Optimised modulation technique for three-phase differential multilevel converters with fundamental frequency switching strategy

In recent years, various modulation techniques have been introduced for different topologies of multilevel converters; every technique has its own advantages as well as disadvantages in practice. This study presents a new optimised variable offset modulation technique for differential multilevel converters that is based on using the concept of optimised offset in a simple buck converter. This modulation technique with achievement to full DC utilisation reduces switching losses. The resultant switching pulses reduce the switching power losses for multilevel converters compared with the conventional techniques. To evaluate the suggested method, the optimised offset has been compared with three conventional modulation techniques. All four modulation techniques are implemented on a reduced structure 16-level converter with fundamental frequency switching strategy. Comparative analysis for the experiments confirms the capability of the presented technique in efficiency enhancement as well as high quality of the output voltage and loss reduction.