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Full Scale Applications of Permanent Magnet Electromagnetic Energy Converters: From Nd2Fe14B to Ferrite
Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Electricity.
2013 (English)Doctoral thesis, comprehensive summary (Other academic)
Abstract [en]

This thesis presents research regarding a full scale linear ferrite permanent magnet generator, installed in a wave energy conversion system. The ferrite based magnetic circuit, supplementing the previous utilized Nd2Fe14B-magnet design, is designed with an electromagnetic numerical simulation tool, where the model is derived from Maxwell’s equations. The full scale design is, known to the author, the first developed linear ferrite based machine. The material change in the magnetic circuit required different mechanical solutions of the generator. The fundamental, primary theory and reasoning behind the new mechanical design is here presented, where sustainability, economy and production have been in focus and affected the final design. Two versions of the generator have been assembled and deployed at the projects experimental site on the Swedish west coast, and three more are under construction, planned to be installed during the autumn of 2013.  

Further, the thesis presents an electric conversion circuit based on the electric resonance phenomena. Full scale experimental results present a successfully achieved electric resonance between the linear wave energy generator and external circuit.

Finally, research regarding a two pole permanent magnet motor for an electrical vehicle is presented. Detailed analytical and numerical calculations are utilized to investigate the losses in the machine over a wide frequency interval. The results indicate the possibility of an increased efficiency of electrical motors in electrical vehicle system and argue for elimination of the gearbox. The system total efficiency and mechanical stability can thereby be increased.   

The work concerning the wave energy converter is a part of a larger project, the Lysekil Wave Power Project, developed by a research group at Uppsala University, whereas the work concerning the electric motor so far has been carried out as an individual project. However, a future goal is to integrate the research on the electric motor for electric vehicles with ongoing research regarding a flywheel based electric driveline for an All Electric Propulsion System.      

Place, publisher, year, edition, pages
Uppsala: Acta Universitatis Upsaliensis, 2013. , 75 p.
Series
Digital Comprehensive Summaries of Uppsala Dissertations from the Faculty of Science and Technology, ISSN 1651-6214 ; 1074
National Category
Water Engineering
Identifiers
URN: urn:nbn:se:uu:diva-207280ISBN: 978-91-554-8752-2 (print)OAI: oai:DiVA.org:uu-207280DiVA: diva2:647550
Public defence
2013-10-25, Polhemsalen, Ångströmslaboratoriet, Regementsvägen 1, Uppsala, 15:55 (English)
Opponent
Supervisors
Available from: 2013-10-04 Created: 2013-09-11 Last updated: 2014-01-23
List of papers
1. Supplementing rare-earth metal with ferrite in wave power generator
Open this publication in new window or tab >>Supplementing rare-earth metal with ferrite in wave power generator
(English)In: Renewable energy, ISSN 0960-1481, E-ISSN 1879-0682Article in journal (Refereed) Submitted
National Category
Energy Systems
Identifiers
urn:nbn:se:uu:diva-207161 (URN)
Available from: 2013-09-10 Created: 2013-09-10 Last updated: 2017-12-06Bibliographically approved
2. Ideal Analytical Expression of the Magnetic Circuit in a Permanent Magnet Linear Machine
Open this publication in new window or tab >>Ideal Analytical Expression of the Magnetic Circuit in a Permanent Magnet Linear Machine
2013 (English)In: Proceedings of the Ecological Vehicles and Renewable Energies (EVER), 2013, 2013, 1-6 p.Conference paper, Published paper (Refereed)
Abstract [en]

The aim of this paper is to presents a study and derived expressions of the magnetic flux density in the air-gap of the linear synchronous permanent magnet generator, utilized in the wave energy converter. The significance of a well-modelled magnetic flux density-term is important, when, for example, modelling the induced voltage and dimension the support structure due to the magnetic force between the stator and translator at no load situation.

National Category
Energy Systems
Research subject
Engineering Science with specialization in Science of Electricity
Identifiers
urn:nbn:se:uu:diva-207165 (URN)10.1109/EVER.2013.6521545 (DOI)000325276700028 ()978-1-4673-5269-7 (ISBN)
Conference
Eighth International Conference and Exhibition on Ecological Vehicles and Renewable Energies EVER’13, March 27-30, 2013, Monte-Carlo, Monaco
Available from: 2013-09-10 Created: 2013-09-10 Last updated: 2014-01-23Bibliographically approved
3. Experimental results from a linear wave power generator connected to a resonance circuit
Open this publication in new window or tab >>Experimental results from a linear wave power generator connected to a resonance circuit
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2012 (English)In: Wiley Interdisciplinary Reviews: Energy and Environment, ISSN 2041-8396, E-ISSN 2041-840X, Vol. 2, no 4, 456-464 p.Article in journal (Refereed) Published
Abstract [en]

The output voltage from a direct-driven permanent magnet linear generator installed in a wave power plant varies both in amplitude and frequency. Electrical conversion is therefore necessary before grid connection can be achieved. The aim of this paper is to present an electrical conversion system based on the electric resonance phenomena. As one of the first steps in the development, and to gain further knowledge and understanding of the proposed resonance circuit, experimental tests with a single-phase permanent magnet linear generator connected to a resonance circuit were performed. The experimental results presented in this paper indicated that a successful resonance between the generator and external circuit was achieved. The research regarding the wave energy converters lies within The Lysekil Wave Power Project at Uppsala University and has been ongoing since 2002.

National Category
Engineering and Technology
Research subject
Engineering Science with specialization in Science of Electricity
Identifiers
urn:nbn:se:uu:diva-190112 (URN)10.1002/wene.19 (DOI)000343208400007 ()
Available from: 2013-01-07 Created: 2013-01-07 Last updated: 2017-12-06Bibliographically approved
4. Electric resonance-rectifier circuit for renewable energy conversion
Open this publication in new window or tab >>Electric resonance-rectifier circuit for renewable energy conversion
2012 (English)In: Applied Physics Letters, ISSN 0003-6951, E-ISSN 1077-3118, Vol. 100, no 4, 043511- p.Article in journal (Refereed) Published
Abstract [en]

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.

National Category
Physical Sciences Electrical Engineering, Electronic Engineering, Information Engineering
Research subject
Engineering Science with specialization in Science of Electricity
Identifiers
urn:nbn:se:uu:diva-171440 (URN)10.1063/1.3680097 (DOI)000300064500076 ()
Available from: 2012-03-19 Created: 2012-03-19 Last updated: 2017-12-07Bibliographically approved
5. A resonance circuit for electrical conversion systems
Open this publication in new window or tab >>A resonance circuit for electrical conversion systems
2011 (English)In: PS Public Service Review, Vol. European Union, no 22, 268-271 p.Article in journal (Refereed) Published
Place, publisher, year, edition, pages
PS Public Service Review, 2011
National Category
Engineering and Technology
Research subject
Engineering Science with specialization in Science of Electricity
Identifiers
urn:nbn:se:uu:diva-164211 (URN)
Available from: 2011-12-16 Created: 2011-12-16 Last updated: 2016-04-20Bibliographically approved
6. Linear Generator Connected to a Resonance-Rectifier Circuit
Open this publication in new window or tab >>Linear Generator Connected to a Resonance-Rectifier Circuit
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2013 (English)In: IEEE Journal of Oceanic Engineering, ISSN 0364-9059, E-ISSN 1558-1691, Vol. 38, no 2, 255-262 p.Article in journal (Refereed) Published
Abstract [en]

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.

Keyword
Linear direct driven generators, resonance circuits, wave energy conversion
National Category
Engineering and Technology
Research subject
Engineering Science with specialization in Science of Electricity
Identifiers
urn:nbn:se:uu:diva-200363 (URN)10.1109/JOE.2012.2227552 (DOI)000317920200004 ()
Available from: 2013-05-28 Created: 2013-05-27 Last updated: 2017-12-06Bibliographically approved
7. Theory and Simulations of an End Stop Solution in a Linear Wave Power Generator
Open this publication in new window or tab >>Theory and Simulations of an End Stop Solution in a Linear Wave Power Generator
(English)Manuscript (preprint) (Other academic)
National Category
Other Civil Engineering
Identifiers
urn:nbn:se:uu:diva-207205 (URN)
Available from: 2013-09-10 Created: 2013-09-10 Last updated: 2014-09-18Bibliographically approved
8. Tolerance Analysis in a Linear Permanent Magnet Generator
Open this publication in new window or tab >>Tolerance Analysis in a Linear Permanent Magnet Generator
(English)Article in journal (Refereed) Submitted
National Category
Energy Systems
Identifiers
urn:nbn:se:uu:diva-207166 (URN)
Available from: 2013-09-10 Created: 2013-09-10 Last updated: 2014-01-23Bibliographically approved
9. Analysis of longitudinal ends effects in a Linear Permanent Magnet Generator
Open this publication in new window or tab >>Analysis of longitudinal ends effects in a Linear Permanent Magnet Generator
(English)Article in journal (Refereed) Submitted
National Category
Energy Systems
Identifiers
urn:nbn:se:uu:diva-207168 (URN)
Available from: 2013-09-10 Created: 2013-09-10 Last updated: 2014-01-23Bibliographically approved
10. Prediction of the Inductance in a Synchronous Linear Permanent Magnet Generator
Open this publication in new window or tab >>Prediction of the Inductance in a Synchronous Linear Permanent Magnet Generator
2011 (English)In: Journal of Electromagnetic Analysis and Applications, ISSN 1942-0730, E-ISSN 1942-0749, Vol. 3, no 5, 155-159 p.Article in journal (Refereed) Published
Abstract [en]

This paper presents calculations of the varying inductances profile for a synchronous linear surface mounted permanent magnet generator in an ABC reference system. Calculations are performed by utilizing the reluctance term, known from analytic calculations and finite element method simulations. With the inductance term identified, the voltage difference between the generator’s no load and load voltage can be calculated and an external circuit can be designed for optimal use of the generator. Two different operation intervals of the linear generator are considered and the results are discussed. The result indicates that time costly finite element simulations can be replaced with simple analytical calculations for a surface mounted permanent magnet linear generator.

Keyword
Wave Power, Synchronous Linear Permanent Magnet Generator, Varying Inductance, ABC of Frame Reference
National Category
Engineering and Technology
Research subject
Engineering Science with specialization in Science of Electricity
Identifiers
urn:nbn:se:uu:diva-164202 (URN)10.4236/jemaa.2011.35025 (DOI)
Available from: 2011-12-16 Created: 2011-12-16 Last updated: 2017-12-08Bibliographically approved
11. Electrical Motor Drivelines in Commercial All Electric Vehicles: a Review
Open this publication in new window or tab >>Electrical Motor Drivelines in Commercial All Electric Vehicles: a Review
Show others...
2012 (English)In: IEEE Transactions on Vehicular Technology, ISSN 0018-9545, E-ISSN 1939-9359, Vol. 61, no 2, 475-484 p.Article in journal (Refereed) Published
Abstract [en]

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.

Keyword
Motor drives, Road vehicle electric propulsion, Road vehicle power systems, Traction motors
National Category
Electrical Engineering, Electronic Engineering, Information Engineering
Research subject
Engineering Science with specialization in Science of Electricity
Identifiers
urn:nbn:se:uu:diva-157858 (URN)10.1109/TVT.2011.2177873 (DOI)000300427400005 ()
Available from: 2012-04-19 Created: 2011-08-24 Last updated: 2017-12-08Bibliographically approved
12. On a Two Pole Motor for Electric Propulsion System
Open this publication in new window or tab >>On a Two Pole Motor for Electric Propulsion System
Show others...
2013 (English)In: International Journal of Engineering Science and Innovative Technology, ISSN 2319 - 5967, Vol. 2, no 1, 99-111 p.Article in journal (Refereed) Published
National Category
Energy Systems
Research subject
Engineering Science with specialization in Science of Electricity
Identifiers
urn:nbn:se:uu:diva-207170 (URN)
Available from: 2013-09-10 Created: 2013-09-10 Last updated: 2016-10-06Bibliographically approved

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