A modified control scheme to alleviate DC voltage stress in active clamp PFC AC/DC converter with universal input

A modified control scheme is proposed to alleviate bulk capacitor voltage stress in active clamp bi-flyback power factor correction (PFC) AC/DC converter with universal input. In the proposed control scheme, the auxiliary switch is turned on with a fixed narrow pulse-width, rather than the conventional complimentary signal of the main switch. As a result, the proposed technique will substantially suppress the DC voltage well below 400 V under the entire input range. The improved performance was experimentally verified through a 28 V, 5.35 A prototype.