This paper presents a fault-tolerant independent pole control scheme for a zigzag modular multilevel converter (MMC) targeting bipolar medium-voltage direct-current (MVDC) distribution systems. An MMC which adopts a zigzag transformer as an AC grid interface transformer, namely zigzag MMC, has inherent bipole operation capability with unbalanced loads of positive and negative poles on the DC side. Nevertheless, this topology has not been thoroughly investigated for its ability to maintain indepe