Recent literature has showcased the flying capacitor multilevel converter as a solution for improving power density and efficiency in many power electronics applications. In practice, however, balancing the flying capacitors at their nominal voltages has proven to be a major challenge for these designs. Prior research has studied flying capacitor balancing through advanced modelling approaches, but such models typically represent the switches as ideal devices with instantaneous commutation at the switching transitions. In contrast, this work investigates how practical commutation events can affect the balancing dynamics. The analysis is performed by examining the commutation process in terms of charge transfers, which are defined by the semiconductor properties. Then, through quantitative analysis and qualitative reasoning, the impact of each charge transfer is assessed to determine if it promotes or degrades the steady-state balancing. Useful design insights are realized from the analysis, including an expression for the strength of the switch capacitance balancing effect, and an illustration of how body diode reverse recovery and asymmetric cell design can degrade balancing.
