Research On Blade Load Control Strategy Of TLP Floating Wind Turbine

As a kind of major clean energy,wind power is developing rapidly and has become the third-largest energy source worldwide.The exhaustion of onshore wind resources and the continuous advancement of the offshore wind power industry emphasize the significance of offshore wind power-related technologies.At present,deep-sea floating wind turbine generator has become the direction of offshore wind power development.Offshore floating wind turbine generators have large unit capacities,complex system models,and large wind turbine sizes.Additionally,the complicated and variable operating environment increases the fatigue load of the blades,especially the blade root load.Therefore,it is crucial to optimize the control strategy of blade root loads of floating wind turbine generators.In this study,the TLP-type floating wind turbine generator is selected as the research object.The wind and sea conditions are first analyzed in view of the complexity of the operating environment of the offshore turbine generator.Additionally,an offshore wind turbine generator–floating foundation–mooring system dynamics model is established on the basis of the driving wind turbine generator and the characteristics of the TLP-type floating foundation.Moreover,we focus on the blade load of the floating wind turbine and its control measures.Finally,the blade root load is improved by controlling the pitch angle of the wind turbine generator,which provides a theoretical basis for subsequent studies.A tower feedback-based PID control strategy for the pitch angle is proposed in this study based on the effect of the change in pitch angle on the blade root load during the operation of a TLP-type floating wind turbine generator.The tower vibration variables of the wind turbine generator are introduced into the PID-based unified pitch control system to generate a pitch angle increment,which is fed back to the pitch angle control system to regulate the pitch angle during the operation of the turbine generator.Simulation results suggest that the controller designed in this study can control the pitch angle variation and thus reduce the blade root load more efficiently.A fuzzy individual pitch-based blade root load control strategy is proposed to address blade vibration caused by uneven blade forces during the operation of offshore TLP-type floating wind turbine generators.After linearizing the turbine generator model based on aerodynamic principles,the unbalanced loads generated by the blades and the Coleman transformation are investigated.In addition,combined with fuzzy logic control strategy,multiple fuzzy logic controllers and Coleman transform to obtain uniform pitch angle and optimal pitch angle signal increment,the two pitch angles are superposed to obtain the pitch angles needed by different blades to realize pitch control.Simulation results suggest that this control strategy reduces the torque at the root of the blade and optimizes the blade load control strategy compared to the conventional uniform pitch control.