NFC transmitter coil placement to minimise degradation of A4WP wireless power transfer efficiency

Abstract

The wireless power transfer (WPT) transmitter (Tx) coil and near field communication (NFC) Tx coil are combined in one transmitter. The coil system consists of an NFC Tx coil and a WPT coil system that includes an A4WP Tx coil and an A4WP receiver (Rx) coil. The WPT coil system uses a magnetic resonance method. A4WP coils are tuned to resonate at 6.78 MHz. The NFC Tx coil is tuned to resonate at 13.56 MHz and positioned between the A4WP Tx and Rx coils. Moving the position of NFC Tx coil near the A4WP Tx coil, interference phenomena among coils are investigated and changes of WPT efficiencies are measured. Optimal placements of the NFC Tx coil that minimise the loss of WPT efficiency are determined based on the analysis data.