A Novel MMC Topology With Lower Power Loss and DC Fault Ride-through Capability

Abstract

Multilevel modular converter (MMC) has been widely applied in high voltage direct current (HVDC) area. The clearance of DC fault is one of the main challenges to MMC-HVDC, and the existing hybrid HVDC circuit breaker is still not mature. Firstly, the existing MMC topologies were analyzed, then a novel MMC topology with lower power loss and DC-fault ride-through capability was proposed. Secondly, the DC fault ride-through mechanism of proposed topology was investigated, and a two-terminal MMC-HVDC adopting the presented topology was built in PSCAD/EMTDC. The capital cost and power loss among different MMC topologies were compared. The result shows that the proposed topology not only has the ability to block the DC-fault current, but also shows lower capital cost and power loss.