Mechanical stress reduction in variable speed wind turbine drivetrains

The use of variable-speed wind power generation has seen considerable growth. The use of gearboxes in wind turbines allows for smaller size, lower weight, and higher speed generators. In this paper, we attempt to describe methods to extend the life and reliability of wind turbine drivetrains by reducing the mechanical stress. We will represent a two-mass model for the drivetrain of a 750-kW wind turbine. This model is verified by using simulation and experimental results. A controller is designed to adjust the generator torque at the end of the drivetrain to remove the unwanted and damaging torque variations from the drivetrain. The ultimate goal of this study is to present a detailed model of the drivetrain, including the gearbox and ways to mitigate the stress on the gearbox.