【作者】 沈辉；

【导师】 裘进浩；

【作者基本信息】 南京航空航天大学 ， 仪器科学与技术， 2010， 博士

【摘要】 能量回收技术是无线传感技术向微型化和实用化发展的关键技术之一。在已有的几类能量回收技术中,基于压电材料的振动能量回收技术最具有发展前途,这是因为其具有较高的能量密度,结构简单易于系统集成,特别适合在MEMS方面的应用。本文从压电能量回收装置的基本架构出发,主要对能量回收接口技术进行了深入研究,提出了两个新的高效接口电路技术,并在振动控制和无线传感技术两方面进行了应用研究。论文的主要工作和创新性成果如下:(1)从压电材料内部能量传递过程分析,结合压电本构方程和结构振动的基本理论给出了压电悬臂梁结构能量回收系统的输出功率的计算分析模型,简要分析了悬臂梁结构、环境振动情况对输出电能的影响。(2)提出了增强型同步开关回收技术(ESSH技术),其可以对压电材料产生的电能进行高效的回收。这种接口电路不仅与标准接口相比回收功率提高了300%(提高倍数会随着应用更低损耗的电感而提高),同时克服了原有串联同步开关电感方法回收功率随负载变化而变化的缺点。同时这种技术己经由低功耗的控制电路(控制电路功耗仅为0.121mW)实现,相比原先的能量自给的串联同步开关电感回收技术,在某些激振较大的场合更具优势。由于这个新接口技术(ESSH)可以实现能量自给,非常适合在远距离、外界能量供给受限制的场合的应用,如自供电的智能微系统(如无线传感网络节点)。另外,作为ESSH能量高效回收技术的一个工程应用,研制出了基于压电能量回收的结构振动与噪声控制装置。实验表明减振效果可以达到-5dB。(3)针对压电能量回收装置可能会工作在宽频带振动环境下或者一阶振动环境中有干扰的情况,提出了一个多模态振动能量回收的策略,即自适应ESSH技术。同时这种技术己经由低功耗的控制电路(控制电路功耗仅为0.328mW)实现。另外作为一个工程应用,其也可以实现能量自给的多模态振动控制。(4)对能量回收技术在振动控制中的应用进行了深入研究。首先研究和设计了一个基于电压同步开关阻尼技术(SSDV技术)低功耗的振动控制系统,其利用能量回收技术从压电片回收能量给半主动振动控制系统供电。与原先能量自给的SSDI控制系统相比,基于SSDV技术的振动控制系统可以使减振效果得到极大的提高。通过实验验证,最终实现了能量自给的振动控制系统。另外,基于自感知原理,即利用自感知技术对压电元件的信号进行提取,设计了一个基于自感知原理的无需外界能量的振动控制系统(控制电路功耗仅为0.322mW)。实验表明,实现了对悬臂梁一阶模态的振动控制,获得了-7.89dB的控制效果。(5)设计了一种基于振动能量回收的无线传感器,其中,包括能量回收单元与低功耗无线传感器单元。首先,优化的机械部分与能量回收接口电路提高了能量回收的效率。其次,无线传感器的设计能够对目标施加的应力应变进行监测,同时,实现了传感器的低功耗与能量自给。通过实验验证了无线传感节点的低功耗特性和实时监测性能。更多还原

【Abstract】 Energy harvesting is one of key technologies for the micromation and practical development of wireless sensor and communication node networks. Among all kinds of energy harvesters,the piezoelectric energy is the most promised one as they are high in energy densities and particularly attractive in MEMS for its relatively simple configuration. In order to improve power harvesting efficiency, two novel techniques for optimizing energy harvesting circuitry are investigated in the dissertation. In addition, two self-powered vibration damping system and a self-powered wireless sensor node for structural health monitor (SHM) are developed, which are the application of the piezoelectric energy harvesting.The main works and novel researched performed in this dissertation include:(1) Based on the constitutive equation of piezoelectric materials and the theory of mechanical vibration, the model of a cantilever bimorph with a proof mass attached to its end is established, which is used to determine the relationship between performance and physical and geometrical parameters.(2) A new technique for optimizing energy harvesting circuitry called enhanced synchronized switch harvesting (ESSH) is presented. Compared with the standard technique of energy harvesting, the new technique dramatically increases the harvested power by almost 300% at resonance frequencies in the same vibration condition (the gain also can be greatly increased using low losses components), and also ensures an optimal harvested power whatever the load connected to the microgenerator. Furthermore, the new technique (ESSH) in the paper can be truly self-powered, a self-powered circuit which implements the technique (ESSH) is proposed. In addition, the overall power consumption for the control circuitry is relatively constant (only about 121μW), which shows more attractive especially in the high excitation. Because the new technique (ESSH) in the paper can be truly self-powered, no external power supply is needed, making the system suitable for more application fields, especially in remote operation. Besides, a self-powered vibration damping system is proposed as the application of the ESSH technique. Experimental results show that a vibration damping of about -5 dB is achieved as a result of energy harvesting, in good agreement with the theory.(3) Another novel technique for optimizing energy harvesting circuitry called adaptive ESSH approach is presented. This technique is based on a control law which deals with the energy harvesting under multimode vibration. Compared with the ESSH technique of energy harvesting, the new technique improve efficiency harvesting efficiency when the piezoelectric energy harvester is excited under two-mode vibration. Furthermore, the new technique (adaptive ESSH) in the paper can be truly self-powered, a self-powered circuit which implements the technique (adaptive ESSH) is proposed. In addition, the overall power consumption for the control circuitry is relatively constant (only about 329μW). Besides, a self-powered multimode vibration damping system is proposed as the application of the adaptive ESSH technique.(4) A vibration damping system powered by harvested energy with implementation of the so called SSDV (Synchronized Switch Damping on Voltage Source) technique is designed and investigated. By supplying the energy collected from the piezoelectric materials to the switching circuit, a new low-power device using the SSDV technique is proposed. Compared with the original self-powered SSDI (synchronized switch damping on inductor), such a device can significantly improve its performance of vibration control. Its effectiveness in the single-mode resonant damping of a composite beam is validated by the experimental results. Besides, a self-powered self-sensing vibration damping system with implementation of the SSDI technique is designed and investigated. Its effectiveness in the single-mode resonant damping of a steel beam is validated by the experimental results. The experimental results show that -7.89dB attenuation for the first mode was achieved. The total power dissipation of the control circuit is only 0.322mW.(5) A wireless sensor based on the energy harvesting from vibrations is designed, which is composed of energy harvesting module and low-power wireless sensor module. Firstly, the structure and electrical interface of energy harvesting module are optimized to enhance the efficiency of transforming mechanical energy to electrical energy. Secondly, a balance technique is introduced during the design of the wireless sensor module, which can not only monitor the real-time structural strain but also be low-powered and meet the need of self-powered sensor node. Finally, an experiment is carried out to test the wireless sensor, which shows its good stability and reliability.更多还原