Research On A Hybrid Vibration Energy Harvester

The limitations of energy supply during the applications of wireless sensors,portable electronic products have appeared,such as battery replacement and maintenance.Vibration energy harvesting technology,which can convert the vibration energy widely existing in the environment into electrical energy,should be an effective battery-free energy supply.Single source vibration harvester,as traditional harvesting technology has been applied widely,which has few disadvantages such as low energy harvesting efficiency and poor overall performance.Hybrid energy harvesting method may be an effective solution to solve the above problems.A piezoelectric-electrostatic hybrid vibration energy harvester,which integrated electrostatic vibration energy harvester(ESVEH)with the traditional cantilever-type piezoelectric vibration energy harvester(PEVEH)was proposed in this thesis,includes theoretical model,parameter optimization,numerical simulation,and experimental testing.The couple-field model of the piezoelectric and the electrostatic module of the hybrid vibration energy harvester set up respectively.The integrated model of hybrid vibration energy harvester was established based on the above model,whose dynamics equations and electromechanical coupling was also derived.The optimal structure design of the piezoelectric module base on orthogonal test method was done base FEM simulation.The optimal design-of the electrostatic module was also discussed base the above method.We can conclude from the above optimal design of the hybrid energy harvester that the peak output power of the optimal piezoelectric and electrostatic module are 1220?W and 1.245?W respectively under 0.25g excitation acceleration at the base of the harvester.The prototype of the hybrid vibration energy harvester was fabricated,which was tested and verified in lab-build experimental platform.The experimental results show that the output powers are 1111.12?W and 1.078?W of the piezoelectric and electrostatic module at an excitation acceleration of 0.25g,respectively,which agrees with the simulation results.The electrical characteristics of the hybrid vibration energy harvester were also tests in follow experiments.The experimental results show that the open circuit output voltage and output power of the hybrid energy harvester,has increased by 2.54V and 1.078?W separately compared with sole piezoelectric module under 0.25g excitation.The average charging power of capacitor which connected with the working hybrid energy harvester in 10s has increased by 0.768?W compared with the piezoelectric module.The simulation and experimental result conformed that,the hybrid vibration energy harvester which combined piezoelectric and electrostatic module has some improvement in performance compared to sole source energy harvester.The hybrid energy harvester could be a potential energy supply for portable electronic devices and wireless sensors node.