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 analysis of a permanent-magnet generator using neodymium-iron-boron magnets for directly coupled 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 magnetic equivalent circuit approach is used for initial design iteration, and the finite-element method is applied to analyze the detailed characteristics. Comprehensive experimental tests were conducted to verify the theoretical predictions. Agreement between the theoretical work and testing results was good.