Analysis of the Isolated Modular Multilevel DC-DC Converter by Considering the Impact of Magnetizing Inductance

Interconnection of Medium Voltage DC (MVDC) grids necessitates reliable and efficient DC-DC converters. Among the existing topologies, the Isolated Modular Multilevel DC-DC (IMM DC-DC) converter is a promising solution. In the technical literature, the impact of the magnetizing inductance of the High Frequency Transformer (HFT) on the operation and control of the converter is neglected. This paper analyzes the IMM DC-DC converter by focusing on the impact of the magnetizing inductance on the operation and control of the converter. Power transfer capability, arm current, reactive power, and soft-switching are discussed by considering the impact of the magnetizing inductance. This paper demonstrates that the magnetizing inductance of the HFT is a key parameter that needs to be carefully selected, as it can improve soft-switching operation, while reducing the power transfer capability of the converter. Simulation studies of a test system in the Matlab/Simulink software environment verify the presented modeling and analysis of the IMM DC-DC converter.