Wideband estimation of the drive torque of a wind turbine using LiDAR measure-ments, blade element momentum theory and Kalman filtering

Abstract

In this paper a method to estimate the drive torques from Light Detection and Ranging (LiDAR) measurements is proposed. Knowledge of these values brings many advantages for turbine control and especially active damping of mechanical oscillations.Primarly a simplified method to calculate the aerodynamic torque from wind speed measurements of a nacelle based LiDARsystem will be presented which bases on blade element momentum theory (BEM). Comparisons of results of the original and a simplified computation method show small deviations in the relevant working range of a wind turbine. Additionally a Kalman Filter is used to estimate the drive torques of the wind turbine.The method is tested in simulation using a model of a doubly fed induction generator (DFIG) wind turbine including a gearbox. Simulation results show good performance of the estimation.