A simple method to determine the performance of two-coil wireless power transfer systems without direct output measurement

Abstract

ABSTRACT Two-coil wireless power transfer systems are composed of two circuits tuned at the same resonance frequency, one containing the source and the other containing the load, where both are connected to each other by a mutual inductance. The power delivered to the load circuit is divided by the total power supplied by the source or, alternatively, by the maximum ideal amount of power that can be delivered to the load circuit, are usual figures of merit known as efficiency and power transfer capability, respectively. Additionally, a third figure of merit can be defined as the power dissipated at the source circuit divided by total power supplied by the source. It has recently been demonstrated that efficiency and power transfer capability are related to this recently defined third figure of merit. In this paper, a simple method is presented to monitor the power dissipated at the source circuit divided by total power supplied by the source, which allows a determination of the efficiency and/or power transfer capability without a direct measurement at the load circuit. The advantages and limitations of the proposed method are discussed in detail. Practical results are included to verify the proposal.