| 1. |
- Bostrom, Cecilia, et al.
(author)
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Electric resonance-rectifier circuit for renewable energy conversion
- 2012
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In: Applied Physics Letters. - : AIP Publishing. - 0003-6951 .- 1077-3118. ; 100:4, s. 043511-
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Journal article (peer-reviewed)abstract
- Variable speed generators are used more frequently for converting the energy from renewable energy sources to electric energy. The power production form a variable speed generator is dependent on the electrical damping of the generator. In this paper, a resonance circuit connected to a direct driven linear generator used for wave energy utilization is investigated. At resonance, the electrical damping in the generator increases which results in an increased power production. The results show that resonance can be achieved with the suggested circuit.
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| 2. |
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| 3. |
- Boström, Cecilia, et al.
(author)
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Linear Generator Connected to a Resonance-Rectifier Circuit
- 2013
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In: IEEE Journal of Oceanic Engineering. - 0364-9059 .- 1558-1691. ; 38:2, s. 255-262
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Journal article (peer-reviewed)abstract
- This paper describes a linear direct driven generator used for wave energy utilization. The generator is placed on the seabed and connected to a buoy on the ocean surface. Due to the reciprocating motion of the translator, an electrical conversion system is needed between the wave energy converter (WEC) and the grid. Depending on how the conversion system is designed, the generator will be subjected to different loads. A novel conversion system is presented in this paper where the voltage from the WEC is rectified in a resonance circuit. Both simulations and experiments are performed on the circuit. The results from the simulations show that a higher power absorption and power production can be achieved with the resonance circuit compared to a WEC connected to a passive rectifier. A WEC, L9, developed by Uppsala University (Uppsala, Sweden) was used in the experiment. Significantly higher power absorption was obtained for L9 compared to power data from the first installed WEC, L1, at the Lysekil research site.
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| 4. |
- Chatzigiannakou, Maria Angeliki, et al.
(author)
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Numerical analysis of an Uppsala University WEC deployment by a barge for different sea states
- 2020
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In: Ocean Engineering. - : Elsevier BV. - 0029-8018 .- 1873-5258. ; 205
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Journal article (peer-reviewed)abstract
- Wave energy converters (WECs) have been deployed onshore, nearshore, and offshore to convert ocean wave movement into electricity. The exploitation of renewable energy sources has restrictions; in the case of wave energy, high installation, maintenance, and decommissioning costs have limited their commercial use. Moreover, these offshore operations can be compromised by safety issues. This paper draws attention to offshore operation safety of a WEC developed by Uppsala University. Specifically, this paper investigates what sea states are suitable for the safe deployment of a WEC from a barge. This study follows recommendations in DNV-RP-H103 for analysis of offshore operations, namely lifting through the wave zone. ANSYS Aqwa is used to find hydrodynamic forces acting on a typical barge, using frequency domain analysis. Based on these hydrodynamic simulation results and methodology given in DNV-RP-H103, tables are created to show the sea states that would allow for the safe installation of a WEC using a typical barge. Considered sea states have significant wave heights varying between 0 m and 3 m and the wave zero crossing periods varying between 3 s and 13 s. The WEC submersions are considered between 0 m and 7 m, i.e. when the WEC is in the air until it is fully submerged. © 2020 Elsevier Ltd
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| 5. |
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| 6. |
- Danyang, Cui, et al.
(author)
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Design of Spoke Type Traction Motor with Ferrite Material for EV Application
- 2022
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In: 2022 International Conference on Electrical Machines (ICEM). - : Institute of Electrical and Electronics Engineers (IEEE). ; , s. 315-320
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Conference paper (peer-reviewed)abstract
- Motor design for electric vehicle application using non-rare-earth permanent magnetic materials has become a research hotspot due to cost reduction and environmental issues. Among different motor topologies, permanent magnet synchronous motor (PMSM) with spoke-type ferrite magnets has great potential because of its competitive performance. In this paper, a novel design of a spoke-type synchronous motor using ferrite Y40 and non-magnetic steel material is presented, with optimizations on the overall structure and considerations on the effects of pole numbers. The performance of the designed motor verified with magnetic simulations shows that it has a high probability to be a candidate for replacing the conventional PMSM with rare-earth materials in Electric Vehicles (EV) application. © 2022 IEEE.
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| 7. |
- de Santiago, Juan, et al.
(author)
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Electrical Motor Drivelines in Commercial All Electric Vehicles : a Review
- 2012
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In: IEEE Transactions on Vehicular Technology. - 0018-9545 .- 1939-9359. ; 61:2, s. 475-484
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Journal article (peer-reviewed)abstract
- This paper presents a critical review of the drivelines in all Electric Vehicles (EVs). The motor topologies that are the best candidates to be used in EVs are presented. The advantages and disadvantages of each electric motor type are discussed from a system perspective. A survey of the electric motors used in commercial EVs is presented. The survey shows that car manufacturers are very conservative when it comes to introducing new technologies. Most of the EV’s in the market mount a single induction or permanent magnet motor with a traditional mechanic driveline with a differential. The study illustrates that comparisons between the different motors are made difficult by the large number of parameters and the lack of a recommended test scheme. The authors propose that a standardized drive cycle is used to test and compare motors.
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| 8. |
- Dolguntseva, Irina, 1981-, et al.
(author)
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Risk based estimation of failure in a steel wire used for the wave energy converter connection line
- 2014
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Conference paper (peer-reviewed)abstract
- The wave energy converter being developed at Uppsala University is of a point absorber type utilizing heaving motion of waves with a direct driven linear generator power take off. The point absorber, a buoy, is placed on the sea surface and is connected to the translator by a connection line. The connection line service life is of large importance for the lifetime of the entire device. Steel wire used as the connection line should be chosen to withstand loadings with different amplitude and frequency. In the present study, the risk of failure in the connection line is estimated.
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| 9. |
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| 10. |
- Ekergård, Boel, et al.
(author)
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Axial Force Damper in a Linear Wave Energy Converter
- 2013
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In: Development and Applications of Oceanic Engineering (DAOE). - 2325-3762. ; 2:2, s. 33-38
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Journal article (peer-reviewed)abstract
- This paper presents a study on the axial force damper in a wave energy converter. The converter itself consists of a linear generator placed on the ocean floor connected to a buoy at the ocean surface. As the development of the complete system goes forward, the economical perspective becomes more and more important. In order to ensure an economically viable alternative to the electric energy conversion, the costs associated with the use of materials have to be reduced while the survivability of the wave power unit has to be prolonged. The study presented in this paper increases the knowledge on axial forces and illustrates the damping system required to prevent the failure of the hull which houses the generator. The results are aimed to be utilized in the future design of wave energy converters and influence the choice of materials, the total costs and prolong the survivability of the wave energy converters in harsh wave climates.
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