Reliability Analysis of Three-Level Neutral Point Clamped Cascaded Converter Used in Advanced Traction Power Supply System

As the core component of the advanced traction power supply system (ATPSS), the reliability of the power electronic converter is very important. In this paper, the method of reliability analysis of the three-level neutral point clamped cascaded converter (3LNPC-CC) is proposed. The reliability block diagram of the cascaded converter and the submodule are respectively set up in this paper, which are based on the fault tree and k/n (G) reliability model. The MTTF of the converter is further derived. Moreover, the structural reliabilities under different redundancy levels are quantitatively analyzed to optimize the stable operation of converter. The results can be provided for the design and the application of the advanced traction power supply system.