State space models for current programmed pulse width modulated converters

Abstract

State space models are derived for pulse-width-modulated power converters operating at constant switching frequency under current programmed control. One model neglects the sample and hold effect of the current loop and is therefore representative of the traditional approach taken to modeling current programmed converters. The order of the model is the same as that of the power stage. A second state space model which incorporates the sample and hold effect is derived. The order of this model is two higher than that of the power stage. A comparison of the two models clearly demonstrates the superiority of the second modeling approach. As the models are in state space form they may be quite readily used in a computer-aided-design package for general power converter analysis and design, to determine all transfer functions and associated pole/zero locations of interest.