Highly Efficient Single-Switch-Regulated Resonant Wireless Power Receiver with Hybrid Modulation

In this article, a highly efficient single-switch-regulated resonant wireless power receiver with hybrid modulation is proposed. To achieve both high efficiency and good output voltage regulation, phase shift and pulsewidth hybrid modulation are simultaneously applied. The soft switching operation in this topology is achieved by the cycle-by-cycle phase shift adjustment between the input current and the gate drive signal and also attributed to the reactive components such as the series-compensated secondary coil ( L_{s} , C_{s} ) and the parasitic capacitor of the active switch ( C_{s1} ). The soft switching operation also leads to high efficiency and low electromagnetic interference (EMI). By adjusting the duty ratio of the switch, tight regulation of the output voltage can be attained. The steady-state and dynamic models of the resonant receiver with hybrid modulation are analytically derived in order to properly design the feedback controller. An experimental setup of a two-coil wireless power transfer (WPT) system, including the hardware prototype of the proposed receiver, is constructed for experimental verification. The experimental results show the effectiveness of the soft-switching operation in the receiver with a maximum ac-dc efficiency of 98% while maintaining good regulation of the output voltage, regardless of line and load variations.