Patent ID: 11264916

Abstract:
A method that operates a modular multilevel converter (MMC), includes controlling a plurality of submodules of an arm of the MMC for a plurality of subsequent periods. Each of the submodules has a capacitor. The controlling includes, for each of the subsequent periods: sampling a value of a reference voltage; determining an integer number n of submodules of the plurality of submodules required to approximate the sampled value; for each submodule of a subset of the n submodules of the plurality of submodules, determining a temperature characterizing the respective submodule; inserting all submodules of the subset of the n submodules except for one remaining submodule; determining, depending on the determined temperatures, a duty ratio; and inserting the one remaining submodule for a duration given by the duty ratio. A minimum temperature of the determined temperatures is identified and the duty ratio is determined depending on the minimum temperature.