Research On Technology Of Environmental Energy Harvesting Based On Piezoelectric Effect

How to power MEMS device for a long time has become an urgent problem to be solved.Seeking sustainable supply way instead of the battery-powered is key technology to break through the wireless sensor life bottleneck. Currently, piezoelectric energy harvesting technology based on environmental vibration is a new method to solve the problem. In the paper, based on the study the relatives between the optimum thickness and generation, a novel loop-piezoelectric energy was designed.Characteristic analysis of output was studied in depth。First of all,the energy conversion model of piezoelectric transducer are established based on the piezoelectric theory and vibration equations under the constant force.There exists an optimal thickness ratio makes the power output better。A novel rectangular-loop piezoelectric energy harvester(RLPEH) was proposed. The static analysis, modal analysis and harmonic response analysis of RLPEH were discussed by using the Finite Element Analysis.The resonant frequency decrease with the increasing number of N.When N is 9,the first three order resonance frequency are respectively 6.3Hz, 32.5Hz and 38.0Hz.A new low-frequency trapezoidal-loop piezoelectric energy harvester(TLPEH) was designed.Simulation showed that TLPEH could harvest energy more effectively than the rectangular-loop piezoelectric energy harvester. The output voltage was increased by71.4% with little change in resonant frequency,and indicator of the inhibition of side peak(SPI) which represented the capability of broad-band energy harvesting rose 16.5%.Finally,the prototype was prepared and the platform for experiment system was built.Theory fits our experimental results nicely. Compared to the RLPEH,the effective bandwidth was improved 13 Hz with above 1.8V.The novel loop piezoelectric energy harvester could generate 150 mW power at a constant acceleration about 5.5 m/s2.The novel piezoelectric energy harvester improve the output power and widen the broadband capability.The new loop configuration of the energy harvester presents a potential solution for harvesting energy at low frequency with higher output voltage.