A Secondary-Side Phase-Shifted Bidirectional Soft-Switching DCDC Converter Employing Step Voltage Switching for Eliminating Device Voltage Overshoot

In this article, we present a modulation strategy for bidirectional power flow for the step voltage switched (SVS) secondary-side phase-shifted (SPS) dc-dc converter that eliminates the device voltage overshoot problem. The voltage overshoot problem arises due to the resonance between the transformer leakage inductance and the output capacitance of the current-fed side metal-oxide-semiconductor field-effect transistor of the converter. Many snubber/clamp circuits were discussed in the literature to suppress this voltage overshoot. However, the power loss in these clamp circuits will affect the converter's efficiency. The bidirectional SVS SPS dc-dc converter presented in this article eliminates the voltage overshoot problem instead of suppressing it and, therefore, nullifies the need for a voltage clamp circuit. And most of all switching devices undergo soft-switching (either zero voltage switching or zero current switching). These factors result in achieving a peak efficiency of 96%. The proposed topology is tested for 1.7 kW at 100 kHz switching frequency with voltage-fed side voltage being 72 V and current-fed side voltage of 400 V. The results obtained prove the feasibility of the proposed work.