Soft-Switching Bidirectional Converter for Electric Vehicle Power Interfaces

This article proposes a bidirectional buck–boost converter for electric vehicle (EV) charging applications, featuring a single-auxiliary switch to achieve zero-voltage switching (ZVS) and enhanced efficiency across a wide operating range. The auxiliary network, composed of a resonant inductor, capacitor, and diodes, enables ZVS in both buck and boost modes regardless of load, duty cycle, or power direction. The converter operates in continuous conduction mode on the low-voltage side with constant-frequency pulsewidth modulation (PWM) control. All switches benefit from soft-switching under light and heavy load conditions. The topology preserves voltage and current stress on the main switch while reducing switching losses and component count. Theoretical analysis, dynamic modeling, and experimental validation using a 48-/160-V, 200-W prototype confirm the effectiveness of the proposed approach.