Fault Tolerant T-Type Nested Neutral Point Clamped (T-NNPC) Converter

The four-level T-Type Nested Neutral Point Clamped (T-NNPC) power converter is one of the recently proposed topologies for high-power and medium-voltage applications. Low component count compared to the conventional four-level power converters and operating over a wide range of voltages (2.3-7.2kV) are the main features of the T-NNPC topology. In this paper, the T-NNPC power converter will be evaluated under fault conditions. This paper demonstrates that this topology benefits the feature of fault tolerant capability without the need to add any additional phase legs or complex control strategies. This concludes that the T-NNPC topology is very attractive for applications where continuous operation of the system must be insured. The performance of the T-NNPC converter is simulated and evaluated under different fault conditions.