Phase-Shift Control of Flying Capacitor Voltages in Multilevel Converters

This paper presents a new phase shift based control method for the flying capacitor voltages of multilevel converters. The new method is immune to load current variation and other stability issues that would arise when controlling the flying capacitor voltages with existing solutions. Experimental results obtained with a 12V-to-5V, 500 kHz, 15 W, 3-Level Flying Capacitor buck converter prototype are provided detailing the proposed control strategy’s behavior, and well as its efficacy under load current and input voltage variations.