Design of a 3MW Wound Rotor Synchronous Generator and Permanent Magnet Synchronous Generator for Wind Turbines With Reduced Torque Ripple

Generators for wind power conversion require a low torque ripple as a high torque ripple translates to vibrations in the machine, affecting its structural stability and causing excessive wear on the drivetrain components. This paper involved the design and optimization of a 3MW medium speed (375 rpm) Wound Rotor Synchronous Generator (WRSG) and Permanent Magnet Synchronous Generator (PMSG). These were compared to determine if the WRSG is a good alternative to the PMSG. This was done through conceptual designs and finite element analysis using Ansys Maxwell as well as a genetic algorithm to reduce the torque ripple. The optimization process focused on determining optimal stator slot dimensions for both generators and rotor slot dimensions for the WRSG. The optimization processes resulted in a reduction of the torque ripple but at the cost of a loss in torque output for both the WRSG and PMSG. The WRSG had the best torque ripple reduction to output torque loss.