A Fault-Tolerant Five-Level Inverter Topology With Reduced Component Count for OEIM Drives

This article proposes a fault-tolerant five-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 two-level inverter cascaded with a capacitor-fed H-bridge inverter) from one end and a secondary inverter (capacitor-fed two-level inverter) from the other end. The ratio of the dc-link voltage to the nominal capacitor voltage in the H-bridge and the secondary two-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 five-level inverter operation with less number of components compared with other existing inverter topologies. Furthermore, the scheme provides fault-tolerant capability against a failure of the power switches in the H-bridges and the secondary two-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.