An electrical approach to wave energy conversion

Leijon, Mats; Danielsson, Oskar; Eriksson, Mikael; Thorburn, Karin; Bernhoff, Hans; Isberg, Jan; Sundberg, Jan; Иванова, Ирина; Sjöstedt, Elisabeth; Ågren, Olov; Karlsson, Karl Erik; Wolfbrandt, Arne

doi:10.1016/j.renene.2005.07.009

Cited by 143 publications

(73 citation statements)

References 14 publications

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“…There is no conclusive approach as to how to include partial stator overlap in the PTO modeling, which is reviewed in the background section. To the authors' knowledge, partial stator overlap in permanent magnet linear generators is a topic for the concept from Uppsala University [15,16], the Archimedes Wave Swing [17,18], the Berkeley Wedge [5] and the linear generator developed at Oregon State University [6].…”

Section: Introductionmentioning

confidence: 99%

Partial Stator Overlap in a Linear Generator for Wave Power: An Experimental Study

Frost

Ulvgård

Sjökvist

et al. 2017

JMSE

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This paper presents a study on how the power absorption and damping in a linear generator for wave energy conversion are affected by partial overlap between stator and translator. The theoretical study shows that the electrical power as well as the damping coefficient change quadratically with partial stator overlap, if inductance, friction and iron losses are assumed independent of partial stator overlap or can be neglected. Results from onshore experiments on a linear generator for wave energy conversion cannot reject the quadratic relationship. Measurements were done on the inductance of the linear generator and no dependence on partial stator overlap could be found. Simulations of the wave energy converter's operation in high waves show that entirely neglecting partial stator overlap will overestimate the energy yield and underestimate the peak forces in the line between the buoy and the generator. The difference between assuming a linear relationship instead of a quadratic relationship is visible but small in the energy yield in the simulation. Since the theoretical deduction suggests a quadratic relationship, this is advisable to use during modeling. However, a linear assumption could be seen as an acceptable simplification when modeling since other relationships can be computationally costly.

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Section: Introductionmentioning

confidence: 99%

Partial Stator Overlap in a Linear Generator for Wave Power: An Experimental Study

Frost

Ulvgård

Sjökvist

et al. 2017

JMSE

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“…Assuming that the fluid flow is inviscid, incompressible, and irrotational, the motion of the WEC can be expressed according to Newton's law as: (6) where m is the total mass of the buoy and translator and is the vertical acceleration of the WEC.…”

Section: Wec Modelmentioning

confidence: 99%

“…A variety of technologies for converting wave energy to electricity have been developed in the past decades [1][2][3][4][5]. This paper focus on a wave energy converter (WEC) concept developed at the Swedish Centre for Renewable Electric Energy Conversion at Uppsala University [6][7][8]. As shown in Figure 1 [9], the WEC contains two main parts, a floating buoy and a submerged linear generator.…”

Section: Introductionmentioning

confidence: 99%

Nonlinear Passive Control of a Wave Energy Converter Subject to Constraints in Irregular Waves

Wang

Isberg

2015

Energies

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This paper investigates a passive control method of a point absorbing wave energy converter by considering the displacement and velocity constraints under irregular waves in the time domain. A linear generator is used as a power take-off unit, and the equivalent damping force is optimized to improve the power production of the wave energy converter. The results from nonlinear and linear passive control methods are compared, and indicate that the nonlinear passive control method leads to the excitation force in phase with the velocity of the converter that can significantly improve the energy production of the converter.

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“…An application of a direct drive PMLG for wave energy conversion (mainly used for the Archimedes Wave Swings) was suggested in [19]. PMLGs for single-body point absorbers were discussed in [20,21] and for two-body floating point absorbers in [22]. Various topologies for PMLG for wave power conversion were summarized in [23], and some generator designs were compared in [23][24][25][26].…”

Section: Introductionmentioning

confidence: 99%

Study of an Altered Magnetic Circuit of a Permanent Magnet Linear Generator for Wave Power

et al. 2017

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The wave energy converter (WEC) studied and developed at Uppsala University in Sweden is a point absorbing buoy connected to a linear generator (LG) on the seabed. Previous studies have improved the sustainability of the generator, changing its magnets from Nd 2 Fe 14 B-magnets to ferrites. In this paper, the magnetic circuit of the linear generator is further studied. Ferrite magnets of two different types (Y30 and Y40) are studied along with different shapes of pole shoes for the system. The finite element method (FEM) simulations in a program called Ace are performed. The results show that a linear generator including both Y30 and Y40 magnets and shortened T-shaped pole shoes can generate a similar magnetic energy in the airgap as a linear generator only containing Y40 magnets and rectangular pole shoes. This shows that the magnetic circuit can be altered, opening up sizes and strengths of magnets for different retailers, and thereby possibly lowering magnet cost and transportation. This work was previously presented as a conference at the European Wave and Tidal Energy Conference (EWTEC) 2017 in Cork, Ireland; this manuscript has been carefully revised and some discussions, on magnet costs for example, have been added to this paper.

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An electrical approach to wave energy conversion

Cited by 143 publications

References 14 publications

Partial Stator Overlap in a Linear Generator for Wave Power: An Experimental Study

Partial Stator Overlap in a Linear Generator for Wave Power: An Experimental Study

Nonlinear Passive Control of a Wave Energy Converter Subject to Constraints in Irregular Waves

Study of an Altered Magnetic Circuit of a Permanent Magnet Linear Generator for Wave Power

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