An adaptive magnetically coupled wireless power transmission system

Abstract

An adaptive control mechanism to improve the efficiency of magnetically coupled resonators (MCRs) used in wireless power transmission is presented. To minimize the degradation in power transfer efficiency, the proposed system dynamically adjusts the capacitance of MCRs as the distance between the transmitter (TX) and receiver (RX) coils changes. The control unit operates in a self-sufficient manner through rectifying a portion of the AC signal present on TX and RX coils. A proof-of-concept circuit operating at 13.56 MHz is designed in a 0.13 μm CMOS technology and simulation results confirm the validity of the proposed scheme.