Isolated Three-Phase Soft-Switching DC-DC Converter With Reduced Voltage Stress on Rectifier Diodes for Off-Board Chargers

This article presents a novel high-frequency isolated dc–dc converter feasible for level 2 and level 3 electric vehicle (EV) chargers. It exhibits pulsewidth modulation characteristics on high-frequency rectification semiconductors, enabling the use of low-voltage diodes. The steady-state analysis is derived in terms of the operating stages, voltage gain behavior, soft-switching regions, and loss mechanism. A laboratory prototype is designed with a rated power of 10 kW and dc output voltage ranging between 200 V and 920 V, aiming to validate the theoretical assumptions. Under nominal operating conditions, the maximum obtained efficiency is above 98% while presenting good performance across the entire operating range for EV chargers.