A Preliminary Evaluation of a Multiple-Generator Drivetrain Configuration for Wind Turbines

The recent trend toward large wind turbines has led to very expensive gearboxes that hinder their feasibility. The gearboxes for these wind turbines are more expensive per kilowatt (kW) of rated power than for smaller turbines because the torque increases more quickly than the power when increasing the rotor diameter. Multiple-generator drivetrain configurations can reduce the drivetrain cost for large wind turbines while increasing the energy capture and reliability. The National Renewable Energy Laboratory (NREL) is reexamining the benefits of multiple-generator configurations through the Wind Partnership for Advanced Component Technology (WindPACT) program. This paper qualitatively compares a multiple-generator drivetrain configuration to a conventional drivetrain.