Design of resonant soft switching converter

This paper presents an easy way to achieve soft switching in the chopper circuit. A near zero voltage switching is realized by adding an simple auxiliary resonant branch to a given chopper circuit. The turn off loss is reduced by connecting snubber capacitors in across the main switches. The design which is carried out is to realize ZVS at the rated load and near ZVS under all other load conditions. In this design on chopper, there is no additional voltage or current stress on the main switches and freewheeling diodes. Also, the auxiliary switch and auxiliary diode is subjected to allowable voltage and current levels. The operating principle and theoretical design analysis has been carried out for this chopper circuit using IGBT as main switches and this has been verified experimentally for 15 volts, 0.75 A at switching frequency of 45 K Hz .Under ZVS condition , the switching loss and dv/dt of the power device can be significantly reduced and the reverse recovery problem of diodes can be avoided as compared with hard-switching case.