混合式三稳态压电能量俘获器动力性能分析

Dynamic Performance Analysis of Hybrid Tri-stable Piezoelectric Energy Harvester

为了提高压电能量俘获器在低强度外界激励下的俘能表现,基于三稳态压电悬臂梁能量俘获器模型,在U形框架和基底之间以及压电悬臂梁固定端与U形框架之间分别装置一个弹性放大器,提出一种混合式三稳态压电能量俘获器(TPEH+DEM)模型。基于Hamilton原理建立了TPEH+DEM系统的非线性力电耦合运动方程,并利用谐波平衡法分析了弹性放大器的质量和弹簧刚度、磁铁之间相对距离、负载电阻等对TPEH+DEM系统能量收集水平的影响。结果表明:在一定的外界激励频率范围内,TPEH+DEM系统的响应输出功率存在两个峰值,合理调节弹性放大器的质量和刚度能使系统在较低的外界激励强度下进入阱间运动,产生很高的输出功率。相比于仅带有弹性基底的传统三稳态压电能量俘获器,TPEH+DEM模型在低频外界激励下具有更好的俘能表现。

To improve the energy harvesting performance of the piezoelectric energy harvester under low external excitation level,based on the multi-stable piezoelectric cantilever energy harvester model,two elastic amplifiers were respectively installed,one was installed between the U-shaped frame and the substrate,and the other was installed between the U-shaped frame and the fixed end of the cantilever beam.Hence,a hybrid tri-stable piezoelectric energy harvester(TPEH+DEM)model was proposed.The nonlinear electro-mechanical coupling equation of the TPEH+DEM system was established by using Hamilton principle.The influences of the mass ratio and spring stiffness ratio of the two elastic amplifiers,the relative distance between the magnets,and the load resistance on the energy harvesting level of the TPEH+DEM system were analyzed.And it turned out that within a certain range of external excitation frequency,the response output power of the TPEH+DEM system had two peak value.Reasonable adjustment of the mass ratio and spring stiffness ratio of the two elastic amplifier can make the system enter inter-well motion under low external excitation intensity,and produce high output power.Compared with the traditional multi-stable piezoelectric energy harvester with only an elastic substrate,the TPEH+DEM model has better energy harvesting performance under low frequency external excitation level.