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Power coefficient measurement on a 12 kW straight bladed vertical axis wind turbine
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.
Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Electricity.
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2011 (English)In: Renewable energy, ISSN 0960-1481, E-ISSN 1879-0682, Vol. 36, no 11, 3050-3053 p.Article in journal (Refereed) Published
Abstract [en]

A 12 kW vertical axis H-rotor type wind turbine has been designed and constructed at Uppsala University. A measurement campaign has been performed to collect data to calculate the power coefficient using the method of bins. The measurement was performed at different constant rotational speeds on the turbine during varying wind speeds to observe the power coefficients dependence on tip speed ratio. The power coefficient peaked at 0.29 for a tip speed ratio equal to 3.3.

Place, publisher, year, edition, pages
2011. Vol. 36, no 11, 3050-3053 p.
Keyword [en]
VAWT, H-rotor, Experimental, Measured, Cp
National Category
Engineering and Technology
Research subject
Engineering Science with specialization in Science of Electricity
Identifiers
URN: urn:nbn:se:uu:diva-156579DOI: 10.1016/j.renene.2011.03.031ISI: 000292441400035OAI: oai:DiVA.org:uu-156579DiVA: diva2:432837
Available from: 2011-08-07 Created: 2011-08-04 Last updated: 2017-12-08Bibliographically approved
In thesis
1. Vertical Axis Wind Turbines: Electrical System and Experimental Results
Open this publication in new window or tab >>Vertical Axis Wind Turbines: Electrical System and Experimental Results
2012 (English)Doctoral thesis, comprehensive summary (Other academic)
Abstract [en]

The wind power research at the division of Electricity at Uppsala University is aimed towards increased understanding of vertical axis wind turbines. The considered type of wind turbine is an H-rotor with a directly driven synchronous generator operating at variable speed. The experimental work presented in this thesis comprises investigation of three vertical axis wind turbines of different design and size. The electrical, control and measurement systems for the first 12 kW wind turbine have been designed and implemented. The second was a 10 kW wind turbine adapted to a telecom application. Both the 12 kW and the 10 kW were operated against dump loads. The third turbine was a 200 kW grid-connected wind turbine, where control and measurement systems have been implemented.

Experimental results have shown that an all-electric control, substituting mechanical systems such as blade-pitch, is possible for this type of turbine. By controlling the rectified generator voltage, the rotational speed of the turbine is also controlled. An electrical start-up system has been built and verified. The power coefficient has been measured and the stall behaviour of this type of turbine has been examined. An optimum tip speed ratio control has been implemented and tested, with promising results. Use of the turbine to estimate the wind speed has been demonstrated. This has been used to get a faster regulation of the turbine compared to if an anemometer had been used.  

Place, publisher, year, edition, pages
Uppsala: Acta Universitatis Upsaliensis, 2012. 77 p.
Series
Digital Comprehensive Summaries of Uppsala Dissertations from the Faculty of Science and Technology, ISSN 1651-6214 ; 981
Keyword
VAWT, H-rotor, start-up, all-electric control, Power Coefficient, stall, tip speed ratio, Renewable energy, Measurement systems, PM-generator
National Category
Energy Systems Other Electrical Engineering, Electronic Engineering, Information Engineering
Identifiers
urn:nbn:se:uu:diva-182438 (URN)978-91-554-8496-5 (ISBN)
Public defence
2012-11-30, Room 2001, Ångströmlaboratoriet, Lägerhyddsvägen 1, Uppsala, 13:00 (English)
Opponent
Supervisors
Available from: 2012-11-07 Created: 2012-10-10 Last updated: 2013-01-23Bibliographically approved
2. A Generator Perspective on Vertical Axis Wind Turbines
Open this publication in new window or tab >>A Generator Perspective on Vertical Axis Wind Turbines
2013 (English)Doctoral thesis, comprehensive summary (Other academic)
Abstract [en]

The wind energy conversion system considered in this thesis is based on a vertical axis wind turbine with a cable wound direct drive PM generator. Diode rectifiers are used to connect several such units to a single DC-bus and a single inverter controls the power flow from the DC-bus to a utility grid. This work considers the described system from a generator perspective i.e. the turbine is primarily seen as a torque and the inverter is seen as a controlled load.

A 12 kW VAWT prototype with a single turbine has been constructed within the project. The power coefficient of this turbine has been measured when the turbine is operated at various tip speed ratios. This measurement determines both how much energy the turbine can convert in a given wind and at what speed the turbine should be operated in order to maximise the energy capture. The turbine torque variation during the revolution of the turbine has also been studied.

A PM generator prototype has been constructed in order to study power loss in the stator core at low electrical frequencies. Heat exchange between the stator and the air-gap between the stator and the rotor has been studied. Heat exchange between the stator and the air-gap is increased by turbulence caused by the rotor. The generator was also used in a demonstration of a DC-grid where two diode rectified PM generators supplied power to a single DC load.  An initial study of an inverter suitable for grid connection of the 12 kW PM generator has been performed.

Several turbine control strategies are evaluated in simulations. The control strategies only require the parameter "turbine speed" to determine the optimal system load.

Place, publisher, year, edition, pages
Uppsala: Acta Universitatis Upsaliensis, 2013. 80 p.
Series
Digital Comprehensive Summaries of Uppsala Dissertations from the Faculty of Science and Technology, ISSN 1651-6214 ; 1034
Keyword
VAWT, PM generator, Wind power, Stator core loss
National Category
Energy Systems
Identifiers
urn:nbn:se:uu:diva-197855 (URN)978-91-554-8642-6 (ISBN)
Public defence
2013-05-22, Siegbahnsalen, Lägerhyddsvägen 1, Uppsala, 09:00 (English)
Opponent
Supervisors
Available from: 2013-04-25 Created: 2013-04-05 Last updated: 2013-08-30Bibliographically approved

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Kjellin, JonBülow, FredrikEriksson, SandraDeglaire, PaulLeijon, MatsBernhoff, Hans

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