Research Of Micro Piezoelectric Wind Energy Harvester Based On Bionic Optimization Structure

The wind energy piezoelectric energy harvesting can convert the wind energy in the environment into usable electrical energy.This study draws inspiration from several typical leaf venations and optimizes the piezoelectric element with bionic stiffeners.Besides,it explores a preferable bionic structure from different leaf piezoelectric elements under the aerodynamic instability condition.This paper analyzes the energy harvesting capacity of piezoelectric devices by research parameters such as output open circuit voltage and output power,and explores the possibility of optimized piezoelectric components in engineering applications.The main research work of this paper is as follows:The basic structure,working form and working environment of the miniature bionic energy harvester using wind energy are expounded.The state of aerodynamic instability is achieved by the vortex-induced vibration(VIV)around the cylinder.After comparing the similarity between piezoelectric elements and plant leaves,the venation-inspired growth optimization method is used to arrange of the stiffeners with reference to examples.Then,this paper estimates the force of the variable-section piezoelectric element subjected to the flow field.Then,the FEM software is used to calculate the theoretical value of the output open circuit voltage under the certain condition,and the result is compared to the test data which proves that the optimized algorithm can be applied.The energy harvesting capability of piezoelectric elements with different optimized structures is studied by measuring the output open circuit voltage.First,the energy harvesting capacity with bionic stiffeners compared to the elements with orthogonal stiffeners and none stiffeners piezoelectric elements is verified.For piezoelectric elements of the same geometry,the piezoelectric element with the bionic stiffeners can increase greatly.The validity of the numerical results is proved by comparing the experimental results with the numerical results.Then,the energy harvesting capacity of the piezoelectric elements of different leaf venations is verified.The experimental results show that the output voltage of the piezoelectric element with the prototype of pinnate leaf is the highest,thus obtaining a better optimized structure of energy harvester.The output power of the piezoelectric element with the pinnate leaf stiffeners and the palmate leaf bionic stiffeners under the load resistance is analyzed and compared.The results show that the output of the piezoelectric element is best when the load resistance is near the theoretical optimal value.In addition,the tests of output power and power density at different wind speed are carried out.The tests results show that the output power and the power density of the pinnate leaf piezoelectric element are both the highest.Finally,the pinnate leaf piezoelectric element is subjected to charge and discharge experiments.The voltage across the capacitor reached 1.952 V,which proves that the energy is harvested by the well piezoelectric energy harvester can be collected and utilized.