Electromagnetic design and performance analysis of large-scale offshore wind generators with modular fractional-slot concentrated winding

Future offshore wind engineering raises demands on higher reliability, better power generating performance, as well as lower manufacturing and transportation cost. This paper presents a direct-driven permanent magnet generator (DDPMG) with modular fractional-slot concentrated winding (MFSCW), to meet the large-scale, low-cost and high-reliability requirements of offshore wind power applications. The corresponding pole–slot combination method and electromagnetic characteristics analysis for this novel generator are proposed and performed in detail, including the winding coefficient analysis, magnetomotive force (MMF) harmonic analysis, cogging torque analysis, finite element simulations and generator parameter optimization. After finite element simulations, a 3.3 MW prototype MFSCW-DDPMG is developed to validate the proposed scheme. The results provide a complete and feasible scheme of pole–slot​ combination and electromagnetic design for future MFSCW-DDPMG engineering applications.