基于线性放大与非线性磁力复合增强的三稳态压电振动能量俘获机理与动力学特性研究

Vibration Energy Harvesting Mechanism and Dynamic Characteristics of a Compound Tri-stable Piezoelectric Vibratory Energy Harvester Combining a Linear Amplifying Mechanism and Nonlinear Magnetic Force

提出一种基于线性放大与非线性磁力复合增强的三稳态压电振动俘能器,实现在宽频范围内有效地采集低能轨道振动能量。将质量块和弹簧组成的线性放大机构置于三稳态压电俘能器与基座之间,调节线性放大机构与俘能器之间的质量比和刚度比,使三稳态俘能器获得较大的输入动能从低能轨道运动跳转到高能轨道运动,从而获得更高的输出性能和更宽的工作频带。利用能量法建立了描述该复合压电振动俘能器系统动态响应的非线性机电耦合数学模型;采用动态分岔图仿真研究了系统质量比和刚度比对压电俘能器动态输出性能的影响及其能量俘获机理。实验验证了理论结果的正确性。研究结果表明:合理调节系统质量比和刚度比,复合俘能器可以在低能轨道振动时获得更宽的工作频带和更高的发电能力。与传统刚性基座三稳态压电俘能器相比,实验获得复合压电俘能器的阱间运动频率范围由3~14 Hz扩大到2~21.5 Hz,从低能轨道振动跳转到高能轨道振动所需的激励加速度由13.5 m/s^(2)降至5.8 m/s^(2)。

A hybrid piezoelectric device combining a tri-stable piezoelectric energy harvester(TPEH) with a linear amplifier and nonlinear magnetic force is presented to enhance the harvesting ability of the low-orbit vibration energy. The linear amplifying mechanism(LAM) composed of a mass and spring is placed between the TPEH and the base to amplify the low-orbit vibration and provide the TPEH enough kinetic energy to overcome the potential barrier, which make the TPEH easily jump to the high-orbit oscillation, resulting in an even better operating bandwidth and higher power generation. The nonlinear electromechanical model describing the dynamic responses of the presented harvester is derived. The effects of the mass ratio and stiffness ratio on the dynamic performances of the hybrid energy harvester are numerically investigated with dynamic bifurcation diagrams method. The results show that the presented harvester has wider frequency bandwidth and higher power generation by properly selecting the mass ratio and stiffness ratio, and it can more easily snap-through from low-orbit oscillation to high-orbit oscillation to reach larger dynamic response at lower excitation levels. Experiments are conducted to validate the simulations, and the experimental results are in reasonable agreement with the theoretical results. Compared to the traditional tri-stable piezoelectric energy harvester, the working frequency band of the compound TPEH enlarges from 3~14 Hz to 2~21.5 Hz, and the excitation acceleration required to jump from low-orbit vibration to high-orbit vibration decreases from 13.5 m/s^(2) to 5.8 m/s^(2).