Energies, Vol. 9, Pages 803: Smooth Switching Technique for Voltage Balance Management Based on Three-Level Neutral Point Clamped Cascaded Rectifier

This paper discussed the topology of in the three-level neutral point clamped cascaded rectifier (3LNPC-CR) for designing the Chinese Power Electronic Traction Transformer (PETT). To balance the DC-link voltage (Vdc) in 3LNPC-CR, a smooth switching technique is proposed in this paper. The controlling processes of each module are relatively independent when the proposed technique is applied in 3LNPC-CR. The proposed technique can keep the switching frequency constantandchangetheswitchstatesmoothlywhilebalancingVdc. TheVdc balanceabilityisanalyzed by calculating the unbalance degree of the loads. Simulation and experiment of three-module 3LNPC-CR are built, and then the effectiveness of the proposed technique is verified.

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