Abstract
Modular multilevel converters (MMCs) are extensively used in flexible high-voltage DC transmission systems. As an important part of them, it plays an important role in the normal use of MMCs. The main additional loss in the system is generated by the second harmonic in the circulating current. By summarizing and comparing current circulation control strategies. Based on the current research status of circulation suppression, we prospect the research direction of the MMC circulating current suppress...
