Flyback DC-DC converter for full load range applications

This paper introduce soft switched flyback dc-dc converter with improved performance in terms of average efficiency, which is achieved by using variable frequency control employing zero-voltage switching in all load conditions. The soft switching is obtained over wide load line ranges by placing two smaller ac capacitors in both side of flyback transformer. The triggering for switches is given by measuring the magnetizing voltage and current. This method provides zero-voltage switching during on and off periods even at light load condition. The input reference current control is employed for obtaining constant output voltage. The new converter has four modes of operation which is described in this paper. The overall size of the system is reduced by increasing switching frequency. In order to provide constant output voltage, current reference control is employed. The simulation results under different load conditions are provided for verify the performance of the new converter.