Family of zero-voltage-switching unregulated isolated step-up DC-DC converters

This study presents a family of zero-voltage-switching (ZVS) unregulated isolated step-up DC-DC converters. All switches can realise ZVS using the magnetising current of the transformer. The ZVS unregulated isolated step-up DC-DC converters are deduced from the basic ZVS cells using the magnetising current. The ZVS condition for the switches is given. The operating principle is analysed taking the ZVS push-pull forward (PPF) unregulated DC-DC converter as an example. The ZVS-oriented parameter design and example are presented. Finally, the experimental results from a 1 kW ZVS PPF unregulated DC-DC converter support the theory.