A New Method for Calculating the Transfer Functions in Quasiresonant Converters

Abstract

A matrix method for deriving the audiosusceptibility and the control to output transfer functions in quasiresonant converters (QRCs) is presented. The method is based on the state-space description of the parent converter and it has the advantage of generality in the sense it can be applied to any topology. Moreover, it can be easily absorbed in MATLAB under Symbolic Toolbox, substantially reducing the calculation effort and time. Using this method the control to output transfer function of the QRC Cuk converter is calculated for the first time. The method is verified compared to other tools and perfect agreement is observed for second order classical converters.

Keywords

• canonical models
• pulse-width modulated converters
• quasiresonant converters
• small-signal
• state-space averaging