A flying capacitor multilevel converter with sampled valley-current detection for multi-mode operation and capacitor voltage balancing

Multi-level hybrid converters have been shown to be a promising class of DC-DC converters. One member of this class is the Flying Capacitor Multilevel (FCML) Converter, which is explored in this work. The multi-mode approach is discussed as a tool to affect high efficiency and power-density across a wide load range, provide variable regulation, and as a general framework to conceptualize the advantages and opportunities of the approach compared to more traditional DC-DC converters. Sampled valley-current detection is explored as a robust control approach for multi-mode regulation. Furthermore, a theoretical framework is developed to show that flying capacitor voltages can be balanced through valley current balancing. Experimental results from a 4-level FCML converter are presented to verify the findings.