Realization of an Optimum Load for Wireless Power Transfer System

Wireless power transfer (WPT) system has been an integral part of personal living since its regained interest, especially the magnetic resonance (MR) scheme. MR-WPT scheme suffers, however, change of the coil separation distance and various alignment errors. This paper reports a realization of optimum load for MR-WPT system, which can change the loading impedance accordingly for different coupling coefficients between the Tx and Rx coils. A simple varactor circuit is adopted to realize the optimum load curve. Usefulness of this is demonstrated through both the steady and transient analysis. The proposed realization relies on an open-circuit scheme, and hence it is suitable for scenarios with low-cost and small-size requirements.