Development of a Modular Multilevel Cascade Converter Based on Full-Bridge Submodules with a Common DC Bus

The Modular Multilevel Cascade Converters (MMCC) present themselves as one of the solutions for high power and high voltage applications. Modularity and low voltage stress in each semiconductor are some of the features of this solution. This paper presents a study with experimental results concerning an MMCC composed by three full-bridge submodules with a common DC-bus and with low frequency cascaded transformers. Sharing the DC bus for each submodule al-lows for a simpler control algorithm as well as a simpler interface point with renewable energy sources or energy storage systems. Along the paper, it is presented the step-by-step methodology to obtain the main parameters of the elements that constitute the MMCC, namely the transformers equivalents model. Thus, it was possible to develop a more realistic simulation model, whose results obtained are very similar to the experimental results.