Minimizing coil power loss in a direct AC/AC converter-based contactless electric vehicle charger

This paper explains an optimum load analysis to reduce power loss in a direct AC/AC converter-based contactless electric vehicle charger. The converter has a fewer number of bi-directional switches than a matrix converter and it uses a resonant circuit to utilize zero-current switching. Output power and power loss depend on coupling factor and output load. A proper load value leads to low loss and maximum transmission efficiency. The value was derived using an iterative-based Weierstrass' method due to converter dynamic switching frequency. Other parameters such as link efficiency, link gain and power loss ratio were derived based on steady-state analysis. Simulation results are then presented to validate the theoretical analyses.