Dynamics of Contactless Ultrasonic Power Transfer for Wireless Devices

在过去十年中，人们对环境机械能（如振动能）转化为低功率电能以实现自供电无线电子元件进行了大量研究。只要在小型装置附近有足够的环境能量，这种能量传递方法是可能的。在一些情况下，没有可用的环境能源，或者不希望或不可能更换电池或固定充电，例如，位于核废料容器等危险环境中的深度植入医疗装置或传感器。在这种情况下，需要非接触式电力传输。本研究的主要目的是对非接触式超声功率传输动力学进行系统级研究，为其在下一代无线设备中的实现奠定基础。最近受到越来越多关注的一种非接触式电力传输的特殊方法是使用超声波（频率高于人类听觉范围的声波）。与流行的功率传输方法（如电感耦合）相比，超声波的使用具有几个优点，例如使用较小的换能器相对较长的功率传输距离，以及消除磁场。这项研究具有重大的技术潜力和广泛的社会影响。无线电子元件的非接触式供电可以减少传感器网络的维护成本和废弃电池的化学废物。无线充电的深度植入医疗设备可以消除与更换电池相关的手术并发症。该项目包括努力招收妇女和少数民族本科生，并让高中教师参与研究经验。由于所涉及的多个领域存在障碍物、反射、衍射、损耗以及声学或机电阻抗匹配问题，因此在无线应用中有效利用超声波功率传输作为使能技术面临着困难的挑战。本研究计划的目标是通过耦合机电系统动力学、压电学、超声波物理和声学超材料，对非接触式超声波功率传输进行系统级的理论和实验研究。该项目将产生关于潜在多物理场动力学的全面知识，用于下一代无线电子设备，从医疗植入物到没有直接物理访问的远程传感器。系统级、经过实验验证的高保真多物理场建模框架将发射器-接收器-电力负载动力学与跨多个域的声学传播相结合，可以实现高效超声功率传输系统的设计。此外，声子晶体和超材料的概念可以用于组合波聚焦和阻抗匹配，相控阵可以用于电力传输中的障碍规避。具体研究目标是：(1)建立全耦合建模框架，分析非接触式超声功率传递的多物理场动力学；(2)利用各种压电收发架构，包括相控阵；(3)利用声子晶体和超材料进行组合波聚焦和阻抗匹配。

The transformation of ambient mechanical energy such as vibrational energy into low-power electricity for enabling self-powered wireless electronic components has been heavily investigated over the last decade. This method of energy transfer is possible as long as sufficient ambient energy is readily available in the vicinity of small devices. There are several conditions where there is no ambient energy available or battery replacement or tethered charging is either undesirable or impossible, for example, deep-implanted medical devices or sensors located in hazardous environments such as nuclear waste containers. In such cases, contactless power transfer is needed. The primary objective of this theoretical and experimental research is to perform a system-level investigation of contactless ultrasonic power transfer dynamics to lay the foundation for its implementation in next-generation wireless devices. One particular method of contactless power transfer that has lately received growing attention is the use of ultrasound waves (which are acoustic waves with frequencies higher than the human hearing range). The use of ultrasound offers several advantages such as relatively long power transmission distances using smaller transducers, and elimination of magnetic fields, as compared to popular power transfer methods such as inductive coupling. The research has significant potential for technological and broad societal impact. Contactless powering of wireless electronic components can reduce the maintenance costs in sensor networks and chemical waste of discarded batteries. Wireless charging of deep-implanted medical devices can eliminate the surgery-related complications associated with battery replacement. The project involves efforts to recruit women and minority undergraduate students and involvement of high school teachers in research experience. The effective use of ultrasonic power transfer as an enabling technology in wireless applications faces difficult challenges due to the presence of obstacles, reflections, diffractions, losses, and acoustic or electromechanical impedance matching issues resulting from the multiple domains involved. The objective of this research program is to perform a system-level theoretical and experimental investigation of contactless ultrasonic power transfer by coupling the dynamics of electromechanical systems, piezoelectricity, ultrasonic wave physics, and acoustic metamaterials. The project will generate a comprehensive knowledge of the underlying multiphysics dynamics to be exploited in next-generation wireless electronic devices spanning from medical implants to remote sensors with no direct physical access. System-level, experimentally validated, high-fidelity multiphysics modeling frameworks that combine transmitter-receiver-electrical load dynamics with acoustic propagation across multiple domains can enable the design of efficient ultrasonic power transfer systems. Additionally, concepts from phononic crystals and metamaterials can be exploited for combined wave focusing and impedance matching, and phased arrays can be leveraged for obstacle circumventing in power transfer. The specific research goals are to (1) establish fully coupled modeling frameworks to analyze multiphysics dynamics of contactless ultrasonic power transfer; (2) leverage various piezoelectric transmitter-receiver architectures including phased arrays; and (3) exploit phononic crystals and metamaterials for combined wave focusing and impedance matching.