Motor Magnetico

NREL/CP-500-24996 Ÿ UC Category: 1213

Axial Flux, Modular, PermanentMagnet Generator with a Toroidal Winding for Wind Turbine Applications

E. Muljadi C.P. Butterfield Yih-Huei Wan National Wind Technology Center National Renewable Energy Laboratory Presented at IEEE Industry Applications Conference St. Louis, MO November 5-8, 1998

National Renewable Energy Laboratory 1617 Cole BoulevardGolden, Colorado 80401-3393 A national laboratory of the U.S. Department of Energy Managed by Midwest Research Institute for the U.S. Department of Energy under contract No. DE-AC36-83CH10093 Work performed under task number WE803020 July 1998

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Axial Flux, Modular, Permanent-MagnetGenerator with a Toroidal Winding for Wind Turbine Applications
E. Muljadi, C. P. Butterfield, Yih-Huei Wan National Renewable Energy Laboratory 1617 Cole Boulevard Golden, CO 80401 Tel. (303)384-6900, Fax (303)384-6999 Eduard_muljadi@nrel.gov, http://www.nrel.gov/wind

Abstract – Permanent-magnet generators have been used for wind turbines for many years. Many small wind turbine manufacturersuse direct-drive permanent-magnet generators. For wind turbine generators, the design philosophy must cover the following characteristics: low cost, light weight, low speed, high torque, and variable speed generation. The generator is easy to manufacture and the design can be scaled up for a larger size without major retooling.
A modular permanent-magnet generator with axial flux direction waschosen. The permanent magnet used is NdFeB or ferrite magnet with flux guide to focus flux density in the air gap. Each unit module of the generator may consist of one, two, or more phases. Each generator can be expanded to two or more unit modules. Each unit module is built from simple modular poles. The stator winding is formed like a torus. Thus, the assembly process is simplified and the windinginsertion in the slot is less tedious. We built a prototype of one unit module and performed preliminary tests in our laboratory. Follow up tests will be conducted in our lab to improve the design. I. INTRODUCTION Using permanent-magnet (PM) generators for small wind turbines is very common. Usually an AC generator with many poles operates between 10-100 Hz. Because the generator is directly drivenby the wind turbine [1,3,5], it is commonly known as a direct drive generator. Many configurations use surface mounted three phase PM synchronous generators with a rectifier connected to the generator terminal. Many types of generator concepts have been used and proposed to convert wind power into electricity. An axial flux generator with a different type of winding and a different magnet...