Design of a Modular Multilevel Converter Prototype for Research Purposes

As modular multilevel converters gradually become the preferred topology for many high-voltage and high-power applications, they are widely studied among researchers, who need experimental results to validate their studies. This paper discusses the design of a down-scaled modular multilevel converter prototype for research purposes, equipped with 30 full-bridge submodules and 10 kW rating. The design of this prototype is aimed at safety, flexibility, orderliness, and compactness. The challenges posed by the implementation of the converter prototype are examined, discussing the design of the prototype structure, the communication scheme, the full-bridge submodules, and the control hierarchy. The control system is based on Xilinx Zynq system-on-chip, which integrates programmable logic and processing system, allowing for extensive computational capability as well as simple reconfiguration. Experimental results showing the prototype in operation at nominal ratings are presented along with the devised graphical user interface.