新型双稳态压电振动俘能系统的理论建模与实验研究

针对线性压电俘能系统的共振频带窄、俘能方向单一、发电效率低等问题,设计了一种双稳态磁力耦合多悬臂梁俘能结构。利用广义Hamilton变分原理建立了系统分布式力-电-磁耦合模型,结合数值计算和实验验证方法揭示了磁铁间距、外界振动激励条件对压电俘能系统响应特性的影响规律。研究结果表明:在合适的磁距和外界振动激励条件下,系统的输出电压可达18V,是线性压电振动俘能系统的3.5倍,有效工作频带是线性压电振动俘能系统的3.1倍,说明双稳态压电振动俘能系统具有明显拓宽有效工作频带和提升发电效率的能力,为压电俘能系统工程化应用提供了理论依据。     

多振子串联压电俘能器性能分析与测试

为实现低频、大振幅、高强度振动能量回收,提出多振子串联压电振动俘能器,在理论、试验两方面研究压电振子数量/电学连接方式、集中质量及激励频率等对其性能影响规律。结果表明,增加集中质量及压电振子数量均可有效降低俘能器基频、提高发电量/输出功率;压电振子电学串/并联时输出电压及使输出功率最大、最佳负载不同,但产生的电能及在最佳负载下的输出功率相同。制作1/2/4组压电振子构成的俘能器,进行不同集中质量、频率、压电振子电学连接方式及负载的对比试验。单组压电振子在集中质量292 g的最佳频率及发电量分别为集中质量36.5 g的0.6倍、1.92倍;4组压电振子电学并联时的最佳频率及发电量分别为单组的0.58倍、2.2倍;两组压电振子电学串/并联的最佳负载及最大输出功率分别为42.3/10.6 kΩ、232.8/202.7 mW。     

拱形-线形非线性磁力耦合压电俘能器建模与特性分析

为分析拱形-线形非线性磁力耦合压电俘能器振动特性,利用磁化电流法建立了磁力模型,实验测量并通过数据拟合方法获取了拱形-线形结构非线性恢复力模型,利用广义Hamilton变分原理建立系统的动力学方程。采用谐波平衡法对动力学方程进行了求解,揭示了不同激励条件、不同磁距对俘能器振动特性的影响关系并开展实验研究。结果表明:拱形-线形压电俘能器大幅响应带宽、响应幅值随激励强度的增大而增大;减小磁距会增加系统大幅响应带宽,但幅值有所降低。相对于直梁式结构俘能器,拱形-线形结构可以提高俘能器输出电压,提升俘能性能。研究为拱形-线形压电俘能器设计提供了理论指导,为改善俘能器性能提供了新的思路。     

三角形状压电振子压电特性分析与仿真

(压电振子的几何形状是影响其振动发电的重要因素之一。在相同压电材料体积下,三角形压电振子相比于矩形和梯形压电振子具有更大的发电能力。选用悬臂梁式三角形状压电振子作为研究对象,利用有限元分析软件ANSYS进行仿真研究。建立有限元模型;通过静力学和模态分析,研究压电振子的几何形状对其输出电压、固有频率的影响规律,然后在满足原来输出电压不下降的前提下对其进行尺寸优化,提高单位体积的发电能力。在相同边界条件和外力作用下,优化尺寸模型的体积是原来的0.94倍,输出电压是原来的1.03倍,取得了很好的优化效果。     

压电-电磁复合振动俘能器的耦合负载特性及俘能性能

基于环境振动的俘能装置作为自供能微电源可以有效避免对外部电源的依赖。提出了一种新型的两端固支式低频压电-电磁复合振动俘能装置。理论推导了复合俘能系统的耦合动力学模型及俘能性能方程。利用搭建的实验平台分别研究了单一压电式、单一电磁式以及复合俘能装置不同激励加速度、频率以及两个支路不同外接负载下的耦合负载特性及俘能性能。实验结果表明:在基础振动加速度0.5g,压电、电磁支路外接最佳匹配阻抗50kΩ和30Ω的条件下,压电俘能支路,电磁俘能支路以及复合俘能装置最大谐振俘能输出功率分别为1.05,7.18及8.23mW。与单一形式的俘能装置相比,提出的复合俘能器提高了俘能效率,并具有一定的宽频俘能特性。     

宽频压电振动俘能器的研究现状综述

随着便携式电子设备、微机电系统(MEMS)和无线传感器网络的广泛应用,化学电池供能的弊端日益显现。压电振动俘能器可以将环境中的振动能转换成电能,实现低功耗微电子产品的无线供能或能量自给。在实际应用中,为了增强俘能器的环境适应能力,提高其俘能效率,宽频压电俘能技术成为当前的研究热点。介绍了压电振动俘能器的工作原理、常用压电材料和工作模式,综述了宽频压电俘能技术的国内外研究现状,分析了当前研究中存在的问题和不足,提出了未来可能的研究方向。压电振动俘能技术为低功耗微电子产品提供了一种稳定、安全、长久的新供能方式,具有良好的应用前景。     

宽频压电振动俘能器的研究现状综述EI北大核心CSCD

随着便携式电子设备、微机电系统(MEMS)和无线传感器网络的广泛应用,化学电池供能的弊端日益显现。压电振动俘能器可以将环境中的振动能转换成电能,实现低功耗微电子产品的无线供能或能量自给。在实际应用中,为了增强俘能器的环境适应能力,提高其俘能效率,宽频压电俘能技术成为当前的研究热点。介绍了压电振动俘能器的工作原理、常用压电材料和工作模式,综述了宽频压电俘能技术的国内外研究现状,分析了当前研究中存在的问题和不足,提出了未来可能的研究方向。压电振动俘能技术为低功耗微电子产品提供了一种稳定、安全、长久的新供能方式,具有良好的应用前景。     

压电俘能技术研究现状综述

摘要：随着微电子、无线网络和MEMS等低耗能产品的应用日益广泛,以化学电池为其主要供能方式存在着诸多弊端,而压电俘能器具有结构简单、不发热、无电磁干扰、无污染和易于实现机构的微小化、集成化等诸多优点,且能满足此类低耗能产品的供能需求而备受关注。综述了压电俘能技术的国内外研究现状。围绕提高压电俘能效率,从压电振子构成形式、能量存储电路和能量存储元件等方面进行了系统的介绍,并对压电俘能技术的发展方向进行了预测。压电俘能技术可应用于导弹引信,海啸预警、桥梁安全监测、石油输油管道监测等重要领域的安全检测装置的自供能系统中,同时也可为无线网络、嵌入式系统和MEMS等低耗能产品的实现无线供能,展现出了压电俘能技术的良好应用前景。     

基于压电俘能器的流体能量俘获技术研究现状

随着压电俘能技术研究的深入,研究重点已从俘能器本身逐渐发展为耦合环境振动源的俘能系统研究,其中基于压电效应的流体俘能技术是一个重要研究方向。鉴于此,对其研究现状和发展趋势进行了分析总结,主要包括单一压电振子俘能(涡激振动式、尾流致振式、颤振式、驰振式、雨滴冲击式)和多压电阵子阵列式俘能等。总结发现:涡激振动式和尾流致振式俘能器适合于低速流体俘能;颤振式和驰振式适合于高速流体俘能;为了提高发电能力,高性能柔性压电材料、宽频带俘能和多俘能器阵列俘能是今后的主要发展趋势。     

电极配置对悬臂梁压电振子发电能力的影响

研究了带末端质量块的悬臂梁压电振子多模态振动时的应变分布特点,针对压电陶瓷表面电极配置对压电振子输出电压的影响关系进行压电-电路耦合有限元分析,并建立悬臂梁压电振子发电测试系统,对工作在一阶和二阶谐振频率附近处的压电振子分段电极和连续电极输出功率进行对比分析。研究结果表明,一阶谐振时分段电极的峰值输出功率与连续电极相接近,二阶谐振时分段电极的峰值输出功率增加了900%。相比于连续电极配置法,分段电极配置法可有效提高压电振子在高频振动时的发电能力。     

New type of linear ultrasonic actuator based on a plate-shaped vibrator with triangular grooves

This paper presents a new type of linear ultrasonic actuator that can drive a slide by ultrasound. The ultrasonic actuator consists of a metal plate with uniform triangular grooves, multilayer piezoelectric vibrator, and supporting structure. The multilayer piezoelectric vibrator is used to excite a flexural vibration in the metal plate that is adjusted to lie horizontally. When the metal plate vibrates, a glass slide on it is levitated in the vertical direction and linearly driven along the length direction. Experimental characteristics of the prototype are presented here. This is the first report case of using the sound field that is generated by a grooved metal plate, to drive a slide levitated by acoustic radiation force.     

双十字压电振子同型弯振模态驱动的平面超声电机

为了丰富平面超声电机的型式,提出一种双十字压电振子同型弯振模态驱动的平面超声电机。利用双十字压电振子的纵杆面内、面外弯振耦合以及横杆面内、面外弯振耦合,分别在两杆的驱动足上合成沿xoz、yoz面行进的两相椭圆轨迹,以交替地推动动子沿x、y向移动。分析了该平面超声电机的驱动机理,并推导出两相椭圆轨迹方程。建立了双十字压电振子机电耦合模型,对其三相工作模态的振型进行仿真分析,并在结构优化的基础上实现了三相工作模态频率一致,使它们分别为43 468,43 552和43 569 Hz。仿真了双十字压电振子的频响特性并实现了干扰模态分离,当驱动电压为250 V时,驱动足x、y、z向振幅分别为1.3,0.8和0.9 μm,满足电机驱动要求。模拟得到定频激励下双十字压电振子驱动足的两相椭圆运动轨迹,验证了所设计平面超声电机驱动机理的有效性。该平面超声电机可输出较大速度与动力,具有广阔的应用前景。     

Analysis of a disk-type piezoelectric ultrasonic motor using impedance matrices

The dynamic behavior and the performance characteristics of the disk-type traveling wave piezoelectric ultrasonic motors (USM) are analyzed using impedance matrices. The stator is divided into three coupled subsystems: an inner metal disk, a piezoelectric annular actuator with segmented electrodes, and an outer metal disk with teeth. The effects of both shear deformation and rotary inertia are taken into account in deriving an impedance matrix for the piezoelectric actuator. The impedance matrices for each subsystem then are combined into a global impedance matrix using continuity conditions at the interfaces. A comparison is made between the impedance matrix model and the three-dimensional finite element model of the piezoelectric stator, obtaining the resonance and antiresonance frequencies and the effective electromechanical coupling factors versus circumferential mode numbers. Using the calculated resonance frequency and the vibration modes for the stator and a brush model with the Coulomb friction for the stator and rotor contact, stall torque, and no-load speed versus excitation frequencies are calculated at different preloads. Performance characteristics such as speed-torque curve and the output efficiency of the USM also are estimated using the current impedance matrix and the contact model. The present impedance model can be shown to be very effective in the design of the USM.     

Active damping of piezo-composite beams

The aim of the present study is to investigate the effects of piezoceramic materials on the active damping of vibrating piezo-composite beams. The active damping is obtained by using an actuator and a sensor piezoceramic layer acting in ‘closed-loop’. By transferring the accumulated voltage on the sensor layer to the piezoelectric actuator layer, the beam can actively damp-out its vibrations. An exact mathematical model, based on a first order shear deformation theory (FSDT) is developed and described. This model allows the investigation of piezo-composite beams with two actuation/sensing type mechanisms, extension and shear. The present study is confined to symmetric lay-up beams using continuous piezoelectric layers. Using the present model, both natural and damped vibrations are calculated. The effects of the feedback gain, G, and the beam length on the damped vibrations are investigated and presented.     

Design and performance testing of an ultrasonic linear motor with dual piezoelectric actuators

In this work, design and performance testing of an ultrasonic linear motor with dual piezoelectric actuator patches are studied. The motor system consists of a linear stator, a pre-load weight, and two piezoelectric actuator patches. The piezoelectric actuators are bonded with the linear elastic stator at specific locations. The stator generates propagating waves when the piezoelectric actuators are subjected to harmonic excitations. Vibration characteristics of the linear stator are analyzed and compared with finite element and experimental results. The analytical, finite element, and experimental results show agreement. In the experiments, performance of the ultrasonic linear motor is tested. Relationships between velocity and pre-load weight, velocity and applied voltage, driving force and applied voltage, and velocity and driving force are reported. The design of the dual piezoelectric actuators yields a simpler structure with a smaller number of actuators and lower stator stiffness compared with a conventional design of an ultrasonic linear motor with fully laminated piezoelectric actuators.     

A novel, single-mode piezoceramic plate actuator for ultrasonic linear motors

A new type of piezoelectric plate actuator for ultrasonic linear motors has been developed. These new piezoelectric actuators use the principle of asymmetric resonant excitation of the piezoceramic plate in a special resonant mode consisting of a standing two-dimensional extensional wave in a piezoceramic plate. The behavior of the actuator has been simulated with finite-element method (FEM) software and the simulation results checked with single-point contact measurements on the surface of the actuator. This paper describes this work and closes by describing the new ultrasonic translation stages based on this design.     

压电风扇非定常流场速度分布的数值研究

压电风扇利用压电材料的压电特性,将压电材料制成作动器激励薄片振动进而带动周围空气流动,可作为电子设备的散热装置。使用Fluent 商用软件,利用动网格技术模拟压电风扇产生的非定常流场。研究振动薄片的振动频率、压电风扇长度(流场长度)以及振动薄片长度与压电风扇长度的比值等参数对压电风扇出口风速的影响。研究表明:增大振动薄片的振动频率、增大压电风扇长度以及在一定范围内增大振动薄片长度与压电风扇长度的比值均能提高出口风速。振动频率与出口风速成线性关系。随着压电风扇长度的增大,出口风速提高得越来越慢。存在一个临界值,当振动薄片长度与压电风扇长度的比值大于该临界值时,出口风速随着比值的增大而下降。     

基于系统相似方法的叠堆型压电驱动器非线性动力学建模及实验研究

根据机械系统与电气系统的相似方法,将叠堆型压电驱动器的非线性电-机械耦合模型完全转换到电气域内,建立了其非线性相似电路模型;给出了非线性相似电路模型中迟滞因子的辨识方法,并对某款商用叠堆型压电驱动器进行了迟滞因子的辨识试验;基于非线性相似电路模型和迟滞因子的辨识结果,对该款叠堆型压电驱动器的非线性特性进行了仿真分析,得到了其非线性位移迟滞回线;仿真结果与试验结果吻合,证明了该建模过程与辨识方法的正确性。该建模方法在电气域内对叠堆型压电驱动器电-机械耦合特性及非线性迟滞特性进行描述,建模过程物理意义清晰且简单实用,对于研究压电驱动器的动态特性及控制算法具有实际意义。     

结构噪声主动控制原理及方法

本文以矩形的板－箱系统作为研究模型，探讨了在外界声源激励下，弹性薄板受激励振动，辐射入箱内噪声的形成机理，并分析了选用压电片作为激励器，进行箱内噪声主动控制的原理，在此基础上，对３种控制方案进行了分析比较，得出最优方案。