Research On Technology Of Environmental Energy Harvesting Based On Piezoelectric Material

Energy is known as an important basic resource of society. The energy harvesting technique is produced in the condition that many renewable energy sources have not been collected and utilized. In this paper,we propose mortar and double-fork piezoelectric harvesters to improve the broadband response ability;To improve the output in the two order bending mode, optimization of the rectangular piezoelectric, we propose an asymmetric double crystal piezoelectric harvester and assessment of the power characteristics of the harvester.First of all, we analyzed the power characteristics of rectangular piezoelectric, established mathematical model of energy, given the theoretical analysis,voltage output model and output power model of d31 mode and d33 mode.We have modeled 3D model of mortar and double-fork piezoelectric harvesters, and the static, modal and harmonic response analysis. We have obtained that mortar piezoelectric harvester output voltage over 5V between 55~78Hz, from 15 Hz to 50 Hz, double-fork piezoelectric output voltage above 8V.A new asymmetric double crystal piezoelectric harvester was designed by rectangular piezoelectric energy harvester. Draw into three parameters include Section ratio λ, Clearance ratio α and Voltage frequency density β to optimize the size of asymmetric double piezoelectric. Results showed that when λ between 0.6~0.7, can achieve better broadband. Asymmetric double piezoelectric strain value and static open voltage is 2.4 times and 1.4 times than the rectangular piezoelectric, respectively. The peak voltage generated by two order frequency of asymmetric harvester is about 60 times than rectangular harvester. The results show that this structure can improve the output of the two order.Produce piezoelectric harvester, set up experimental system and verify the final. Results show that asymmetric piezoelectric harvester’s effect is about 2.21 times higher than the rectangular energy harvester in 30~50Hz, under conditions of bandwidth which refers to continuous output voltage above 1.5V, asymmetry piezoelectric ’s broadband effect is 7 times than rectangular harvester. Based on the piezoelectric harvesters of d31 and d33, the highest peak voltage increases from 4.2V to 8V, the output voltage is increased by 90.5%.