Design And Experimental Study Of Bending And Torsional Coupled Bi-stable Piezoelectric Energy Harvester

Energy is the cornerstone of society.The history of human development is the history of the replacement of energy,but the process of finding new energy is very slow.In some special cases,natural weather and geology can cause serious damage to the energy system of working devices.Therefore,it requires developing power supply units adapted to these special circumstances.Micro-power-consumption devices are usually powered by battery.This article proposed a wide-band,high-power bi-stable piezoelectric energy harvesting device adapted to low-frequency environments.Firstly,use magnets to achieve the bi-stable structure and make the nonlinear characteristics more obvious,widen the response bandwidth of the power generation device,expand the overall effective deformation,and improve the power generation capacity.Then,doing structural design to reduce the bending and torsional frequency,adjust this two modes to adjacent position to realize the bending and torsional coupling vibration mode,which enhances the power generation effect in a low frequency environment.The main content of the paper is as follows.1.Collate the research background and application direction of piezoelectric power generation devices,introduce the characteristics of non-linear piezoelectric systems compared to linear systems,analyze the threshold problem of chaotic motion,and compare the effects of different energy harvesting circuits.Establish the magnetic potential energy model of the bi-stable system,combine Hamilton principle and the piezoelectric field constant hypothesis to derive the dynamic model,and obtain the magnetic zero calculation formula;establish the equivalent circuit model,and solve the inhomogeneous linear equations to derive the output voltage and output power expression.2.Using COMSOL simulation software to perform modal and harmonic response analysis to determine the working mode,and then analyze the effect of the size of the piezoelectric substrate on the natural frequency and output voltage;explore the influence of the magnet distance on the bi-stable characteristics of the system,and determine the distance should be less than 7mm.Finally,the effect of external resistance on the output power is analyzed.When the resistance is 50k?,it can reach a maximum power of 310 mw.3.Make a bi-stable piezoelectric energy harvesting device and conduct experimental research.Based on the previous theoretical model and simulation analysis results,set up an experimental platform to explore the substrate output size,presence / absence of magnetic force,clamping method and magnet spacing on the system output capability The effect proves the advantages of the bi-stable system's power generation capacity compared with the tradition system.4.Investigate the influence of bending-torsional coupling deformation motion on bi-stable piezoelectric energy harvesting system,and conduct simulation analysis to compare the stress distribution?output voltage? and response of bending-torsional coupled bi-stable system and simple bi-stable system under the same conditions.Bandwidth and other parameters verify the effect of bending-torsional coupling motion on power generation.The bending-torsional coupling motion after offsetting the mass increases the amount of deformation of the entire substrate and has a higher power generation capacity under the same excitation.In summary,this paper analyzes the dynamic response characteristics of the bi-stable piezoelectric power generation system,and conducts in-depth research on the relevant parameters affecting the power generation capacity of the system.It is proposed to introduce the bending-torsional coupling motion to improve the power generation capacity.This article provide a reference for the research of piezoelectric power generation devices.