Reduced redundant power processing concept: A reexamination

The Reduced Redundant Power Processing (R2P2) concept was introduced in literature with the aim of improving the overall conversion efficiency of two-stage high-quality rectifiers, capable of providing high power factor and tight output voltage regulation, but it has been applied to DC-DC conversion too. The idea is to have one converter processing only a fraction of the total output power, the remaining part coming directly from the other converter or, in DC-DC converter applications, directly from the input source. This idea, that is at first sight very appealing, has been implemented in different ways using basic converter topologies. In this paper, it is demonstrated that most of the R2P2 implementations that have been proposed in literature are actually not able to achieve a better efficiency compared with a full power processing, because they do not represent a correct implementation of the concept. Indeed, it is possible to demonstrate that they are equivalent to solutions that process the entire load power. It is demonstrated that it is possible to develop R2P2 structures that achieve better efficiencies compared to the full power processing counterparts, but only at the expense of more complicated topologies, and for specific applications in which the processed power is a tiny fraction of the overall output power.