Averaged modeling of switched DC-DC converters based on Spice models of semiconductor switches

A generalization of the model of PWM (Pulse Width Modulation) switch according to Dijk et al. [1] for averaged modeling of switched DC-DC converters is proposed. The original model by Dijk consists of controlled current and voltage sources for modeling the ideal active and passive switch. A new model, proposed in this paper, is based on the same strategy, but it takes into account the nonideal V/I characteristics of semiconductor switches. The rules for determining the parameters of controlled sources from converter state variables remain the same as in [1], but a special procedure provides for the extraction of these parameters directly from PSpice models of concrete transistors or diodes, representing the active and passive switches. The way this model is compiled allows for the influence of parasitic ESRs of the capacitors in the circuit such that the resulting equations are equivalent to the averaged state space equations. The procedure of PSpice modeling and the results of computer simulation of boost converter are shown.