Research On Hybrid Piezoelectric And Electromagnetic Power Generation Technology

With the development of low-power electronic device manufacturing technology,researchers are paying more and more attention to the application of distributed wireless sensor networks for environment and structure monitoring.At present,most nodes of wireless sensor networks use battery to supply power.There are shortcomings such as short life span,high replacement cost and environmental pollution caused by the supply of traditional chemical batteries,which greatly limits the development of wireless sensor networks.However,the energy in the global environment is almost ubiquitous.Therefore,it is a new research hotspot to obtain energy from the environment to replace the chemical battery for the wireless sensor network node.The collection of vibration energy is a common way to get energy from the environment.In view of the problem of low output power in the traditional single piezoelectric power generation,some theories,simulations and experimental studies are carried out in this paper.First of all,the mathematical model of the output power of hybrid devices is established and the influence of relevant parameters on power generation performance is analyzed which based on the piezoelectric equations,structural mechanics,electromagnetic induction,vibration theory and other related knowledge.Secondly,the power output is analyzed by using the finite element software.COMSOL software is used to establish the model of the piezoelectric energy harvesting unit,and the modal analysis and transient analysis are carried out to obtain the output power of the energy harvesting device with the change of relevant parameters.Maxwell software is used to analysis the static magnetic field and transient field of the electromagnetic energy harvesting unit.Simulation analysis solves the relationship between the output power and the related parameters of the electromagnetic energy harvesting unit and the electromagnetic damping ratio.After introducing the electromagnetic damping,the finite element analysis of the piezoelectric and electromagnetic energy harvesting units are analyzed once again.Then,based on the magnetic properties of the magnetically permeable material,an improved structure is designed and simulated by finite element method.The results proves that the improved structure has better power generation performance than the traditional structure.Finally,a piezoelectric and electromagnetic hybrid device was fabricated,and the experimental research on the power generation characteristics was carried out.An energy harvesting circuit was designed for verification.The experimental platform of vibration trap was set up.The experimental research on the power generation performance of the independent piezoelectric energy harvesting unit and the independent electromagnetic energy harvesting unit was carried out.Then,the initial structure of the hybrid unit was experimentally studied.Then,the power generation performance of the hybrid device is tested.The experimental results show that the peak output power of the independent piezoelectric unit at the optimal load of 51k? is 3.89 mW under the condition of the vibration frequency of 20 Hz and the acceleration of 0.4g.The peak output power of the independent electromagnetic unit at the optimal load of 1.61k? is 1.96 mW and the output power of the combined trap device is 4.59 mW.Compared with the independent piezoelectric and electromagnetic unit before compounding,output power increased by 18% and 134%,and the improved structure output of the electromagnetic section is increased by about 35% compared to the electromagnetic section of the initial structure.Therefore,the piezoelectric electromagnetic hybrid captive mode is more advantageous than the single captive mode and the application of magnetic materials can improve the electromagnetic output power.