Research On Load Reduction Control Technology Of Wind Turbine Based On FAST

As the international energy market continues to fluctuate and the "twocarbon" target is proposed,China attaches more importance to the use of renewable energy.In 2021,China’s newly installed wind power capacity will account for 40%of the world’s total,making wind power generation an important part of China’s modern energy system.In order to improve power generation efficiency and reduce power generation costs,wind turbines have been developing towards the direction of large scale.However,the softening of unit structure and the increase of wind turbine sweep area have resulted in more complex load conditions for wind turbines.Among them,the structure of the wind turbine may be damaged by the same frequency resonance that may be generated when the wind turbine is running below the rated power,as well as the limit load and unbalanced load when maintaining the rated power.On the basis of previous studies,this paper studies the load reduction control technology of wind turbine,and the specific contents are as follows:(1)After the basic theory of wind turbine is studied,the NREL 5MW wind turbine model and the traditional variable speed and variable paddle controller are built based on the FAST-Simulink platform.The operation control process of the model is analyzed,and the corresponding load reduction control mode is given according to the different operating states of the wind turbine.(2)In this paper,two solutions are proposed for the same frequency resonance that may occur when the unit is running below the rated power.The first scheme is applied to small units,and a 2MW wind turbine is taken as an example.By adding frequency constraints,the tower structure is optimized to avoid resonance and avoid the fatigue load generated by resonance in the design stage.The second scheme is applied to large units.An active resonance crossing algorithm is proposed,and a criterion is proposed to judge whether the active resonance crossing control is realized.Taking NREL 5MW unit as an example,the simulation verifies that the active resonance crossing control achieves the expected load reduction effect.(3)In order to solve the problem of unbalanced load and limit load on the turbine sweep surface when the unit is running at rated power,an independent paddle control mode based on blade root load feedback is proposed in this paper.On this basis,the PID controller is optimized through IRN neural network,and then an independent paddle control mode based on IRN-PID is proposed.Taking NREL 5MW wind turbine as an example,the two independent paddle control methods have achieved the expected load reduction effect.