Analysis on normalized distance and scalability in designing wireless power transfer

Wireless power transfer (WPT) technology has been applied in a wide range of applications. However, directly comparing dissimilar designs with respect to PTE and transfer distance is misleading due to the differences in the design parameters. The term normalized distance has been proposed to compare diverse designs with different coil sizes and transfer distances. This paper presents an analysis on normalized distance and scalability of WPT systems considering maximum power transfer efficiency, transmitter (Tx) and receiver (Rx) coil radii and transfer distance. Merits of normalized distance and its limitations are investigated. Results in this paper propose to define more generalize term for normalized distance incorporating transfer distance, Tx and Rx coil radii, ratio between Tx, Rx coil radii and number of turns in each coil.