| 1. |
- Angquist, Lennart, et al.
(författare)
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Low-Cost Ultra-Fast DC Circuit-Breaker Power electronics integrated with mechanical switchgear
- 2018
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Ingår i: 2018 IEEE INTERNATIONAL CONFERENCE ON INDUSTRIAL TECHNOLOGY (ICIT). - : IEEE. - 9781509059492 ; , s. 1708-1713
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Konferensbidrag (refereegranskat)abstract
- The paper describes a concept for fast-acting circuit-breaker using vacuum interrupter (VI) assisted by a power-electronic converter with low output voltage. The converter excites a passive resonant circuit to create current zero-crossing in the arc in the VI to make it extinguish the current. A fast-acting actuator using a Thomson coil separates the contacts in a few milliseconds. The principle is outlined, and a laboratory prototype is described. In experiments 10 kA was successfully interrupted against 9 kV in 3 ms.
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| 2. |
- Baudoin, Antoine, et al.
(författare)
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Assessment of Thermal Cycling in a Rectifier For WavePower Generation
- 2016
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Konferensbidrag (refereegranskat)abstract
- Natural convection allows for passive cooling which isused in many engineering applications. Placing dissipatingcomponents on a common vertical heatsink can be opti-mized to give the best possible cooling capacity. In thisstudy, a numerical model for three-dimensional conjugatedconvective and conductive heat transfer was used to evalu-ate the distribution of up to 36 ush-mounted rectangularheaters. The temperature proles and the heat uxes werecompared with experimental data for validation. The dis-sipated power was set as an input parameter and the op-timal distribution was selected as the one with the lowesttemperature elevation. Two dierent heuristicsa geo-metric parameter and an articial neural networkwereproposed and evaluated as alternatives to heavy CFD cal-culations.
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| 3. |
- Baudoin, Antoine
(författare)
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Cooling Strategies for Wave Power Conversion Systems
- 2016
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- The Division for Electricity of Uppsala University is developing a wave power concept. The energy of the ocean waves is harvested with wave energy converters, consisting of one buoy and one linear generator. The units are connected in a submerged substation. The mechanical design is kept as simple as possible to ensure reliability.The submerged substation includes power electronics and different types of electrical power components. Due to the high cost of maintenance operations at sea, the reliability of electrical systems for offshore renewable energy is a major issue in the pursuit of making the electricity production economically viable. Therefore, proper thermal management is essential to avoid the components being damaged by excessive temperature increases.The chosen cooling strategy is fully passive, and includes no fans. It has been applied in the second substation prototype with curved heatsinks mounted on the inner wall of the pressurized vessel. This strategy has been evaluated with a thermal model for the completed substation. First of all, 3D-CFD models were implemented for selected components of the electrical conversion system. The results from these submodels were used to build a lumped parameter model at the system level.The comprehensive thermal study of the substation indicates that the rated power in the present configuration is around 170 kW. The critical components were identified. The transformers and the inverters are the limiting components for high DC-voltage and low DC-voltage respectively. The DC-voltage—an important parameter in the control strategy for the WEC—was shown to have the most significant effect on the temperature limitation.As power diodes are the first step of conversion, they are subject to large power fluctuations. Therefore, we studied thermal cycling for these components. The results indicated that the junction undergoes repeated temperature cycles, where the amplitude increased with the square root of the absorbed power.Finally, an array of generic heat sources was optimized. We designed an experimental setup to investigate conjugate natural convection on a vertical plate with flush-mounted heat sources. The influence of the heaters distribution was evaluated for different dissipated powers. Measurements were used for validation of a CFD model. We proposed optimal distributions for up to 36 heat sources. The cooling capacity was maximized while the used area was minimized.
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| 4. |
- Baudoin, Antoine, et al.
(författare)
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Experimental Optimization of Passive Cooling of a Heat Source Array Flush-Mounted on a Vertical Plate
- 2016
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Ingår i: Energies. - : MDPI AG. - 1996-1073. ; 9:11
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Tidskriftsartikel (refereegranskat)abstract
- Heat sources, such as power electronics for offshore power, could be cooled passively—mainly by conduction and natural convection. The obvious advantage of this strategy is its high reliability. However, it must be implemented in an efficient manner (i.e., the area needs to be kept low to limit the construction costs). In this study, the placement of multiple heat sources mounted on a vertical plate was studied experimentally for optimization purposes. We chose a regular distribution, as this is likely to be the preferred choice in the construction process. We found that optimal spacing can be determined for a targeted source density by tuning the vertical and horizontal spacing between the heat sources. The optimal aspect ratio was estimated to be around two.
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| 5. |
- Baudoin, Antoine, et al.
(författare)
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Experimental results from a Thomson-coil actuator for a vacuum interrupter in an HVDC breaker
- 2019
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Ingår i: The Journal of Engineering. - : INST ENGINEERING TECHNOLOGY-IET. - 2051-3305. ; :17, s. 3527-3531
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Tidskriftsartikel (refereegranskat)abstract
- Recent developments in high-voltage direct current transmission technology and the plans for multi-terminals motivate research efforts on the fast DC breaker. A novel concept to interrupt current up to several kiloamperes within a few milliseconds is presently under development, using a vacuum interrupter together with power electronics to create an artificial zero-crossing in the current through the switch. To achieve this objective, one critical component in the concept is an ultra-fast linear mechanical actuator. A prototype has been developed based on a Thomson coil. The experimental results are presented and show how a contact gap in a vacuum interrupter was effectively created in a controlled manner. Current of several kiloamperes was successfully interrupted within 3ms, thanks to the high-speed operation of the linear actuator.
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| 6. |
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| 7. |
- Baudoin, Antoine, 1984-, et al.
(författare)
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Optimized distribution of a large number of power electronics components cooled by conjugate turbulent natural convection
- 2017
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Ingår i: Applied Thermal Engineering. - : Elsevier BV. - 1359-4311 .- 1873-5606. ; 124, s. 975-985
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Tidskriftsartikel (refereegranskat)abstract
- Natural convection allows for passive cooling which is used in many engineering applications. Placing dissipating components on a common vertical heatsink can be optimized to give the best possible cooling capacity. In this study, a numerical model for three-dimensional conjugated convective and conductive heat transfer was used to evaluate the distribution of up to 36 flush-mounted rectangular heaters. The temperature profiles and the heat fluxes were compared with experimental data for validation. The dissipated power was set as an input parameter and the optimal distribution was selected as the one with the lowest temperature elevation. Two different heuristics-a geometric parameter and an artificial neural network-were proposed and evaluated as alternatives to heavy CFD calculations.
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| 8. |
- Baudoin, Antoine, 1984-, et al.
(författare)
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Temperature and velocity measurements in a buoyant flow induced by a heat source array on a vertical plate
- 2017
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Ingår i: Experimental Thermal and Fluid Science. - : Elsevier BV. - 0894-1777 .- 1879-2286. ; 88, s. 234-245
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Tidskriftsartikel (refereegranskat)abstract
- Heat source arrays are common in engineering applications. Natural convection is a reliable and silent cooling strategy. Therefore, an array of flush-mounted heat sources has been studied under conjugate conduction and natural convection condition. This studies was performed for a system with relatively large dimensions, typical for power electronics, and a modified Rayleigh number up to 2 . 10(10) A modular set of heaters was designed to vary the distribution of heat sources on the plate and investigate the influence of the spacing. Velocity and temperature were measured in the convective flow with particle image velocimetry and micro-thermocouple. The velocity field was analyzed with proper orthogonal decomposition. The first instabilities of the convective flows were described. The results gave abetter understanding of the heat transfers in these configurations and are valuable for model validation.
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| 9. |
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| 10. |
- Baudoin, Antoine, et al.
(författare)
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Thermal modelling of a passively cooled inverter for wave power
- 2015
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Ingår i: IET Renewable Power Generation. - : Institution of Engineering and Technology (IET). - 1752-1416 .- 1752-1424. ; 9:4, s. 389-395
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Tidskriftsartikel (refereegranskat)abstract
- Owing to very costly maintenance operations, the reliability of electrical systems for offshore renewable energy is a major issue to make electricity production economical. Therefore proper thermal management is essential in order to avoid the components from being damaged by excessive temperature increase. Both analytic and computational fluid dynamics (CFD) models were implemented to assess the temperature increase in the inverter installed in a submerged substation and during working conditions. It was shown that this inverter could transmit a total power of up to about 35 kW. This limit is dependent on a certain distance between the modules and a perfect thermal contact with the hull. The influence of several of such parameters as well as the efficiency of passive cooling were studied.
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| 11. |
- Baudoin, Antoine, 1984-, et al.
(författare)
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Thermal Rating of a Submerged Substation for Wave Power
- 2016
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Ingår i: IEEE Transactions on Sustainable Energy. - 1949-3029 .- 1949-3037. ; 7:1, s. 436-445
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Tidskriftsartikel (refereegranskat)abstract
- The costs of offshore maintenance operations put high reliability-requirements on offshore equipment for ocean energy, especially on submerged ones. Thermal management is thus essential in the design of the prototypes of a marine substation, developed at Uppsala University, for grid interface of wave power parks. The cooling system itself should be efficient as well as reliable. Therefore, the feasibility of a completely passive cooling strategy was evaluated. The studied substation includes various power components, which dissipate heat and are installed in one pressurized vessel. Thermal cross-coupling was investigated with 3-D submodels and a thermal network model. An electric circuit was coupled to determine the rated power of the substation. The results depend mainly on the dc-voltage, the seawater temperature, and the thermal contact between the components and the hull.
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| 12. |
- Baudoin, Antoine
(författare)
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Thermal Study of a Submerged Substation for Wave Power
- 2014
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Licentiatavhandling (övrigt vetenskapligt/konstnärligt)abstract
- At the Division of Electricity of Uppsala University, a wave power concept is being developed.It relies on wave energy converters, one buoy and one linear generator placed on the seabed, connected together to a submerged substation. The mechanical design is kept as simple as possible to ensure reliability. The submerged substation includes power electronics and different types of electric components. High reliability requirements on such subsea devices make thermal management a keyaspect in the design. Besides, no fans are used and the cooling strategy is fully-passive. The overall approach for thermal modelling of the substation is based on a thermal network atthe system level, and both analytic- and CFD- modelling at the component level. This work is focusing on the second prototype of substation developed at Uppsala University. In this thesis, this overall strategy is presented as well as a comprehensive temperature study for the inverterinstalled in the substation.In the present configuration, the inverters are limited to about 35 kW. The seawater temperature,the choice of material for the heat-sink, and the spacing of the component, were identified tohave an influence on this value. The importance of a good thermal contact between the heat-sink and the hull was also illustrated.
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| 13. |
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| 14. |
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| 15. |
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| 16. |
- Lindblad, Liselotte, et al.
(författare)
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Measurement System For Wave Energy Converter - Design And Implementation
- 2014
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Ingår i: 33Rd International Conference On Ocean, Offshore And Arctic Engineering, 2014, Vol 9A. - : AMER SOC MECHANICAL ENGINEERS. - 9780791845530
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Konferensbidrag (refereegranskat)abstract
- A Wave Energy Converter (WEC) measurement system has been constructed and installed with the purpose to measure, log and evaluate the WEC's performance during operation at sea. The WEC is to be deployed at Uppsala University's wave power research site in Lysekil on the west coast of Sweden. In designing such a system the key research objectives has been (1) to study the risk of overheating due to high currents in the stator windings, (2) to evaluate how the WEC's outer structure withstands drag and bending forces from the buoy line and (3) to construct a detection system which indicates if water leaks into the generator. The measurement system was designed to collect data essential to study these key objectives. Transducers were used to measure: buoy line force, translator position, phase currents, bending and tensile strain on the generator hull, water level inside generator and the temperature at multiple places inside the generator. The measurement system has been installed and calibrated in the WEC. Furthermore, the design has been evaluated in lab experiments in order to verify the function and accuracy of the different measurements. This paper presents the underlying research objectives for developing the WEC generator measurement system, together with a description of the technical implementation.
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| 17. |
- Parwal, Arvind, et al.
(författare)
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Wave Energy Research at Uppsala University and The Lysekil Research Site, Sweden : A Status Update
- 2015
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Konferensbidrag (refereegranskat)abstract
- This paper provides a summarized status update ofthe Lysekil wave power project. The Lysekil project is coordinatedby the Div. of Electricity, Uppsala University since 2002, with theobjective to develop full-scale wave power converters (WEC). Theconcept is based on a linear synchronous generator (anchored tothe seabed) driven by a heaving point absorber. This WEC has nogearbox or other mechanical or hydraulic conversion systems,resulting in a simpler and robust power plant. Since 2006, 12 suchWECs have been build and tested at the research site located atthe west coast of Sweden. The last update includes a new andextended project permit, deployment of a new marine substation,tests of several concepts of heaving buoys, grid connection,improved measuring station, improved modelling of wave powerfarms, implementation of remote operated vehicles forunderwater cable connection, and comprehensive environmentalmonitoring studies.
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| 18. |
- Ängquist, Lennart, et al.
(författare)
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VARC - A Cost-Effective Ultrafast DC Circuit Breaker Concept
- 2018
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Ingår i: 2018 IEEE POWER & ENERGY SOCIETY GENERAL MEETING (PESGM). - : IEEE. - 9781538677032
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Konferensbidrag (refereegranskat)abstract
- A concept for a dc circuit-breaker is proposed. A vacuum interrupter is used together with a resonant circuit excited by a power electronic converter to create a zero-crossing in the interrupter current. A low amount of semiconductor devices is needed because they perform repeated switching operations during current excitation. Tests have been performed with a prototype interrupting 10 kA against 9 kV in 3 ms.
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