Machines 2014, 2(2), 120-133; doi:10.3390/machines2020120

A Complete Design of a Rare Earth Metal-Free Permanent Magnet Generator

1,* email, 1email, 1email and 1,2email
Received: 25 February 2014; in revised form: 2 April 2014 / Accepted: 13 May 2014 / Published: 16 May 2014
(This article belongs to the Special Issue Advances in Machinery for Renewable Power Generation)
This is an open access article distributed under the Creative Commons Attribution License which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.
Abstract: The price of rare-earth metals used in neodymium-iron-boron (NdFeB) permanent magnets (PMs) has fluctuated greatly recently. Replacing the NdFeB PMs with more abundant ferrite PMs will avoid the cost insecurity and insecurity of supply. Ferrite PMs have lower performance than NdFeB PMs and for similar performance more PM material has to be used, requiring more support structure. Flux concentration is also necessary, for example, by a spoke-type rotor. In this paper the rotor of a 12 kW NdFeB PM generator was redesigned to use ferrite PMs, reusing the existing stator and experimental setup. Finite element simulations were used to calculate both electromagnetic and mechanical properties of the design. Focus was on mechanical design and feasibility of construction. The result was a design of a ferrite PM rotor to be used with the old stator with some small changes to the generator support structure. The new generator has the same output power at a slightly lower voltage level. It was concluded that it is possible to use the same stator with either a NdFeB PM rotor or a ferrite PM rotor. A ferrite PM generator might require a larger diameter than a NdFeB generator to generate the same voltage.
Keywords: rare earth metal-free; permanent magnet; synchronous generator
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MDPI and ACS Style

Eklund, P.; Sjökvist, S.; Eriksson, S.; Leijon, M. A Complete Design of a Rare Earth Metal-Free Permanent Magnet Generator. Machines 2014, 2, 120-133.

AMA Style

Eklund P, Sjökvist S, Eriksson S, Leijon M. A Complete Design of a Rare Earth Metal-Free Permanent Magnet Generator. Machines. 2014; 2(2):120-133.

Chicago/Turabian Style

Eklund, Petter; Sjökvist, Stefan; Eriksson, Sandra; Leijon, Mats. 2014. "A Complete Design of a Rare Earth Metal-Free Permanent Magnet Generator." Machines 2, no. 2: 120-133.

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