Date of Award


Document Type

Master Thesis

Degree Name

Master of Engineering (Research)


Electrical & Electronic Engineering

First Advisor

Dr. Noel M. Barry


Isolated power converters are primarily used in applications where electrical galvanic isolation is required for safety purposes. They are also used in applications, which require various output voltages level. They have been studied from many different aspects, but in this thesis the fundamental circuits of the flyback, the forward and the half-bridge converters are studied and compared extensively, with regard to their dynamic performance.

This analysis will lead us to a better understanding of their behaviour, that is a crucial point in the selection of each topology for a particular application. Moreover, the dynamic response of each converter is different; this aspect is investigated as well.

An analysis of the behaviour and the dynamic response of each topology operating in both, the continuous and the discontinuous conduction mode of operation is presented. This is done by modelling the primary parasitic elements of the converter components to obtain as faithful as possible responses that correspond with the real case.

The steady-state dc voltage conversion ration, and the small-signal ac control to output and the small-signal ac line to output transfer functions Bode diagrams response of the three converters, m both modes of conduction, are presented. Our analysis utilises Maple and Matlab, to obtain the state descriptions of the converters and then calculates the average plant response in the two different modes of operation.

A unique table is presented which contrasts and compares the small-signal ac transfer functions of each of the topologies in ideal and non-ideal situations, in a coherent and user friendly manner.

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