Research On Piezoelectric Environmetal Energy Harvesting Technology

As the continuous development of Internet of Things technology and integrated circuit technology, more and more low-power sensor nodes are used leading to diversify power source demands. Collecting energy from local environment to provide the power source for sensors can solve the energy problem,and turn the wasted energy into treasure as well. It also makes the power supply multifarious.This thesis studies the energy harvesting system from the wind power based on the piezoelectric materials. The main research work is as follows:(1) The piezoelectric material,the theory of piezoelectric effect, piezoelectric equation, and energy acquisition technology based on piezoelectric composites are studied.(2) Based on the ANSYS finite element analysis software, the modal and harmonic response analysis of the bimorph cantilever beams are analyzed, of which the resonant frequencies and vibration characteristics are examined in detail. The optimization of the piezoelectric cantilever beam structure is carried out including length of the beam, thickness of the substrate and the substrate material features.Finally, the bimorph cantilever beam specimens are fabricated based on the analysis.(3) A cup-type wind energy acquisition device connecting to an electric energy harvesting system based on the bimorph cantilever beam with PVDF piezoelectric material is designed and manufactured. The output voltage distribution characteristics of the system are studied with experiment. The experimental research is also carried out for the relationship between the output voltage and fan blade overlap distance, the relationship between the output voltage and wind speed, and the relationship between the output power and wind speed.(4) The piezoelectric energy storage circuit is designed and fabricated including:voltage doubling rectifying circuit, switching circuit, voltage regulator circuit and lithium battery charging circuit. The Altium Designer software is used to analyze and optimize the circuit. Finally, the experiment demonstrates the effectiveness of the circuit in storing the energy collected by piezoelectric composites.