Roadway Embeddable Multi-MHz Capacitive Wireless Charging System with Matching Network Realized using Wiring Parasitics

This paper introduces a roadway embeddable multi-MHz capacitive wireless power transfer (WPT) system suitable for EV charging that realizes its roadway-side matching network using the parasitics of the wires connecting the charging pad to the curbside power electronics. Various implementations of this parasitics-based matching network that enable high voltage gain and reactive compensation are investigated and compared in terms of stray electromagnetic fields and overall system efficiency. A novel design for a roadway embeddable charging pad which achieves a favorable tradeoff between system efficiency and pad thickness is also presented. A 13.56-MHz 12-cm air-gap kilowatt-scale capacitive WPT prototype utilizing the proposed parasitics-based roadway-side matching network and roadway embeddable charging pad is designed and built and tested upto 100 W power level. The performance of the prototype is in good agreement with theoretical predictions.