Multilevel converters and derived topologies for high power conversion

This paper deals with techniques for series connection of semiconductors, of converters, or of commutation cells (including imbricated cells converters). The pros and cons of each technique are studied, as well as the specific know-how related to these techniques. A special point of interest concerns the possible improvement of input and output waveforms by increasing the apparent switching frequency and interleaving of the control signals. A few actual examples are given in the field of choppers and voltage-source inverters. Finally, current balancers for parallel associations are derived from the study of the voltage-balancing property observed in multilevel converters