Abstract: There is provided a method of controlling a plurality of converter cells in a phase arm of a modular multilevel converter (MMC) in accordance with a main reference. The method includes dividing the main reference into a plurality of reference parts, and, by using a grouping of the plurality of converter cells into a plurality of groups, operating a plurality of modulators in parallel, each modulator controlling a respective one of the groups of converter cells in accordance with one of the reference parts. A phase arm controlled in accordance with such a method is also provided, as well as an MMC including at least one such phase arm, and a converter station including at least one such MMC.

Abstract: A method can be used to synchronize time between nodes of a converter device for high voltage power conversion. The method is performed in a first node of the converter device and includes receiving a time reference from a second node of the converter device, obtaining a delay value for receiving time references from the second node, determining a compensated time by adding the delay value to the time reference, and setting a clock in the first node to be the compensated time.