modular multilevel converter (mmc) comprising multiple submodules connected in series with one another; and a controller for controlling on / off switching of submodules

摘要

The present invention provides a modular multilevel converter (mmc) in which redundant submodules m are additionally arranged in addition to the submodules n which are required for operation, and the n + m submodules are controlled in order to participate in switching. The mmc according to one embodiment of the present invention includes multiple serially connected submodules and a controller for controlling on / off switching of submodules. here, multiple submodules include submodules n participating in mmc operation and redundant submodules m to replace a failed submodule when at least one of the submodules n fails, and the controller turns on the submodule if the carrier wave assigned to them is larger than than a preset reference signal, and turn off the submodule if the carrier wave assigned to them is less than the reference signal.