Multicell converters: derived topologies

Multicell converters were introduced ten years ago and, over this period, their properties have been thoroughly analyzed. Since then, this concept has lead to some other innovative topologies which are briefly presented in this paper. Different ways to introduce soft switching in multicell converters are investigated. The concept of distributing power over several switches, giving more degrees of freedom and using less passive components, is extended further with the stacked multiceli topology. Finally, direct ac-ac converters using the multicell approach are described. Index Terms--AC-AC power conversion, insulated gate bipolar transistors, multilevel systems, power electronics, power systems harmonics, resonant power conversion, variable-speed drives.