Considering Source Dynamics in Computer-Aided Parameteric Average-Value Modeling of PWM Converters

Average-value modeling of PWM converters has received significant attention in the literature, wherein the computer-aided methodologies appear to be particularly promising. A numerical procedure has recently been proposed that avoids excessive analytical derivations and results in fairly accurate dynamic average-value models that include effects of parasitics. This methodology is extended here to account for input source dynamics. In particular, the so-called duty-ratio constraint and correction matrix are expressed as nonlinear functions of the duty cycle and the new quantity defined through the averaged dynamic impedance of the switching cell. The resulting model is shown to be accurate in predicting large-signal time-domain transients and small-signal frequency-domain characteristics