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Power And Energy Needed For Starting A Vertical Axis Marine Current Turbine
Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Electricity. (Marine Current Power)
Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Electricity.
Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Electricity.
2017 (English)Conference paper, Published paper (Refereed)
Abstract [en]

A marine current power station has been deployed in Söderfors, Sweden. It comprises a five bladed fixed pitch vertical axis H-rotor turbine directly connected to a permanent magnet synchronous generator. The turbine is rated for 1.3 m/s, but at lower water speeds the turbine is generally not self starting. This paper investigates the energy and power needed to at low speeds start the turbine electrically with a BrushLess DC (BLDC) motor until  he turbines gives a net positive torque to the generator. A range of startup BLDC powers have been investigated. It is shown that for three water speeds (0.98 m/s, 1.04 m/s and 1.16 m/s) the energy needed for start up is equivalent to less than 1.2 s of power production at maximum power capture of the turbine. The startup time is mostly dependent on BLDC power setting, not on water speed. A BLDC power of 1/7th of rated power of the machine is enough to start the machine within 2 seconds. The results suggest that a higher BLDC power than that will not significantly reduce the startup time nor reduce the energy needed (increase the efficiency of the startup process). The water speed has the highest impact on the time it takes to recover the energy needed for startup once the BLDC power is well above the losses in the system.

Place, publisher, year, edition, pages
2017.
Keywords [en]
Marine current power, startup energy, Söderfors, vertical axis turbine
National Category
Engineering and Technology
Research subject
Engineering Science with specialization in Science of Electricity
Identifiers
URN: urn:nbn:se:uu:diva-330188OAI: oai:DiVA.org:uu-330188DiVA, id: diva2:1144905
Conference
Proceedings of the 12th European Wave and Tidal Energy Conference 27th Aug -1st Sept 2017, Cork, Ireland
Projects
Marine Current Power
Funder
Vattenfall ABStandUpÅForsk (Ångpanneföreningen's Foundation for Research and Development)Swedish Energy AgencySwedish Research CouncilAvailable from: 2017-09-27 Created: 2017-09-27 Last updated: 2018-10-25Bibliographically approved
In thesis
1. Studies of a Vertical Axis Turbine for Marine Current Energy Conversion: Electrical system and turbine performance
Open this publication in new window or tab >>Studies of a Vertical Axis Turbine for Marine Current Energy Conversion: Electrical system and turbine performance
2018 (English)Doctoral thesis, comprehensive summary (Other academic)
Abstract [en]

Ocean energy is a field of growing interest when it comes to renewable energy thanks to its high density of energy per unit area, and to the high predictability. Conversion of hydrokinetic energy, found in marine currents, is the utilization of the energy in free-flowing water for conversion to electric energy. This thesis presents experimental data from a test site with a marine current converter.

The converter system features a vertical axis turbine directly connected to a permanent magnet synchronous generator placed on the riverbed. The converter is controlled by an electrical system. The focus of the work is to evaluate power control methods and turbine performance.  

Results of a simple voltage control system is presented and compared with operation without control. The turbine type in the converter system is not self-starting. The startup power and energy has been investigated through experiments. The converter system has been connected to the local electric utility grid and the first experimental results are presented.  

The performance of the turbine for a range of water speeds is investigated. The range of experiments are limited by the water velocity at the experimental site. To address the issue, a simulation model coupling the electrical system and hydrodynamic model into one has been validated. One factor affecting the turbine's power capture is the angle of the blade pitch relative to the water flow. The influence of blade pitch on turbine performance is studied with experiments and two 3D simulation models.

The possibilities of powering a desalination plant using marine current converters is discussed. Water speed data from outside the east coast of South Africa has been used for a case study. The study investigates how many people can early be supplied with freshwater using the converter system at the experimental site as a model. 

Place, publisher, year, edition, pages
Uppsala: Acta Universitatis Upsaliensis, 2018. p. 77
Series
Digital Comprehensive Summaries of Uppsala Dissertations from the Faculty of Science and Technology, ISSN 1651-6214 ; 1739
National Category
Engineering and Technology
Research subject
Engineering Science with specialization in Science of Electricity
Identifiers
urn:nbn:se:uu:diva-363256 (URN)978-91-513-0491-5 (ISBN)
Public defence
2018-12-13, 80101, Ångströmslaboratoriet, Lägerhyddsvägen 1, Uppsala, 09:15 (English)
Opponent
Supervisors
Available from: 2018-11-21 Created: 2018-10-25 Last updated: 2018-11-30

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Forslund, JohanThomas, KarinLeijon, Mats

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