Parameter trade-off between electric load, quality factor and coupling coefficient for performance enrichment of wireless power transfer system

Abstract

Accomplishing high efficiency with acceptable output load power is a formidable design challenge in resonant wireless power transfer (WPT) system employed for charging Electric Vehicle (EV). This necessitates a trade-off among the assorted parameters like coil quality factor, coupling coefficient, and electric load for performance enrichment of resonant WPT system. It is realized that the high value of quality factor does not ensure higher power transfer efficiency, but it is largely influenced by the electric load. For each coupling coefficient there exists an optimum load for which maximum power can be delivered. It is also perceived that for a fixed vertical separation gap of the coils, increasing receiver coil quality factor has no profound effect on the output load power as well as efficiency. The circuit model based analytical results agree well with the comprehensive experimental ones and elucidate the strategic design guidelines for a competent wireless electric vehicle charging system.