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| 2. |
- Boström, Cecilia, et al.
(författare)
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Design proposal of electrical system for linear generator wave power plants
- 2009
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Ingår i: 35TH ANNUAL CONFERENCE OF IEEE INDUSTRIAL ELECTRONICS. - : IEEE. - 9781424446483 - 9781424446506 ; , s. 4180-4185
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Konferensbidrag (refereegranskat)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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| 3. |
- Boström, Cecilia, et al.
(författare)
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Experimental results from an offshore wave energy converter
- 2008
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Ingår i: Volume 6. ; , s. 653-657
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Konferensbidrag (refereegranskat)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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| 4. |
- Boström, Cecilia, et al.
(författare)
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Experimental Results From an Offshore Wave Energy Converter
- 2010
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Ingår i: 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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Tidskriftsartikel (refereegranskat)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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| 5. |
- Boström, Cecilia, et al.
(författare)
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Study of aWave Energy Converter Connected to a Nonlinear Load
- 2009
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Ingår i: IEEE Journal of Oceanic Engineering. - 0364-9059 .- 1558-1691. ; 34:2, s. 123-127
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Tidskriftsartikel (refereegranskat)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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| 6. |
- Boström, Cecilia, et al.
(författare)
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Temperature measurements in a linear generator and marine substation for wave power
- 2010
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Ingår i: PROCEEDINGS OF THE ASME 29TH INTERNATIONAL CONFERENCE ON OCEAN, OFFSHORE AND ARCTIC ENGINEERING 2010, VOL 3. - 9780791849118 ; , s. 545-552
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Konferensbidrag (refereegranskat)abstract
- This paper analyzes temperature measurements acquired in offshore operation of a wave energy converter array. The three directly driven wave energy converters have linear generators and are connected to a marine substation placed on the seabed. The highly irregular individual linear generator voltages are rectified and added on a common DC-link and inverted to 50 Hz to facilitate future grid-connection. The electrical power is transmitted to shore and converted to heat in a measuring station. First results of temperature measurements on substation components and on the stator of one of the linear generators are presented from operation in linear and in non-linear damping. Results indicate that there might be some convective heat transport in the substation vessel. If high power levels are extracted from the waves, this has to be considered when placing components in the substation vessel to avoid heating from neighbouring components. The results also indicate that the temperature increase in the linear generator stator is very small. Failure due to excessive heating of the stator winding PVC cable insulation is unlikely to occur even in very energetic sea states. Should this conclusion be incorrect, the thermal conductivity between the stator and the hull of the WEC could be enhanced. Another suggested alteration would be to lower the resistive losses by reducing the linear generator current density.
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| 7. |
- Boström, Cecilia, et al.
(författare)
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Temperature measurements in a linear generator and marine substation for wave power
- 2012
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Ingår i: Journal of Offshore Mechanics and Arctic Engineering-Transactions of The Asme. - : ASME International. - 0892-7219 .- 1528-896X. ; 134:2, s. 021901-
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Tidskriftsartikel (refereegranskat)abstract
- This paper analyzes temperature measurements acquired in the offshore operation of a wave energy converter array. The three directly driven wave energy converters have linear generators and are connected to a marine substation placed on the seabed. The highly irregular individual linear generator voltages are rectified and added on a common dc-link and inverted to 50 Hz to facilitate future grid-connection. The electrical power is transmitted to shore and converted to heat in a measuring station. The first results of temperature measurements on substation components and on the stator of one of the linear generators are presented based on operation in linear and in nonlinear damping. The results indicate that there might be some convective heat transfer in the substation vessel. If high power levels are extracted from the waves, this has to be considered when placing components in the substation vessel in order to avoid heating from neighboring components. The results also indicate that the temperature increase in the linear generator stator is very small. Failure due to excessive heating of the stator winding polyvinyl chloride cable insulation is unlikely to occur even in very energetic sea states. Should this conclusion be incorrect, the thermal conductivity between the stator and the hull of the wave energy converter could be enhanced. Another suggested alteration is to lower the resistive losses by reducing the linear generator current density.
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| 8. |
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| 9. |
- Ekström, Rickard, et al.
(författare)
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Evaluating Constant DC-Link Operation of Wave Energy Converter
- 2012
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Ingår i: Proceedings of the 31st ASME International Conference on Ocean, Offshore and Arctic Engineering, vol. 7. - 9780791844946 ; , s. 269-276
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Konferensbidrag (refereegranskat)abstract
- A Wave Energy Converter (WEC) based on a linear generator and a point-absorbing buoy has been developed at Uppsala University. Interconnecting an array of WECs in parallel requires a point of common coupling, such as a common DC-bus. The DC voltage level seen by the generator is directly linked to the electromagnetic damping of the generator A lower DC-level results in a higher damping factor and is important for increased absorption of the wave power The drawback is increased losses in generator windings and cable resistance. There will be an optimal DC-level for maximum power output. This is a function of not only generator and buoy characteristics, but the current sea state. Experimental results of the full-scale system have been carried out, and used as validation of a simulation model of the system. The model is then used to evaluate how the DC-level seen by the generator influence the power output. The results indicate that higher DC-levels should be used at higher sea states, and power output may vary by up to a factor five depending on which DC-level is chosen.
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| 10. |
- Leijon, Mats, et al.
(författare)
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A wave power unit
- 2009
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Patent (populärvet., debatt m.m.)
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