Design and finite-element analysis of an outer-rotor permanent-magnet generator for directly coupled wind turbines

This paper presents the design and finite-element (FE) analysis of a perman ent-magnet generator using neodymium-iron-boron magnets for directly couple d wind turbines. For the sake of small size and light weight with extra low speed for direct coupling, the outer rotor structure is used. The simple m agnetic equivalent circuit approach is used for initial design iteration, a nd the finite-element method is applied to analyze the detailed characteris tics. Comprehensive experimental tests were conducted to verify the theoret ical predictions. Agreement between the theoretical work and testing result s was good.