磁力耦合阵列式压电俘能器振动特性研究

Vibration performance analysis of magnetic coupling array piezoelectric energy harvester

振动能量收集技术有望解决无线传感节点自供电的难题。通过引入非线性磁力,本文设计了一种磁力耦合阵列式压电俘能器(MA-PEH)。基于磁偶极子法建立非线性磁力模型,利用有限元方法获取组合梁的恢复力模型,根据牛顿第二定律及基尔霍夫定律建立系统的动力学模型。仿真分析了激励幅值、激励频率对动力学响应的影响规律,并进行实验验证。研究结果表明:在非线性磁力作用下,系统在谐振频率附近出现混沌和阱间周期运动,这将有利于拓宽俘能器的工作频带;随着激励频率改变,各组合梁始终保持相同的运动状态,当系统处于阱间周期运动状态时,只存在一种类型的组合梁处于高能输出状态。当激励频率分别处于两个组合梁的谐振频率附近时,增大激励幅值,将导致一种类型的组合梁输出被提升,而另一种类型的组合梁输出被抑制。

Vibration energy harvesting technology is expected to solve the problem of self-powered wireless sensor nodes.By intro⁃ducing nonlinear magnetic force,a magnetic coupling array piezoelectric energy harvester(MA-PEH)is designed in this paper.The nonlinear magnetic force model is established based on magnetic dipole method.The restoring force model of composite beam is obtained by finite element method.According to Newton’s second law and Kirchhoff’s law,the dynamic model of the system is established.The influence of excitation amplitude and excitation frequency on dynamic response is analyzed by simulation and veri⁃fied by experiment.The results show that under the action of nonlinear magnetic force,the system appears chaos and periodic mo⁃tion between wells near the resonant frequency,which can help to broaden the working frequency band of the energy harvester.As the excitation frequency changes,each composite beam always maintains the same motion state.When the system is in a periodic motion state between wells,only one type of beam is in a high-energy output state.When the excitation frequency is near the reso⁃nant frequency of the two beams,increasing the excitation amplitude will lead to the boosting of the output of one type of beam,while the output of the other type of beam will be suppressed.The research provides theoretical guidance for the design of array piezoelectric energy harvesters and new research ideas for improving the output performance of piezoelectric energy harvesters.