Modular multilevel converters technology: a comprehensive study on its topologies, modelling, control and applications

A modular multilevel converter (MMC) is one of the perfect topologies for high power and medium-/high-voltage energy conversion systems. The MMC has attractive features such as modularity, voltage and current scalability, transformerless operation, fault blocking capability, reduced filter size, a reduced ripple of the output current, high efficiency, and low expense on redundancy. These features attracted industries over the past few years, notable research has been carried out on MMC topologies, their operation, and control. This study presents a review of MMC topologies and their mathematical models. Furthermore, their control schemes (classical as well as model predictive controls) and modulation techniques are discussed. Finally, MMC applications and their future challenges are highlighted.