The Simulation And Experiment Study Of The Wide-band Harvester Based On PVDF Piezoelectric Film

Traditional battery already cannot meet the needs of electronic products,since it has large bulk,limited energy,short life,environmental pollution and so on.So researchers start to study how to harvest energy from the environment.Energy harvester based on piezoelectric principle can convert mechanical energy into electric energy.Piezoelectric harvester is concerned greatly by experts at home and abroad since it owns the advantages of simple structure,processing simplicity,non-electromagnetic interference,environment friendliness etc.A wide-band piezoelectric harvester based on cantilever beam structure is proposed in this paper.First of all,it is concluded through experiments that cantilever beam has higher sensitivity and larger output voltage than other structures.And it will be better when cantilever beams are in parallel.To reduce harvester's resonant frequency,a mass is added at the top of the beam.Mathematical model of cantilever beam is established according to material mechanics,vibration theory and piezoelectrics.The numerical simulation is carried out on the model established by MATLAB software.And how the length of beam and the size of mass influence the output voltage of harvester is analyzed.To widen frequency band of harvester,increasing the number of mass and paralleling cantilever beams.Based on theoretical analysis,establishing finite element model of cantilever beam.The model is analyzed through ANSYS software to research the influence regulation of the size of mass,the location of mass,the number of mass,the gap of masses to frequency,bandwidth,output voltage of harvester.Studying output characteristics of wide-band harvester by modal analysis and harmonic response analysis.Then,the traditional rectifier filter circuit is improved.LTC3588-1 chip is adopted to design power management circuits,which perfectsenergy conversion efficiency,enhances integration,realizes miniaturization of circuits.Experiments are carried out to verify feasibility of wide-band harvester.First,the relation between output characteristics of harvester and size,location,number,gap of masses is researched by experiments of single cantilever beam harvester.Then,broadband characteristic of multiple cantilever beams is verified through comparing single cantilever beam to multiple cantilever beams.Next,The best match resistance is obtained by experiments.Finally,Energy harvesting experiment powering pedometer verifies validity and effectiveness of wide-band harvester and energy harvesting circuit.