A Nine-Level Inverter with Reduced Number of Components for Open-End Winding Induction Motor

In this paper, a novel nine-level inverter topology for open-end winding induction motor is proposed. This topology requires less number of components as compared to conventional topologies. The proposed inverter uses two three-phase three-level cascade inverters to generate nine-level in the phase voltage of open-end winding induction motor. An interesting feature of this topology is that in case of failure of any three-level inverter, it can be bypassed and the proposed topology can operate in three-level mode hence reliability of the circuit is improved. Out of two three-level inverters, the inverter which operates at higher DC link voltage switches less as compared to the inverter which operates at a lower DC link voltage, thus switching losses are reduced. A 1.5-kW induction motor is run with the proposed inverter at different modulation indices, and the performance of the drive is evaluated under steady and transient states.