Lumped Parameter Evaluation Model Analysis and Load Coupling Modeling of Piezoelectric Composite Cantilever Beam

Abstract

In order to study the working mechanism of piezoelectric composite cantilever beam and improve the ability of predicting the power generation performance of piezoelectric composite cantilever vibration energy harvester (CVEH), the simple and high-precision analysis models of equivalent mass and equivalent stiffness of CVEH are proposed. The natural frequency method is used to compare the calculation results of the evaluation model, Rayleigh Ritz method and finite element simulation, and the results show that the consistency (Ω) between the evaluation model and the finite element simulation is more than 95%. The influence of the mass ratio (α) between the end mass of the beam and the weight of the beam itself on Ω is analyzed by using the proposed evaluation model, which shows that Ω increases with the increase of α, and the increase is more significant in the range of 0<α<4. The analysis of the influence of α on the natural frequency of the beam () shows that decreases with the increase of α, and the decrease is more obvious in the range of 0<α<2. According to the evaluation model, the electromechanical conversion analysis models of CVEH and its control equation with coupling of standard energy harvesting (SEH) interface circuit and Double synchronous switch harvesting (DSSH) interface circuit are established respectively, and the mathematical models of its output voltage are derived. The power generation experiment of CVEH is carried out, and the results show that the proposed models are in good agreement with the experimental results.