New voltage balancing strategy for flying capacitor multilevel converters

Multilevel converters topologies present important benefits when they are used on medium and high power applications. However, it is necessary to design new alternating methods to control easily the internal dynamics of the converter. This paper presents a new voltage balancing strategy for a flying capacitor multilevel converter in conjunction with a space vector modulation technique. The advantages of this strategy with respect to others control methods are, the equilibrated use of the switches in the converter, the independence from the modulation method and the easy implementation. The proposed strategy is based on the redundancy of switching states and it is designed to accomplish three objectives: a) ensure the demanded voltage level by the pulse width modulation strategy, b) balance the capacitor voltages, and c) ensure the equilibrated use of the converter switches. The performance of the proposed technique is validated by simulation and experimental results in a 5-level inverter.