A Windbell Inspired Piezoelectric Kinetic Harvesting System

Wireless Sensor Network attracted numerous attention due to the promising applications in military and civil fields.Traditional batteries have such disadvantages as large size,environmental pollution and regular replacement,which restricted greatly the development of Wireless Sensor Network.Small kinetic harvesters,which convert the kinetic energy existing in natural environments to electric energy,are ideal power sources of wireless sensor nodes.Therefore,it is significant to study the small or micro kinetic harvesting system.A piezoelectric kinetic harvesting system which can scavenge low-level,low-frequency and broadband vibration energy and wind energy in environments was proposed.The theoretical model of the harvesting system was established and the output performance of the harvesting system was tested under vibration and wind excitations,respectively.Effects of some parameters on the performance of the harvesting system were analyzed.A wireless sensor node for temperature and humidity powered by the harvesting system was tested.The main work includes:(1)The advance in the small piezoelectric vibration energy harvester and the small wind energy harvester was analyzed and summarized.(2)According to the characteristics of the vibration and wind in natural environments and inspired by windbells,a piezoelectric kinetic harvesting system was proposed.(3)The operational mechanism of the piezoelectric kinetic harvesting system was analyzed and a theoretical model of the harvesting system was established.(4)The prototype of the piezoelectric kinetic harvesting system was fabricated.The output performance under vibration and wind excitations was tested.The results show that the output powers of one piezoelectric cantilever was 97.9 ?W under the vibration excitation of 0.1g and 8.8 Hz and 149.3 ?W under wind of 12m/s when the load resistance was 160 k?.(5)A wireless sensor node for temperature and humidity was driven successfully by the harvesting system.The node sent the temperature and humidity every 420 s under the base excitation with the amplitude of 0.2 g and the frequency of 8.6 Hz,or every 973 s under wind speed of 12 m/s.