Wireless power transfer technology using full-bridge current-fed topology for medium power applications

This paper studies, explores and analyses a wireless power transfer (WPT) system using current-fed power electronics topology for electric vehicles and battery charging applications. The main contribution is analysis, design, and implementation of a current-fed technology for WPT application. The required resonance in both the transmitter and receiver coils is parallel (L)(C) and series (LC) type, respectively. A detailed mathematical analysis and design have been reported. Stiff DC current at the input of the inverter limits the inverter switch current stress. Also, the inductor in DClink provides natural short-circuit protection during inverter fault. It is quite important in such application. Resonant converter facilitates soft-switching at turn-off of the transmitter side switches. Also, soft-commutation of rectifier diodes reduces reverse recovery loss. Mathematical analysis is verified by simulation results using PSIM 9.3. A 420 W proof-of-concept lab hardware prototype is developed and the experimental results are demonstrated to validate the mathematical analysis and simulation results. The maximum efficiency of DC-DC WPT stage obtained from the proof-of-concept lab-prototype is close to 90% with a coefficient of coupling 18%. It is suitable for solar-to-vehicle and single-phase residential slow charging.