Quasi- Two-Level Switching for Active Balancing of Flying Capacitor Multilevel Converters Under Light-Load Conditions

This work presents a quasi-two-Ievel (Q2L) switching scheme and accompanying controller for active balancing of capacitor voltages in the Flying Capacitor Multilevel Converter. Compared to prior work relying on Phase-Shifted Pulse-Width Modulation, the proposed switching scheme enables active balancing at average load currents approaching and equal to zero. The proposed switching method and active balancing controller are validated in a 6-level hardware prototype, verifying capacitor voltage tracking at light-load under supply voltage transients.