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DESIGN OF A FLYBACK CONVERTER FORIMPROVED CONVERSION EFFICIENCY AND
REDUCED NO-LOAD POWER LOSS.
Sachin George Thomas
Applied Electronics and Instrumentation
College of Engineering Trivandrum
Guided By : Ms. Chandini G.S.
October 30, 2015
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Overview
Introduction
Motivation
Problem Definition
Methodology
References
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Introduction
Most of the portable products in our lives are powered by d.cvoltage and ac-dc adapters are used for conversion from theac voltage to the required dc voltage.
The ac-dc adapter is composed of a rectifier, a dc buscapacitor and a dc-dc converter.
The dc-dc converter can be of the isolated type whichincludes flyback converters and forward converters or thenon-isolated type .
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Introduction
The flyback convertor which comes under the category of isolated converter is of particular interest in this work.
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Motivation
Compared to the flyback converters , the forward convertersrequires a reset winding , an output inductor and a free
wheeling diode which causes larger volume and more cost.
Even the conventional flyback converters suffers from lowconversion efficiency and high no-load power loss.
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MOTIVATION
Furthermore , the parasitic capacitance of the transformerbetween the primary and secondary windings needs to bereduced inorder to keep the common voltage under control.
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Problem Definition
Requirement for a flyback converter with improved conversionefficiency, reduced no-load power loss , and a power factorcorrection circuitry.
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Methodology
Design of the lossless snubber circuit for suppressing thevoltage spikes
fig : Flyback convertor with RCD snubber
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Methodology
Design of the energy recovery winding to recycle the energy
discharged from the gate -source capacitor of the main switch.
Check for the feasibility of a Power Factor Correction (PFC)circuitry and if possible integrating the same.
Integration of all the circuits .The simulation can be carriedout in SIMULINK/SIMPLIS.
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References
Ray-Lee Lin and Shih-Ho Hsu , ”Design andImplementation of Self-Oscillating Flyback Converter
With Efficiency Enhancement Mechanisms” IEEETransactons on Industrial Electronics,Volume 62,Issue11,pages 6964-6955,November 2015
J.Y.Guo, ”Design and implementation of forward-flyback
converter with feed forward mechanism for mobile
phone”M.S thesis,National Cheng Kung University,May 2013
Hao Ma , Yue Ji and Ye Xu, ”Design and Analysis of
Single-Stage Power Factor Correction Converter With a
Feedback Winding” IEEE Transactons on PowerElectronics,Volume 25,Issue 6,pages 1460-1471,June 2010
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The End