A Novel Modular Converter-Transformer for AC/DC, DC/AC and DC/DC HV Applications

This paper proposes a novel solution for modular converters integrated with power transformers, intended for high voltage interconnections between AC and DC lines or between two DC lines. This new family of devices aims at ensuring the same advantages in terms of harmonic content typical of modular multilevel converters, while proposing a strategy for opening fault currents using the same protections adopted on AC grids. This manuscript reports their working principles and some preliminary simulation results for a low-voltage prototype.