Analytical Modelling of Capacitor Voltage Imbalance Created by Input Filter Ripple in a Three-Level Flying Capacitor Multilevel Converter

The flying capacitor multilevel converter is positioned to become a key technology in emerging power electronics applications. However, maintaining the flying capacitor voltages balanced at their nominal values presents a major practical challenge for these designs and has impeded their industrial adoption. While prior literature has identified the input filter ripple as the dominant mechanism causing imbalance, a detailed analytical model of this effect has been missing. To address this research gap, this work symbolically derives and experimentally validates a new three-level converter model that captures the effect of the input ripple, enabling accurate prediction of the flying capacitor voltage imbalance.