Researchers are reviewing and developing various aspects of multi-level inverters for use in grid-interfaced solar PV systems, including modulation, control, and fault-tolerant design. New designs and optimization techniques are being explored, such as reduced switch count inverters and hybrid multilevel inverters, to improve efficiency and reliability. Studies are also focusing on specific inverter topologies, including cascaded H-bridge and active neutral point clamped inverters, to enhance performance in renewable energy applications.