多场耦合多方向振动俘能器建模及响应分析

针对多方向振动俘能器对低频、低幅值激励的响应输出性能低等问题,在振动俘能结构中引入非线性磁吸力,提高俘能器的响应频带和能量转换效率。研究了非线性磁振子模型,建立了基于广义Hamilton变分原理的横、纵向振动系统机电耦合模型,对系统动力学方程进行无量纲化并数值求解。搭建了振动俘能器性能测试平台,开展了多场耦合振动俘能器频谱特性及响应输出的分析实验。结果表明,引入磁铁可显著提高系统能量转换效率,当磁铁间距15mm、激励幅值0.5m/s~2时,相比无磁力输入的情况,系统响应电压提高了6倍左右,谐振频率从18Hz降至9.5Hz左右,解决了压电俘能器频带窄、响应频率高及输出电压低等问题。

Modeling and Response Analysis of a Multi-field Coupled Multi-direction Vibration Energy Harvester

Aiming at low response performance of vibration energy harvester to low-frequency and low-amplitude excitation, the nonlinear magnetic attraction is added to energy harvesting structure to improve frequency band and energy conversion efficiency. Nonlinear magnetic models are studied, the distributed electromechanical coupled models of transverse and longitudinal vibrations are established by using the generalized Hamilton variation principle, and system dynamic equation is addressed dimensionless and solved numerically. The experimental platform of vibration energy harvester is built, the spectral characteristics and response output is obtained. Results show that, when magnet spacing is 15mm and excitation amplitude is 0.5m/s2, the energy conversion efficiency increases by about 6 times compared with that with no magnetic, and resonance frequency decreases from 18Hz to 9.5Hz, which solves problems of narrow band, high response frequency and the low output voltage of piezoelectric energy harvester.