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Implementation of control system for hydro-kinetic energy converter
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.
Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Electricity.
(English)In: Journal of Control Science and Engineering, ISSN 1687-5249, E-ISSN 1687-5257Article in journal (Refereed) Submitted
National Category
Energy Systems Other Electrical Engineering, Electronic Engineering, Information Engineering Control Engineering
Identifiers
URN: urn:nbn:se:uu:diva-181554OAI: oai:DiVA.org:uu-181554DiVA: diva2:556733
Available from: 2012-09-26 Created: 2012-09-26 Last updated: 2017-12-07Bibliographically approved
In thesis
1. 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
2. Grid Connection of Permanent Magnet Generator Based Renewable Energy Systems
Open this publication in new window or tab >>Grid Connection of Permanent Magnet Generator Based Renewable Energy Systems
2016 (English)Doctoral thesis, comprehensive summary (Other academic)
Abstract [en]

Renewable energy is harnessed from continuously replenishing natural processes. Some commonly known are sunlight, water, wind, tides, geothermal heat and various forms of biomass. The focus on renewable energy has over the past few decades intensified greatly. This thesis contributes to the research on developing renewable energy technologies, within the wind power, wave power and marine current power projects at the division of Electricity, Uppsala University. In this thesis grid connection of permanent magnet generator based renewable energy sources is evaluated.

A tap transformer based grid connection system has been constructed and experimentally evaluated for a vertical axis wind turbine. Full range variable speed operation of the turbine is enabled by using the different step-up ratios of a tap transformer. This removes the need for a DC/DC step or an active rectifier on the generator side of the full frequency converter and thereby reduces system complexity. Experiments and simulations of the system for variable speed operation are done and efficiency and harmonic content are evaluated. 

The work presented in the thesis has also contributed to the design, construction and evaluation of a full-scale offshore marine substation for wave power intended to grid connect a farm of wave energy converters. The function of the marine substation has been experimentally tested and the substation is ready for deployment. Results from the system verification are presented. Special focus is on the transformer losses and transformer in-rush currents.

A control and grid connection system for a vertical axis marine current energy converter has been designed and constructed. The grid connection is done with a back-to-back 2L-3L system with a three level cascaded H-bridge converter grid side. The system has been tested in the laboratory and is ready to be installed at the experimental site. Results from the laboratory testing of the system are presented.

Place, publisher, year, edition, pages
Uppsala: Acta Universitatis Upsaliensis, 2016. 79 p.
Series
Digital Comprehensive Summaries of Uppsala Dissertations from the Faculty of Science and Technology, ISSN 1651-6214 ; 1436
Keyword
VAWT, H-rotor, Tap Transformer, Cascaded H-bridge Multi-Level, Renewable Energy, Wind power, Wave power, Marine Current Power
National Category
Engineering and Technology
Research subject
Engineering Science with specialization in Science of Electricity
Identifiers
urn:nbn:se:uu:diva-304659 (URN)978-91-554-9712-5 (ISBN)
Public defence
2016-11-25, Polhemsalen, 10134, Ångströmlaboratoriet, Lägerhyddsvägen 1, Uppsala, 09:00 (English)
Opponent
Supervisors
Projects
Wind PowerWave PowerMarine Currnet Power
Available from: 2016-11-03 Created: 2016-10-06 Last updated: 2016-11-16Bibliographically approved

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