A Rare-Earth Free Magnetically Geared Generator for Direct-Drive Wind Turbines

Reza Zeinali and Ozan Keysan
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Reza Zeinali: Electrical and Electronics Engineering, Middle East Technical University (METU), Ankara 06800, Turkey
Ozan Keysan: Electrical and Electronics Engineering, Middle East Technical University (METU), Ankara 06800, Turkey

Energies, 2019, vol. 12, issue 3, 1-15

Abstract: A novel Vernier type magnetically geared direct-drive generator for large wind turbines is introduced in this paper. Conventional Vernier-type machines and most of the direct-drive wind turbine generators use excessive amount of permanent magnet, which increases the overall cost and makes the manufacturing process challenging. In this paper, an electrically excited (PM_less) claw-pole type Vernier machine is presented. This new topology has the potential of reducing mass and cost of the generator, and can make the construction easy in manufacturing and handling. Analytical designs are verified using 3D finite-element simulations and several designs are evaluated to find the optimum design for a 7.5 MW, 12 rpm wind turbine application. It is shown, that the required torque can be achieved with an outer diameter of 7.5 m, and with a mass of 172 t (including the structural mass). The proposed generator is compared with commercial direct-drive generators, and it is found that the proposed generator has the highest torque density with 34.7 kNm/t.

Keywords: direct-drive generators; magnetic-geared generators; Vernier type machines; wind turbines (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: 2019
References: View references in EconPapers View complete reference list from CitEc
Citations: View citations in EconPapers (3)

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