Research On Micro Wind Energy Harvester With Resonant Cavity

Traditional batteries have a large size, need to be replaced or recharged, have highrequest to environment, thus making them difficult to meet the requirements of wirelesssensor networks. Micro energy that harvest energy from environment and convert toelectrical energy has a light weight, small volume, and long service life, does not needto be replaced or recharged. These advantages make it an ideal power supply forwireless sensor network nodes and it has become a hotspot on micro energy research athome and abroad. The study on micro energy that converts wind energy that widelyexisted in natural environment into electric energy has important significance to thedevelopment of microsystem technology and wireless sensor network technology.In order to improve the efficiency of wind energy acquisition, expand theapplication range of the wind speed, this paper put forward a micro wind energyharvester with resonant cavity, and analyze the influence of various factors exert on thewind energy harvester output performance.The main work of this thesis includes:(1) Analyze and summarize the research status and development of micro windenergy harvester at home and abroad, then put forward the structure of micro windenergy harvester with resonant cavity;(2) Establish the continuous model and lumped parameter model of micropiezoelectric generator with cantilever beam, deduce the expressions of inherentfrequency and output voltage of the harvester;(3) Study the amplification effect of resonant cavity to the micro structure windinduced vibration, complete the structure design of wind energy harvester;(4) Complete the processing of micro wind energy harvester. Study the influence ofsize of piezoelectric beam and size of flexible beam, entrance width of resonant cavityand thickness of flexible beam exert on the wind energy harvester output performance.Experimental results show that, the output power of the wind energy harvester can reach1.31mW with load resistance of250K when the wind speed is17m/s, and the powerdensity is about66μW/cm3.