The Rotor and Tower Vibrations Damping Monitoring in the Case of Total Pitch Servomotors Failure

Abstract

In this paper, a strategy is proposed to deal with the total pitch actuator failure in the modern wind turbines. The fault is firstly detected using a suitable proportional residual which rises when the measured rotor dynamics match the pure wind turbulence driven dynamics of the reference model. The fault tolerant control method relies on the distribution of the control signal on the remaining actuators, namely the generator torque and the yaw actuator. The pseudo inverse is applied on the residual between the measured and the nominal dynamics of the tower and the rotor. The distributed control signal is then suitably filtered in order to match the production and the safety objectives. Firstly, the generator torque filter comes to minimize the high frequencies on the rotor speed for a stable production to the grid. Secondly, the band pass yaw angle filter comes to minimize the mean yaw misalignment between the yaw nacelle and the wind direction. The method shows good dynamics reconstruction capabilities while keeping a stable production within a safe environment.