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1.
A new energy harvester using a piezoelectric and suspension electromagnetic mechanism 总被引：1，自引：0，他引：1
This study presents a new design of a piezoelectric-electromagnetic energy harvester to enlarge the frequency bandwidth and obtain a larger energy output. This harvester consists of a primary piezoelectric energy harvesting device, in which a suspension electromagnetic component is added. A coupling mathematical model of the two independent energy harvesting techniques was established. Numerical results show that the piezoelectric-electromagnetic energy harvester has three times the bandwidth and higher power output in comparison with the corresponding stand-alone, single harvesting mode devices. The finite element models of the piezoelectric and electromagnetic systems were developed, respectively. A finite element analysis was performed. Experiments were carried out to verify the validity of the numerical simulation and the finite element results. It shows that the power output and the peak frequency obtained from the numerical analysis and the finite element simulation are in good agreement with the experimental results. This study provides a promising method to broaden the frequency bandwidth and in- crease the energy harvesting power output for energy harvesters. 相似文献
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研究目的：对一种两自由度的压电-电磁复合能量收集器进行发电性能研究。创新要点：建立了一种两自由度压电-电磁复合能量收集器发电性能的数学模型,该数学模型可以评估两自由度压电-电磁复合能量收集器中压电元件、电磁元件以及系统总输出功率。研究方法：对一种两自由度的压电-电磁复合能量收集器进行数学建模,并实验验证数学模型的正确性。基于实验测试得到的系统参数值,理论研究压电元件和电磁元件的机电耦合系数对不同能量收集器发电性能的影响关系,并对几种能量收集器的发电能力进行对比分析。重要结论：对于非强耦合（弱或中间耦合）的两自由度机电转换器,复合能量收集器（压电＋电磁）具有比单一能量收集器（压电或电磁）更高的发电能力。 相似文献
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魏胜 《深圳职业技术学院学报》2012,11(3):7-12
研究了双层压电悬臂梁的工作原理及其有效机电耦合系数,借助ANSYS软件并选用Solid5（压电材料）,Solid45（中间金属层）,Circu94（电阻）3种元素类型建立压电换能器的有限元模型,通过谐振仿真分别求出压电装置的短路和开路谐振频率,得到其有效机电耦合系数．仿真结果表明,压电装置的有效机电耦合系数要小于压电材料的耦合系数,且与理论计算结果基本一致,仿真方法可有效地评价压电换能器的工作性能,并为后续实验提供理论指导． 相似文献
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In the USA, there are over 4 million miles (6 million km) of roadways and more than 250 million registered vehicles. Energy lost in the pavement system due to traffic-induced vibration and deformation is enormous. If effectively harvested, such energy can serve as an alternative sustainable energy source that can be easily integrated into the transportation system. It is well known that most piezoelectric materials are also pyroelectric materials, which convert temperature change into electricity. However, the potential of polyvinylidene fluoride (PVDF) as a hybrid piezo-pyroelectric energy harvester has been seldom studied. The uniqueness of this study lies in that the electrical responses of PVDF under coupled mechanical and thermal stimulations are investigated. Through a series of well controlled experiments, it is found that there exists an interesting coupling phenomenon between piezoelectric and pyroelectric effects of PVDF: the voltage generated by simultaneous mechanical and thermal stimulations is the algebraic sum of voltages generated by separate stimulations. This means that there is neither strengthening nor weakening coupling effect when the piezoelectric and pyroelectric phenomena are coupled. This also makes the modeling process of the hybrid piezoelectric and pyroelectric effect straightforward. An estimation of power generation through piezoelectric and pyroelectric effect is conducted, and the overall effects of temperature on hybrid piezo-pyroelectric energy harvesting are discussed. 相似文献
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针对柔性悬臂梁的振动问题,开展了PPF振动控制实验研究．首先研究了单模态PPF控制器和多模态PPF控制的主动控制技术,介绍了各控制参数的调整方法,然后建立柔性悬臂梁的实验装置,对系统进行了参数辨识,并进行了PPF控制实验．实验结果表明,压电陶瓷驱动的PPF振动控制对柔性悬臂梁振动抑制具有良好的效果,而且设计方法简单,易于工程实现． 相似文献
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径向模式振动的压电变压器是由硬的压电材料建成,具有较高的机械品质因数Qm,它是沿厚度方向极化。首先根据压电变压器等效电路模型图建立压电变压器的动力学模型,根据各个负载电阻,测定的电压升压比,输出功率,效率方面的电性能,得出电压升压比与负载电阻成比例地增大,之后对不同厚度的压电变压器进行Comsol仿真,对比得出最优的压电变压器。后通过MATLAB仿真得出电阻最佳时,效率达到最大可以达到90%,升压比为1.5,对这些结果进行比较,从等效电路的分析计算,得出他们有很高的效率和稳定性,可以解决原有卫星推进器效率低、不稳定的状况。 相似文献
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采用偶应力理论对单层压电悬臂梁式微执行器在强外加电场作用下的非线性静态特征进行了研究.悬臂式执行器包括压电层、被动（弹性）层和2个电极层.首先,采用瑞利-里兹方法分析了在强外加电场作用下由于压电层电致伸缩效应引起的执行器非线性静态特性.其次,由于悬臂执行器的厚度在μm量级,存在变形尺度效应,采用偶应力理论对变形的尺度效应进行了分析.分析结果表明：悬臂执行器的非线性随着外加电场强度的增大而增大,当外加电场很大时,出现刚度软化现象;而且,执行器被动层和压电层厚度比的最优值不是通常采用的1.0.在微尺度下,由于微梁变形存在尺度效应,该厚度比的最优值应比1.0大. 相似文献
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A displacement sensor based on the fiber Fabry-Perot （F-P） cavity was proposed in this paper. Theoretical and experimental analyses were presented. Displacement resolution was demonstrated by spectrum-domain experiments to obtain the dynamic range of the F-P sensor, and a piezoelectric crystal unit （PZT） was used as the driver. The output signal was modulated by a piezoelectric ceramic ring and demodulated by a phase-locked oscillator. The experimental results show that the displacement resolution of the F-P sensor is less than 5 nm and the dynamic range is more than 100 μm. As acceleration is the second-order differential of displacement, an accelerometer model was proposed using the finite element method （FEM） nd ANSYS software. 相似文献
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INTRODUCTION Passive methods have played an important role for a long time (Snowdon, 1973; Nelson, 1982; Pan et al., 1992) in vibration and noise control. However, with inrush of some novel engineering structures and machines, such as super high-speed machine tools, long-span bridges, thin shell structures, micro elec- tromechanical systems and so on, traditional passive control approaches are not efficient enough for con- trolling structure noise and vibration from these novel systems an… 相似文献
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基于欧拉-伯努利梁理论,设计了一种新型的微型同位素辐射能收集器二维机电模型。该模型解决了一维机电模型无法涵盖的诸多问题。算例分析表明:本模型能较准确地描述实验过程和预测实验结果。通过对结果进行分析,得出了影响微悬臂梁的位移、梁的往返周期和梁中存储能量的一系列因素。 相似文献
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Under an in-phase assumption, the complete charging for an energy harvesting system is studied, whichconsists of a piezoelectric energy harvester （PEH）, a bridge rectifier, a filter capacitor, a switch, a controller and arechargeable battery. For the transient charging, the results indicate that the voltage across the filter capacitor increasesas the charging proceeds, which is consistent with that reported in the literature. However, a new finding shows thatthe charging rate and energy harvesting efficiency decrease over time after their respective peak values are acquired.For the steady-state charging, the results reveal that the energy harvesting efficiency can be adjusted by altering thecritical charging voltage that controls the transition of the system. The optimal energy harvesting efficiency is limitedby the optimal efficiency of the transient charging. Finally, the relationship between the critical charging voltage andthe equivalent resistance of the controller and rechargeable battery is established explicitly. 相似文献
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In this study a new dynamic model of a rotor system is established based on the Hamilton principle and the finite element method (FEM). We analyze the dynamic behavior of the rotor system with the coupled effects of the nonlinear oil film force, the nonlinear seal force, and the mass eccentricity of the disk. The equations of the motion are solved effectively using the fourth order Runge-Kutta method in MATLAB. The dynamic behavior of the system is illustrated by bifurcation diagrams, largest Lyapunov exponents, phase trajectory diagrams, and Poincaré maps. The numerical results show that the rotational speed of the rotor, the pressure drop in the seal, the seal length, the seal clearance, and the mass eccentricity of the disk are the key parameters that significantly affect the dynamic characteristics of the rotor system. The motion of the rotor system exhibits complex types of periodic, quasi-periodic, double-periodic, multi-periodic, and chaotic vibrations. This analysis can be used to guide the design of seal parameters and to diagnose the vibration of rotor/bearing/seal systems. 相似文献
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Jun-yi LIANG Jian-long ZHANG Xi ZHANG Shi-fei YUAN Cheng-liang YIN 《浙江大学学报(A卷英文版)》2013,14(8):535-553
To solve the low power density issue of hybrid electric vehicular batteries, a combination of batteries and ultra- capacitors （UCs） could be a solution. The high power density feature of UCs can improve the performance of battery/UC hybrid energy storage systems （HESSs）. This paper presents a parallel hybrid electric vehicle （HEV） equipped with an internal combus- tion engine and an HESS. An advanced energy management strategy （EMS）, mainly based on fuzzy logic, is proposed to improve the fuel economy of the HEV and the endurance of the HESS. The EMS is capable of determining the ideal distribution of output power among the internal combustion engine, battery, and UC according to the propelling power or regenerative braking power of the vehicle. To validate the effectiveness of the EMS, numerical simulation and experimental validations are carried out. The results indicate that EMS can effectively control the power sources to work within their respective efficient areas. The battery load can be mitigated and prolonged battery life can be expected. The electrical energy consumption in the HESS is reduced by 3.91% compared with that in the battery only system. Fuel consumption of the HEV is reduced by 24.3% compared with that of the same class conventional vehicles under Economic Commission of Europe driving cycle. 相似文献
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采用线性霍尔电路和永磁体,基于悬臂梁弹性体系统,研制了一种霍尔式肌张力换能器。2个线性霍尔电路以永磁体为对称中心,构成对称互补取样电路,以差分方式输出信号电压;张力使悬臂梁发生弹性形变,携带磁体产生位移并引起磁场变化,应用霍尔效应实现了肌张力与信号电压的线性变换。取样系统的对称互补式设计,抵消了非线性变量对测量的影响,换能器具有高线性度指标;差分式输出能够抑制共模干扰和零点漂移,并增大了信号幅度;非接触式的测量方法,提高了换能器的可靠性。新型换能器应用于医学物理实验,灵敏度高、抗干扰能力强,实验效果优于应变式换能器。 相似文献
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We used computational fluid dynamics （CFD） and mode superposition method instead of the energy balance method to compute transmission line aeolian vibrations induced by the Karman vortex. Firstly, we obtained the wind power inputs using CFD theory. The result is effective for aeolian vibration analyses compared with the power which were measured in wind tunnel tests. Then a new aeolian excitation was derived using the wind power equivalent principle, and the aeolian vibration distribution along transmission lines and the wind power input obtained by CFD can be account. Secondly, we formulated the motion equation of a conductor-damper system and derived a semi-analytial solution using the mode superposition method. The Stockbridge-type dampers attached were simplified to the forces transmitted by the clamps. Finally, the semi-analytical solution can be solved by iterative methods. Taking a 1 000 kV Ultra High Voltage transmission line as an example, we analyzed the line with and without dampers by the semi-analytical solution. Compared with the results which were computed by the energy balance method, the semi-analytical solution is precise enogh for aeolian vibration analyses. Besides, we also analyzed the influence of damper position and quantity. 相似文献
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ＩＮＴＲＯＤＵＣＴＩＯＮＡｓｗｅｋｎｏｗ ,ｔｈｅｃｏｍｐｕｔａｔｉｏｎａｌｐｉｅｚｏｅｌｅｃｔｒｉｃｄｙｎａｍｉｃｅｑｕａｔｉｏｎｓｆｏｒｈｉｇｈｆｒｅｑｕｅｎｃｙａｃｏｕｓｔｉｃｗａｖｅｐｒｏｐａｇａｔｉｏｎｓｗｅｒｅｏｒｉｇｉｎａｌｌｙｅｘｐａｎｄｅｄｆｒｏｍｔｈｅｇｅｎｅｒａｌｃｏｍｐｕｔａｔｉｏｎａｌｓｔｒｕｃｔｕｒａｌｍｅｃｈａｎｉｃｓ,ａｎｄｔｈｅｆｉｎｉｔｅｅｌｅｍｅｎｔｍｅｔｈｏｄｓ(ＦＥＭ)ｉｎｉｔｉａｌｌｙｆｒｏｍａｅｒｏｓｐａｃｅａｎｄｃｉｖｉｌｅｎｇｉｎｅｅｒｉｎｇ .Ｔｈｅ… 相似文献
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This paper discusses the validity of (adaptive) Lagrange generalized plain finite element method (FEM) and plate element method
for accurate analysis of acoustic waves in multi-layered piezoelectric structures with tiny interfaces between metal electrodes
and surface mounted piezoelectric substrates. We have come to conclusion that the quantitative relationships between the acoustic
and electric fields in a piezoelectric structure can be accurately determined through the proposed finite element methods.
The higher-order Lagrange FEM proposed for dynamic piezoelectric computation is proved to be very accurate (prescribed relative
error 0.02%–0.04%) and a great improvement in convergence accuracy over the higher order Mindlin plate element method for
piezoelectric structural analysis due to the assumptions and corrections in the plate theories. The converged Lagrange finite
element methods are compared with the plate element methods and the computed results are in good agreement with available
exact and experimental data. The adaptive Lagrange finite element methods and a new FEA computer program developed for macro-
and micro-scale analyses are reviewed, and recently extended with great potential to high-precision nano-scale analysis in
this paper and the similarities between piezoelectric and seismic wave propagations in layered structures and plates are stressed.
Project supported by SRF for ROCS, SEM of China and partially by Zhejiang Provincial Natural Science Foundation (NSF) of China. 相似文献
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研究目的：求斛双圆盘转了-密封系统的非线性振动特性和运动响应 创新要点：采用有限元法（FEM）和拉格朗目方程求解双圆盘转子-密封系统,进而为研究多级转了系统的非线性振动问题提供有效方法。研究方法：基于有限元法（FEM）和拉格朗目方程。同时利用四阶龙格-库塔法求解系统动特性运动响应情况,利用风岔图、时间历程图、轴心轨迹图、庞加莱映射和幅值谱等分析图研究双圆盘转子-密封系统的非线性振动特性。重要结论：随着转速的增大,双圆盘转子-密封系统呈现丰富的非线性运动形式,包括周期性运动、多周期运动,准周期运动以及混沌运动。在右端圆盘不平衡质量小于34kg、密封间隙范围为0.376mm-0.54mm、密封长度大于0.13m或者密封压差高于0.104MPa的情况下均有利于提高双圆盘转子-密封系统的稳定性。 相似文献
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LAU C.W.H. LIM C.W. LEUNG A.Y.T. 《浙江大学学报(A卷英文版)》2005,6(9):962-966
INTRODUCTION Piezoelectricity is an electromechanical phe- nomenon which couples elasticity and electricity through the existence of pressure induced electrical field or electric induced stress field. The piezoelectric materials are usually surface bonded in patches or fully embedded in the host structure, so that the structure becomes a laminated piezoelectric beam. Tzou and Gadre (1989), Lee (1990), Crawly and Lazarus (1991) developed laminated plate models incorporating the piezoelect… 相似文献