Individual Pitch Control For Wind Turbine Based On Blades Loads

In order to reduce the cost of wind power, as well as to further scaleindustrialization and benefits of wind power optimization, stand-alone wind turbinecapacity is further increased, reaching a megawatt-class. The size and weight alsobecome very large, which generates a series of attendant problems, such as thestability issues of security and control. Especially unbalanced aerodynamic loads onlarge-scale wind turbine are more and more obvious. WT withstand large loadfluctuation, it is difficult to achieve stable operation control, but also greatly reducethe mechanical life of WT. The traditional collective pitch control cannot overcomethese problems. Therefore, the independent pitch control strategy came into being.The wind turbine is a complex, multi-coupling system, which is difficult to establish aprecise mathematical model. Even under the assumption of certain ideal conditions tocreate a mathematical model, it hardly control accurately. In this paper, individualpitch control strategy based on the model-free adaptive control theory is proposed. Theloads on each blade as a reference, the pitch angle of each blade as an output, andreached through the online observation with the feedback control to reduce the bladeroot unbalance load. The control strategy does not rely on mathematical models, itcombines feedback control and dynamic modeling by observing I/O data. It’s basedon General-model theory, link online identification with real-time control, establish a"model" according to the new observational data, thereby overcoming a large timedelay, strong coupling, and other defects in complex systems, thus improving thecontrol performance.At last, in GH Bladed the simulation analysis using new method was made, bytaking advantage of ability to calculate online in the software itself. For flapwisemoment and swing moment, etc. Compared with the traditional collective pitchcontrol, The results show that individual pitch control method based on themodel-free adaptive control strategy can significantly reduce the unbalanced aerodynamic load from each blade. Thus, it achieves the purpose of mitigating windturbine blade load fluctuation.