Design and Efficiency Improvement of Flyback Converter

Abstract

Dc-dc converter is the essential part of any payload for earth observation satellite. It provides low noise multi-output supply lines to different sub-systems of Electro-Optical payload such as detector signal processor, payload controller, output data formatter, circuit blocks, etc. These dc-dc converters provide regulated output lines with input side isolation, over current protection and telemetry signals. The project mainly aims to develop an isolated flyback converter with synchronous rectification in place of the diode rectification in order to reduce the losses occurring in the diode and increase the overall efficiency. The key requirement for the given dc-dc supply is for payload controller block which requires 3.8 V output voltage with 4 A of load current. The usage of a low voltage low Rds(on) MOSFET has become very much popular in place of the schottky diode in high current application due to the ample amount of loss reduction with good thermal management of entire system by reducing the cost of heat sink. The project objective includes design, mathematical analysis, simulation of the circuit the y-back converter in open loop and close loop system. The flyback converter in open loop and close loop with diode rectification and synchronous rectification has been designed, simulated. The close loop of diode rectification design has been printed on the printed circuit board (PCB) and tested from minimum load (0.4 A) to maximum load (4 A). The results of the simulation as well as experiments are shown and future enhancement are discussed.