宽频压电振动能量采集器的力-电输出特性分析

压电振动能量采集器是一种新型的力(加速度)-电耦合转换输出器件,为了提高单自由度悬臂梁压电振动能量采集器的输出功率和工作频带,通过在单自由度悬臂梁压电振动能量采集器模型基础上增加一个弹性放大器的方法,构造形成了具有两自由度的宽频压电振动能量采集器。利用ANSYS有限元软件建立了宽频压电能量采集器的有限元力-电耦合模型,数值分析了模型中各参数(如质量比、阻尼比以及负载电阻等)对系统力特性(速度、加速度等)和电输出特性(电压、电流、输出功率等)的影响。研究结果表明：大的质量比和小的阻尼比能够提高压电悬臂梁能量采集器的输出功率并拓展其工作频带;短路谐振状态下的匹配电阻能够使能量采集器产生较大的输出电流,而开路谐振状态的匹配电阻能够使能量采集器产生较大的输出电压,优化后的短路谐振和开路谐振最大输出功率分别达到4386.5 mW/g2和4263.4 mW/g2。频带宽度达到10 Hz,且是SDOF系统的5倍。     

多方向压电振动能量收集装置及其优化设计

摘要：为实现对不同方向环境振动能量的收集,提出了一种新颖的多方向振动能量收集装置的设计结构,装置的换能部分采用了一种Rainbow型压电结构。为提高多方向振动能量收集装置收集能量的效果,以多方向振动能量收集装置输出的总电能为目标函数,综合考虑金属弹性基片的强度、装置振动的固有频率及装置的尺寸空间要求等多种因素,采用序列二次规划法对能量收集装置的结构参数进行了优化。该多方向振动能量收集装置经过优化后,在Y向激励时,其输出的总电能为37.146μJ,比优化前提高了30.82%,当沿装置体对角线方向激励时,结构装置输出的总电能为58.715μJ,比优化前提高了29.24%,装置的能量收集效果得到了明显提高。分析结果为多方向振动能量收集装置的设计、制造及应用提供了技术依据。     

磁力非线性耦合的I-L组合压电梁俘能器发电性能试验研究EI北大核心CSCD

针对线性的压电振动俘能器俘能频带过窄,输出较低等问题,提出了一种磁力非线性耦合的I-L组合压电梁俘能器。俘能器由带永磁铁的I型压电梁和L型压电梁组成,可通过调节两永磁铁间的水平距离,得到不同的非线性磁力耦合效应。试验结果表明:存在最优电阻使压电俘能系统的输出功率最大;对比无磁力系统,磁力耦合的I-L组合压电梁俘能器共振频率发生了明显的偏移:I型压电梁向左偏移,L型压电梁向右偏移,拓宽了系统的俘能频带;当激励加速度为0.2 g水平距离为20 mm、激振频率为18.4 Hz时,俘能器最大可得到1.2 mW的输出功率。     

Low-frequency meandering piezoelectric vibration energy harvester

The design, fabrication, and characterization of a novel low-frequency meandering piezoelectric vibration energy harvester is presented. The energy harvester is designed for sensor node applications where the node targets a width-to-length aspect ratio close to 1:1 while simultaneously achieving a low resonant frequency. The measured power output and normalized power density are 118 μW and 5.02 μW/mm(3)/g(2), respectively, when excited by an acceleration magnitude of 0.2 g at 49.7 Hz. The energy harvester consists of a laser-machined meandering PZT bimorph. Two methods, strain-matched electrode (SME) and strain-matched polarization (SMP), are utilized to mitigate the voltage cancellation caused by having both positive and negative strains in the piezoelectric layer during operation at the meander's first resonant frequency. We have performed finite element analysis and experimentally demonstrated a prototype harvester with a footprint of 27 x 23 mm and a height of 6.5 mm including the tip mass. The device achieves a low resonant frequency while maintaining a form factor suitable for sensor node applications. The meandering design enables energy harvesters to harvest energy from vibration sources with frequencies less than 100 Hz within a compact footprint.     

基于双ZnO薄膜单元并联结构的微型压电振动能量采集器(英文)

报道了一种基于ZnO压电薄膜双单元结构的压电式微型振动能量采集器,其中的双压电元件是并联结构.采用射频磁控溅射技术制备ZnO压电薄膜,同时,该压电式振动能量采集器采用微加工技术制作.测试表明该器件的共振频率为1 300 Hz,基于ZnO薄膜双单元并联结构的压电式振动能量采集器比起具有同样尺寸的传统型压电振动能量采集器有更高的输出性能.在频率为1 300 Hz,加速度为10 m/s2的外界振动激励下,该压电式振动能量采集器在1 MΩ负载电阻上产生的电压为2.06 V;当负载电阻为0.6 MΩ时,输出功率最大为1.25μW.     

A multisource energy harvesting utilizing highly efficient ferroelectric PMN-PT single crystal

This paper demonstrates a multi-source energy harvester that is able to utilize simultaneously both piezoelectric and pyroelectric effects in lead magnesium niobate-lead titanate (PMN-PT) single crystal. The paper presents a study of PMN-PT single crystal with a (67:33) composition grown in our laboratory via a vertical gradient freeze method without any flux. The performance of the piezoelectric and pyroelectric energy harvester using unimorph device structure was evaluated via modeling and experiment. The theoretical study was implemented based on a distributed parameter electromechanical model and the modelling procedure was approximated using finite element analysis to predict the electromechanical behavior of the harvester. The maximum power density at a resonance frequency of 50 Hz and optimum resistance of 2 MΩ was 16.7 nW/(g² cm³) under a 1 g acceleration of vibration. The measured values of electrical output parameters were in good agreement with theoretical and modelling results using MATLAB and COMSOL Multiphysics, respectively. By using the pyroelectric effect along with the piezoelectric effect, the output voltage of the energy harvester was found to be enhanced at the optimum resistance and specific frequency values. It was noticed that the output voltage was increased monotonically with temperature-difference (ΔT) and reaches up to 180 % of its original value under temperature difference of 1.7 °C at a frequency value of 49 Hz.     

直线式压电垂直驱动振动给料机设计

目的 为了满足现代电子工业领域中对微小电子元器件高速送料的需要,采用环形压电双晶片,设计一种直线式压电垂直驱动振动给料机。方法 首先对给料机结构进行设计,阐述其工作原理,通过对环形压电双晶片进行模态分析,确定双晶片工作振型。然后利用小挠度的弹性薄板理论,推导压电双晶片输出力的表达式,利用Matlab软件,探究压电陶瓷和基板的厚度与出力系数的关系,以及压电陶瓷和基板的弹性模量与出力系数的关系。最后制作振动给料机样机,并对其进行实验测试。结果 测试结果表明,系统有效工作频率为184～190 Hz,当驱动电源电压为220 V,频率186.8 Hz时,对3.2 mm×2.8 mm的发光二极管(LED)给料速度可达到22.6个/s,比市场上同型号的矩形压电双晶片驱动给料机速度提升了14.7%。结论 在精密电子元件高速输送的自动化包装或自动化检测线上具有良好的应用前景。     

悬臂梁压电振动能采集器的集总参数模型和实验验证

压电振动能采集器是无线传感节点的一种理想电源,近年来受到广泛关注．考虑质量块和逆压电效应影响,建立了在基础激励作用下的悬臂梁压电振动能采集器的集总参数运动微分方程,得到了采集器固有频率的解析表达式．引入了2个反映压电层连接方式的常数,建立了对单压电层、双压电层并联和双压电层串联的悬臂梁压电振动能采集器均适用的耦合电路方程．求解以上方程,得到了简谐基础激励下的输出电压表达式．实验结果表明,固有频率和输出电压表达式的相对误差分别小于10％和20％．     

Modeling and fabrication of a piezoelectric vibration‐induced micro power generator

Abstract

In this paper, theoretical and experimental study on a piezoelectric vibration‐induced micro power generator that can convert mechanical vibration energy into electrical energy is presented. The mechanical‐electrical energy conversion mechanism is a voltage between two capacitors, which belong to the mechanical and the piezoelectric equivalent circuits, respectively. To verify the theoretical analysis, two clusters of transducer structures are fabricated. Piezoelectric lead zirconate titanate (PZT) material is chosen to make the energy conversion transducer. The desired shape of the piezoelectric generator with its resonance frequency in accordance with the ambient vibration source is designed by finite element analysis (FEA).

Experimental results show that the maximum output voltages are generated at the first mode resonance frequencies of the structure. The overall conversion efficiency is measured to be 33%. The experimental results coincide with the theoretical analysis.     

间接激励压电发电机的建模仿真与试验研究

为满足旋转机械监测系统的自供电需求、解决现有压电发电机可靠性低及有效带宽窄等问题,提出一种基于移动凸轮间接激励并限幅的旋转式压电发电机(简称间接激励压电发电机).介绍了发电机的结构原理并进行了建模仿真与试验测试,获得了激励磁铁数量比、凸轮升程及升角对激振力形式/幅值、压电振子变形量/输出电压及发电机带宽等的影响规律.结...     

Z型梁结构压电式能量采集性能分析

振动能量采集能够将外部环境中的振动能转化为电能,具有绿色可持续、节能环保、设计灵活等优势,在工业、生物、医学、军事等领域具有广阔的应用前景.为使振动型能量采集器适应更为复杂多变的工作环境,提高其采集功率和工作频带,提出一种多梁结构-Z型梁结构压电式能量采集器.理论分析了该采集器的固有振动特性,并通过有限元分析了结构尺寸...     

压电梁振动的多输入多输出主动控制

对表面上贴有多个用作驱动器和传感器的压电陶瓷片的“压电梁”结构，导出了从驱动器到传感器的频响函数公式，作为压电结构设计和振动控制的数学模型。提出了压电梁对缓变周期扰动振动环境的多输入多输出振动抑制方法。     

Nondestructive Evaluation on Strain Sensing Capability of Piezoelectric Sensors for Structural Health Monitoring

A kind of strain-sensing-based piezoelectric sensor was fabricated, and the mixture of cement powder and epoxy resin was used as the packaging layer. A nondestructive strain sensitivity testing method based on strain-sensing capability of piezoelectric sensor is presented. The theoretical foundation indicates that output voltage of piezoelectric sensor and strain of structure keep linear relationship when corresponding parameters are ascertained. Quasi-static responses and low-frequency (0–40 Hz) dynamic responses of piezoelectric sensors and strain gauges are analyzed. The results show that the piezoelectric sensors are sensitive and can accurately reflect the strain variation of structures. The quantification of output voltage and strain is investigated, and quasi-static and dynamic sensitivities were acquired (159.52–515.48 mV/με). With increasing of vibration frequency, the area of hysteresis loop decreases, and the strain sensitivity of sensor increases. Combining sensitivities with output voltages of sensors, the strain variation of structures could be obtained, which exhibit great application potentials of piezoelectric sensors for structural strain monitoring in low-frequency vibrations in civil engineering.     

Nonlinear characteristics of a circular plate piezoelectric harvester with relatively large deflection near resonance

Based on the von Karman thin circular plate theory, we report in this paper the analysis of the nonlinear behavior of a power harvester consisting of a circular piezoelectric plate and an electric resistance. Dependence of the output power of the harvester upon driving frequency for different electric loads and different applied forces is obtained. Numerical results show that the output power exhibits multi-valuedness and a jump phenomenon near resonance.     

电液伺服阀用压电弯曲元件特性的实验研究

研制了一种压电弯曲元件型压电驱动器,该驱动器用于电液伺服阀的电-机械转换器.压电驱动器由三层结构构建,其中中间弹性层为铍青铜,在铍青铜的上下表面各粘接一片压电晶片,材料为PZT-5H.利用激光测微仪LC-2400A及LV-1610对压电驱动器的输出位移、位移滞环及谐振频率进行了实验测量,分析了压电驱动器尺寸与其特性之间的关系.实验结果表明,该驱动器满足所设计电液伺服阀的性能要求.     

基于等效线性化方法的非线性振动能量采集器功率分析

输出功率分析是振动能量采集器结构设计、参数选择的重要依据.有鉴于传统功率分析方法比较复杂,以一类电磁式振动能量采集器为对象,提出了一种新的非线性振动能量采集器功率分析方法,其核心是将非线性振动方程进行等效线性化处理,并借助传递函数开展功率优化分析.首先,考虑非线性磁力以及基尔霍夫电流定律,建立了通用化的采集器1.5自由...     

Nano piezoelectric/piezomagnetic energy harvester with surface effect based on thickness shear mode

BackgroundEnergy harvesters with piezoelectric materials are widely discussed for the new kinds of smart structures. However, reports on the energy harvesters at the nano scale which have large potential applications in the future are rather limited.MethodsIt’s well known that the surface or interface stress can affect the mechanical properties of nanostructures. This work proposes the nano energy harvester with piezoelectric/piezomagnetic structure, in which the thickness-shear mode is considered by the surface stress model.ResultsThe vibration motion and output power density are derived and calculated. The peak value of the power density can be enlarged by increasing the residual surface stress and the surface effect on the nano-plate energy harvester can be influenced by both the surface piezoelectric and piezomagnetic elastic constants. Moreover, the harvesting ability can be improved by increasing the thickness of the piezoelectric layer.ConclusionThe capability of the energy harvester depends on the residual surface stress and the surface material constants. The proposed model provides the possibility of applying nano composite structures to the energy harvester.     

基于PVDF压电传感器测量振动结构体积位移

控制振动板结构的体积位移是降低结构总声功率的一种有效策略。本文以工程常见四端位移为零的振动板为例，提出一种新的压电式传感器的设计方法测量体积位移。利用正弦函数展开近似表示固定板振动位移，通过设计特殊形状的PVDF压电薄膜，使PVDF输出信号为所需要的振动结构体积位移。结果表明这种体积位移传感器不仅适用四边简支、四边固定以及介于两者之间的边界条件板结构，而且作为一种误差传感器测量振动结构体积位移是可行的。并对实验数据进行了分析比较。     

Piezoelectric ceramic rectangular transducers in flexural vibration

Based on the equivalent elastic method and coupled vibration theory, an analytic method is presented to study the flexural vibration of rectangular transducers consisting of piezoelectric ceramic thin plates. By introducing a mechanical coupling coefficient, the flexural vibration of the piezoelectric ceramic rectangular thin plate is reduced to two simple, one-dimensional flexural vibrations of narrow piezoelectric ceramic strips. The resonance frequency equations for the piezoelectric ceramic rectangular thin-plate transducers in flexural vibration are derived under the free and simply supported boundary conditions analytically. The relationship between the resonance frequency and the flexural vibrational order, the geometrical shape, and the dimensions of the piezoelectric ceramic rectangular thin-plate transducer is analyzed. It is demonstrated that the one-dimensional vibrational theory for the flexural vibration of a narrow piezoelectric ceramic strip and the stripe-mode flexural vibrational theory for the piezoelectric ceramic rectangular thin plate can be derived directly from the theory obtained in this paper. Experimental results show that the measured resonance frequencies of the piezoelectric ceramic rectangular thin-plate transducers in flexural vibration under free-boundary conditions are in good agreement with the calculated results. The method presented in this paper can be used in the resonance frequency analysis of vibrating systems in coupled vibration.     

弹性地基上输流管道主参数共振的主动振动控制

研究了弹性地基上输送脉动流管道主参数共振的主动振动控制问题。在管道上、下两侧对称的粘贴一对陶瓷压电片,利用压电效应使压电片对管道施加控制力矩。对运动微分方程中由控制力矩产生的Dirac Delta函数对轴向坐标的一阶导数,利用Fourier级数进行展开,再采用微分求积法对控制微分方程和边界条件进行离散化处理,得到了时变系统的状态方程。以管道的横向振动变形和输入控制能量之和达到最小的最优控制原则,对简支输流脉动流管道的时变系统受控前后某些点的挠度响应进行了数值仿真。数值计算结果表明,采用的最优控制方案能有效地控制输送脉动流管道的主参数共振问题。