Design And Research On Nonlinear Piezoelectric Beam Array Vibration Energy Harvester

Currently,world energy shortage problem is getting worse.In addition to the power grid and batteries,the way to get power is relatively limited.In off-grid areas,when the battery capacity can not meet the requirements of the situation,the use of ambient energy such as solar energy,wind energy,the environment and other vibrational energy is the unique way to generate electricity in order to solve the power supply problem.With the rapid development of low-power electronic devices and social urgent need for new energy sources,energy harvesting system has become more important,and the piezoelectric energy harvester with its life,high energy density has become a hotspot.However,conventional piezoelectric energy harvester has a low output performance in low-frequency environment,narrow working bandwidth.Based on piezoelectric beam array vibration energy harvester,the new non-linear piezoelectric beam array vibration energy harvester is designed,intended to improve the operating bandwidth,low-frequency output power and ability to adapt the low-frequency environment.First,according to Rayleigh-Ritz method and the Euler-Bernoulli beam theory,partial differential equation is established.Subsequently,based on Kirchhoff's law and Gauss theorem,the mechanical part and the circuit portion are coupled together,and mechanical vibration response and electrical response are obtained.Based on distributed-parameter electromechanical model,single piezoelectric system is optimized by using MATLAB.On the basis of piezoelectric beam array vibration energy harvester,nonlinear magnetic force is introduced,a nonlinear piezoelectric beam array vibration energy harvester is designed.According to the distributed-parameter electromechanical model,its lumped-parameter electromechanical model is corrected and established.The higher order differential equations of lumped-parameter electromechanical model is reduced to the first-order differential equations,and then by using high-order Runge-Kutta method,first-order differential equations can be calculated,and harmonic excitation response is obtained.By using vibration bifurcation diagram,Lyapunov maximum exponent spectrum,and Poincare map,the vibration characteristics can be obtained,to study how do the excitation frequency,excitation amplitude and the displacement of the magnets affect the vibration displacement and the effective output applied voltage,to analyze the underlying mechanism.Subsequently,the output voltage,output power and the energy conversion efficiency of nonlinear piezoelectric beam array vibration energy harvester is researched under the white noise excitation.Theoretical research shows that: nonlinear piezoelectric beam array vibration energy harvesterhas a higher operating bandwidth,output power and ability to adapt to the environment compared to the linear array of piezoelectric energy harvester.Finally,set up experimental platform,by changing the input frequency of the vibration and acceleration,to observe the effects of the end of the piezoelectric sheet mass piezoelectric energy harvester,the advantages of an array of piezoelectric energy harvester,and low-frequency output characteristics and operating bandwidth of nonlinear piezoelectric beam array vibration energy harvester.The results coincide with the theoretical study and verify the correctness of the distributed-parameter electromechanical model and thelumped-parameter electromechanical model.