Research On Energy Management Of Photovoltaic Power Supply System In Wireless Sensor Network

With the rapid development of the Internet of Things,Wireless Sensor network(WSN)as the nerve endings of the Internet of Things are playing an increasingly important role.Wireless Sensor Network is widely used in industrial,military,medical and other fields due to its advantages of flexible Network setup and node distribution,which are not easily affected by geographical location.At present,most WSNs still use the traditional power supply mode of large-capacity dry batteries.For nodes in field work,once the battery energy is exhausted,it is not easy to replace the battery manually and the cost is high,which is prone to the situation that the node fails to work when the battery energy is exhausted.Therefore,it is the core problem to study the power supply mode of WSN to improve the working life of WSN nodes.Solar energy,as one of the research hotspots of new energy in recent years.For WSN nodes working outdoors,if the WSN is powered by solar energy,the power can be continuously supplied without replacing the battery.And the energy management module can make energy collection and power supply more efficient.By optimizing the energy management module of the photovoltaic power supply system,the energy conversion efficiency can be improved,the power supply cost can be reduced,and the data loss caused by the power consumption of the node can be reduced,thus extending the working cycle of WSN.The main work of this paper is as follows:(1)First of photovoltaic power supply system architecture of wireless sensor network were studied.WSN energy management part of the photovoltaic power supply by energy acquisition module and storage module two big modules,energy acquisition module is roughly divided into photovoltaic cells,DC-DC converter.The voltage regulator module three parts of this second principle analysis of various parts and components selection.Based on the analysis and simulation modeling of the photovoltaic cell physical model,the nonlinear working characteristics of the photovoltaic cell and the importance of the Maximum Power Point Tracking(MPPT)algorithm are analyzed.Next,super capacitor is selected as the energy storage unit in this paper,and low-power linear voltage regulator is selected for the voltage regulator module.Finally in the comparative analysis of several commonly used DC-DC,has some advantages such as simple circuit structure,low power consumption and can realize bidirectional energy flow characteristics of active clamp bidirectional flyback as DC-DC part,from the work mode and the condition to realize soft switch these two aspects to analyze the working principle of the converter,on the basis of the waveform figure gives its work.(2)Secondly,the principles of several MPPT algorithms commonly used in WSN photovoltaic power supply system are analyzed,and their advantages and disadvantages are compared through simulation modeling.Based on this,an MPPT algorithm for improving the disturbance observation method of fuzzy control is proposed,which optimizes the input quantity of fuzzy control,greatly simplifies the fuzzy control rules,and thus reduces the complexity of the fuzzy control algorithm.(3)Finally,the system hardware platform construction and energy management strategy of the software system design.Firstly,the overall hardware structure of the photovoltaic power supply system of the wireless sensor network is designed.Secondly,the components of the main circuit are calculated and selected.The circuit diagram of each hardware part is given.The experimental results show that under different temperature and light intensity,the system can meet the power demand of nodes in a short period of operation,can also store more power rapidly,and has a long survival cycle.The realization of wireless sensor network can meet the power demand only by solar power without any external power supply.