Design And Experimental Study Of Broadband Piezoelectric Energy Harvester And Its Interface Circuit

With the rapid development of wireless sensor technology,the traditional electrochemical battery has been exposed to short life,environmental pollution and regularly replacing.Piezoelectric vibration energy harvester which can replace the electrochemical battery has the advantages of sustainable,environmental,long service life.It has become a research hotspot.However,the vibration in the environment is random,the piezoelectric vibration energy harvester is not effective in the frequency range far from its natural frequency,so as to most of single-frequency piezoelectric vibration energy harvesters at present have the problems of narrow working frequency and low energy conversion efficiency,which is difficult to meet the demand of existing microelectronic devices.And the harvested energy must be rectified to supply to load,so the design of efficient energy recovery interface circuit is also an important part of energy harvesting.Therefore,this paper mainly studies the design and experiment of broadband piezoelectric vibration energy harvester and its interface circuit.The main content of this paper consists of the following four parts:In the first part,the research progress at home and abroad and the existing problems of piezoelectric vibration energy harvester are introduced,as well as the basic theoretical knowledge related to the research content,including piezoelectric ceramic,piezoelectric effect,piezoelectric equations and the cantilever beam bending vibration theory.In the second part,the structure of linear single-frequency piezoelectric vibration harvester and its output performance are introduced firstly.Then this part focuses on the motion equation establishment about the distributed parameter model of linear broadband piezoelectric vibration energy harvester.Effects of structural parameters(mass ratio,stiffness ratio and damping ratio,etc.)on the vibration performance and electrical output performance are numerically analyzed.Finally some experiments are carried out to compare the performance of single-frequency piezoelectric harvester with broadband piezoelectric energy harvester,also compare the performance predict accuracy of the broadband piezoelectric energy harvester distribution model with lumped parameter model.In the third part,the structure of the nonlinear piezoelectric vibration energy harvester and the effect of terminal permanent magnet on the system are introduced.Then this part focuses on the motion equation establishment about the distributed parameter model of the nonlinear broadband piezoelectric vibration energy harvester.Effects of structural parameters(mass ratio,stiffiness ratio and the distance of magnets,etc.)on the vibration performance and electrical output performance are numerically analyzed.Three previously mentioned energy harvesters were compared and analyzed.Finally,the output performance of the nonlinear broadband piezoelectric energy harvester is verified by experiment.In the forth part,three kinds of energy recovery interface circuits named Standard?Self-power S-SSHI and Self-power P-SSHI are designed,the output waveform and recycling power of them under the constant displacement amplitude is obtained by simulation.Experimental setup is developed,the recycling power of Standard.SP-SSSHI?SP-PSSHI under a constant open circuit voltage and the optimal load are compared by experiment.