This work proposes a dc/dc isolated modular multilevel converter (IMMC) with reduced arm and fault blocking capability for a medium-voltage direct current (MVDC) railway electrification system. The proposed IMMC converts the overhead MVDC voltage into the required dc voltage for the traction motor by employing a medium frequency intermediate transformer. The proposed circuit uses only one arm of conventional half-bridge MMC, resulting in a substantial reduction in switch counts compared to conventional half-bridge MMC. The topology, moreover, has inherent fault current blocking capability without any extra circuitry, which helps during dc and ac short-circuit (SC) faults. The impressed voltage on the transformer primary is nearly sinusoidal with little dv/dt. This work includes an analysis of the proposed converter both in steady state and during fault circumstances. A down-scale laboratory prototype and a computer simulation model are used to evaluate the performance of the proposed IMMC.
An Isolated Reduced Arm Modular Multilevel Converter With Fault Blocking Capability for MVDC Rail Traction
IEEE Transactions on Transportation Electrification ; 11 , 1 ; 86-96
2025-02-01
6276686 byte
Article (Journal)
Electronic Resource
English