Volume 12 Issue 1
Study of an Altered Magnetic Circuit of a Permanent Magnet Linear Generator for Wave Power
Jennifer Leijon, Jonathan Sjölund, Boel Ekergård, Cecilia Boström, Sandra Eriksson, Irina Temiz and Mats Leijon
1Department of Engineering Sciences, Uppsala University, Box 534, 751 21 Uppsala, Sweden
2Seabased Industry AB, Verkstadsgatan 4, 453 30 Lysekil, Sweden
3Department of Electrical Engineering, Chalmers University of Technology, 412 96 Gothenburg, Sweden
*Author to whom correspondence should be addressed.
Abstract
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 Nd2Fe14B-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.
Keywords: wave energy converter (WEC); linear generator (LG); ferrite permanent magnets (PMs); renewable energy sources