Derivation of Flying-Type Multilevel Converter Topologies with a Voltage-Level Extension Method

Multilevel converters have become more and more popular in various industrial applications. One of the important research topics for multilevel converters is how to obtain new and existing topologies. This paper has presented a voltage-level extension (VLE) method, which can derive a series of flying-type multilevel converters in a simple way by extending the existing multilevel converters. This paper derives some new flying-type converters and more multilevel topologies can be obtained through the proposed VLE method. A novel flying-type converter is analyzed in detail as an example. A new redundant level modulation (RLM) is used to control the capacitor voltages successfully, where conventional methods cannot achieve. The simulation and experimental results are provided to verify the corresponding theoretical analysis. Based on the VLE method and the RLM method, it is expected more new multilevel topologies can be invented and used for emerging industrial applications.