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Experimental setup: Low speed permanent magnet generator for marine current power conversion
Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Electricity. (Elektricitetslära)
Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Electricity. (Elektricitetslära)
Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Electricity. (Elektricitetslära)
Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Electricity. (Elektricitetslära)
2007 (English)In: Proceedings of the 26th International Conference on Offshore Mechanics and Arctic Engineering, Vol 5, 2007, 459-462 p.Conference paper, Published paper (Refereed)
Abstract [en]

Marine currents, e.g. tidal currents, ocean currents and unregulated water courses are characterized by a fairly steady or regular flow and pose a significant potential for electricity generation. An ongoing research project at Uppsala University is looking into an energy conversion system with a vertical axis turbine and a permanent magnet direct drive generator placed directly in the water flow, i.e. without using a dam. This choice of technology is intended to provide a simple and robust system with low maintenance needs and minimal environmental impact. During 2006 an experimental setup has been built. It consists of a frequency converter, a motor and a gearbox to drive the generator, the generator itself, and a resistive load to consume the generated power. The generator is two meters in diameter and is built on an elevated structure over the motor and gearbox. A stainless steel structure supports the cable wound stator. The permanent NdFeB magnets are fastened in milled grooves in the rotor. The experimental setup will be used for verification of a simulation and optimization program.

Place, publisher, year, edition, pages
2007. 459-462 p.
National Category
Engineering and Technology
Identifiers
URN: urn:nbn:se:uu:diva-96613ISI: 000249559500056ISBN: 978-0-7918-4271-3 (print)OAI: oai:DiVA.org:uu-96613DiVA: diva2:171250
Conference
26th International Conference on Offshore Mechanics and Arctic Engineering San Diego, CA, JUN 10-15, 2007
Available from: 2008-01-11 Created: 2008-01-11 Last updated: 2013-01-23Bibliographically approved
In thesis
1. Low Speed Energy Conversion from Marine Currents
Open this publication in new window or tab >>Low Speed Energy Conversion from Marine Currents
2007 (English)Doctoral thesis, comprehensive summary (Other academic)
Abstract [en]

The focus of this thesis is research on the performance of very low speed direct drive permanent magnet generators for energy conversion from marine and tidal currents. Various aspects involved in the design of these generators and their electromagnetic modelling using the finite element simulations are presented. For a detailed study, a 5 kW prototype generator has been designed and constructed based on finite element based simulations. Several experiments were conducted on the prototype generator. The experimental results were compared with the corresponding case simulations on the designed generator. The differences between the results predicted by the simulations and those predicted by the measurements were less than 10%. The part and overload performance of the generator has been investigated and it is found from both simulations and measurements that the generator is capable to efficiently operate at varying speeds. The tests on the experimental generator were made for speeds between 2 and 16 rpm and for load variations of 0.5 to 2 per unit. In this thesis it is shown that it is possible to design a very low speed direct drive generator for more or less any given marine current site and this is beneficial for projects aiming to develop a technical and economical viable marine current energy conversion system.

Place, publisher, year, edition, pages
Uppsala: Acta Universitatis Upsaliensis, 2007. 68 p.
Series
Digital Comprehensive Summaries of Uppsala Dissertations from the Faculty of Science and Technology, ISSN 1651-6214 ; 383
Keyword
Electrical power technology, Direct Drive Generator, Finite Element Method, Marine Current Energy, Synchronous Generator, Permanent Magnet, Tidal Current Energy, Elkraftteknik
National Category
Other Engineering and Technologies
Identifiers
urn:nbn:se:uu:diva-8400 (URN)978-91-554-7063-0 (ISBN)
Public defence
2008-02-01, Häggsalen, Ångströmlaboratory, Lägerhyddsvägen 1, 751 21 Uppsala, 13:15 (English)
Opponent
Supervisors
Available from: 2008-01-11 Created: 2008-01-11 Last updated: 2010-04-23Bibliographically approved
2. System Perspectives on Hydro-Kinetic Energy Conversion
Open this publication in new window or tab >>System Perspectives on Hydro-Kinetic Energy Conversion
2012 (English)Doctoral thesis, comprehensive summary (Other academic)
Abstract [en]

Free-flowing water currents such as tides and unregulated water courses could contribute to world electricity production given the emergence of robust technical solutions for extracting the energy. At Uppsala University, a concept for converting the energy in water currents to electricity using a vertical axis turbine with fixed blade-pitch and a direct-drive permanent magnet generator is studied.

Technological equipment for extracting energy from water currents can be studied at desktop to some extent, but physical realizations, first in a laboratory setting, and later in a natural aquatic setting, are necessary. For this reason, a laboratory generator has been constructed and evaluated, and an experimental setup comprising turbine, generator and control system has been constructed. The turbine and generator are to be deployed in the Dalälven River in Söderfors, and operated from an on-land control station. The author has worked with constructing and evaluating the low-speed laboratory generator, participated in the design and construction of the Söderfors generator, and designed and constructed the control system for Söderfors.

The generator design incorporates a low rotational speed, permanent magnets, and many poles, in order to adapt the generator to the nature of water currents. Simulations and experimental data for the laboratory prototype have been compared and show that the simulation tool used is adequate for design studies of this type of generator. The generator has also been shown to be able to operate with the intended turbine design and range of water velocities. The control system to be used in Söderfors has been tested in a laboratory environment. Simulations of the control system show that it should be able to operate the turbine and generator at the desired rotational speeds in water velocities up to about 1.8 m/s. Simulations of the system have also shown that maximizing system power output may not correspond with maximizing turbine power.

Place, publisher, year, edition, pages
Uppsala: Acta Universitatis Upsaliensis, 2012. 65 p.
Series
Digital Comprehensive Summaries of Uppsala Dissertations from the Faculty of Science and Technology, ISSN 1651-6214 ; 976
Keyword
tidal energy, permanent magnet, direct-drive, in-stream power converter, load control, vertical axis turbine, renewable energy, engineering science
National Category
Energy Systems Other Electrical Engineering, Electronic Engineering, Information Engineering
Research subject
Engineering Science with specialization in Science of Electricity
Identifiers
urn:nbn:se:uu:diva-181555 (URN)978-91-554-8479-8 (ISBN)
Public defence
2012-11-09, Polhemsalen, Ångströmlaboratoriet, Lägerhyddsvägen 1, Uppsala, 09:15 (English)
Opponent
Supervisors
Available from: 2012-10-18 Created: 2012-09-26 Last updated: 2013-01-23Bibliographically approved

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Yuen, KatarinaNilsson, KarinGrabbe, MårtenLeijon, Mats

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