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Advanced Traction Power Supply System Based on Modular Multilevel Converters

In order to solve the problems of neutral section and power quality in traction power supply system, a novel traction power supply system based on MMC (Modular Multilevel Converter, MMC) structure is proposed in this paper. The system takes electricity from the three-phase power grid, connects to the three-phase MMC rectifier through the connected transformer, and converts it into a single-phase high-voltage alternating current through HVDC (high-voltage direct current, HVDC) transmission and single-phase MMC inverters. Each substation supplies the traction network with 27.5kV singlephase alternating current with the same output phase through the single-phase step-down transformer of the same ratio to realize the advanced co-phase power supply. This paper verifies the correctness and feasibility of the system through simulation and building a low-power experimental platform.