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

无线电力传输（WPT）技术与现在主导最终用户应用的无线通信一样，即将接管当今的许多有线电力输送。然而，阻止WPT更广泛采用的主要限制之一是其在现有实现中严格的方向和对齐要求。学术界和工业界目前的努力导致了对于大多数应用来说过于庞大的3维（3D）多线圈结构或仅解决未对准问题而未解决取向问题的2维（2D）平面线圈阵列。这个CAREER项目的目标是实现高效的全向WPT系统，该系统具有新的空间校准方法，可以动态地塑造磁场方向，以匹配接收器设备的方向，从而在不使用庞大的3D结构的情况下实现最佳功率传输。通过解决WPT的这一重大挑战，该项目将使广泛的应用受益，从体内方向/位置不确定的低功耗植入式或可摄入式医疗设备到更高功率的消费电子产品，而无需与无线发射器进行仔细的方向和位置对准，揭示了无线供电技术的全部潜力。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课程。这些教育活动将弥合大学教育和行业需求之间的差距，更好地培训学生，以满足全国工业对劳动力的需求。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，为他们提供更多机会获得知识和技能，以追求工程师或科学家的职业目标，从而帮助培养更多样化的STEM劳动力。为了实现3D全向WPT，而无需使用庞大的3D结构，将开发受控的2D近场线圈阵列，以利用实时空间校准技术对磁场进行整形，从而确定并产生驱动阵列中的线圈的最佳相位和幅度。将针对具有不同约束的不同应用场景探索三种系统级方法，即：1）接收器反向激励，其受经典电磁学中的互易性理论的启发，以反向地感测接收器驱动的信号，从而在发射器处拾取潜在的最佳驱动信号; 2）发射机正向激励，通过检测发射机驱动电压和电流来分析反射阻抗，然后计算最佳驱动参数; 3）反馈引导搜索，通过优化搜索空间，然后利用来自接收器的反馈信号来搜索最佳驱动参数。此外，当发射器不具有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2D方法。在每种方法中，将进行系统级拓扑结构、芯片级集成电路和闭环控制技术的理论分析和硬件开发，以进行原型设计和测量。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。该CAREER项目的成功完成将使WPT得到更广泛的采用，引发创新，开启全向无线供电应用的新趋势，并在社会上产生广泛的影响。该项目由通信，电路和传感系统（CCSS）计划和既定计划，以刺激竞争研究（EPSCoR）该奖项反映了NSF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.