Abstract: A power factor of one is the main goal of any electric utility to have a better efficiency. Here, a single phase Uninterruptible power supply( UPS) is proposed which has a unity power factor for all linear and nonlinear loads. The proposed UPS uses an active PFC circuit to achieve unity power factor, a battery charger using Flyback converter, push pull converter is used as a battery discharger, a half bridge inverter for DC-AC conversion. Simulations are carried out for two conditions one for power factor variation in the mains and the other during power outage.Simulations are done using MATLAB/Simulink.

Keywords: UPS,Active PFC circuit, Flyback converter, Push Pull converter, half bridge inverter.