Highly Integrated Hybrid Inductive and Capacitive Power Transfer System With Asymmetrical Printed-Circuit-Board-Based Self-Resonator

This article presents a highly integrated and compact hybrid wireless power transfer (WPT) system with asymmetrical printed-circuit-board (PCB) based self-resonators. The PCB-based self-resonant coupler consists of four PCB-coil plates with two different sizes, which can work as the transmitter/receiver for inductive power transfer as well as the capacitive plates for capacitive power transfer. With a typical stacked four-plate configuration, both inductive and capacitive mutual couplings are achieved between transmitter and receiver, contributing to a highly compact and integrated self-resonant hybrid WPT system without any external compensation components. Detailed theoretical analysis and system modeling are provided based on the two-port parameter theory and a 300 W hybrid WPT prototype is implemented with an asymmetrical coupler consisting of 210 and 140 mm PCB-coil plates. The implemented hybrid WPT system is tested at 80, 60, 37, and 12 mm with self-resonant working frequencies of 3.845, 3.75, 3.57, and 3.19 MHz, respectively, and the system performance in terms of output current property, power transfer capability, dc–dc efficiency, and misalignment tolerance are evaluated in details, which demonstrate a peak dc–dc efficiency of 87.3% with 155.7 W at 12 mm and 86.7% with 237.5 W at 37 mm, validating the effectiveness of the designed hybrid WPT system.