Research On Energy Management Of Self-powered Wireless Sensor System Based On Environmental Energy Harvesting

The continuous development of Wireless Sensor Networks technology makes it possible to collect the massive,low-cost,high-quality data that required by the Internet of Things(Io T),big data and Artificial Intelligence(AI),which helps to achieve the ubiquitous intelligent sensing and will eventually profoundly affects the future of human society.Intelligent wireless sensor networks can provide humans with the ability to sense,measure,and process environmental information without wiring constraints.It is another important technology that will change the way that human living and producing after the Internet.As the basic component of the WSN,the wireless sensor node is mainly applied to realize the acquisition,processing and communication of the sensing data from the monitoring area across the WSN.Because of the characteristics of large-scale ad hoc networks,wireless sensor nodes are limited by cost and volume,which leads the node to be a micro-embedded system with limited hardware resources.At the same time,due to the battery supply power with limited energy storage,wireless sensor nodes also have energy limitation constraints such as limited working lifetime,high cost of battery replacement and maintenance.When the hardware resources and energy are simultaneously limited,the problem of energy supply,storage and use of the node will directly affect the performance and even the service lifetime of the overall WSN,and become the key point that limits the practical application of WSN.To solve this problem,on the one hand,we can improve the performance of the battery itself,or reduce the power consumption level of the node from the energy efficiency of the system through innovating the design of the device,circuit and system.On the other hand,based on the environmental energy harvesting technology,designing the theoretical model and design method of information processing for energy management from the aspect of the energy supply and demand of the whole system,reforming the energy supply structure of wireless sensors,and at last achieving the wireless sensor technology that has no need of battery replacement or even battery-free WSN nodes,provides an effective way to solve the bottleneck of battery capacity limitation.Based on the environmental energy harvesting technology,this paper aims at researching,designing and achieving the battery-free self-powered WSN node.Due to the wide application scenarios of WSN,it is applicable for the environmental energy harvesting technology for it covering various forms of the energy source including acoustic,optical,electricity,thermal and others.The various output characteristics of different energy sources causes the self-powered WSN node facing the unsimilar energy mismatch problems between the environmental energy harvesting equipment and the lowpower-consumption node,and increases the design difficulty and period of the batteryfree self-powered WSN node.This paper solves the problem of energy supply and demand mismatch between environmental energy harvesting equipment and low-powerconsumption node from the system framework and self-powered energy management algorithm.Based on this,a design of battery-free self-powered WSN node in specific application scenarios is designed and implemented.1)For the problem of energy form mismatch and instantaneous power mismatch between environmental energy harvesting equipment and low-power load in self-powered WSN nodes,this paper adds self-powered energy management module to form the basic system framework for self-powered WSN based on traditional WSN node architecture.Then based on the “collection-storage-use” system,a specific framework of the self-powered energy management module is designed.Finally,based on the principle of “energy neutrality”,the basic strategy of self-powered energy management algorithm,based on the output energy of environmental energy source,environmental information and operating state of the load,is studied.2)In order to further verify the effectiveness of the designed self-powered WSN node system framework and self-powered energy management algorithm,this paper designs a battery-free self-powered WSN node verification platform in the scenario of human walking biological information monitoring based on piezoelectric energy harvesting technology.According to this specific application scenarios,the self-powered energy management algorithm is implemented in a targeted circuit.3)A test platform for self-powered low-power WSN nodes is built.In the ideal and the actual situation,this paper discusses the measurement and analysis process of the control signal of the self-powered energy management algorithm and the energy consumption information of each module.4)Finally,this paper discusses the next research direction of this topic.