Research On Triboelectric Nanogenerator And Self-powered Mornitoring System Based On Charge Excitation Shift Stratagy

With the development of technologies,human beings are stepping into the era of intelligence.Real-time monitoring of environmental parameters such as agricultural and marine environments will play an indispensable role in national development.At present,the demand for the distributivity of monitoring sensors is increasing sharply,and the distributed power supplies for these sensors become the primary issue in its development.There is a large amount of distributed energy in the natural environment,and various energy harvesting technologies have been explored,such as solar energy generator,wind power generator,which have outstanding advantages in energy harvesting efficiency and durability.But the generated power is poor in cloudy weather or in low wind speed.Triboelectric nanogenerator(TENG)is an emerging technology that can effectively harvest low-frequency and random energy distributed in the environment and convert it into electrical energy.It has the characteristics of high sensitivity,low cost,and small size,which provides an effective environmental energy harvesting technology for powering the distributed sensors.The charge excitation strategy can continuously inject charges from the pump TENG into the main TENG,which effectively improves the output performance of TENG.It has many advantages such as significant effects and simple implementation.The energy in the natural environment varies hugely with weather,seasons,and some other factors.The threshold range of energy harvesting is important for the efficiency of environmental energy harvesting.Therefor,this work proposes "primary-secondary" architecture for TENG that can broaden the thresholds range of energy harvesting.It can not only improve the output performance of TENG,but also improve the environmental adaptability.The research contents of this paper include the following aspects:(1)A "primary-secondary" design concept for triboelectric nanogenerator is proposed.When external excitation is weak,the primary block serves as a voltage source to provide energy to the load,while the secondary block does not work to reduce startup energy.When external excitation is strong,the primary block automatically shifts to a charge source to continuously inject charges into the secondary block,and the charge excited secondary block provides energy to the load.This architecture can achieve automatic charge excitation shift strategy,which can expand the threshold range for energy harvesting,and improve the environmental adaptability of the TENG.(2)Research on the charge excitation theory of TENG under the "primary-secondary" architecture.In primary block,the theoretical research and design of the voltage doubling circuit is accomplished based on the internal equivalent capacitance of the TENG,which doubles the charge excitation voltage.In secondary block,the physical and electrical models of multi-layer coupling structure are established,and the key parameters such as charge,voltage,and separation distance are analyzed.Besides,a two-channel charge excitation circuit is designed to improve the output performance of the TENG.These researches provide a solid theoretical basis for the subsequent works.(3)Design a novel mechanical structure and hardware circuit for the "primary-secondary" triboelectric nanogenerator(PS-TENG).PS-TENG uses a slider centrifugal structure to automatically adapt to the strength of the external excitation,achieving the charge excitation shift strategy.The designs of a shift mechanism with automatical mechanical frequency doubling function,as well as a two-channel charge excitation circuit and output circuit can improve the output performance of PS-TENG by more than 40 times.It is shown from the experiments that PS-TENG takes only 25.8 s to charge a 100 μF capacitor from 0 V to 3 V,and can drive 320 LEDs or a hygrothermograph to work continuously and stably.(4)Based on the designed PS-TENG,a self-powered environmental temperature and humidity monitoring system is established to achieve real-time measuring of environmental temperature and humidity.Powered by the PS-TENG that can harvest energy from environmental energy,the end node can measure the temperature and humidity of the environment and transmits the data to remote sink node.These data are then transferred to host computer to implement functions such as display,alarm and query.Besides,through hardware design,software design and parameter configuration,the average power consumption of the end node has been optimized to only 0.65 m W.In summary,this paper focuses on the research of charge excitation shift strategy,and proposes a "primary-secondary" design concept for TENG.This work designs the mechanical structure and hardware circuit of PS-TENG,and builds a self-powered environmental temperature and humidity monitoring system.A comprehensive and detailed study is conducted from theoretical analysis and simulation verification in the early stage,to scheme design and prototype optimization during the work carried out,and then to parameters measurement,characteristics testing,and service characteristics research in the later stage.It can not only enhance the performance of TENG,but also realize automatic charge excitation shift strategy,which improves adaptability to the environment.This work can promote the practical application of TENG in harvesting the environmental energy,and provide a new solution for powering the distributed wireless sensor networks.