The modelling of quasi-resonant and multi-resonant boost converters

Szabo, A, 1998. The modelling of quasi-resonant and multi-resonant boost converters. PhD, Nottingham Trent University.

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Abstract

This thesis presents a method for the modelling of quasi-resonant and multi-resonant boost converters using the averaging technique.

The concept of characteristic functions is introduced, which allows the derivation of a unified model of all classes of boost converters - multi-resonant, quasi-resonant and pulse-width-modulated. The characteristic functions describe the average behaviour of switching devices in a dc-dc converter. Quasi-resonant converters have one characteristic function, which can be seen as the equivalent duty ratio of the converter, and its analytic expression is determined. Multi-resonant converters have two characteristic functions and a numerical method is developed to evaluate them.

The dc (steady-state) model of quasi-resonant and multi-resonant boost converters is related to the conventional pulse-width-modulated boost converter. The expression of the voltage conversion ratio of resonant boost converters is obtained from the pulse- width-modulated converter by replacing the duty ratio with the characteristic function. The dc models are verified by simulations using PSPICE and hardware implementation.

The small-signal model of resonant boost converters is obtained in circuit form. In this model, the switching devices are represented by controlled voltage and current sources, whose coefficients depend on the characteristic functions of the converters. The small- signal control-to-output and line-to-output transfer functions of the quasi-resonant and multi-resonant boost converters are derived. Their expressions are compared to the ones of the pulse-width-modulated converter. It is shown that the resonant elements do not increase the order of the small-signal model, therefore, the well-known methods for the design of the feedback loop of pulse-width-modulated converters can be applied to resonant converters.

This approach is extended to the buck and buck-boost converters and a general unified method for the modelling of quasi-resonant and multi-resonant dc-dc converters is presented.

Item Type:	Thesis
Creators:	Szabo, A.
Date:	1998
ISBN:	9781369323436
Identifiers:	Number Type PQ10290094 Other
Divisions:	Schools > School of Science and Technology
Record created by:	Linda Sullivan
Date Added:	02 Oct 2020 08:32
Last Modified:	28 Sep 2023 09:58
URI:	https://irep.ntu.ac.uk/id/eprint/41093

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