Analytical and Multiphysics Approach to the Optimal Design of a 10-MW DFIG for Direct-Drive Wind Turbines

This work deals with a 10-MW doubly fed induction generator (DFIG) for direct-drive operation of wind turbines with a reduced-size converter. The work includes a lumped parameter design, an optimization procedure, a finite-element analysis (FEA), and an electrical performance assessment. A monetary cost was assumed as a cost function, and an approximation of the construction cost as a function of the axial length was obtained. The found solutions were checked by FEA in order to assure the mechanical feasibility. Further verifications were developed to allow a conclusive performance evaluation. The optimization improved the cost of the proposed DFIG, including materials, losses, and converter, making it slightly cheaper than an available permanent-magnet synchronous generator.