CAREER: Towards 3D Omnidirectional and Efficient Wireless Power Transfer with Controlled 2D Near-Field Coil Array

无线电力传输（WPT）技术，就像现在主导终端用户应用的无线通信一样，正准备接管今天的许多有线电力传输。然而，阻碍WPT广泛采用的主要限制之一是其在现有实现中严格的定向和对齐要求。目前学术界和工业界的努力导致了三维（3D）多线圈结构对于大多数应用来说过于笨重，或者二维（2D）平面线圈阵列只解决了错位问题，而没有解决方向问题。CAREER项目的目标是通过新的空间校准方法实现高效的全方位WPT系统，该系统可以动态地塑造磁场方向，以匹配接收器设备的方向，从而在不使用笨重的3D结构的情况下实现最佳的功率传输。通过解决WPT的这一重大挑战，该项目将受益于广泛的应用，从低功耗可植入或可摄入的医疗设备，在体内的方向/位置不确定，到更高功率的消费电子产品，而不需要仔细的方向和位置对准无线发射器，揭示无线电源技术的全部潜力。在教育方面，该项目将为本科生提供芯片级设计经验，与行业专业人士就实际应用进行互动的机会，以及新的课程。这些教育活动将弥合大学教育与行业需求之间的差距，为学生提供更好的培训，以满足全国范围内的行业劳动力需求。与各组织密切合作的外展活动也将通过增加代表性不足的少数群体学生的参与，为他们提供更多获得知识和技能的机会，以追求工程师或科学家的职业目标，从而帮助培养更多元化的STEM劳动力。为了在不使用庞大的3D结构的情况下实现3D全向WPT，将开发一种受控的2D近场线圈阵列，通过实时空间校准技术来塑造磁场，以确定和产生驱动阵列中线圈的最佳相位和振幅。针对不同约束条件下的不同应用场景，将探索三种系统级方法，即：1)受经典电磁学中互易理论的启发，接收器反向激励，反向感知接收器驱动信号，从而在发射机处拾取可能最优的驱动信号；2)发射机正向激励，通过感知发射机驱动的电压和电流，分析反射阻抗，进而计算出最优驱动参数；3)反馈引导搜索，通过优化搜索空间，然后利用接收端反馈信号搜索最优驱动参数。此外，当发射器不具备实现平面多线圈阵列的灵活性时，还将开发具有薄膜接收器结构的伪二维方法。在每种方法中，系统级拓扑、芯片级集成电路和闭环控制技术的理论分析和硬件开发将用于原型和测量。为了提高系统效率，将进行线圈和谐振链路的自适应优化以及非线性功率和电压调节技术的开发，并进行测量验证。CAREER项目的成功完成将使WPT得到更广泛的应用，引发创新，为全向无线供电应用开辟新趋势，并对我们的社会产生广泛的影响。该项目由通信、电路和传感系统（CCSS）计划和促进竞争研究的既定计划（EPSCoR）共同资助。该奖项反映了美国国家科学基金会的法定使命，并通过使用基金会的知识价值和更广泛的影响审查标准进行评估，被认为值得支持。

Wireless power transfer (WPT) technology, like wireless communications now dominating end-user applications, is poised to take over many of the wired power deliveries today. However, one of the major limitations that prevents wider adoption of WPT is its stringent orientation and alignment requirements in existing implementations. Current efforts from both academia and industry resulted in either 3-dimensional (3D) multi-coil structures that are too bulky for most applications or 2-dimentional (2D) planar coil arrays that only addressed misalignment issues while leaving the orientation issue unresolved. The goal of this CAREER project is to achieve efficient omnidirectional WPT systems with new spatial calibration methodologies that can dynamically shape the magnetic field direction to match the orientation of the receiver device for optimum power transfer without using a bulky 3D structure. By addressing this major challenge of WPT, this project will benefit a wide range of applications, from low-power implantable or ingestible medical devices with orientation/location uncertainties inside the body to higher-power consumer electronics, without the need for careful orientation and position alignment with the wireless transmitter, revealing the full potential of wireless power technology. In terms of education, this project will provide undergraduate students with chip-level design experience, opportunities to interact with industry professionals on practical applications, and new courses. These education activities will bridge gaps between university education and industry needs with better training of students to address the nationwide workforce demand in industry. The outreach activities in close collaboration with various organizations will also help develop a more diverse STEM workforce by increasing the participation of students from underrepresented minority groups and providing them with more opportunities to obtain the knowledge and skills to pursue career goals as engineers or scientists.To achieve 3D omnidirectional WPT without using bulky 3D structures, a controlled 2D near-field coil array will be developed to shape the magnetic field with real-time spatial calibration techniques to determine and generate the optimal phases and amplitudes driving the coils in the array. Three system-level approaches will be explored for different application scenarios with different constraints, namely: 1) Receiver Backward Excitation, which is inspired by the theory of reciprocity in classical electromagnetism to sense the receiver-driven signals in reverse to pick up potentially optimum driving signals at the transmitter; 2) Transmitter Forward Excitation, to analyze the reflected impedance by sensing the transmitter-driven voltages and currents, and then calculate the optimum driving parameters; 3) Feedback Guided Searching, by optimizing the search space and then utilize feedback signals from the receiver to search for optimal driving parameters. In addition, a pseudo-2D approach with thin-film receiver structure will also be developed when the transmitter does not have the flexibility to implement a planar multi-coil array. In each approach, theoretical analysis and hardware development of system-level topologies, chip-level integrated circuits, and closed-loop control techniques will be performed for prototyping and measurement. To improve system efficiency, adaptive optimizations of coils and resonant links and development of nonlinear power and voltage regulation techniques will be performed with measurement verifications. The successful completion of this CAREER project will enable wider adoption of WPT, trigger innovations, open new trends for omnidirectional wireless powered applications, and generate broad impacts in our society.This project is jointly funded by the Communications, Circuits and Sensing Systems (CCSS) Program and the Established Program to Stimulate Competitive Research (EPSCoR).This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.