T-Type Multilevel Converter Topologies: A Comprehensive Review

Renewable energy systems integration prefers DC–AC converters of high efficiency, low harmonic injection and small size. Multilevel converter (MLC) is preferred compared to two-level converter thanks to its low harmonic injection, even at low switching frequency values, and accepting high power as well as voltage levels. Among reduced switching devices count MLCs is the T-type topology. This article introduces a review of the different advanced topologies of T-type MLC in comparison with the conventional neutral point clamped converters. The operation of each topology, the design consideration and the performance in low-voltage applications such as AC drive systems, grid-tie integration of renewable energy and power train drive applications are discussed. In addition, the design considerations using enhanced semiconductor switches are elaborated. Different studies regarding MLCs—like common-mode voltage elimination or reduction, open-switch fault diagnosis, open- as well as short-circuit fault tolerance, and DC link capacitor voltage balancing for T-type topologies—are illustrated. Finally, recommendations for future work research directions are highlighted.