Novel aspects of an application of `zero´-ripple techniques to basic converter topologies

Based on a short summary of the theoretical basics of the zero-ripple current phenomenon a special zero input current ripple boost converter topology as presented in the literature is investigated. It is shown that the complete suppression of the input current ripple of the system is only given in a theoretical extreme case. For a practical realization only such a ripple reduction of the input current of the basic converter structure is obtained as corresponds to a simple low-pass input filter. This is proven by a detailed analysis also for a zero-ripple Cuk and for a zero-ripple SEPIC converter structure. Furthermore, it is shown that the realization of a zero-ripple Cuk or zero-ripple SEPIC converter is not linked to a magnetic coupling of the input and output inductors, but can also be achieved by a simple rearrangement of the elements of the basic converter structures. There one can see that the operating behavior of a zero input current ripple SEPIC converter is equivalent to the operating behavior of a buck-boost converter stage with LC input filter. Finally, the advantages and disadvantages of the different realization approaches of zero-ripple topologies are compared. Also, an outlook towards the planned further treatment of the topic is given