Computer-Aided Analysis of Regulated Switched Power Supplies with Unified Baseband Models for Continuous and Discontinuous Conduction Mode

The conception of baseband modelling provides an efficient method for the computer-aided analysis of switched mode power supplies. The basic converter models derived by Cuk and Middlebrook enable the investigation of power supplies in time- and frequency-domain with closed loop as well as open loop configurations using a general purpose circuit analysis program, This paper deals with large signal baseband models for flyback and forward converters which - in addition - allow a unified treatment of both continuous and discontinuous conduction mode operation. The justification of the derived models is demonstrated by numerical comparison of the model´s frequency response with closed form solutions for linear switched networks (implemented in a special purpose switched capacitor circuit analysis program). Results of comparable time domain simulations are presented which are based on the state space representation of periodically switched systems.