Characteristic evaluation of wireless battery chargers for electric vehicles

Wireless energy transfer systems (WETSs) using the inductive coupling resonant topology are receiving much attention in recent days for their numerous benefits, especially in charging the batteries of the electric vehicles. After reviewing the basic topology of the resonant WETSs, the paper defines a full set of figures of merit for the evaluation of the WETS characteristics. Then two key topologies of resonant WETSs are considered and their figures of merit are obtained. Afterwards, the characteristics of the resonant WETSs are evaluated and compared under varying load and coupling coefficient. Throughout the paper, the characteristics of the inductive WETSs are used as a point of referenc