Enhancing Power Supply Performance using Parallel Flyback Converters

Abstract

Increasing of ac/dc power supply in smart grids, losses, power factor, and harmonic problems arise due to the presence of the converter. Therefore, this paper introduces a new topology of dual flyback converters operated in parallel to correct the power factor and reduces the harmonic and the losses. The first flyback converter is utilized as dc/dc stage used to regulate the output voltage by adjusting the duty cycle. While the second flyback converter is utilized as ac/dc stage, used for power factor correction and reducing the harmonics. The second flyback converter generates the input current to be in phase with the input voltage by regulating the variable frequency and switching period keeping the switching on-time fixed. This topology improves the voltage regulation even if the input voltage is reduced by approximately 60%, small circuit size, and reducing the total harmonic distortion. Besides, the circuit efficiency is increased by operating the dual converters at discontinuous current mode also recovering the stored energy in the leakage inductance of the coupled inductor. Finally, a prototype platform which has the ability to deal with universal input $80 \sim 260 \mathrm{V}_{\mathrm{rms}}$ is carried out. The measurements have verified the theoretical analysis to verify the effectiveness of the proposed system.