Research On Micro-power Wind Energy Power Supply System For Wireless Sensor Network Nodes

With the rapid development of technologies such as Wireless Sensor Networks(WSN),Micro-Electro-Mechanical System(MEMS)and the increase in power consumption,the research on alternative energy harvesting methods is gradually intensifying to power low-power micro-power electronics through energy conversion.Wind energy harvesting is one of the ways to extract energy.In this paper,a micro-power wind energy power supply system for wireless sensor network nodes is designed.The piezoelectric wind energy collection device and the charge conditioning circuit convert wind energy into electrical energy,the low-power power management circuit is used to store and manage the output AC voltage of the charge conditioning circuit,and convert it into a stable +3.3 V DC voltage to supply power to the WSN temperature measurement system.The thermocouple temperature measurement amplifying circuit will use the Zig Bee network to upload the measured thermal electromotive force value representing the wind temperature to the host computer after WSN processing for real-time monitoring,display and storage of the wind temperature data.First,a piezoelectric wind energy harvester based on vortex-induced vibration converts wind energy into mechanical vibration energy.Polyvinylidene fluoride(PVDF)piezoelectric film is used as an energy transducer to convert mechanical vibration energy into electric charge.The conditioning circuit converts the amount of charge into a voltage.The effects of factors such as wind speed,load resistance,cylindrical bluff body size,and PVDF piezoelectric film connection method were experimentally studied on the output performance of the charge conditioning circuit.The experimental results show that in the research range,the output voltage of the circuit increases with the increase of the diameter of the cylindrical bluff body.When the PVDF piezoelectric films are connected in series,the output voltage increases,and the internal resistance of the circuit doubles.When the PVDF piezoelectric films are connected in parallel,the output power increases,and the internal resistance of the circuit decreases.Secondly,the experiment explores the load capacity of the power management circuit under different PVDF piezoelectric film connection methods.The energy supply effect is best when the diameter of the blocking bluff body is 40 mm and three PVDF piezoelectric films are connected in series.Finally,a wind tunnel experimental platform and a WSN temperature measurement system powered by wind energy are built,and temperature compensation is performed on the measured wind temperature,the power supply time of the system is compared after changing the wind speed and the WSN sleep time.The experimental results show that the wind power energy acquisition and its management circuit based on vortex-induced vibration can supply power to the WSN temperature measurement system composed of JN5168,and complete the monitoring and display of wind temperature.When the wind speed range is 0.7～7.3 m/s,the nosleep and sleep time is 2s,5s,and 10 s,connecting the piezoelectric wind energy harvesting device can extend the power supply time of the WSN terminal node by170～273%,172～271%,164～259%,and 187～278% respectively.