A nine-level switched-capacitor multilevel inverter based on ANPC topology with optimized component count and suppressed charging current

Abstract

Abstract This paper presents a nine-level switched-capacitor (SC) based on ANPC inverter structure, where efficiency, compactness, and reliability are essential. Unlike conventional ANPC-based and previously reported SC topologies, the proposed structure suppresses the hard charging issue in SCs by inserting an inductor in the charging path, effectively reducing peak charging currents and associated switch stress. The inverter achieves natural self-starting and self-voltage-balancing of capacitors without additional circuitry, while requiring fewer active switches in the conduction path. These features lead to reduced component count, and minimized power losses. A peak efficiency of 96.9% is obtained at a rated power of 0.3 kW. Experimental verification confirms the theoretical predictions, demonstrating stable capacitor voltage under varying load conditions and modulation indices. Comparative analysis highlights the superiority of the proposed topology over existing SCMLIs in terms of efficiency, charging current suppression, and reduced component requirements.