Application of the commutated power concept to the classical isolated dc-dc converters

In order to define which power converter topology is the most adequate one for a given application, several aspects must be analyzed, such as cost, efficiency, size, and volume of the chosen structure. This paper extends the concept of the commutated power to classical dc-dc high-frequency isolated converters e.g. the one-switch and two-switch forward converters. It allows determining which topology has the best performance from the efficiency point of view considering the stresses in the semiconductor elements. Initially, it is necessary to obtain the expressions that provide the commutated power for each structure. By defining a given operating point and properly designing the converters, it is possible to estimate conduction and switching losses so that the concept is validated. Finally, the theoretical curves for the total commutated power are compared with the ones obtained in SPICE simulations, while relevant issues are discussed.