A power factor corrected two stage switched mode power supply

Abstract

This paper deals with the design of a power factor corrected (PFC) two stage multiple output dc-dc converter based switched mode power supply (SMPS) to improve the power quality at ac mains. The SMPS system consists of two stages, in which first stage is a non-isolated dc-dc converter fed from single-phase ac mains through a diode bridge rectifier (DBR) and the second stage is a boost half-bridge dc-dc converter having five isolated outputs normally used in computer systems. Boost half bridge dc-dc converter is chosen as a second stage as it offers no dc offset in the current passing through the high frequency transformer (HFT) and so its design can be optimized. Proposed PFC two stage multiple output dc-dc converter based SMPS is designed, modeled and its performance is simulated in Matlab/Simulink environment. Simulated results are presented to validate the design of the proposed PFC two stage multiple output dc-dc converter based SMPS. Improved power quality is observed with almost unity power factor (PF) over a wide range of the load variation.