Research On Node Power Supply System Of Wireless Sensor Network

Wireless sensor network node distribution in karst mountain area of outdoor conditions,on the one hand,most nodes are arranged in the dangerous rocks,cliffs,forest and valleys,of a single energy power supply or use a battery-powered cannot provide node energy,reliable and continuous lead to node shorten the life,not a long-term missions.On the other hand,due to the mountain scenic spot full of large amounts of renewable energy resources environment,some nodes located in the place with enough light energy,some is located in the place with enough wind energy resources,natural resources division is not uniform,studies how to effectively use these environmental energy,is of great significance to solve the problem of power supply of the node.This dissertation studies the collection,conversion,energy storage and node power supply of solar and wind energy.This dissertation designs a kind of wind-complementary wireless sensor network node power supply system.Firstly,the overall design scheme of the system is determined,the components of each part of the structure are selected and the hardware circuit is built,the software control part is written,and finally the physical object is built for testing.In the wind power supply part,the weak wind energy cannot be utilized due to the low output voltage amplitude of the miniature wind turbine and the large rectification loss of the traditional two-stage pipe.The AC-DC synchronous rectifier scheme using MOSFET instead of two-stage tube,can reduce the loss.To further improve the scheme,a four times voltage synchronous rectifier circuit is designed to improve the output voltage.In view of the traditional wind power MPPT algorithm cannot be applied to micro wind power generator,a MPPT boost converter with matching load impedance and power impedance is designed.Based on PROTEUS circuit simulation software,the model of wind power supply system is built and the design scheme is simulated and verified.For the photovoltaic power supply part,the maximum output power of the small photovoltaic cell is 3W.For the small photovoltaic cell in the node environment,it is easy to be blocked by local shadow,and the traditional MPPT algorithm is not applicable.A particle swarm optimization（PSO）based MPPT algorithm for small photovoltaic cells was designed.Small photovoltaic cells were modeled on MATLAB/Simulink,and Boost DCDC conversion circuit was built.The traditional MPPT algorithm and particle swarm optimization algorithm were simulated,and the output characteristic curves were compared.The experimental results show that the wind power supply part can capture the weak wind energy under low wind speed and improve the utilization efficiency of wind energy.Compared with the traditional algorithm,particle swarm optimization MPPT algorithm can find the maximum power point in the global range under the condition of local shadow,and the output power can reach two times of the traditional algorithm.The physical model was built to test the power supply of the node.The average charging power of wind energy was about 27.7m W,and the average charging power of photovoltaic cells was 1.4W on sunny days,which could provide a voltage value of 3.3V and meet the stable power supply demand of the node.