Design Assessments of a Magnetic-Geared Double-Rotor Permanent Magnet Generator

By adopting the double-rotor structure and the coaxial magnetic gear concept, a permanent magnet (PM) generator is proposed for harvesting the wind energy directly without mechanical conversions. In addition to the physical model realizations, this paper will present the detailed design and implementation concerns of the magnetic-geared double-rotor PM generator along with thorough loss assessments. The comparisons of PM magnetization directions and arrangements, the selections of proper windings, and the operational efficiencies of this machine along with the terminal voltage phase shifts due to different loading conditions will all be summarized. The realization process of a portable 2.5-kVA generator that can be directly coupled to the mechanical driven source without additional mechanical gears will be demonstrated, and the feasibility of such a machine structure can certainly be confirmed from the satisfactory performance results.