A Grid Connected Multilevel Inverter With Improved Reliability and Fault Tolerant Capability

The multilevel inverters are less reliable than two-level inverters as it require more semiconductor devices. Hence, this work proposes a grid connected fault-tolerant five level inverter (FT5LI) that can endure the switch open-circuit fault. The proposed FT5LI generate 5L voltage during normal operation, and can able to produce either five, three or two level voltages during any switch open circuit fault. Further, the switching strategy for the proposed FT5LI is comprehensively detailed alongside fault-tolerant operation schematics. In addition, several simulation results are shown to verify the reliability of the proposed FT5LI during normal, fault, and post-fault settings to confirm the proposed concepts.