A High-Bandwidth Parallel Active Balancing Controller for Current-Controlled Flying Capacitor Multilevel Converters

This work presents a capacitor voltage balancing controller for current-controlled flying capacitor multilevel (FCML) converters. An averaged small-signal plant model of the converter, derived from standard application of state-space averaging, informs the parallel controller structure. The proposed design decouples flying capacitor control loops and prevents mutual interaction between the capacitor voltages and inductor current. Experimental results of closed-loop line and load transient responses demonstrate significant performance improvements with the proposed active balancing architecture compared to a converter relying on natural capacitor balancing.