A new Push-pull Class-Φ Converter for Multi-MHz Dual-frequency Wireless Power Transfer Applications

We propose a novel converter for simultaneous dual-frequency wireless power transfer (WPT) devices. The proposed converter realizes independent WPT channels at two frequencies: the main frequency f
s
and the second harmonic 2f
s
. With the coupled-T-network, a new class-Φ based push-pull inverter is introduced to provide load-independent currents for two transmitter coils. The power channels at two frequencies are decoupled and independent from each other, providing high flexibility for individual or simultaneous WPT at both frequency bands. The experimental WPT system has verified the characteristics of the proposed converter, realizing 64 W: 16 W power transfer for 6.78 MHz and 13.56 MHz receivers, respectively, with 80 % system efficiency.