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Multilevel converters (MLCs) are widely recognized for their exceptional benefits and have emerged as the preferred choice for medium- and high-power/voltage applications. Their usage has also been extended to low-power applications to overcome issues associated with high switching frequencies and electromagnetic interference (EMI) commonly encountered in two-level converters. Common dc-link MLCs have received particular attention in industry due to their ability to eliminate the need for bulky and inefficient transformers and rectifiers, making them a compelling option for different applications, primarily medium- and high-power/voltage applications such as wind turbine (WT) power conversion systems. Furthermore, common dc-link topologies are required for back-to-back (BTB) configurations, as they facilitate the use of a shared dc-link between the rectification and inversion stages. Despite their popularity, there is currently no comprehensive review article dedicated to common dc-link topologies. This article addresses this gap by presenting a comprehensive review of common dc-link MLCs, covering their topological evolution, features, topologies comparison, modulation techniques, control strategies, and industrial application areas. Additionally, future perspectives and recommendations are discussed to provide researchers and engineers with a better understanding of the potential applications and advantages of these converters.

The emphasis on clean and green technologies to curtail greenhouse gas emissions due to fossil fuel-based economies has originated the shift towards electric mobility. As on-road electric vehicles (EVs) have shown exponential growth over the last decade, so have the charging demands. The provision of charging facilities from the low-voltage network will not only increase the distribution system’s complexity and dynamics but will also challenge its operational capabilities, and large-scale upgrades will be required to meet the inevitably increasing charging demands. An ultra-fast (UF) charging infrastructure that replicates the gasoline refueling network is urgently needed to facilitate a seamless transition to EVs and ensure smooth operation. This paper presents a review of state-of-the-art DC fast chargers, the charging infrastructure’s current status, motivation, and challenges for medium-voltage (MV) UF charging stations (UFCS). Furthermore, we consider the possible UFCS architectures and suitable power electronics topologies for UF charging applications. To address the peak formation issues in the daily load profile and high operational expenses of UFCSs, integration of renewable energy sources and energy storage systems due to their technological and economic benefits is being considered. The benefits of line frequency transformer (LFT) replacement with a solid-state transformer (SST), SST models, SST-based UF chargers, and MV SST-based UFCS architectures, as well as related MV active front-end and back-end power electronics topologies, are presented. Finally, the application of microgrids’ hierarchical control architecture is considered for chargers and system-level control and management of UFCSs.