Coil-levitated Hybrid Generator For Mechanical Energy Harvesting And Wireless Vibration Monitoring

Fossil energy sources such as coal,oil,and natural gas are facing serious practical problems such as resource depletion and serious pollution emissions.The imbalance of energy distribution has become increasingly obvious,the degree of separation of energy supply and demand has continued to deepen,the scale of global energy trade has continued to expand,and per capita energy consumption has continued to increase.These make the energy consumption structure tend to be clean,low-carbon,environmentally friendly,green and diversified.Hydrogen energy,solar energy,tidal energy,wind energy,ocean energy,etc.have become a new generation of clean energy.The vibration energy in the environment is not only abundant in total,but also low-carbon,environmentally friendly,renewable,and has great potential for future development.Vibration energy is mostly wasted in the form of mechanical energy,kinetic energy,potential energy,etc.At present,more and more workers design various structures,use different principles to effectively collect environmental vibration energy,and store it as electrical energy through low-power circuits or directly drive electronic equipment to work.The current environmental energy collection methods include:triboelectric generator,electromagnetic generator,piezoelectric generator,and hybridized generator.On the other hand,the booming Internet of Things has been used in all walks of life.As the Internet of Things has slowly developed into the world,everything can be connected.The Internet of Things has triggered a wave of industry due to its universality and simplicity.The human-computer interaction of portable and mobile smart terminals is getting closer and closer,becoming an inseparable part of human beings.Mobile smart terminals are mostly powered by lithium batteries,but lithium batteries have a short lifespan and need to be replaced regularly.The disadvantage of polluting the environment makes them unsuitable in many environments.Harvesting vibration energy in the environment,combine the converted electric energy with miniaturization technology and low-power management solutions,avoiding the shortcomings of frequent battery replacement,short battery life,environmental pollution,and inapplicability to complex environments.It provides a practical solution for the power supply of smart terminals in the Internet of Things.In this paper,a coil-levitated hybrid generator is manufactured.It takes the coil-levitated structure as the sensitive unit,and adopts the micro-cylindrical design package to effectively integrate the friction,electromagnetic and piezoelectric power generation units.It is worth mentioning that the coil-levitated has high sensitivity and is not affected by the metal magnetic field environment.It is cleverly combined with friction and piezoelectricity to realize the combination of multiple energies in a limited space.Among them,the copper metal material of the friction power generation part is removed through the water-assisted oxidation process to remove the messy copper oxide,and a layer of dense and regular copper surface microstructure is re-oxidized,and on this basis,a friction membrane switch is further fabricated.We tested and analyzed the output performance of the hybrid energy harvester.The open circuit voltage and short circuit current of the three power generating units of friction,electromagnetic and piezoelectric are tested and analyzed.Then the multiple responses of a single excitation are analyzed,and the influence of vibration frequency and amplitude on the output electrical performance is explored with the control variable method,which proves that the frequency has a greater weight on the output electrical performance.In order to ensure the stability and reliability of the output,the effects of continuous working time,external impedance,and device placement tilt angle on the stability of output performance are studied.The optimal impedance matching and adaptive tilt angle range of the device were obtained,which proved the energy harvesting ability of the hybrid generator,and the reliability of the device was further verified and analyzed by experiments.Finally,the application verification experiment of LED lighting and the functional application of wireless passive monitoring system were carried out on the composite energy harvester,including the charging experiment of capacitor and lithium battery.The coil-levitated hybrid generator made in this paper has higher feasibility in actual engineering.It satisfies high-efficiency and sensitive output and is also suitable for metal magnetic field environment.It integrates hybrid generator and energy harvesting module,signal processing module,power management module,wireless transmission module and other back-end circuits,and establishes a complete wireless self-powered vibration and temperature monitoring system,which can be used to monitor the working status of mechanical equipment in complex environments,such as the vibration of the key components of coal mining equipment in underground environments,temperature signals,etc.This is of great significance to the development of the Internet without power supply sensing monitoring.