Modeling and Analysis of Shutdown Dynamics in Flying Capacitor Multilevel Converters

This work explores the dynamic behavior of the flying capacitor multilevel (FCML) converter during unplanned shutdown. A model for a general N-level FCML converter is developed, which captures capacitor nonlinearities, component leakage paths, and body diode behavior. This work highlights how switch voltage ratings may be exceeded during unplanned shutdown, and proposes several mitigation strategies. Using a ten-level FCML converter hardware prototype, the time-domain behavior of the model is verified, and a successful hardware mitigation strategy is demonstrated which ensures safe and rapid converter shutdown.