Modular Multilevel Converters for Transportation Electrification: Challenges and Opportunities

The power converters based on a modular structure have gained importance for electric transportation applications, including electric vehicles (EVs), EV charging stations, railway traction, and electric ships. Modular multilevel converters (MMCs) are recognized as one of the promising topologies to improve the energy conversion efficiency and fault-tolerant ability of power conversion systems. This paper aims at a review of latest research contributions regarding the evolution of circuit topologies, operational challenges, control schemes, and fault-tolerant strategies of the MMC. Finally, the current state of the art, opportunities and the future perspective of MMC in electric transportation applications are addressed.