A Comprehensive Review of Multilevel Inverter Topologies and Control Strategies for Grid-Connected Photovoltaic Battery Energy Storage Systems Integrating Active Power Filter

The growing integration of renewable energy sources (RESs), especially solar photovoltaic (PV) systems, has intensified the demand for high-quality and stable grid connections. This study reviewed shunt active power filter (SAPF) configurations and multilevel converters (MLCs), with a focus on improving power quality, scalability, and fault diagnostics in large-scale PV and battery energy storage systems (BESS) applications. A comprehensive methodology was employed to review and analyze multilevel SAPF topologies, inverter control strategies, modulation techniques, and hybrid semiconductor devices. The research discussed integration challenges, including current harmonics, voltage instability, and fault localization in MLCs using model-based and data-driven strategies. Review findings highlight the superior performance of five-level MLC-based SAPFs in reducing harmonic distortion, improving waveform quality, and enhancing control flexibility. Additionally, hybrid Si/SiC switch strategies and advanced modulation techniques like LS-PWM and predictive control demonstrate improved efficiency and fault tolerance in grid-connected applications. The study recommends further development of intelligent control schemes, modular SAPF design, and integration with energy storage for robust and adaptive grid systems. Advancements in semiconductor technologies and AI-based diagnostics are key to future reliability and performance enhancements.