Quasi-Static Modeling and Optimization of Two-Layer PCB Resonators in Wireless Power Transfer Systems for 110-kV Power Grid Online Monitoring Equipment

The expanding functions of the emerging smart grid have posed new technical challenges on the power supplies for online monitoring systems in the transmission and distribution networks. A recent study has suggested that magnetic energy around the transmission line can be harvested and delivered wirelessly to the monitoring equipment through printed circuit board (PCB) resonators embedded inside an insulation rod. This article presents a rigorous analysis, modeling, and optimization of such PCB resonators. A new closed-form quasi-static model of the PCB resonators is derived. A fully automated simulation-driven optimization framework is constructed to enhance the quality factor of the resonator. Practical measurements show that the optimal design improves the quality factor (Q factor) from 52 to 132 as compared to the existing trial-and-error design. The corresponding wireless power transfer efficiency in a 20-W prototype across a 1.14-m distance improves significantly from 11 to 46%.