Design and Implementation of a Modified Push-Pull Parallel-Series Resonant Converter

Abstract

This study presents a modified Push-Pull Parallel Resonant Converter (PPRC) for efficient wireless charging of electric vehicles (EVs), addressing key limitations of the conventional Series-Series Full Bridge Resonant Converter (SS-FRC). The proposed PPRC features a dual primary coil design that integrates the resonant tank, current-splitting transformer, and DC inductor—resulting in reduced component count, simplified circuit architecture, and lower implementation cost. A scaled 18W laboratory prototype was developed to validate the design. Experimental results showed a peak efficiency of 93.4% at a 1 cm air gap, significantly outperforming the SS-FRC’s 30% under the same conditions. Even at 3 cm and 5 cm gaps, the PPRC maintained superior efficiency. The converter also demonstrated improved soft-switching behavior, reduced voltage spikes, and enhanced waveform stability. Compared to existing push-pull and cascaded designs in literature, the PPRC offers comparable or better performance with less complexity. Additionally, the system incurs approximately 50% less conduction loss than the SS-FRC and operates at the SAE J2954 standard frequency of 85 kHz, making it suitable for current-generation wireless EV charging infrastructure. This work contributes a practical, cost-effective solution for next-generation inductive power transfer systems and offers valuable insights into converter topology design and energy optimization for smart EV charging.