On the Optimal Pole Width for Direct Drive Linear Wave Power Generators Using Ferrite Magnets

Anders Hagnestål
Additional contact information
Anders Hagnestål: Department of Electric Power and Energy Systems, School of Electrical Engineering and Computer Science, KTH Royal Institute of Technology, Teknikringen 33, 100 44 Stockholm, Sweden

Energies, 2018, vol. 11, issue 6, 1-24

Abstract: In this work, ferrite magnet linear generators for wave power applications are considered. These machines operate at unusually low speeds, around and even below 1 m/s, at which the optimal geometry differs from standard machines, since the copper loss and the force density become considerably more important. The focus is on translator design, and analytical two-dimensional (2D) expressions for the optimal 2D geometry are derived. Finite Element Analysis (FEA) is also applied to verify the analytical expressions and to determine effects from leakage fluxes and iron saturation. Demagnetization of ferrite magnets is also discussed and calculations are made to show the demagnetization situation for the magnets in different geometries. Finally, an example generator design is made to illustrate the findings. This generator is compared to three other generator concepts. It is concluded that ferrite magnet generators can have at least nearly the same shear stress as surface mounted neodymium magnet generators at low speed if the airgap is 3 mm or less, provided that a proper pole length is chosen, and that they can be economically competitive to neodymium magnet generators for wave power. It is also concluded that the demagnetization situation for the magnets can be severe, and that the choice of magnet grade and pole length is crucial in this respect.

Keywords: direct driven generators; ferrite magnets; linear generators; PTO systems; wave power (search for similar items in EconPapers)
JEL-codes: Q Q0 Q4 Q40 Q41 Q42 Q43 Q47 Q48 Q49 (search for similar items in EconPapers)
Date: 2018
References: View references in EconPapers View complete reference list from CitEc
Citations:

Downloads: (external link)
https://www.mdpi.com/1996-1073/11/6/1356/pdf (application/pdf)
https://www.mdpi.com/1996-1073/11/6/1356/ (text/html)

Related works:
This item may be available elsewhere in EconPapers: Search for items with the same title.

Export reference: BibTeX RIS (EndNote, ProCite, RefMan) HTML/Text

Persistent link: https://EconPapers.repec.org/RePEc:gam:jeners:v:11:y:2018:i:6:p:1356-:d:149086

Access Statistics for this article

Energies is currently edited by Ms. Agatha Cao

More articles in Energies from MDPI
Bibliographic data for series maintained by MDPI Indexing Manager ().