Drivetrain control strategy for wind turbines

This paper presents a new approach for the control of wind turbines. The goal is to maximise the output power while limiting the drivetrain fatigue load. The proposed strategy can be decomposed in two parts. In a first part, a nonlinear control strategy for rotor speed regulation is proposed as in [1]. It guarantees convergence of the rotor speed to its desired value. This first part only looks at the rotor dynamics and the aerodynamics. The drivetrain dynamics is not taken into account. However, drivetrain failure is a big contributor to the time a wind turbine spends out of commission. According to data gathered from existing offshore wind farms, drivetrain, generator, and gearbox failures account for around 14% of all down time for offshore turbines. Therefore, in a second part, a dedicated control action that minimize the drivetrain fatigue is proposed. The strategy is validated in simulation.