Scalable multi phase interleaved boundary mode PFC concept enabling energy- and cost efficient PSUs in the kW-range

A new concept of an interleaved multi phase power factor correction (PFC) rectifier which is operating at the boundary of discontinuous to continuous conduction mode (DCM/CCM boundary) is presented in this paper. DCM or DCM/CCM boundary mode operation of boost PFC topologies inherently avoids reverse recovery losses within the switching diodes which do occur at conventional CCM operation. This offers the possibility to employ cheaper Si- instead of high-performance SiC diodes (as required for efficient CCM operation) and, at the same time is even more energy efficient. Based on digital control this paper introduces a new extended concept of interleaving four or more boost phases in boundary mode operation yielding a modular PFC approach which is N times scalable with respect to the desired output power. Experimental results of a 1500W prototype PFC converter verify the proposed concept.