New medium-voltage inverter design with very high power density

The three-level NPC VSC topology and press-pack IGBT (PPI) devices are the key technologies for high-power medium-voltage (MV) drives. In this paper, a novel design for a MV inverter based on these technologies is presented. The main feature of the new converter is the integration of the dc-capacitor bank into the converter cubicle. Any kind of clamp capacitors are omitted. This simplifies the converter structure and reduces the part count, thus increasing its reliability and power density. The design of the low-inductive bus bars between the semiconductor stacks and the dc capacitor bank, the mechanical design, and the controls are discussed in the paper. Measurement results are presented that prove the excellent performance of the inverter.