A Fault Tolerant Five-Level Inverter Topology with Reduced Component Count for Open-End IM Drives

In this project, a fault tolerant 5-Level inverter scheme for Open End Induction Motor (OEIM) drive application using a single DC-link. The drive is fed with a primary inverter (a 2-Level inverter cascaded with a capacitor fed H-bridge inverter) from one end and a secondary inverter (capacitor fed 2-Level inverter) from other end. The ratio of the DC-link voltage to the nominal capacitor voltage in the H-bridge and the secondary 2-Level inverter is maintained at 4:2:1. The capacitor balancing in the proposed scheme is achieved by Space Vector (SV) redundancy. The proposed scheme gives 5-Level inverter operation with less number of components compared to other existing inverter topologies. Further, the scheme provides fault tolerant capability against failure of the power switches in the H-bridges and the secondary 2-Level inverter. The experimental results in steady and transient states are presented. Also, the inverter operation during fault is provided to validate the effectiveness of the proposed scheme.

Keywords: —5-Level Multilevel Inverter, Open End-Induction Motor drive, Fault-tolerant operation, Pulse Width Modulation (PWM).