Study On Resonant Cavity Wind Energy Harvesting Device Based On Tuning Fork Reeds

The rapid development and fusion of microelectronics,sensors and wireless communications led to the birth of the wireless sensor network,which has played an important application value in ecological environment monitoring,building security,military reconnaissance warning,and many other fields.However,most of the existing wireless sensor network nodes now rely on battery,the problems of environmental pollution,limited life,difficulties of charge or replacement become the main factors hindering the development of the wireless sensor network technology.Along with the development of ultra low power electronic technology,power consumption of wireless sensor network nodes can be reduced to below milliwatts level,which makes it possible to harvest the weak energy of environment as the power supply of sensor node.Since wind power is renewable and widespread energy in the nature,developing miniaturized wind energy harvesting device as power supply for wireless sensor network nodes in remote areas will have a broad application prospect.In order to improve the efficiency of wind energy harvesting and working stability of the device,this thesis proposes a new resonant cavity wind energy harvesting device based on tuning fork reeds.The main works of this thesis are as follows:(1)The basic structures and principles of wind energy harvesting devices based on wind-induced vibration and the basic theories of piezoelectric cantilever are summarized.Theories in basis of resonant cavity wind energy harvesting device based on tuning fork reeds are established.(2)Modal simulations and fluid-structure coupling simulations of resonant cavity wind energy harvesting device with single reed and double reeds are conducted respectively.The inherent frequencies,vibration forms and interaction effects of air flow and cavity of the two devices are compared.(3)The prototypes of resonant cavity wind energy harvesting device with single reed and double reeds are fabricated.With testing platform,the influences of structure and electrical parameters on the harvesting efficiency are tested and the wind energy harvesting performances of the two prototypes are compared.Experimental results show that appropriate size matching of cavity and reeds can obtain a lower cut on wind speed and wide wind speed range;Installation direction of the reeds has little effect on wind energy harvesting performance,installation angle of reeds has a great influence on cut on wind speed and output voltage;wind energy harvesting device with tuning fork reeds has better harvesting performance.The tuning fork reeds resonant cavity wind energy harvesting device with a cavity size of 40 × 40 × 140 mm~3 can product 0.83 mW and energy conversion efficiency of 0.37% with a matching load of 0.15 M? and wind speed of 6 m/s.In conclusion,the proposed resonant cavity wind energy harvesting device based on tuning fork reeds has a good wind energy conversion performance and can be used for powering wireless sensor network node in remote area with abundant wind energy.