evaluation of soft switching step-down converters

The high step-down converters have many applications in industry, such as battery chargers, electric vehicles, telecommunication systems, etc. one of the problems of the conventional buck converters is the high voltage stress on switch and diode, in addition to their very narrow duty cycle, which limits the use of this converter. in order to solve this problem, the converter voltage gain should be reduced in order to increase duty cycle and prevent the switch current stress. for this purpose, various techniques such as coupled inductors, switched capacitors, etc. have been presented, which in addition to reducing voltage gain, have reduced elements voltage and current stress as well.