非线性宽频压电振动能量采集器的研究

Research on a nonlinear broadband piezoelectric vibration energy harvester

为改善双稳态压电振动能量采集器在基础低幅值激励条件下的输出性能,提出了一种带有线性放大器的非线性宽频压电振动能量采集器,通过线性放大器对基础低幅值激励进行一级放大后,激发双稳态压电振动能量采集器进入高能轨道的大幅值周期振动,从而提高能量采集器的输出性能。根据力学和电学平衡方法建立了非线性宽频压电振动能量采集器的两自由度集总参数模型和运动微分方程,并对系统模型进行时域和频域求解,仿真分析了系统质量比、刚度比等参数对系统输出特性(振动位移、速度、相图和输出电压等)的影响。最后,通过与双稳态压电振动能量采集器输出性能的实验结果对比分析,表明非线性宽频压电振动能量采集器在较小的激励幅值作用下具有更高的输出特性和更宽的工作频带。

In order to improve output performances of a bistable piezoelectric vibration energy harvester （BPH） operated under a low level excitation, a nonlinear broadband piezoelectric vibration energy harvester was proposed which was consisted of a BPH and an elastic magnifier （EM）. The EM positioned between the BPH and the EM was used to magnify the base vibrating level to excite the BPH easily oscillating in a high-energy orbit which could greatly improve the output performances of BPH. A two-degree-of-freedom （TDOF） lumped parameter model and the motion differential equations were derived, and solutions in time-domain and in frequency-domain of the motion equations were calculated respectively. Effects of mass ratio and stiffness ratio of the system on the output performances （ such as vibrating displacement, velocity and the phase portraits） of the BPH were numerically simulated. Finally, the validity of the proposed model was testified with the experimental results. Research results showed that the BPH with an EM had a better output performance and a broader operating frequency band than that of BPH without an EM.