Control and modelling of quasi-resonant converters

Student thesis: Doctoral Thesis


This document is a statement of the independent and original contribution to knowledge represented by published work in partial fulfilment of the requirements of the University of Brighton for the degree of Doctor of Philosophy (by publication).

The results of research conducted between 1990 – 1999 on the dynamic modelling, control and simulation of single and multi-output resonant switched mode converters is presented in this thesis. The research has a common theme of analysing, designing, controlling and simulating resonant switched mode circuits with a common goal of reducing the volume and mass of dc power supplies.

After establishing the present capability of Switched Mode Power Supplies (SMPS) and in particular resonant converters, these studies concentrate on the dynamic modelling and control of quasi-resonant converters (QRCs).

An investigation into the dynamic modelling and control of switched mode QRCs is reported. The small-signal models are derived through the dynamic analysis of QRCs circuits and are used to design controllers for single and multi-output QRCs. The principles of these designs are given and illustrated with examples.

The steady-state analysis and small-signal analysis of a dual-output forward zero-current QRC is presented. Steady-state analysis of the circuit is used to design the resonant tanks, the output filters and the transformer; small-signal analysis is used to design the control circuit for this converter.

In addition, a method of modelling dc-dc converters is developed using a computer-aided design package, SIMULINK. The SIMULINK modelling technique developed in these studies requires less CPU time compared to PSPICE when simulating complex dc-dc converters complete with their control circuits.
Date of AwardAug 2001
Original languageEnglish
Awarding Institution
  • University of Brighton
SupervisorAlan Piercy (Supervisor) & Chris Garrett (Supervisor)

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