Auto-tuning matching network for wireless power transfer
Date of Issue2016
School of Electrical and Electronic Engineering
Wireless power transfer is increasingly attractive to electronic products, especially for implantable devices. One of the challenges is to maintain maximum power transfer efficiency even in dynamic environment (distance, alignment and load). The application of magnetically resonant coupling technology can achieve strong coupling between two coils, where the coupling coefficient between two coils can reach 0.7-0.9 and hence high power transfer efficient is possible. However, the power transfer efficient suffers significantly with a slight impedance mismatch at both the transmitter and receiver in high quality factor (Q) system. This dissertation focuses on the matching network of the receiver where coupling coefficient of 0-0.9 is investigated. The impedance matching network using parallel capacitors with binary value is constructed. An improved auto-tuning algorithm is proposed based on the simulation result that the output voltage and matching capacitance present a parabolic relation. Following which, the algorithm is implemented into digital circuit using Verilog Hardware Description Language (HDL). Mixed-signal simulation (analog and digital circuit) shows that the optimum matching state can be tracked adaptively through the digital circuit. Additionally, a printed circuit board has been successfully designed and built to verify the auto-tuning function of the adaptive matching system in dynamic environment.
DRNTU::Engineering::Electrical and electronic engineering