【作者】 朱莉娅；

【导师】 陈仁文；

【作者基本信息】 南京航空航天大学 ， 仪器科学与技术， 2012， 博士

【摘要】 随着大规模集成电路技术、超精密加工技术及网络通信技术的发展，各种微机电系统及微小型电子设备的应用日趋广泛。目前，多数微小型电子设备供电依赖于电池或电线供电。使用电池或电线供电存在代价大、更换困难、污染严重等问题，寻找清洁、可再生的能量取代传统供电方式是解决能量问题的关键所在。压电式振动能量收集技术因其能量转换效率高、结构简单、易于实现微型化与集成化等优点，成为研究较为集中的能量收集技术。本项目组针对目前所研究的压电式振动能量收集结构只能对单一方向振动激励进行能量收集的特点，提出并研制了立方体-球状及蒲公英状多方向振动能量收集器。本文主要研究了多方向振动能量收集结构中各压电换能元件输出信号电学特征，完成了相应充电控制电路拓扑的设计及其无源开关策略实现，并研究了面向振动能量收集结构的自适应频率调谐方法，以提高其对外界频率的适应性。主要研究工作及创新点如下：首先从压电能量收集结构基本工作原理出发，结合压电方程和振动理论给出了一种典型压电能量收集结构---悬臂梁式压电振动能量收集结构的输出功率的理论模型。在此基础上建立了立方体-球、蒲公英状多方向振动能量收集结构的动力学模型，并分析了不同压电换能元件上输出的电压或电流信号之间的幅值、相位关系，为下一步充电电路设计提供了依据。针对单电荷源情况，提出了一种改进的无源同步电荷提取（SCE）电路，及一种基于倍流整流的同步开关电感（SSHI-CDR）电路，并对开关电路中所采用的无源开关（Electronic Breaker）策略进行了理论分析。其中，改进的SCE电路输出功率为经典AC-DC电路最大输出功率的2.98倍。且该电路输出功率恒定，解决了能量收集电路输出功率受负载影响的问题。新型SSHI-CDR电路有效利用了开关过程中电感剩余磁能，在一个机械振动周期内完成四次充电过程，最大输出功率为已有串联同步开关电感（Series SSHI）电路的1.8倍，为经典AC-DC电路的8.4倍。同时，证明了将Electronic Breaker开关电路分别与SCE及并联同步开关电感（Parallel SSHI）电路结合，可以实现不同开关时间，且该开关电路功耗极低，可以实现各类开关电路的能量自给。针对多方向振动能量收集结构的特殊情况，首先提出了多源全桥并联电路与多源全桥串联电路，然后将单电荷源下所提出的改进的无源SCE电路及Parallel SSHI电路应用于多电荷源情况，最后提出一种基于倍压整流的同步开关电感（SSHI-VDR）电路。其中，多源全桥并联电路与多源全桥串联电路下，输出功率分别为单电荷源下经典AC-DC电路的1.98倍与1.96倍。多源SCE电路及多源Parallel SSHI电路下，输出功率分别为多源全桥并联电路的4倍与14.36倍。而新型多源SSHI-VDR电路的最大输出功率达到多源Parallel SSHI电路最大输出功率的1.55倍。同时证明了上述多方向能量收集电路输出功率均不受电荷源相位差影响，适合相位差变化的多源情况。最后，设计了一种低功耗电能调理电路，结合能量收集接口电路，可以输出稳定的3.6V直流电压。为解决能量收集结构输出功率受激励频率影响的问题，提出了一种改进的半主动自适应频率调谐策略。以立方体状多方向能量收集结构为研究对象，利用同步开关刚度控制（SSSC）电路，改变能量收集结构固有频率，使之趋近于外界激励频率。实验结果表明，在该策略调节作用下，结构固有频率频率变化率达到5.45%。且在一定外界激励范围内，可以实现能量自给。本文在机械结构力学及控制国家重点实验室完成。更多还原

【Abstract】 With the development of the large scale integration technology, the precision manufacturingtechnology and the network communication technology, the applications of microelectromechanicalsystems (MEMS) and microelectronic equipments have been spread. At present, most microelectronicequipments are powered by batteries or wires. The traditional power methods may induce the problemof a costly maintenance, the difficulty in installation and the environmental pollution. To solve theseproblems, clear sustainable power generation methods have been researched. Piezoelectric energyharvesters have received much attention since they have high electromechanical coupling, have simplestructures and are suitable for integration. Since most piezoelectric energy harvesters developed aresensitive to unidirectional vibration excitation, the cube-type and the dandelion-type multidirectionalpiezoelectric energy harvesters have been proposed.Thus the paper mainly focuses on the investigation of the characteristics of the charge outputs of thedifferent energy harvesting elements, the charging strategies in the case of multidirectional chargingsources and the passive switching control methods. Meanwhile, the frenquency self-tuning method hasbeen proposed to widen the response range of the energy harvester. The main research work andinnovations are summarized as follows.Based on the working principles of piezoelectric energy harvesting, the theoretical model of theoutput power for the cantilever energy harvesting structure has been set up. And then the kinetic modelsof the cube-type and the dandelion-type multidirectional energy harvesters have been built. Finally, thecharacteristics of the voltage or the current sources of the different piezoelectric elements have beenanalized in order to provide a reference for the circuit design.In the case of a unidirectional charging source, an improved Synchronous Charge Extraction (SCE)interface and a new interface named the Synchronized Switch Harvesting on Inductor with CurrentDoubler Rectifier (SSHI-CDR) have been proposed. Meanwhile, the mechanism of the passiveswitching control method named the Electronic Breaker adopted in the synchronized switching energyharvesting interfaces has been investigated. As shown in experiment, the output power of this circuitleads to a gain of2.98compared with the maximal power of the standard circuit. And the power gainremains constant for any load resistance, solving the problem that the maximum harvested poweroccurs only at the optimal load resistance. By taking into account not only the energy transferred fromthe piezoelectric element to the load but also that stored on the inductor during the non-linear switchingprocess, the SSHI-CDR circuit allows four energy extraction cycles per vibration period. Experimental results show that the proposed circuit allows a power gain of8.4compared to the standard circuit and apower gain over1.8compared to the existed series SSHI interface. Moreover, it has been proved thatthe electronic breaker circuit can fulfill different switching times with different energy harvestinginterfaces. Since the switching method consumes ultralow power of that harvested, the energyharvesters can be truly self-powered.In the case of the multidirectional charging sources, the two AC-DC interfaces separately with theparallel rectifier bridge and with the series bridge are researched. Then the improved SCE interface andthe existed Parallel SSHI interface in the case of the unicharging source are adopted in themulticharging case. Furthermore, a new interface named the Synchronized Switch Harvesting onInductor with Voltage Doubler Rectifier (SSHI-VDR) has been proposed. Among these interfaces, thepower gains of the two different AC-DC interfaces under multicharging sources are separately1.98and1.96compared to the AC-DC circuit under unicharging source. The power gain of the SCE interfaceand the Parallel SSHI interface separately reaches4and14.36in comparison with the AC-DC interfacewith the parallel rectifier bridge.And the maximal output power of the SSHI-VDR circuit leads to again of1.55compared to the Parallel SSHI interface. Meanwhile, all of these energy harvestinginterfaces discussed are independent of the phase conditions of the charging sources. In the end, apower conditioning circuit is proposed with a stable output voltage of3.6V.Since the piezoelectric generator could obtain the maximum power only when the excitationfrequency matches exactly with the resonance frequency of the generator, a semi-active frequencyself-tuning method is proposed. Taking advantage of the Synchronized Switch Stiffness Control (SSSC)circuit, the resonance frequency of the energy harvester can be tuned. Experimental results show thatthe variation of the resonance frequency for the cube-type energy harvester reaches5.45%in terms ofthe resonance frequency. Meanwhile, the self-tunable generator could be self-powered within certainfrequency range.This paper is supported by State Key Laboratory of Mechanics and Control of MechanicalStructures.更多还原