Is loss free modulator the central component of switching power electronics? application to flyback structure

To account for time variation in equivalent circuits, we introduce a macro component: the loss free modulator (lfm). In practice, it is made of a chopper inserted between two loss free smoothing filters so it behaves as an ideal transformer with a time varying voltage ratio. That way, a converter can be presented as a set of inductors and capacitors, only required to temporally store energy, associated to one or more lfm. As a first illustration, behavior of modulated inductors and capacitors, made of an lfm loaded respectively by an inductor or a capacitor, is derived and some surprising applications of these circuits are described. Then, it is shown that, whatever its structure, a power factor corrected ac-dc converter must store a minimum energy to work properly. In most of practical designs, this minimum is overcome by a 10 ratio. Lowering this energy close to its minimum, offers an opportunity to use the lfm concept. Owing to two lfm, one of which being digitally controlled, the goal is reached. Simulated and measured results are presented and discussed. Finally, the approach followed in this paper is summed up and it is suggested that it can be useful for many converter designs.