非线性压电振动能量采集器的振动特性与实验研究

为了提高线性压电振动能量采集器的输出特性,在线性压电振动能量采集器悬臂梁末端引入Duffing非线性磁力,构造了一种双稳态非线性压电振动能量采集器;综合考虑能量采集器的动态振型与轴向应变分布情况,建立了系统非线性机电耦合集总参数运动控制模型,并利用4阶、5阶Runge-Kutta算法对能量采集器的非线性振动特性进行了数值模拟;利用谐波平衡法计算获得了能量采集器的幅频响应方程,数值分析了激励频率、激励幅值以及磁铁间距等对系统非线性振动特性的影响,发现双稳态运动可以极大地提高能量采集器的频率响应范围和能量采集效率,并且能量采集器在低频、低幅值激励情况下可以产生大幅值周期运动;最后,通过实验对数值计算结果进行了验证.     

带弹性放大器的双稳态压电振动能量采集器

针对带弹性放大器的双稳态压电振动能量采集器,利用Hamilton原理和Raleigh-Ritz方法建立了压电振动能量采集器的机电耦合分布参数模型.重点分析了激励频率Ω≥1时系统质量比、刚度比、磁铁对间距等参数对系统输出性能的影响.研制了压电振动能量采集器原理样机,搭建了实验测试平台,实验测试了压电振动能量采集器的输出性能.研究结果表明带弹性放大器的压电振动能量采集器是一个非线性双自由度系统,具有两个双稳态运动区域;在激励频率Ω≥1时压电振动能量采集器需要较大的激励能量才能进入大幅值周期振动状态.     

超声液体环境下压电式振动能量采集的研究

针对在液体环境下工作的器件不利于直接供能这一难题,制作了一种可在液体环境下工作的振动能量采集器,采用压电悬臂梁结构在液体环境中采集水中的超声能量,在32 kHz超声频率激励下,最高获得了5.04V的输出电压.通过改变超声波与悬臂梁的相对方向及液体盐分质量分数,发现能量采集器在超声液体环境下工作的发电效率随盐分质量分数的...     

一种宽频的磁式压电振动能量采集器

基于环境能量采集的压电振动能量采集器为无线传感器和微机电系统的长期供能提供了一种有效解决方案.目前研制的压电式振动能量采集器存在工作频率高,且频带窄的问题.给出了一种通过磁力的引入使其在低频下工作的、宽频的压电振动能量采集器,并搭建了测试系统对器件进行分析测试.在压电悬臂梁上放置永磁铁取代传统的质量块,同时在悬臂梁的上...     

基于卡门涡街的水下振动能量采集器的设计与研究

针对传统的单自由度压电能量采集器工作带宽窄的现状,提出了在水下流激振动环境下的一种基于卡门涡街的二自由度宽频压电能量采集器来提高压电能量采集器的带宽,3 种二自由度压电能量采集器分别被设计、制造,并且测试了能量采集性能。结果表明,采用二自由度能量采集器比采用传统的单自由度能量采集器具有更好的采集效率,根据仿真和实验结果,H型压电能量采集器具有更好的振动能量采集效率。     

基于弹性支撑与放大的宽频压电振动能量采集器模型与实验研究

针对刚性支撑压电振动能量采集器工作频带窄、采集效率低等问题,提出了一种基于弹性支撑与放大的宽频压电振动能量采集器.利用有限元方法建立了宽频压电振动能量采集器的机电耦合模型,通过Ansys软件仿真分析了能量采集器结构参数对其频域输出特性的影响;根据力学和电学平衡方法建立了宽频压电振动能量采集器的集总参数机电耦合运动微分方程,利用4-5阶龙格库塔算法对方程进行了时域求解,仿真分析了能量采集器在不同结构参数下的振动位移、速度、输出电压和功率等性能.研制了弹性支撑和放大的宽频压电振动能量采集器原理样机,建立了样机系统实验平台,并对理论研究结果进行了实验验证,结果表明本文所提的宽频压电振动能量采集器具有工作频带宽、输出性能高等优点,适合为微电子器件进行供电.     

基于MEMS的压电微能量采集器的电路研究与测试

微能量采集技术是利用某种效应把周围环境中的某种形式的能量转换成电能,为嵌入式系统和无线传感网络中的MEMS器件供能。本文探讨了一种基于MEMS技术的压电型微能量采集器。微能量采集器工作于低频环境,当给其振动激励信号时,它能够把机械能转换为电能。但是能量采集器直接输出的是交流电压,一般不能直接为器件供能。所以,利用AC-DC电路把交流转换为直流,实现为MEMS器件供能。文中给出了微能量采集器的测试电路,同时给出了测试结果,论证了在低频环境下这种微能量采集器的可行性。     

折叠梁式振动能量采集器的设计

单自由度压电能量采集器因其结构特点,其有效工作频带范围较窄,难以在实际的无线传感器网络节点和可穿戴设备等领域应用。本文提出一种基于折叠梁结构的压电振动能量采集器,以提高采集器的工作带宽。首先,对折叠梁式振动能量采集器进行理论建模及有限元分析。其次,分析不同质量块的质量对所提出的能量采集器的影响。最后,对所提出的能量采集器进行实验研究。实验结果表明,在频域为0~ 100Hz,加速度为0.3g的条件下,“L”型振动能量采集器的工作带宽为1Hz,“Z”型振动能量采集器的工作带宽为3Hz,扩增为“L”型带宽的300%。其次,“Z”型振动能量采集器在0.2gn,0.25gn,0.30gn激励下的最佳匹配负载电阻分别为0.21ＭΩ,0.27ＭΩ 以及0.21ＭΩ,最大输出功率为509.122mW,921.926mW以及1331.230mW,初步验证了折叠梁式能量采集器的性能。本文所提出的折叠梁式能量采集器可以兼顾降低谐振频8.率和增加低频段的谐振阶数的需求,有效提高了能量采集效率,为待供能设备提供充足的电能。     

带质量块的微型压电式风能采集器研究

基于风致振动机理的微型风能采集器可以将风能转换为电能,在无线传感等领域具有广阔应用前景.漩涡脱落频率与风速成正比,当漩涡脱落频率与微型风能采集器固有频率接近时,采集器有较高输出功率,因此为了在低风速环境应用风能采集器,需要降低其固有频率.引入质量块可以降低微型压电式风能采集器的固有频率,使其在较低风速下产生较高输出功率...     

基于振动能量采集器的无源无线传感节点技术研究

随着以MEMS技术为依托,结合压电效应的振动能量采集技术的日臻完善,如何利用振动能量采集器构成高效的无源无线传感节点成为近期研究热点,而能量采集器输出的电能储存控制和低功耗发射技术是实现该节点的难点。在设计出对储能电容电压具有双阈值检测与控制功能的低功耗电路基础上,给出了一种自报警、无源无线低功耗传感节点。实验表明,在频率52 Hz正弦振动、振动加速度幅值为5 gn激励下,经过125 s的能量储存,节点能够以+10 dBm功率在16 ms内完成发射及无线报警,发射距离可达1.31 km。该节点构成的无线传感网络可广泛应用于石油管线、桥梁和军事侦察等外部供电极度受限环境的现场监控等用途。     

Power sensitivity of vibration energy harvester

This paper deals with a power sensitivity improvement of an electromagnetic vibration energy harvester which generates electrical energy from ambient vibrations. The harvester provides an autonomous source of energy for wireless applications, with an expected power consumption of several mW, placed in environment excited by ambient mechanical vibrations. An appropriately tuned up design of the harvester with adequate sensitivity provides sufficient generating of electrical energy for some wireless applications and maximal harvested power depends on a harvester mass, frequency and level of the vibration and sensitivity of the energy harvester. The design of our harvester is based on electromagnetic converter and it contains a unique spring-less resonance mechanism where stiffness is provided by repelled magnetic forces. The greater sensitivity of the harvester provides more generated power or decrease of the harvester size and weight.     

A micro electromagnetic low level vibration energy harvester based on MEMS technology

This paper presents a micro electromagnetic energy harvester which can convert low level vibration energy to electrical power. It mainly consists of an electroplated copper planar spring, a permanent magnet and a copper planar coil with high aspect ratio. Mechanical simulation shows that the natural frequency of the magnet-spring system is 94.5 Hz. The resonant vibration amplitude of the magnet is 259.1 μm when the input vibration amplitude is 14 μm and the magnet-spring system is at resonance. Electromagnetic simulation shows that the linewidth and the turns of the coil influence the induced voltage greatly. The optimized electromagnetic vibration energy harvester can generate 0.7 μW of maximal output power with peak–peak voltage of 42.6 mV in an input vibration frequency of 94.5 Hz and input acceleration of 4.94 m/s² (this vibration is a kind of low level ambient vibration). A prototype (not optimized) has been fabricated using MEMS micromachining technology. The testing results show that the prototype can generate induced voltage (peak–peak) of 18 mV and output power of 0.61 μW for 14.9 m/s² external acceleration at its resonant frequency of 55 Hz (this vibration is not in a low ambient vibration level).     

Design and experimental study of broadband hybrid energy harvester with frequency-up conversion and nonlinear magnetic force

In this paper, a novel broadband hybrid piezoelectric and electromagnetic energy harvester using in the low frequency vibration environment is proposed, which combines nonlinear magnet force and frequency-up conversion mechanism simultaneously. Performances are studied by theoretical analysis and experimental test. Electromechanical governed equations of harvester are established, and analytical solutions of vibration response, output voltage and power are derived. Then, effects of nonlinear force, spacing between low frequency vibration beam and piezoelectric beam, load resistance and input excitation on harvester performances are investigated by experimental test. It can be concluded that the harvester can be used to work at the low-frequency environment efficiently, and the resonant frequency and harvesting bandwidth can be tuned by the nonlinear force between the magnets and the spacing between beams. Moreover, the larger the nonlinear magnetic force and the smaller the distance between two beams, the lower working frequency and the larger bandwidth. Compared with the corresponding linear apartment, output power and bandwidth of proposed harvester are improved 90% and 125% respectively.

     

一种振动自供能无线传感器的电源管理电路

针对振动能量采集器的输出功率过低不足以直接驱动无线传感器的问题,设计了振动自供能无线传感器的电源管理电路,根据调谐和阻抗变换原理对能量采集器进行了阻抗匹配,以最大功率对储能超级电容进行充电,对能量存储和电源管理电路的充放电特性进行了理论分析和实验验证。结果表明,该电路大幅度提高了采集器的输出功率和对储能超级电容充电的效率,当0.47 F超级电容电压达到0.6 V时,能量瞬间释放电路控制超级电容瞬间放电,成功驱动最大功耗为75 mW的无线传感器工作。     

Model-based design and test of vibration energy harvester for aircraft application

This paper deals with a development process of a vibration energy harvesting device in aircraft applications. The vibration energy harvester uses ambient energy of mechanical vibration and it provides an autonomous source of energy for wireless sensors or autonomous applications. This application presents a complex engineering problem and the vibration energy harvester consists of precise mechanical part, electro-mechanical converter, electronics and a powered application. It can be perceive as a mechatronic system and a mechatronic approach was used for development of our vibration energy harvester. An essential step of development process is simulation modeling which is based on mechatronic approach. Presented model-based design of vibration energy harvester is very useful during development process and the whole development process of the autonomous energy source is presented in this paper. The main aim of the paper is an introduction of our development methodology and our approach is presented on a sample of the vibration energy harvester for aircraft applications under project ESPOSA.     

A design method for low-frequency rotational piezoelectric energy harvesting in micro applications

A rotational piezoelectric energy harvester is an electromechanical device that converts ambient mechanical rotation into electric power. The gravity-based method of using the gravity to excite the cantilever beam to deform in the vertical plane has received great attention. The harvester operates effectively at a narrow frequency band, which must be matched with the excitation frequency. For micro applications, low-frequency harvesters are often very difficult to design due to the specific limitations of the size and weight and the thickness of the piezoelectric material. Moreover, low-frequency harvesters require high precision in production and assembly, and small errors can cause large frequency error deviations. In response to this problem, this paper proposes a scheme for designing low-frequency rotational piezoelectric energy harvester, wherein the tuning is accomplished by changing the distance between the mass and the center of rotation. Furthermore, the paper establishes a theoretical model and presents a relationship for frequency adjustment. The experimental results achieved with a piezoelectric fiber composite fit the theoretical results well. The simulation and experimental results show that the resonance frequency of the harvester could be decreased by 63% when the distance between the mass and the center is five times the length of the harvester.

     

带谐振腔的微型压电风能采集器

为了提高基于风致振动机理的微型风能采集器在低速风作用下的输出功率,提出一种带谐振腔的微型压电风能采集器结构,该采集器由谐振腔和振动梁构成,振动梁由压电梁和柔性梁组成。谐振腔可以改变振动梁附近的流场分布,扩大作用于振动梁的动风载荷,从而提高了采集器在低速风作用下的输出功率。实验分析了风速、压电梁长度和柔性梁长度对采集器输出性能的影响。当谐振腔尺寸为64 mm×22 mm×14 mm,振动梁长度和宽度分别为38 mm和6.4 mm时,微型风能采集器在17 m/s风载荷作用下的最大输出功率达到1.28 mW。     

基于GMM的轨道无线传感网络能量收集装置研究

随着轨道无线传感器网络技术的推广,改善无线传感器的供电问题显的刻不容缓。研究一种基于超磁致伸缩材料（GMM）的轨道振动能量收集器,将收集器安装于钢轨与轨道板之间,收集钢轨的振动能。建立车辆轨道垂向耦合模型,将钢轨垂向位移和支反力作为能量收集器的激振源。利用超磁致伸缩材料的维拉里效应,将振动能转换为电能。经过MATLAB理论分析,能量收集器大致能收集到能量大约237.1584 J。收集的电能足以解决无线传感器的供电问题。