Novel multi-terminal MMC-based dc/dc converter for MVDC grid interconnection
Multi-terminal modular multilevel converter (MMC)-based dc/dc converter with the medium-frequency ac-link transformer is an attractive and feasible solution for interconnecting medium-voltage direct-current (MVDC) grids. This study proposes a novel multi-terminal dc/dc converter which features significantly reduced number of components compared with the conventional converter topology. The proposed dc/dc converter is capable of interconnecting multiple MVDC grids with different voltage levels as well as controlling the power flow between them. A combination of sine wave modulation scheme and phase disposition level-shifted pulse-width modulation is developed and employed for voltage balancing and controlling the power flow in the proposed converter. Several simulations, experimental and real-time hardware-in-the-loop case studies are carried out to demonstrate the dynamic response and capacitor voltage balancing capability of the proposed MMC and dc/dc converter under the developed control strategy.
Publication Source (Journal or Book title)
IET Power Electronics
Jafarishiadeh, S., Dargahi, V., Sadigh, A., & Farasat, M. (2018). Novel multi-terminal MMC-based dc/dc converter for MVDC grid interconnection. IET Power Electronics, 11 (7), 1266-1276. https://doi.org/10.1049/iet-pel.2017.0164