A seven-level multilevel inverter using switched capacitors with reduced component counts and high reliability

Multilevel inverters (MLIs) are widely used in medium- and low-voltage applications for efficient power conversion. However, conventional MLIs often suffer from high component count, voltage stress, and complexity, limiting their practical implementation. This paper proposes a novel seven-level switched-capacitor multilevel inverter (SC-MLI) aimed at achieving high voltage gain with reduced components and improved reliability. The inverter employs 8 IGBT switches, 2 diodes, and 2 capacitors, which are charged simultaneously and discharged sequentially in series from a single supply. The capacitors are charged simultaneously and discharged sequentially in series from a single supply, providing inherent voltage boosting without magnetic components or sensors. Level-Shifted Pulse Width Modulation controls the switching sequence for seven distinct output levels. The performance of the proposed SC-MLI is validated through MATLAB and PLECS simulations and experimental testing, focusing on output voltage quality, capacitor voltage self-balancing, dynamic load behavior, and efficiency. Experimental results demonstrate a triple voltage gain with stable capacitor voltages and a peak efficiency of 96%, while maintaining low voltage stress on power devices. A comprehensive comparison with recently reported seven-level MLIs shows that the proposed topology achieves the lowest component count and normalized cost function among comparable designs. The proposed SC-MLI offers a compact, efficient, and reliable solution for medium-low voltage applications requiring high-performance multilevel inverters.