Simulation Of Interface Circuit And Experimental Study On Energy Harvesting Performance Of Wind-induced Vibration Piezoelectric Energy Harvester

With the increasing demand for energy and the shortage of energy output,the advent of the Internet of things has exacerbated the energy crisis,and the energy demand of various small and micro devices is difficult to be met.Therefore,the collection and reuse of natural energy has become the first choice to solve such problems,Researchers found that there is a high energy density in environmental vibration and it is easy to collect.Therefore,if we can collect and store the vibration energy everywhere in our daily life and use it reasonably,it can provide a good idea of energy use for the power supply of low-power electronic equipment and MEMS.At present,scholars have accumulated rich experience in the research of piezoelectric energy harvesting technology and interface circuit,but for the energy harvesting of interface circuit,vibration exciter is often used to provide constant excitation force or displacement,which can not fully realize the uncertainty and diversity of flow induced vibration energy in nature.Therefore,this paper focuses on the wind-induced vibration cantilever piezoelectric energy harvesting system According to different interface circuits,considering the effect of galloping force of wind-induced vibration and the influuence of load variation of interface circuit on output power,the simulation and wind tunnel experiment of piezoelectric energy collector and interface circuit are carried out.The main contents of the study are as follows:(1)Based on the characteristics of piezoelectric materials and the theory of piezoelectricity and interface circuit,The electromechanical coupling model of piezoelectric energy harvesting system is established,and the system theory is analyzed.The constitutive equation of piezoelectric energy harvesting system is derived by combining the electromechanical coupling coefficient,strain constant,dielectric constant and elastic modulus of piezoelectric elements,which provides reference for the subsequent interface circuit simulation theoretical basis.(2)In view of the problem that the output voltage of piezoelectric energy harvesting system is sinusoidal alternating current and cannot supply energy directly for the power equipment,the output characteristic curve of each interface circuit under constant vibration displacement excitation is obtained by simulation analysis of piezoelectric energy harvesting system and interface circuit,the interface circuit is simulated and analyzed by software,and the load resistance curve,the theoretical maximum output power and the optimal load resistance value of the interface circuit are obtained.The connection between the maximum output power of each circuit is obtained by comparing the simulation results with the theoretical analysis.(3)In order to verify the energy harvesting and interface circuit performance of the interface circuit under the actual conditions,the experimental platform of energy harvesting device is built.The piezoelectric energy harvesting system is combined with the interface circuit.Relying on the wind tunnel experimental platform,the energy harvesting performance of SEH,SECE,P-SSHI and S-SSHI interface circuits in the experiment is tested under the same excitation displacement(same wind speed).The experimental results show that the interface circuit can effectively rectify the output voltage of the piezoelectric element,and has a significant effect on improving the output power under the condition of stable wind speed.The wind-induced vibration characteristics of the cantilever piezoelectric energy harvesting system and its interface circuits are verified theoretically and experimentally,and the interface circuit has certain feasibility in the specific natural environment and it provides theoretical and experimental guidance for the successful application of flow induced vibration piezoelectric energy harvester.