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Enhanced Operation of Hybrid MMC under Reduced DC-link Voltage
Journal
2022 IEEE Energy Conversion Congress and Exposition, ECCE 2022
Date Issued
2022-01-01
Author(s)
Rao, Nallamatti Poornachandra
Shukla, Anshuman
Abstract
The hybrid modular multilevel converter (MMC) comprises of both half-bridge submodules (HBSMs) and full-bridge submodules (FBSMs) connected in the same arm. In recent times, it is gaining a lot of attention since it enables dc fault blocking capability along with good efficiency in high-voltage direct-current (HVDC) transmission systems. Under the operational constraints such as bad weather or pole to ground fault, the negative insertion of FBSMs allows hybrid MMC to operate at reduced dc-link voltage by maintaining the nominal voltage across each submodule. Furthermore, it allows the converter to operate at reduced power without exceeding the rated value of dc-link current. This paper proposes an enhanced operation to the conventional one, where hybrid MMC can operate with further reduction in the dc-link voltage for the same number of FBSMs inserted in negative. The proposed scheme is verified with simulation as well as experimental results.
Subjects