Isolated step-down DC-DC converter based-on push-pull topology with reduced voltage stress of the primary side transformer windings

This paper presents new results of a push-pull step-down converter with reduced winding voltage stress. The concept of the system, where an input voltage divider and two branches were used to supply the primary windings was demonstrated. This allows to dv/dt between windings reduction and capacitive current decrease. Operation with two switching sequences is proposed and presented, which allow for a lower maximum value of the magnetic flux, or a lower frequency of core remagnetisation. Selection of switching method may be used to optimize the converter. The natural voltage balance of the input divider and the ability to operate the system with two sources were also demonstrated. The results of efficiency and power losses balance are presented, as well as waveforms for the analysed concepts of converter configuration and control, such as current, voltage and magnetic flux.