Experiment of five-level BTB-system with common flying capacitors

In this paper, a new 5-level converter with common flying capacitors (FCs) is proposed. The unique feature of this configuration makes contribution to reduce the total number of FCs compared with the other topology which has FC in each phase, because FC is shared by all phases. The voltage of FCs in the proposed topology can be controlled more steadily compared with the previous topology, because the new topology doesn't have an interference between FC voltage control and the switching mode of phase modules. An experiment was conducted to verify the validity of the proposed topology using 400V, 8 kVA prototype model.