Zero-current-transition two-switch flyback pulse-width modulated DC-DC converter

This study presents a zero-current-transition (ZCT) two-switch flyback pulse-width modulated (PWM) DC-DC converter with a simple auxiliary circuit. The auxiliary circuit consists of an active switch and a clamp capacitor. The clamping diodes on the primary side of the two-switch flyback topology clamp the peak voltage across each main switch to the DC input voltage V_I. This feature of the two-switch flyback converter is combined with the ZCT feature provided by a simple auxiliary circuit connected on the secondary side of the transformer, which results in a soft-switching two-switch flyback converter. Circuit description, principle of operation, steady-state analysis and design procedure of the ZCT two-switch flyback converter are presented. Simulation and experimental results from a laboratory prototype are given to validate the theoretical analysis.