| 1. |
- Boström, Cecilia, et al.
(author)
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Design proposal of electrical system for linear generator wave power plants
- 2009
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In: 35TH ANNUAL CONFERENCE OF IEEE INDUSTRIAL ELECTRONICS. - : IEEE. - 9781424446483 - 9781424446506 ; , s. 4180-4185
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Conference paper (peer-reviewed)abstract
- This paper describes an electrical system layout for a wave power plant connecting linear generators to the grid. The electrical power out from the wave energy converters must be converted before they can be connected to the grid. The conversion is carried out in marine substations that will be placed on the seabed.The paper presents experimental power data from a wave energy converter that has been in operation at the Lysekil research site since March 2006. Moreover, results and analyses from experiments and simulations from tests with the generator connected to a rectifier and filter are presented. A simulation is made to show the difference between having the generator connected to a linear load and a nonlinear load, which would be the case when the generator is connected to the grid.
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| 2. |
- Boström, Cecilia, et al.
(author)
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Experimental results from an offshore wave energy converter
- 2008
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In: Volume 6. ; , s. 653-657
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Conference paper (peer-reviewed)abstract
- Anoffshore wave energy converter (WEC) was successfully launched at theSwedish west coast in the middle of March 2006. TheWEC is based on a permanent magnet linear generator locatedon the ocean floor driven by a point absorber. Ameasuring station has been installed on a nearby island whereall measurements and experiments on the WEC have been carriedout. The output voltage from the generator fluctuates both inamplitude and frequency and must therefore be converted to enablegrid connection. In order to study the voltage conversion, themeasure station was fitted with a six pulse diode rectifierand a capacitive filter during the autumn of 2006. Theobject of this paper is to present a detailed descriptionof the existing wave energy system of the Islandsberg project.Special attention will be given to the power absorption bythe generator when it is connected to a non linearload
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| 3. |
- Boström, Cecilia, et al.
(author)
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Experimental Results From an Offshore Wave Energy Converter
- 2010
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In: Journal of Offshore Mechanics and Arctic Engineering-Transactions of The Asme. - : ASME International. - 0892-7219 .- 1528-896X. ; 132:4, s. 041103-
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Journal article (peer-reviewed)abstract
- An offshore wave energy converter (WEC) was successfully launched at the Swedish west coast in the middle of March 2006. The WEC is based on a permanent magnet linear generator located on the sea floor driven by a point absorber. A measuring station has been installed on a nearby island where all measurements and experiments on the WEC have been carried out. The output voltage from the generator fluctuates both in amplitude and frequency and must therefore be converted to enable grid connection. In order to study the voltage conversion, the measuring station was fitted with a six pulse diode rectifier and a capacitive filter during the autumn of 2006. The object of this paper is to present a detailed description of the Lysekil research site. Special attention will be given to the power absorption by the generator when it is connected to a nonlinear load.
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| 4. |
- Boström, Cecilia, et al.
(author)
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Study of aWave Energy Converter Connected to a Nonlinear Load
- 2009
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In: IEEE Journal of Oceanic Engineering. - 0364-9059 .- 1558-1691. ; 34:2, s. 123-127
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Journal article (peer-reviewed)abstract
- This paper presents experimental results from a wave energy converter (WEC) that is based on a linear generator connected to a rectifier and filter components. The converter-filter system is installed onshore, while the linear wave generator operates offshore a few kilometers from the Swedish west coast. The power from the generator has been rectified with a diode bridge and then filtered using a capacitive filter. Performance of the whole conversion system was studied using resistive loads connected across the filter. The aim was to investigate the operational characteristics of the generator while supplying a nonlinear load. By changing the value of the resistive component of the load, the speed of the translator can be changed and so also the damping of the generator. The power absorbed by the generator was studied at different sea states as well. The observations presented in this paper could be beneficial for the design of efficient wave energy conversion systems.
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| 5. |
- Hai, Ling, et al.
(author)
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Force in the connection line for a wave energy converter : simulation and experimental setup
- 2014
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In: 33Rd International Conference On Ocean, Offshore And Arctic Engineering, 2014, Vol 9A. - San Francisco, USA. - 9780791845530
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Conference paper (peer-reviewed)abstract
- In order to capture ocean wave energy and transform it into electric energy, Uppsala University has developed a point absorber wave energy converter (AVEC) for electricity production. For a better understanding of a torus shaped buoy's performance, this paper conducts a force analysis under linear conditions, to investigate the hydrodynamic characteristic and line force differences between the torus buoy that is going to be deployed, and two similar cylindrical buoys. The result reveals the line force fromthis torus buoy is roughly 5% larger than from cylindrical buoys for the most energy dense wave climate in Lysekil test site, and negative added mass phenomena won't have a significant impact for the line force. To measure the line force, a force measurement system has been designed. A detailed description is given on the design of the 500 kN force measurement system, and the major differences compared with former force measurement systems. Onshore test result has also been presented. With the force measurement experiment, hydrodynamic analysis for torus buoy can be validated when the system performs linearly, and extreme force for storm weather can be monitored to provide information for future WEC structure's mechanical design.
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| 6. |
- Hedström, Erik M, et al.
(author)
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Epidemiology of fractures in children and adolescents
- 2010
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In: Acta Orthopaedica. - : Medical Journals Sweden AB. - 1745-3674 .- 1745-3682. ; 81:1, s. 148-153
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Journal article (peer-reviewed)abstract
- Background and purpose Fractures are most common in youth and in the elderly, with differences in incidence over time and between regions. We present the fracture pattern in a population of youths ≤ 19 years of age, who were seen at Umeå University Hospital, Sweden. Material and methods All injuries seen at the hospital have been recorded in a database since 1993. The data include variables such as age, sex, date, type of injury, mechanism of injury, and treatment. For the period 1993–2007, there were 10,203 injury events that had resulted in at least 1 fracture. Results The incidence for the whole period was 201/104 person years. The incidence increased by 13% during the period 1998–2007, when we were able to control for registration errors. The most common fracture site was the distal forearm. The most common type of injury mechanism was falling. The peak incidence occurred at 11–12 years in girls and at 13–14 years in boys, with a male-to-female incidence ratio of 1.5. We found variations in mechanisms and activities at injury with age, and over time. Interpretation Fractures are caused by a combination of intrinsic and extrinsic factors that vary with age. We believe the increase in incidence is partly explained by changes in children's activity patterns over time. Further research may help to identify preventive measures to reduce the number of fractures, in particular those involving hospital care, surgical treatment, and—most importantly—long-term impairment. Read More: http://informahealthcare.com/doi/abs/10.3109/17453671003628780
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| 7. |
- Hedström, Erik M, et al.
(author)
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Epidemiology of fractures in children and adolescents : Increased incidence over the past decade: a population-based study from northrn Sweden
- 2010
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In: Acta Orthopaedica. - : Medical Journals Sweden AB. - 1745-3674 .- 1745-3682. ; 81:1, s. 148-153
-
Journal article (peer-reviewed)abstract
- Background and purpose Fractures are most common in youth and in the elderly, with differences in incidence over time and between regions. We present the fracture pattern in a population of youths <= 19 years of age, who were seen at Umeå University Hospital, Sweden. Material and methods All injuries seen at the hospital have been recorded in a database since 1993. The data include variables such as age, sex, date, type of injury, mechanism of injury, and treatment. For the period 1993-2007, there were 10,203 injury events that had resulted in at least 1 fracture. Results The incidence for the whole period was 201/104 person years. The incidence increased by 13% during the period 1998-2007, when we were able to control for registration errors. The most common fracture site was the distal forearm. The most common type of injury mechanism was falling. The peak incidence occurred at 11-12 years in girls and at 13-14 years in boys, with a male-to-female incidence ratio of 1.5. We found variations in mechanisms and activities at injury with age, and over time. Interpretation Fractures are caused by a combination of intrinsic and extrinsic factors that vary with age. We believe the increase in incidence is partly explained by changes in children's activity patterns over time. Further research may help to identify preventive measures to reduce the number of fractures, in particular those involving hospital care, surgical treatment, and-most importantly-long-term impairment.
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| 8. |
- Leijon, Mats, et al.
(author)
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A wave power unit
- 2009
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Patent (pop. science, debate, etc.)
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