Integration of Renewable Energy Sources into MVDC Railways through Input-Independent Output-Series Connected Multi-Level Converters

In recent years, the integration of renewable energy sources (RESs) into the DC electrified railways has gained significant attention. This is due to the rising need for sustainable, environment-friendly, and optimal transportation systems. Due to voltage fluctuations and irregular voltage levels in the catenary system, the traction railway always requires voltage maintenance methods to ensure the efficient operation of the system. To maintain the voltages at their threshold level, this paper proposes the integration of renewable energy sources into medium-voltage direct current (MVDC) railways using input-independent output-series (IIOS) connected multi-level converter. To evaluate the performance of renewable energy through IIOS multi-level converter, a comprehensive simulation study is conducted in MATLAB/Simulink. Moreover, in simulations, the number of levels of the converter is considered as per the maximum available voltage rating of electronic switches in the market. The results of the proposed scheme depict improved voltages of the catenary system having fewer fluctuations, reduced losses, and effective utilization of environment-friendly RESs in MVDC railways.