This paper proposes an attractive direct line-frequency three-phase to a higher frequency single-phase AC/AC converter for a contactless electric vehicle charger. It removes a DC-link capacitor of a conventional AC/AC converter but has a smaller number of bi-directional switches than a matrix converter. It operates using injection and free-oscillation modes based on a zero-current switching mechanism. Circuit descriptions including a topology, commutations and a modulation strategy are discussed using some illustrations and diagrams. An on-off control is used to simplify control of resonant current. Simulation results to study some effects due to different coupling factor and load are then presented to show converter's performance and capabilities in contactless power transfer.

This paper explains a procedure on how to select resonant circuit components of a unique direct threephase to single-phase AC/AC converter for a contactless electric vehicle (EV) charger. The topology has a fewer bi-directional switches than a matrix converter and consists of a resonant circuit to utilize a zero-current switching (ZCS) mechanism. The selection goal was to realize a working prototype that does not violate each electrical component's limitations as well as has a low resonant damping ratio since the switches are driven based on a resonant current. Selection methods were based on graphical analysis of damping factor, resonant frequency, and primary circuit voltage and current characteristics derived from dynamic and steady-state models. Simulation results are then presented to validate the selection procedures.