Multilevel Inverters Design, Topologies, and Applications: Research Issues, Current, and Future Directions

Multilevel inverters (MLIs) have remained a promising contribution to research in the modern era, especially in the area of energy conversion. Their popularity, nominal and optimal operations have merged them into low, medium, and high-power applications. Their use in advanced and wide range of applications have proved them as innovative solutions to many issues. Advanced MLIs structure tackle high-profile total harmonic distortion (THD) issues, maximum switching losses, low fault tolerance, low-quality output voltage, high rating of devices, low switching frequency, and frequency interfacing. Such factors classify them into various categories, which specify their operations in multiple applications. The existing literature lacks proper control strategies, design mechanisms, mathematical and application analysis. The aforementioned strategies help to investigate switching losses, configuration complexity, cost analysis, load management, input and output voltage categorization and many other prominent features of MLIs. Therefore, this paper provides a detailed review study and investigates various MLI topologies based on their structure, synthesis, mathematical explanations, control strategies, design mechanisms and utilization in various applications. The evolution of MLIs their classification, advantages, disadvantages, design mechanisms, control strategies, load vs input voltage interfacing and applications based utilization are tabulated to highlight their importance in various sectors. The proposed review study is compared with other prominent review studies and have covered a wide range of MLI topologies based on their evolutional development, mathematical representations, generic utilization and design methodologies.