Modeling of PWM converters in discontinuous conduction mode. A reexamination

Six existing methods for modeling PWM converters in discontinuous conduction mode (DCM) are reviewed. They are classified as either reduced-order or full-order model methods, and the methods in each group are shown to produce exactly the same averaged models. Using the concept of duty-ratio constraints, a new method is presented that leads to either the conventional reduced-order model or a new full-order model, depending on how the duty-ratio constraint is derived. With a boost converter as an example, the new full-order averaged model is shown to be more accurate than previously published models.