A procedure for choosing optimal materials of wind turbine flexible blades

The question of the scope and the applicability of a new passive pitch control method using homogeneous soft blades is studied. After reminding the role of pitch control in wind turbines, the model for the deformation of wind turbine flexible blades is presented. The soft blade is modeled as a thin plate with the Kirchhoff-Love plate theory. Centrifugal and aerodynamic forces are considered. First, the model finds the optimal variation of the pitch angle of rigid blades with respect to the operation range. Then using a reduced parameter set of three dimensionless numbers (θ₀, C_Y, C_C), the model also quickly determines the soft materials which passively reproduce the more accurately the optimal variation of the pitch angle on the operation range found previously. Numerical results show that already existing soft materials can passively mimic the ideal pitch angle variation, leading to an efficiency gain of 8%.