A high gain high efficiency and compact isolated sepic DC-DC converter

Abstract

A Sepic converter for high power and the high gain application has been proposed in this paper. Generally, due to magnetic limitation, a single Flyback transformer cannot handle high power. Hence, for relatively higher power applications, people prefer the use of interleaved Flyback converter structures. But the interleaved Flyback converter requires the use of two switches. The interesting feature of the proposed converter is that power handling of both the Flyback transformers can be done by a single switch of same voltage rating as that of the conventional interleaved Flyback converter. Hence the solution requires less number of components resulting in a compact and low-cost structure. The voltage rating of the power electronic devices used is much less than the total output voltage in the ideal condition. This results in low conduction loss and high efficiency of voltage step-up conversion. As the output of the two Flyback sub-converters is connected in series to boost the voltage level, the requirement of the turn's ratio of each transformer is less if we compare the turn's ratio requirement of the interleaved Flyback converter used presently. This result in tighter coupling between the windings of the transformer, which reduces the value of the leakage inductance, which causes high losses and unwanted voltage spikes along with radiated noises affecting various part of the circuit and the surrounding. Detailed Explanation of the working of the circuit is given through the modes of operation and a detailed steady-state analysis has been done. The analytical results are verified through the simulations were done using Matlab-Simulink software.