A new integrated high step‐up quasi‐resonant flyback‐forward converter

Abstract

SummaryThis study presents a new high step‐up, high efficiency, flyback‐forward converter. The proposed converter employs 2 transformers, operating in flyback and forward modes at different intervals, to achieve the high voltage gain. In favor of high power density, transformers have been installed on 1 core. Furthermore, all switches are turned on under zero voltage switching condition, and all diodes are turned off under zero current switching condition. Also, the proposed converter utilizes resonant operation that leads to a reduction in switching loss, turning the converter to a highly efficient one. A 150‐W prototype has been implemented to verify the theoretical analysis, and a complete analysis has been done to investigate the effect of transformers integration.

Design, modelling, and implementation of a modified double‐switch flyback‐forward converter for low power applications

“…The circuit of [23] The circuit of [24] The circuit of [33] The circuit of [7] The proposed circuit number of components…”

“…However, the number of required windings is still a disadvantage for this topology. According to the reported experimental result of [33], the withstand voltage of each switches must be , which is three times greater than our proposed converter. The proposed flyback‐forward converter in [7] has a resonant controller with high efficiency; however, it requires two separate transformers which will make it too expensive.…”

“…Combining the flyback and forward converters make a new topology providing the advantages of both flyback and forward converters and eliminates some issues [7,[23][24][25][26][27][28][29][30][31][32][33]. Also, the model of the energy transferring from the primary to the secondary side changes by using the flyback-forward converter.…”

“…Modifying the configuration of components on the secondary side of the transformer helps to achieve the claimed solution. Salehi Dobakhshari et al [33] introduce a new modified flyback-forward converter with a softswitching controller improving the efficiency of the classical flyback-forward converter. However, the number of required windings is still a disadvantage for this topology.…”

“…It requires single secondary side windings. This solution reduces the number of secondary side windings of the proposed converter in [24], and in similar condition, the proposed DSFF needs a fewer number of windings than the other DSFF [33]. Adding an auxiliary winding for designing the self‐biasing circuit and multiple windings for having various output voltage level will not have the adverse effects of the previous DSFF on the transformer size.…”