Active clamped current-fed full-bridge integrating LLC converter with low current and voltage stress

This paper presents an active clamped current-fed full-bridge converter integrating LLC converter for fuel cell power system. In the proposed converter, the half-bridge LLC converter is integrated into the conventional active clamped current-fed full-bridge (ACCF) converter without additional active components and volume increasing. The proposed converter has a low voltage stress on the primary switches because a high step-up voltage conversion ratio can be realized with the low duty ratio D. In addition, due to two transformers structure, the conduction loss of main switches (S₁-S₄) is decreased by reducing of the peak current. Moreover, the turn-off and conduction losses of auxiliary switch (S_aux) are reduced by sinusoidal shape resonant current of the LLC resonant tank. To verify the performance of the proposed converter, the prototype converter with 36V-57V input and 400V/1kW output is implemented.