High efficiency single phase AC/DC converter with high power factor and tight output voltage regulation

This thesis investigates improvements possible in a single phase switch mode AC/DC converter by using a non dissipative snubber. A parallel connected single phase power factor corrected AC/DC converter topology using two flyback converters is implemented. Flyback converter 1 with a DC/DC stage regulates the output voltage and transfers 55% of the power. Flyback converter 2 with a power factor correction stage shapes the input current to improve the power factor and transfers the remaining 45% of power. The parallel connected scheme provides tight output voltage regulation while maintaining a high input power factor. The power factor plays a key role in many kinds of electronic equipments since improving it lowers the electricity bill.;The efficiency of the parallel connected single phase switch mode AC/DC converter is improved by adding a non dissipative snubber circuit. The switching losses at the MOSFET of the flyback converter contribute a major part of the total losses in the system. By adding a non dissipative snubber to the two flyback converters, the voltage stress on the switches can be reduced thereby reducing the switching losses, and the efficiency of the system is improved. The efficiency improvement calculation with supporting simulation graphs is shown. The simulation in this thesis is done using the simulation software LTSPICE.