Design And Implementation Of A Piezoelectric And Magnetoelectric Vibration Energy Harvester

With the rapid development of MEMS and low-power technology today,more and more wireless sensors and small portable electronic terminals come into service.Traditional battery's small storage,frequent changing,environment polluting and difficult to exchange make effective energy supplement an increasingly prominent.People want to find a clean energy that can be independent,durable,long time free to maintain to replace the traditional batteries in the small scale,then the energy harvesting technology rise into response.The energy that can be harvested in the environment includes:vibration,thermal,solar,wind,magnet and so on.Of these the vibration is abundant and more stable than the others.Currently,the energy harvesting technology mainly consists of three forms: piezoelectric,electromagnetic,and electrostatic.This paper combines piezoelectric and electromagnetic energy harvesting to design and implement a composite vibration energy harvester.The piezoelectric part adopts the cantilevered beam structure,which adjusts the resonant frequency by changing the mass block's mass to achieve the purpose of harvesting the vibrational energy of different frequencies.The electromagnetic part uses the permanent magnet as a mass,which is combined with the coils to form electromagnetic energy harvesting at one end of the piezoelectric plate.Then begin with their principles,analyze the impact factors of their outputs by the equations.At the same time use COMSOL Software to model and simulate the piezoelectirc and electromagnetic energy harvesting,verify the optimum parameter while providing simulation data for the comparison with actual data.There is a phase difference in the output between the piezoelectric part and the electromagnetic part.The output of them is matched by the addition of the phase shift circuit.The direct output of the two kinds of energy harvesting is ac electric power,which cannot be directly used by the devices,so use the rectifier circuit to convert ac to dc,then the energy will be stored in the storage capacitance for small devices such as sensors and so on.Design and manufacture the energy collector architecture by 3D printing technology.After setting up the vibration test platform,test the energy harvester.By testing,The piezoelectric output is 0.7845 m W,the electromagnetic output is 6.8692 m W,and the direct series output of them is 6.3263 m W,This shows that there is a power attenuation between the two outputs by the phase difference.After using phase shift circuit,we get the joint output is 7.5944 m W,which is basicly the sum of the two kinds of outputs,This shows that phase shift circuit can reduce the power attenuation.Compared with single piezoelectric structure,the composite energy structure of energy harvestor increases the power output enormously.