Design and Evaluation of a Multilevel Switched Capacitor Rectifier for Wireless Fast Charging

In order to enable wireless charging of mobile electronics to compete with wired alternatives, wireless receivers need to operate at power levels sufficient to accommodate fast-charging standards. The receiver efficiency, harmonic content and total volume are key design metrics for wireless receivers. In this paper, four candidate topologies are compared, under 20 W fast-changing conditions, with respect to power loss, harmonic distortion, and power density. Each of the metrics are analyzed and verified experimentally. In coordination with the transmitter, a system-level approach to minimizing distortion is presented. Finally, the multilevel switched-capacitor rectifier is demonstrated to be a good candidate for wireless fast charging of mobile devices with high efficiency, small size, and suitable structure for future integration.