Application of Zero Overvoltage Switching in Switched Mode Power Supplies

With the increasing adoption of wide bandgap (WBG) semiconductor devices, new methods are required to manage their faster switching characteristics, particularly addressing voltage overshoots caused by fast switching. Zero Overvoltage Switching (ZOS) leverages circuit resonances during the turnoff process to nearly eliminate voltage overshoot, making fast switching essential and reducing switching losses to a minimum. This paper explores two methodologies for a novel ZOS current control in DC/DC converters: Variable Frequency Forced Continuous Conduction Mode (VF-FCCM), while efficient under specific conditions, suffers from turn-off overvoltages and significant AC losses due to high current ripple, making it unsuitable for low-load operations. In contrast, Valley Switching Discontinuous Conduction Mode (VS-DCM) mitigates overvoltage spikes and switching losses, maintaining a consistent ripple but struggles with low-load scenarios due to frequency limitations. Both methodologies were simulated and tested on a lightweight aircraft DC/DC prototype. The findings suggest VS-DCM as a promising candidate for future development.