Piezoelectric Vibration Energy Research Articles

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

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.

Bimorph Vibration Energy Harvester with Flexible 3D Mesh Structure

In this paper, we propose a piezoelectric bimorph vibration energy harvester (VEH) with flexible 3D mesh elastic layer for the purpose of improving output power and lowering resonance frequency. Due to the high void ratio of the 3D mesh structure, it is possible to lower the bending stiffness of the cantilever. So, the deflection of the harvester and the strain in the piezoelectric layer increase. As a result of a vibration test, the resonance frequency is 26% lower and the output power is 1.5 times higher than the conventional solid flat plate VEH. Compared with the flat plate VEH, the proposed mesh VEH has 1.3 times larger tip deflection and the total output power is 20.4 μW that is possible to use as a power supply of low-power consumption sensor nodes for WSNs.

Analyses of vibration-based piezoelectric power generator in discontinuous operation mode

Vibration energy can be converted into electrical energy using piezoelectric power generator. The electrical energy is usually collected in a storage capacitor. The storage capacitor discharges to the load only when enough energy is harvested for the required operation. The time interval between successive required operations depends on several parameters: characteristics of piezoelectric power generator and vibration magnitude, energy requirement and voltage interval, and value of the storage capacitor. In this paper, theoretical and experimental analyses of these parameters are performed to choose appropriate values of the voltage interval and storage capacitor to minimize the time interval. Theoretical analyses are well conformed by the experimental results. Analysis results are instructive for applications of both macro and MEMS-based piezoelectric power generator.