Shape Morphing Mechanism for Improving Wind Turbines Performance

Abstract

Wind energy technology is facing new challenges due to the increment in rotor diameter. Nowadays, several studies focus on the development of new flow control methods for load alleviation, in order to increase the lifetime of the blades. This paper describes a shape morphing-based method for smart blades. The study includes an aerodynamic model with a computational search algorithm to find the optimal Cp. A section with shape morphing technology was developed to prove the performance of the method. The smart blade prototype section incorporates a novel structure with a flexible skin and a compliant mechanism. This deformable structure achieves the required displacements for different NACA profiles through camber morphing. In this way, the efficiency and the load variations are improved. The compliant mechanism has to be as light as possible and it has to be competitive in cost. In order to achieve these limitations, different actuating mechanisms were evaluated. Among different possibilities, servo actuators presented higher load/weight capabilities and the required displacement ratios to cover the entire deformable range. The airfoil is modified according to the wind condition and the wind speed is the input variable for controlling the actuators displacement. The control algorithm has a very high frequency response; in this way, the blade profile can be modified in a shorter time and it can respond to high wind velocity variations. Therefore, a deformable section improves the overall performance of wind turbines since it increases power and extends the lifetime of the blades.