The flying-capacitor SEPIC converter with the balancing circuit

Abstract

The paper presents investigation results of the natural balancing phenomena in the flying-capacitor SEPIC converters. The SEPIC converters topologies can be reconfigured to the flying-capacitor topology. Owing to this modification the advantageous increase of frequency of the current in the chokes and the decrease of semiconductors voltages can be achieved which is shown in this paper. Similarly to other multilevel flying capacitor topologies the adequate voltage sharing of the flying capacitors is an important issue for safe operation of the converter. The paper focuses on the analysis of the flying capacitor voltages balancing in the converter by natural currents as well as by the application of the additional RLC balancing booster. The paper proves that the natural balancing can be achieved by the specific application of the balancing circuit in the flying-capacitor SEPIC topology and proves the specific differences in the balancing process by natural currents of converter and with the usage of the balancing circuit. An operation of the converter with the balancing circuit and the natural balancing ability is studied here.