Input Current Ripples Cancellation in A New Three-level Neutral-Point-Clamped Bi-directional Coupled Quasi Z-Source Inverter

In this paper, the three-level (3L) neutral-point- clamped (NPC) bi-directional coupled quasi Z-source inverter (BCQ-ZSI) is proposed. The inductors of Z source network are coupled for the purpose of input current ripples cancellation. The detailed design of the coupled inductors have been given in terms of electrical and magnetic circuit constraints. Compared with the conventional 3L NPC QZSI, the proposed 3L NPC BCQ-ZSI can achieve completely input current ripples cancellation and also possess the capability of bi-directional power flow. The proposed 3L NPC BCQ-ZSI can avoid discontinuous conduction mode (DCM) with stable dc-link peak voltage under low power factor condition. Simulation results are presented to verify superiorities of the proposed 3L NPC BCQ-ZSI.