An unified topological approach to modelling of switching dc-dc converters

An unified continuous small-signal modelling technique of switching dc-dc converters in duty-ratio programmed mode is developed. This technique is based on the unified choice of tree and chord-set in topological graphs representing converter structure in consecutive intervals of switching period. The averaged and linearized topological relationships are easily recognized in the form of electronic equivalent circuit model. The unified approach to derivation of steady-state operating point is presented. Finally, the design-oriented canonical ac circuit model is established and the general expressions for its coefficients are given. The Cuk converter is modelled to illustrate the usefulness of the proposed technique.