A Nine-Level Inverter For Open-end Induction Motor

A novel nine-level inverter topology is presented for an open-end winding induction motor drive. The presented topology has the highest number of levels for a given number of dc sources and power electronics switches. The conventional configurations for multi-level inverter are neutral point clamp (NPC), flying capacitor (FC) and series/cascade H-bridge. The proposed topology does not require any clamping diodes as they are needed in NPC. Apart from this there is no requirement of capacitor bank as compare to flying capacitor schemes where for nine-level inverter, twenty eight capacitor banks per phase are required. The proposed inverter scheme requires only four DC sources whereas series/cascade H-bridge nine-level inverter requires at least six DC sources. Extensive simulation study of the presented topology is done for the complete modulation range.