【作者】 黄金鑫；

【导师】 李庆民；

【作者基本信息】 山东大学 ， 高电压与绝缘技术， 2012， 博士

【摘要】 发展智能电网是当今电力工业的核心内容,而无线传感器网络作为智能电网高级量测体系的重要组成部分,也成为工业界和学术界的研究热点。现场供能问题是束缚无线传感器网络规模化应用的重要瓶颈,而自供能技术的发展为其提供了一种有效的解决途径。基于变电站空间电磁能的自供能技术,因比其他自供能方式更具优势而受到更多关注,在高压电力系统中的应用前景广阔。本文旨在发展基于空间电磁能的无线传感器自供能技术,分别针对电场能和磁场能的收集开展相关理论探索与技术创新研究,以期解决制约工程化应用的关键问题。针对平板型电场集能转换器适应性差、集能效率低等问题,研究提出一种新的球冠型集能转换器拓扑,并在圆环坐标系下基于分离变量法建立了其解析模型,导出转换器空间电势及电容的完整解析形式。提出储能增量系数的概念以表征球冠型转换器对电容储能的改善程度,并导出以球冠开口半径与球半径之比为变量的储能增量系数表达式,可作为拓扑优化的目标函数。针对不同空间尺寸的球冠型拓扑进行储能增量系数的测试研究,验证了所建立球冠型转换器拓扑解析模型的正确性。研究结果为自供能装置集能转换器的优化设计奠定了理论依据。为解决传统调理单元电路存在的负载适应性差、传输效率低、启动时间长等问题,提出两种调理单元拓扑形式以适应不同的外电场工况条件建立了含稳压电路调理单元拓扑的大信号模型和动态扰动分析模型,藉此研究其静态稳定性和动态扰动工作特性,获得关键参数计算公式,实现反馈补偿网络的设计。证明存在最优占空比使得电路具有最大输出功率,并据此设计了以输出功率最大化为目标的调理单元闭环控制驱动电路。仿真结果验证了上述调理单元拓扑建模及参数选择方法的有效性。在电场集能转换器和调理单元优化分析的基础上,设计了不同类型的自供能装置实验样机并搭建了实验平台,对自供能系统的整体性能开展测试研究。实验结果验证了上述建模和优化方法的有效性,并指出不同调理单元拓扑可稳定工作的电场变化范围,为自供能装置的工程应用提供了重要依据。论文还针对基于磁场能的自供能技术开展了探索研究,提出环绕式和分离式两种磁能转换器拓扑结构。建立了环绕式磁能转换器拓扑的数学模型,并定义感应系数以表征其磁能收集能力,给出环绕式磁能转换器的优化设计原则。针对分离式磁能转换器,提出有效磁导率的概念及其计算方法,并以骨架长度与直径之比为变量给出有效磁导率的函数表达式,进而由此建立转换器最大输出功率的估算方法。实验研究表明该估算方法有效,可为分离式磁能转换器的优化设计提供理论和实验依据。本文研究重点围绕基于空间电磁能的自供能关键技术,进一步发展了相关理论基础、系统建模与仿真分析方法。更多还原

【Abstract】 Development of smart grid technologies has been the kernel and prevailing tasks of nowadays power industry, among which wireless sensor technology as an important part of smart measurement and monitoring turns to be a hot area of research preference. Energy scavenging technology provides an effective solution to the self-sustained power supply issues that obstructs application of the wireless sensors. Energy scavenging technology based on spatial electromagnetic coupling renders outstanding advantages compared with other available methods and sightsee a promising future in high voltage power systems.The dissertation aims to develop energy scavenging technology based on special electromagnetic coupling for powering wireless sensors. Theoretical exploration and technological innovation are intentionally achieved as to solve the power supplying problem which restricts engineering application of the smart transducers.A new topology with spherical cap for energy harvesting is proposed to overcome the unsatisfactory adaptability and low efficiency of the traditional converting topologies. Based on the method of separated variables within the toridal coordinate system, a corresponding analytical model for spherical cap converter is further established so as to obtain the analytic expressions of the topology capacitance and the output voltage. The concept of energy increment factor is specifically defined to denote the improvement of energy storage efficiency. In term of the radius ratio between a spherical cap and a sphere cap, numerical expression of the energy increment factor is presented, which can be used as the objective function for topological optimization. With regard to spherical cap converters of different dimensions, the measured values of energy increment factor coincide well with the theoretical equivalents, indicating an effective verification of the proposed analytical model for the spherical cap converter topology. The research results present theoretical basis for optimal design of the energy scavenging devices.Traditional conditioning unit for energy scarvenging devices show some unique disadvantages such as poor adaptability, low transmission efficiency and long starting time. Two novel types of conditioning units are presented for different environmental conditions of electric field. A large-signal model as well as a dynamic disturbance model is established so as to analyze the static and dynamic characteristics of the conditioning unit, and the computational formula for key parameters are deduced, which form the basis for optimal design of the feedback compensation network. The relationship between the duty ratio and the output power is expored and the driving circuit is designed with a closed-loop control scheme as to obtain the maximum output power. Simulation results verified the effectiveness of the proposed topology structure and the parameter selection methodologies. Based on optimization of the converter topologies and the conditioning units, different prototypes of energy scavenging devices are designed and an experimental rig is also set up for overall performance test of these prototypes. Experimental results demonstrated the effectiveness of the proposed methodology for modeling and optimization. The optimal range of electric field intensity in which conditioning units can operate steadily is indicated, which is of sensible significance for engineering application of the energy scavenging devices.Exploratory research on magnetic energy scavenging is also carried out. Two types of magnetic energy converters, namely armillary and standalone, are proposed respectively. For the armillary topology, a mathematical model is established and the optimal design principle is further given. A specific inductive factor is defined to represent energy scavenging capability of the armillary converter. For the standalone topology, the concept of effective permeability together with corresponding algorithms is put forward. The ratio of framework’s length to topology diameter being the variable, a formula for the effective permeability is achieved, with which an estimating method for maximum output power of the standalone converters is further proposed. Experimental studies show feasibility and effectiveness of the control scheme.The innovative research of the dissertation further develops fundamental theories, modeling schemes and simulation methodologies for the energy scavenging technology based on spacial electromagnetic coupling.更多还原