EAGER:Capturing Stray Magnetic Fields for Ubiquitous Wireless Power

摘要：非技术性：输电电缆、与电器(如电水壶、洗衣机、烘干机等)相连的电线中的电流产生微小磁场。和电子设备。输电和配电设施，以及住宅布线和家用电器，构成了家庭的背景磁场。在不靠近高压电力电缆的家庭中，这个背景电场很小，但在电力电缆正下方，电场要强得多。利用磁-机-电转换原理，可以将这种背景磁场转化为有用的电能。产生的电能可以储存在超级电容器或充电电池中，并用于各种目的，如为传感器和移动设备供电。该项目将利用压电-压磁材料耦合在一起的叠层复合材料结构，提供磁场到电场的转换。作为示范，该项目将以安装在飞行在输电线路上的无人机上的无线传感器为目标。在能量转换过程的优化方面将取得几个根本性的进展，包括：(I)在给定的形状和体积内设计能够导致磁通放大和退磁场减小的复合结构，(Ii)理解在不同长度尺度上发生的物理相互作用并在能量转换器的设计中解决这些相互作用，(Iii)全系统建模以揭示材料、结构和电气变量的作用并使用该模型来提高系统效率。这些在描述电力传输电缆、家用电器和住宅电线等来源的动态磁场能量转换过程方面的进展将为开发新一代无线电源提供机会。该项目产生的知识将被总结成跨学科的网络教程，并将通过能源收集学会的网站向公众提供。将与促进工程多样性中心合作，为人数不足的高中生和教师举办夏令营，包括讲座和参观实验室。将与韩国材料科学研究所建立国际合作，以加快无线电源技术的发展。技术：该项目的总体目标是量化拟议的压电-压磁复合材料的磁能到电能的转换能力。在此过程中，将为在不同磁场环境下工作的复合材料建立全面的合成-结构-性能关系。基于本构方程、唯象和细观力学的分析模型将被用来理解参数响应，重点是阐明界面耦合项的作用。有限元模型将用于设计具有匹配的机械阻抗和最佳磁通浓度并减小退磁效应的复合材料结构。优化的复合材料结构将采用基于加法制造的工艺制造。将设计动态阻抗匹配电路，以高效地将电能从转换器传输到存储介质(超级电容器或电池)。现场测试将包括从传输电缆中实时收集能量。综合这些结果，将有助于评估磁机电转换机构的功率密度和效率(输出电能/输入磁能)的极限。

Abstract:Nontechnical:Small magnitude magnetic fields arise from the current flow in the power transmission cables, wires connected to appliances (such as electric kettle, washer, dryer, etc.) and electronic devices. Electric transmission and distribution facilities, as well as residential wiring and appliances, account for background magnetic fields in the home. In homes not located near high-voltage power cables, this background field is small but directly beneath the power cables, the fields are much stronger. This background magnetic field can be converted into useful electricity by using the principle of magneto-mechano-electric conversion. Generated electricity can be stored into supercapacitor or rechargeable battery and used for various purposes such as powering sensors and mobile devices. The project will utilize piezoelectric - piezomagnetic materials that are coupled together in a laminate composite structure to provide conversion of magnetic field into electric field. As a demonstration, the project will target powering wireless sensors mounted on unmanned aerial vehicle flying over the power transmission lines. Several fundamental advances will be made in optimizing the energy conversion process including (i) design of the composite structure that results in magnetic flux amplification and reduction of demagnetization field within given shape and volume, (ii) understanding of the physical interactions occurring at varying length scales and addressing them in design of energy converter, (iii) full system modeling to reveal the role of materials, structure, and electrical variables and using the model to improve the system efficiency. These advancements in describing the dynamic magnetic field energy conversion process from sources such as power transmission cables, household appliances, and residential wiring will provide opportunity for developing new generation of wireless power sources. The knowledge generated from the project will be summarized into interdisciplinary web-based tutorial which will be offered to public through Energy Harvesting Society website. Summer camp comprising of lectures and laboratory tours for underrepresented high school students and teachers will be implemented in collaboration with the Center for the Enhancement of Engineering Diversity. International collaboration with Korea Institute of Materials Science will be established to expedite the development of wireless power source technology.Technical:The overarching objective of this project is to quantify the magnetic-to-electric energy conversion capability of proposed piezoelectric - piezomagnetic composite. In doing so, comprehensive synthesis - structure - performance relationships will be established for composites operating under varying magnetic field environment. Analytical modeling based upon constitutive equations, phenomenology and micromechanics will be used to understand the parametric response with emphasis on elucidating the role of interfacial coupling term. Finite element model will be used to design the composite architecture with matching mechanical impedance and optimum flux concentration with reduced demagnetization effect. Optimized composite structure will be fabricated using additive manufacturing based process. Dynamic impedance matching circuit will be designed to transfer power with high efficiency from the converter to storage media (supercapacitor or battery). Field testing will comprise of real-time energy harvesting from transmission cables. Combined these results will assist in evaluating the limits on power density and efficiency (output electrical energy/input magnetic energy) of magneto-mechano-electric conversion mechanism.