Small-signal analysis of parallel power converters

Abstract

A small-signal analysis and modelling approach is developed for parallel power converter modules. The small-signal model of parallel buck converter modules is developed in detail to demonstrate the modelling approach. It is shown that a multiple power converter module system can be reduced to an equivalent single-module system to facilitate system analysis and design. Different forms of current-mode control and their applications to single and multiple modules are discussed. Detailed procedures are then developed for the design of a current-mode control circuit for single or multiple power converter modules. The applications of the design procedures and the analysis results are demonstrated for several converter design examples. The use of a secondary output filter on the output of power converters is discussed. The effect of this filter and its interaction with the stability and closed-loop performance of the converter are analyzed in detail.