Performance comparison of five-level NPC and ANPC converters in medium voltage drives for hydro power application

This paper compares the performance of a five-level neutral-point clamped (NPC) converter and a five-level active neutral-point clamped converter (ANPC) for a medium voltage and variable speed pumped-storage hydropower application. It is found that the ANPC converter has a lower current total harmonic distortion (THD) compared with the NPC converter under the same switching frequency, while the losses are higher. However, the simple structure and the easiness of controlling the DC-link voltage means that the five-level ANPC converter has a high potential in the market of the aforementioned application.