Design of a 10 MW multi-phase PM synchronous generator for direct-drive wind turbines

This paper presents the preliminary design of a 10 MW permanent magnet synchronous generator (PMSG) for off-shore direct drive wind turbines (DDWT). In order to improve the DDWT torque quality, energy efficiency, power management, fault tolerance and reliability a twelve-phase PMSG made of four independent three-phase star connected subsystems has been considered. With the aim of satisfying the several constraints related to cogging torque reduction, stator and rotor diameter limitation, low speed operation and magnetic decoupling of four three-phase subsystems, a multi-star fractional-slot tooth concentrated winding PMSG has been designed. The analytical results have been validated by means of Finite Element Analysis (FEA) highlighting the worth and effectiveness of the proposed configuration.