Modelling hydraulic pitch actuator for wind turbine simulation under healthy and faulty conditions

Abstract

A detailed nonlinear model for a hydraulic pitch actuator under healthy and faulty situations is introduced in the FAST/AERODYN wind turbine simulator. Frequency response functions (FRF) are determined by using a random phase multi-sine excitation for different healthy and faulty operating conditions. The major changes observed in the FRF arise significantly above the actuator bandwidth. A linear model of the actuator thus appears to be sufficient to simulate the wind turbine in healthy conditions. However, when it comes to the study of fault diagnosis, it is advised to use a nonlinear model and to resort to active fault detection methods to probe the high frequency behaviour. Finally a user friendly graphical interface is presented for the wind turbine simulator.