Research On The Dynamic Characteristics Of A Three-dimensional Piezoelectric Cantilever Energy Harvesting System

In the past few decades,MEMS technology has been developing rapidly,leading the facilities like wireless sensors,data transmission and medical implants to size and efficiency miniaturization.As energy supply device for a long time,battery has many drawbacks.Firstly,conventional batteries restrict the microminiaturization of microelectronics.Secondly,battery life is limited,and it need to be recharged or replaced after a period of usage.Moreover,in some remote area and harsh environment,it is hard to generate electricity.Some renewable alternatives are developed like solar energy and wind energy,however they are also limited by environment,which is also restricted for implementation.Therefore,a new method of powering is required.Vibration energy makes it possible for low-power devices to harvest energy from the environment,achieving self-powered.Piezoelectric cantilever energy harvesting(PEH)system is the most common approach.Traditional linear cantilever-beam system is consist of one or several piezoelectric cantilevers.However,it is hard to be implemented because of its narrow bandwidth.Nonlinear piezoelectric cantilever energy harvester is capable of broadening the bandwidth,making it possible of fitting many kinds of excitation situations.Traditionally,PEHs can only harvest energy from the uni-directional mechanical vibration,whereas vibration in environment could distributed in many directions.Therefore,to build a multi-directional vibration energy harvesting system based on piezoelectric cantilevers,and achieve a high-efficiency energy conversion has important research value and significance.This paper focuses on three-dimensional vibration energy harvesting method,exploring the characteristics of a novel nonlinear three-dimensional harvester under Gauss random excitation.Firstly,this paper present a novel and simple three-dimensional nonlinear PEH,which is consisted of only three piezoelectric cantilevers.Its lumped parameter model,dynamic model,magnet force model,and potential energy functions are analyzed.In order to simulate the ambient vibration excitation situations in the real environment,this paper utilize narrow band Gaussian white noise as input excitation into numerical simulations.Then the experiments are carried out and compared with the simulations to prove the accuracy.To sum up,this paper introduced the background and significance of the research,reveled the current research status,and illustrated the mechanism of the PEH.Based on this,a deep research on the vibration characteristics of a proposed three-dimensional PEH are carried out.Theoretical and experimental analysis show that to a certain bandwidth and intensity range of random excitation,the system has at least one magnet interval which leads to the peak value of output voltage in two axes directions,meanwhile ensures a high-level in the third axis direction.By adjusting this optimal distance,the energy harvesting can be kept in a high-efficiency state without structural adjustments in real vibrational environment.