Resonant hybrid flyback: A novel topology with wide voltage range for DC microgrid applications

DC microgrids are becoming very popular due to the increasing deployment of distributed power generation systems. This presents new challenges for power converters, including how to achieve a wide range of input and output voltages in a small volume. State-of-the-art solutions include flyback -based and LLC-based converters. The first ones are bulky due to the large size of magnetic required to store the energy and their efficiency is limited by their capability to recycle the energy from parasitic elements. The second ones offer good efficiency but a limited range for input and output voltage, and may involve a large number of semiconductors. This paper studies the application of a novel topology, the asymmetrical half-bridge flyback, whose hybrid operation principle combines the advantages of forward and flyback converters while keeping a small number of switches. A design process to accomplish the outstanding requirements with the topology is presented. The theoretical analyses are supporter by a 240 W DC-DC prototype with an input range of 320 V-400 V and an output range of 5 V-24 V. A peak efficiency of 97.6 % is measured. The achieved power density of the converter is 65 W/inch3 uncased. Finally, a comprehensive numerical comparison with the LLC and flyback converters in the state of the art is carried out to show the potential of the proposal.(c) 2023 Published by Elsevier Ltd. This is an open access article under the CC BY-NC-ND license (http://creativecommons.org/licenses/by-nc-nd/4.0/).