Single-Stage AC/DC Boost–Forward Converter With High Power Factor and Regulated Bus and Output Voltages

Unlike existing single-stage AC/DC converters with uncontrolled intermediate bus voltage, a new single-stage AC/DC converter achieving power factor correction (PFC), intermediate bus voltage output regulation, and output voltage regulation is proposed. The single-power-stage circuit is formed by integrating a boost PFC converter with a two-switch-clamped forward converter. The current stress of the main power switches is reduced due to separated conduction period of the two source currents flowing through the power switch. A dual-loop peak-current-mode controller is proposed to achieve PFC and ensure independent bus voltage and output voltage regulations. Experimental results on a 24-V/100-W hardware prototype are given to confirm the theoretical analysis and performance of the proposed converter. The converter has conversion efficiency ranging from 86% to 92% at full-load condition.