A Review of Multilevel Converters With Parallel Connectivity

Cascaded-bridge converters (CBCs) and modular multilevel (MMCs) enjoy growing popularity mostly due to modularity scalability. Conventionally, their submodules allow only serial bypass operation so that the use of low-voltage components for high-voltage output becomes possible. Dually, submodule parallelization adds switched-capacitor behavior CBCs/MMCs has witnessed an upward trend in recent years. The salient advantages parallel comprise sensorless voltage balancing, capacitance saving, current sharing, system efficiency optimization. To capture advancement field, this article reviews state-of-the-art with connectivity, covering various submodules, macrolevel circuit topologies, implementation challenges, solutions, as well control optimization schemes. In particular, derives classifies macro-level topologies according basic H-bridge, asymmetrical half-bridge, symmetrical half-bridge submodules. On top that, introduces strategies simplification creation novel yet maintaining connectivity. We highlight role graph theory creating new analytic synthetic methodologies converters. addition, discloses relationship between connectivity