Two-phase interleaving configuration of the LLC resonant converter - Analysis and experimental evaluation

The LLC resonant converter has become quite popular in recent years and is more and more used for DC-DC converters within cost effective as well as high performance power supplies. Since in case of high output power and low output voltage it is typically beneficial to use paralleled converters, this paper investigates the load sharing issue of two LLC converters connected in parallel and operated with interleaved driving signals. Value deviations of all the three passive components of the LLC resonant circuit are considered and the worst case scenarios are highlighted. Moreover a simple and practical solution to the load sharing issue applicable to a high power server PSU is presented, including measurements on a prototype to support the theoretical analysis.