Cascaded- and Modular-Multilevel Converter Laboratory Test System Options: A Review

The increasing importance of cascaded multilevel converters (CMCs), and the sub-category modular (MMCs), is illustrated by their wide use in high voltage DC connections static compensators. Research being undertaken into these complex pieces hardware software for a variety grid support services, on top fundamental frequency power injection, requiring improved control non-traditional duties. To validate results, small-scale laboratory prototypes are often required. Such systems have been built many research teams around globe also increasingly commercially available. Few publications go detail construction options prototype CMCs, there lack information both design considerations lessons learned from build process, which will hinder best application important units. This paper reviews options, gives key examples leading teams, summarizes knowledge gained development test rigs to clarify when constructing laboratory-scale CMCs.