A Frequency-Sweep Based Load Monitoring Method for Weakly-Coupled Series-Series Compensated Wireless Power Transfer Systems

In this paper, a frequency-sweep based load monitoring method is proposed for weakly-coupled series-series (SS) compensated wireless power transfer (WPT) systems. By only measuring the input voltage and current of the transmitter coil, the proposed monitoring method can estimate the load resistance without any feedback signals from the receiver even for mid-range applications with very small coupling coefficients. Compared to the existing monitoring methods for short-range applications, the proposed monitoring method uses a simpler estimation equation. Both simulation and experimental results are included to confirm that the proposed monitoring method can accurately estimate load resistances of weakly-coupled SS compensated WPT systems.