Open AccessModular multilevel converter with modified half‐bridge submodule and arm filter for dc transmission systems with dc fault blocking capability
Author(s) -
Ahmed Khaled H.,
Adam Grain P.,
Abdelsalam Ibrahim A.,
Aboushady Ahmed A.
Publication year - 2018
Publication title -
iet power electronics
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.637
H-Index - 77
eISSN - 1755-4543
pISSN - 1755-4535
DOI - 10.1049/iet-pel.2018.5081
Subject(s) - blocking (statistics) , modular design , bridge (graph theory) , fault (geology) , filter (signal processing) , transmission system , computer science , transmission (telecommunications) , electronic engineering , engineering , electrical engineering , computer network , medicine , seismology , geology , operating system
Although a modular multilevel converter (MMC) is universally accepted as a suitable converter topology for the high‐voltage dc transmission systems, its dc fault ride performance requires substantial improvement in order to be used in critical infrastructures such as transnational multi‐terminal dc (MTDC) networks. Therefore, this study proposes a modified submodule circuit for MMC that offers an improved dc fault ride through the performance with reduced semiconductor losses and enhanced control flexibility compared to that achievable with full‐bridge submodules. The use of the proposed submodules allows MMC to retain its modularity; with semiconductor loss similar to that of the mixed submodules MMC, but higher than that of the half‐bridge submodules. Besides dc fault blocking, the proposed submodule offers the possibility of controlling ac current in‐feed during pole‐to‐pole dc short‐circuit fault, and this makes such submodule increasingly attractive and useful for continued operation of MTDC networks during dc faults. The aforesaid attributes are validated using simulations performed in MATLAB/SIMULINK and substantiated experimentally using the proposed submodule topology on a four‐level small‐scale MMC prototype.