A low-speed permanent magnet (PM) cable wound generator for electrical energy conversion from marine or tidal currents has been designed and constructed. A key feature of this variable speed direct drive generator is its capability to efficiently generate electricity from tidal currents with very low velocities, in the order of 1 m/s. In arriving at an appropriate design for the generator typical characteristics of tidal currents were considered. Using these characteristics as input, and accounting for the electromagnetic losses, detailed computer simulations using a finite-element method software were carried out to come up with the final design. Various parameters that can influence the generator design are presented. An experimental set-up has been constructed based on the above-mentioned design in order to study the electrical and mechanical performance of the generator through a variety of experiments. The power input for this set-up is a variable speed motor, capable of operating the generator at rotational speeds of 0–16 r/min, representing tidal currents with very low velocities. The generator presented in this paper may be beneficial for a better understanding of an appropriate design and layout of tidal energy conversion systems.
NilssonK.Low speed generators for marine current power conversion. UURIE 229–05L, Uppsala, 2005.
2.
Non Nuclear Energy – JOULE II, wave energy project results. The exploitation of tidal marine currents. EU JOULE contract JOU2-CT94-0355. Technomare SpA, IT Power Ltd 1996.
Department of Trade and Industry, UK.Tidal Stream Energy Review. ETSU-T/05/00155/REP, 1993.
5.
BlundenL S.BahajA S.Tidal energy resource assessment for tidal stream generators. Proc. IMechE, Part A: J. Power and Energy, 2007, 221, 137–146.
6.
FrauJ. P.Tidal energy: Promising projects La Rance, a successful industrial-scale experiment. IEEE Trans. Energy Convers., 1993, 8(3), 552–558.
7.
AndreH.Ten years of experience at the “La Rance” Tidal Power Plant. Ocean Management, 1978, 4, 165–178.
8.
HammonsT. J.Tidal power. Proc. IEEE., 1993, 81(3), 419–433.
9.
BernshteinL. B.Tidal power development – a realistic justifiable and topical problem of today. IEEE Trans. Energy Convers., 1995, 10(3), 591–599.
10.
ClarkeJ. A.ConnorG.GrantA. D.JohnstoneC. M.Regulating the output characteristics of tidal current power stations to facilitate better base load matching over the lunar cycle. Renew. Energy, 2006, 31, 173–180.
BedardR.Survey and characterization of tidal in stream energy conversion (TISEC) devices. Report: EPRI-TP-004 NA, EPRI, 9 November 2005.
13.
SöderlundL.ErikssonJ.-T.SalonenJ.VihriäläH.PeräläR.A permanent magnet generator for wind power applications. IEEE Trans. Magnet., 1996, 32(4), 2389–2392.
14.
LampolaP.PerhoJ.Electromagnetic analysis of a low speed permanent magnetized wind generator. In Opportunities and Advances in International Power Generation, Durham, UK, 18–20 March 1996, conference publication number 419.
15.
SpoonerE.WilliamsonA. C.Direct coupled, permanent magnet generators for wind turbine applications. IEE Proc., Electr. Power Appl., 1996, 143(1), 1–8.
16.
Wind energy – the facts. An analysis of the wind energy in the EU-25, vol. 1: technology. A report published by The European Wind Energy Association (EWEA), p. 42, available from http://www.ewea.org/index.php?id=91, accessed 12 April 2007.
17.
LeijonM.NilssonK.Direct electric energy conversion system for energy conversion from marine currents. Proc. IMechE, Part A: J. Power and Energy, 2007, 221(A2), 201–205.
WangD.AtlarM.SampsonR.An experimental investigation on cavitation, noise and slipstream characteristics of ocean stream turbines. Proc. IMechE Part A: J. Power and Energy, 2007, 221, 219–231.
20.
CraiuO.DanN.BadeaE. A.Numerical analysis of permanent magnet DC motor performances. IEEE Trans. Magnet., 1995, 31, 3500–3502.
21.
ReeceA. B. J.PrestonT. W.Finite element methods in electrical power engineering, 2000, p. 121 (Oxford science publications).
22.
TsukermanI. A.KonradA.MeunierG.SabonnadiereJ. C.Coupled field-circuit problems: trends and accomplishments. In Digest of the Fifth Biennial IEEE Conference on Electromagnetic Field Computation, 1992.
23.
VassentE.MeunierG.FoggiaA.ReyneG.Simulation of induction machine operation using a step by step finite element method. IEEE Trans. Magnet., 1991, 27, 5232–5234.
24.
Anon. 2. Ace, modified version 3.1, ABB common platform for field analysis and simulations. ABB Corporate Research Centre, ABB AB, Corporate Research, Västerås, Sweden.
25.
DahlgrenM.FrankH.LeijonM.OwmanF.WalfridssonL.Windformer – wind power goes large scale. ABB Rev., 2000, 3, 31–37.
26.
LeijonM.LiuR.Energy technologies: electric power generators, vol. 3, 2002, pp. 151–164 (Landolt-Börnstein).
27.
LeijonM.DahlgrenM.WalfridssonL.MingL.JakstsA.Windformer–a recent development in the electrical insulation systems of generators and transformers. IEEE Electric. Insul. Mag., 2001, 17(3), 10–15.
28.
Draka product information, available from http://www.draka.se, accessed 25 September 2007.
29.
WatersR.StalbergM.DanielssonO.SvenssonO.GustafssonS.StrömstedtE.ErikssonM.SundbergJ.LeijonM.Experimental results from sea trials of an offshore wave energy system. Appl. Phys. Lett., 2007, 90, 034105.
30.
ErikssonS.Vertical axis wind turbines with direct driven generators. UURIE 302–06L, Uppsala, 2006.
31.
JadricI.BorojevicD.JadricM.Modeling and control of a synchronous generator with an active DC load. IEEE Trans. Power Electron., 2000, 15(2), 303–311.
32.
EsmailiR.XuL.NicholsD. K.A new control method of permanent magnet generator for maximum power tracking in wind turbine application. In the IEEE Power Engineering Society General Meeting, vol. 3, 2005, pp. 2090–2095.
33.
DanielssonO.LeijonM.SjöstedtE.Detailed study of the magnetic circuit in a longitudinal flux permanent-magnet synchronous linear generator. IEEE Trans. Magnet., 2005, 41(9), 2490–2495.
34.
Product information, hysteresis data for M800–100A, available from http://www.sura.se, accessed 25 September 2007.
GuptaR.YoshinoT.SaitoY.Finite element solution of permanent magnetic field. IEEE Trans. Magnet., 1990, 26(2), 383–386.
37.
IEEE Guide 115–1995: Test procedures for synchronous machines, part I–Acceptance and performance testing; part II–Test procedures and parameter determination for dynamic analysis. IEEE, 1 May 1995, 192 pp.
38.
SKF – Product information and models to calculate losses, available from www.skf.com, accessed 25 September 2007.
