Modeling and Analysis of 5-Level Diode-Clamped and Flying-Capacitors Converters

Unique features of multi-level converters have recently nominated them as significant alternatives for solid-state power converting units, even in the low and medium power range. Some topological limitations such as DC side voltage balancing, however, have hindered the use of these converters as a handy means for various power conversion systems. Modeling and analysis is an essential step that can provide solutions and eliminate barriers to the use of multi-level converter topologies. This paper presents novel modeling and analysis approach for diode-clamped and flying capacitors multilevel converters. Independent of the modulation strategy, developed switching function models facilitate the study of the dynamic performance of both converter topologies. For flying-capacitor topology, this study presents small signal and averaged models in dqo rotating frame and based on these models a capacitor voltage balancing method is derived. Eventually, simulation results are provided to validate the proposed models and control system