Wireless Power Transfer System Design for Electric Vehicle Charging Considering A Wide Range of Coupling Coefficient Variation Depending on the Coil Misalignment

Abstract

Wireless power transfer (WPT) system is an area where many studies have been conducted for electric vehicles (EV s) charging. Loosely coupled transformer with a wide range of coupling coefficient (k) value is a main factor of WPT system. Coupling coefficient variation which is highly sensitive to the coil misalignment causes a change in overall system performance. Therefore, this paper introduces design method of WPT system insensitive to coupling coefficient variation depending on the coil misalignment. The actual coupling coefficient variation is discussed using the coils shown in SAE J2954 as standard for electric vehicle charging. Charging current (i_{ text{batt}}) control methods based on the connection of post-regulator and their effects on the system performance are also studied. Finally, efficiency analysis of designed WPT system from inverter to rectifier according to control methods is discussed.