A Research Of Piezoelectric-electrostatic Coupled Energy Harvesting Device

With the development of advanced sensing technologies and smart city strategies,attention has been paid to the research of vibration energy harvesting.Harvesting vibration energy from the environment is an attractive alternative to battery for wireless sensor node and portable electronics.However,the research of the current energy harvesters is limited to a single piezoelectric transformation mechanism,and its output energy density is low in real world environment.Hybrid energy harvesting which integrates into the piezoelectric system with electromagnetism,electrostatics and friction is an effective way to improve the performance of the harvester.Inspired by the hybrid energy harvesting,a new type of hybrid vibration energy harvester which uses piezoelectric-electrostatic mechanisms in the same device was proposed.The piezoelectric mode can provide the initial charge for the electrostatic mode by the coupling mechanism.The working principle of the harvester was analyzed,the theoretical model of the energy system was established.The output performance of the harvesting system was tested.A process flow based on MEMS technology was designed and a testable device by the method of MEMS-PCB integrated assembly was made.The main work includes:(1)The advantages and disadvantages of the single conversion mode and coupled conversion mode were analyzed and summarized.(2)A new type of hybrid vibration energy harvester which uses piezoelectric and electrostatic mechanisms in the same device was proposed.The corresponding structure and working principle were designed.The theoretical model of the system was established by distributed parameter model.(3)The mathematical analysis of the device using MATLAB and the finite element analysis of the structure using ANSYS were completed,and the interface circuit simulation analysis of simplified coupled model was made;(4)A prototype of the hybrid energy harvester was fabricated.Through the experiment,the output performance of the single piezoelectric mode and simplified coupling mode were tested and verified.It proved that the working principle of coupling model was effective;(5)The process flow based on MEMS technology for the harvester was designed and a testable device by the method of MEMS-PCB integrated assembly was made.A set of MEMS processing methods and MEMS-PCB assembly integration methods were formed.It is significant for the next step.