Primary-Side-Controlled AC-DC Single-Stage Active Clamp Flyback Converter

Abstract

In this study, a primary-side regulation controller for single-stage active clamp flyback (ACF) converter is proposed. The relationship between the primary-side current and the secondary-side current is investigated. By sensing midpoint current of power switch and auxiliary winding voltage in primary side, the output voltage and current estimations are achieved. Also, the dual loop controller with the inner loop and outer loop for power factor correction and output voltage/current regulation, respectively, is proposed. The proposed control method is verified by building an experimental prototype with rated power of 100 W (20 V/5 A), universal input voltage of 90-264 V ac , and switching frequency of 60 kHz. The micro-controller dsPIC33CK256MP508 is used to realize the proposed controller. The experimental results show that the output voltage and current control errors are within 7.15% and 6%, respectively. Moreover, the power factor is higher than 0.92, and the highest efficiency achieved is 91.2%.