Voltage stress suppression method using coupled transformer for phase shift controlled converter

A new method to suppress voltage stress of switches and transformers is proposed for phase shift controlled dc-dc converter. In the proposed method, two transformers are used and secondary windings are connected in series, which allows zero voltage switching of the switches. Since switching nodes are coupled together by transformer, the locations of them do not matter, so series connection of power switches is capable. The main advantage of the proposed method is reduced voltage stress that is decreased a half of that of conventional converter. Since switches with small on resistances can be used, power efficiency is also improved.