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.
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.
