Adaptive link capacitor voltage control for server power system

An adaptive link capacitor voltage variation control method for server power supply is proposed. In this paper, to increase the efficiency under light load condition, the proposed scheme adjusts nominal link capacitor voltage with the consideration of the hold-up time requirement. Thereby, the effective duty ratio of DC/DC stage can be expanded and we can save the power loss. Therefore, power losses on the major components of both PFC stage and DC/DC stage can be decreased when the proposed scheme is applied. The analysis and design considerations are presented. To confirm the validity of the proposed control scheme, experimental results from the 1200 W prototype power supply are presented.