**9. Conclusions**

This review provides an efficient summary of multilevel inverters to emphasize the necessity for new or modified multilevel inverters for grid-connected sustainable solar PV systems. Firstly, this review presented a detailed survey of reduced switch count multilevel inverter (RSC-MLI) topologies, including their designs, typical features, limitations, assessment parameters, and selection for particular applications. Secondly, this review presented a comprehensive analysis of MLIs and a classification of the existing MLI topologies, along with their merits and demerits. Thirdly, this review also included a survey of SC-MLI topologies with a qualitative assessment to aid in the direction of future research due to their variety of applications such as inductor-less or transformer-less operation, enhanced voltage output, improved voltage regulation, low cost, reduced circuit components, size, and less electromagnetic interference. Lastly, this review serves as a valuable resource for

engineers and researchers because it provides a detailed look at parametric comparisons of the total number of power semiconductor switches, DC sources, passive elements, total standing voltage, reliability assessment, applications, challenges, and recommendations.

**Author Contributions:** Conceptualization and methodology, S.N.; validation, D.C.; formal analysis, S.N.; investigation, D.C.; resources, D.C.; data curation, S.N.; writing—original draft preparation, S.N.; writing—review, S.N.; editing, D.C.; visualization, D.C.; supervision, D.C.; project administration, D.C. All authors have read and agreed to the published version of the manuscript.

**Funding:** This research received no external funding.

**Data Availability Statement:** This review has no information related to it.

**Acknowledgments:** The authors further thank the Vellore Institute of Technology in Vellore, India, for their assistance and also the authors wish to thank the particular copyright holders for allowing approval to use the pictures, graphics, tables, and figures in this work.

**Conflicts of Interest:** The authors declare no conflict of interest.
