System Modeling And Experimental Study Of A Piezoelectric Cantilever Energy Harvester

In recent years,with the development of wireless communication and MEMS,micro sensor and actuator technology are widely used.The power consumption of this type of device is very low,which requires the power supply to be high integration,small volume,no replacement,unattended,long service life etc.The piezoelectric energy harvesting technology based on the piezoelectric effect is on the satisfaction of above and has the advantages of simple structure,miniaturization,easy integration,reliable,which has been paid more and more attention at home and abroad.In this paper,the mathematical model and FEM analysis model of the piezoelectric cantilever are built to optimize and improve structure,increase bandwidth of working frequency,improve output response to more adapted to the low-frequency vibration environment.Then,new type of piezoelectric electromagnetic coupling cantilever is designed.Its lumped parameter model is established to analyze the output characteristics under harmonic excitation and random excitation,the influence of different parameters on output performance of the structure.Finally,the output characteristics of the structure are obtained through experiment to further verify the reliability of the theoretical analysis.The main work is as follows:(1)This paper brings a basic structure of piezoelectric energy harvesting,and establishes the kinematics model and lumped parameter model,and deduction the expression of the fundamental resonance,output charge,output voltage and output power,and analyzes the influence of different parameters on the output characteristics.(2)The simulation and optimization of piezoelectric cantilever energy harvester based on FEM.Structure modeling,static analysis,modal analysis and harmonic response analysis are completed in ANSYS.The analysis includes the influence of length,width and thickness of substrate,the quality of block height,piezoelectric layer thickness on the performance of frequency and output voltage of the structure.(3)This paper analyzes the output characteristics of the bimorph-piezoelectric cantilever energy harvester and brings a piezoelectric electromagnetic coupling cantilever energy harvester.The equivalent lumped parameter model,dynamic equation and circuit equation are established.The output characteristics under harmonic excitation or random excitation are obtained through Runge-Kutta method.Then,analysis of influence of load,magnet spacing,frequency on output performance is done.(4)Set up the experimental platform by using the existing equipment and piezoelectric materials.The influence of mass size?excitation frequency?load and acceleration on output performance of the system,such as voltage and power are obtained by the experiment.