Edgewise Vibration Reduction of an Small-Scale Wind Turbine Blade with Considering Coupling Vibrations

Vibration in wind turbine blades is one of the important factors that result in reducing performance of wind turbines. Therefore, control or reduction of the mentioned vibrations can be of great help in increasing efficiency of wind turbines. In this paper, an optimal tuned mass damper (TMD) is proposed to reduce edgewise vibration of an small-scale horizontal axis wind turbine blade (5 KW) with considering the coupling between edgewise and flapwise vibrations. For this purpose, partial differential equations governing dynamics of the system are derived using the Lagrange method. These equations are completely nonlinear and linearization is not performed to avoid possible errors in the analysis and also, the blade is considered as a flexible member. In deriving governing equations, coupling effect between in-plane and out-of-plane vibrations of the blade, effect of pre-twist angle in the coupling, and effect of centrifugal forces and gravity are considered. In order to reduce vibration of the blade, TMD is used and its parameters are optimized using one of the genetic algorithm methods for a real blade sample. Finally, with applying wind force as a sweep sine excitation, effectiveness of the optimized TMD in vibration reduction of the blade in four different wind speeds is investigated and the related results are presented. Results show that the wind turbine blade vibration reduction is achieved properly using the optimal TMD.