Duty Cycles Control in Three-phase Multilevel Converters for Switching Loss Reduction

There are various modulation techniques for different topologies of multilevel converters that every technique has its own advantages as well as disadvantages in practice. This paper develops a new efficient modulating technique for three-phase differential multilevel converters that is based on using the concept of offset optimization and duty cycles control in a simple buck converter. The proposed modulation technique with achievement to full DC utilization reduces switching losses. To evaluate the suggested method, the modulation technique with three other conventional methods are implemented on an asymmetric 16–level converter. Comparative analysis for the experiments confirms that applying the presented technique on multilevel converter leads lower switching losses, better THD as well as optimal usage of the DC-link.