An optimized variable-offset modulation technique for three-phase differential multilevel converters

In recent years many different modulation techniques have been introduced in order to support the growing number of multilevel converter topologies. These techniques have own disadvantages and some limitations. This paper presents a new optimized variable offset modulation technique for differential multilevel converters. The proposed modulation technique with achievement to full DC utilization reduces switching losses. For a comprehensive analysis the optimized offset has been compared with three conventional modulation techniques. Modeling and analysis are first introduced for a buck converter, and then are expanded to a general differential three phase multilevel converter. Furthermore, simulation verification are taken place on a 16 level cascaded multilevel converter in order to confirm the introduced technique as well as theoretical analysis. Simulations results verify the introduced modulation techniques.