Modelling, control and realisation of the single-ended forward converter with resonant reset at the secondary side

This study presents modelling, control and realisation of a forward converter with resonant reset at the secondary side. The transformer reset occurs through the resonance between its magnetising inductance and the resonant capacitor during the switch off time. The mechanism is similar to a forward converter with resonant reset at the primary side. The only difference is that the transformer-stored energy can now be partially delivered to the load instead of being dissipated in the switch at turn-on. Another advantage compared with conventional forward converters is the lower switch voltage stress and transformer size, which are theoretically proved to be lower. Furthermore, this converter can be used as a step-up and step-down converter. To verify all the mentioned features, simulations were carried out and a 600 W prototype was implemented experimentally, reaching a maximum efficiency of 94.3%.