Event-Triggered H-Infinity Pitch Control for Floating Offshore Wind Turbines

The complex wind and wave environment can lead to increased external disturbances and power fluctuations of floating offshore wind turbines, posing a significant challenge to their stable operation. To cope with this issue, this paper formulates an event-triggered H-infinity pitch control strategy for floating offshore wind turbines. Firstly, a linear parameter varying model of floating offshore wind turbines is proposed, utilizing the dynamic characteristics of subsystems while considering the combined external disturbances from wind and wave. Then, the event-triggered control strategy is introduced into the H-infinity pitch control of floating offshore wind turbines. Based on this, a criterion for the asymptotic stability and H-infinity norm boundedness of floating offshore wind turbines is derived. Furthermore, an algorithm is presented for designing feedback gain matrices of the event-triggered H-infinity pitch control, which can effectively reduce the update frequency of the controller. Finally, a simulation is conducted on the IEA 15 MW Reference Wind Turbine by integrating OpenFAST with MATLAB/Simulink. The simulation results provide a comparative analysis of the event-triggered H-infinity pitch control strategy and the continuous-time pitch control strategy, demonstrating the superiority of the method proposed in this paper.