Interleaved Two-Switch Flyback Converter with Power Factor Correction for UPS Applications

This paper presents an interleaved two-switch Flyback converter operating in discontinuous conduction mode (DCM) for On-line Uninterruptable Power Supply (UPS) applications, capable of providing power factor correction (PFC) to a single-phase rectifier. It has as advantages: high power factor, balanced voltage and current shared through the semiconductors, which provides higher power processing, and a simple voltage control strategy. For the closed-loop control design, all parameters of the proposed converter are referred to the transformer primary side in order to obtain an equivalent non-isolated Buck-Boost converter, whose transfer functions are already consolidated in the technical literature. To verify the operation of the proposed topology, simulation results are provided with the following specifications: mains voltage input 220 V +/- 20% and frequency of 60 Hz, 250 V output voltage and output power rated at 1 kW.