Capacitive wireless powering for electric vehicles with near-field phased arrays

This work demonstrates a simple approach for mitigating the high fringing electromagnetic fields produced by high-frequency capacitive wireless powering of electric vehicles. A 6.78 MHz (ISM band) single module Capacitive Wireless Power Transfer (CWPT) system based on GaN on Si inverters and rectifiers provides an output power of 110W with an efficiency of 90%. The electric field produced by the single module is measured to be above the safety exposure limits provided by ICNIRP, consistent with previously reported CWPT. To reduce the E-field produced, while maintaining the required power transfer, a multimodule approach is introduced in which the separate modules are phased to provide a measured field reduction of over 24% and 43% for two and four module systems, respectively.