, a fixed pulse width modulated DC load and a DC bus voltage control of a DC load. Experimental results show that the DC bus voltage control reduces the variation of rotational speed with a factor of 3.5. For all three cases, the tip speed ratio of the turbine can be kept close to the expected optimal tip speed ratio. However, for all three cases the average extracted power was significantly lower than the average power available in the turbine times the estimated maximum power coefficient. A maximum power point tracking system, with or without water velocity measurement, should increase the average extracted power.
A simulation model has been validated using experimental data. The simulated system consists of the electrical system and a hydrodynamic vortex model for the turbine. Experiments of no load operation were conducted to calibrate the drag losses of the turbine. Simulations were able to predict the behaviour in a step response for a change in tip speed ratio when the turbine was operated close to optimal tip speed ratio. The start position of the turbine was varied in the simulation to view the influence on the step response from a changed turbine position relative to the direction of the water flow.
Place, publisher, year, edition, pages
Uppsala: Uppsala universitet, 2015. , 53 p.
UURIE / Uppsala University, Department of Engineering Sciences, ISSN 0349-8352 ; 345-15L
Marine Current; Vertical Axis; Load Control;
Engineering and Technology
Research subject Engineering Science with specialization in Science of Electricity
IdentifiersURN: urn:nbn:se:uu:diva-268867OAI: oai:DiVA.org:uu-268867DiVA: diva2:881408
2015-12-16, Å4101, Lägerhyddsvägen 1, Ångströmlaboratoriet, Uppsala, 09:15 (English)
Blackmore, Tom, PhD
Leijon, Mats, ProfessorThomas, Karin, PhD, Senior LecturerSundberg, Jan, PhD, Senior Lecturer
FunderStandUpÅForsk (Ångpanneföreningen's Foundation for Research and Development)Vattenfall ABSwedish Research CouncilSwedish Energy Agency
Funders: J Gust Richert, Bixia Miljöfond2015-12-102015-12-102015-12-10Bibliographically approved
List of papers