Analysis of Level Shifting Multicarrier Based Hybrid Multilevel Inverter with Open Circuit Fault-Tolerant Capability Using Single and Multiple Switch Fault

MLI is widely used in applications such as renewable energy systems, electric vehicles, HVDC, FACTS devices, etc. This paper analysis the Fault tolerant operation of a hybrid multilevel inverter. The proposed multilevel inverter structure utilizes only eight unidirectional switches, four diodes, and 4 DC sources employing Geometric Progression (GP) based binary asymmetric DC source configuration to produce 31-level output. The phase disposition pulse width modulation method is applied to create the commutating pulses to the proposed inverter. The fault analysis deals with fault identification, isolation, and compensation. The fault-tolerant block does the fault identification. The isolation and compensation of fault are done by the FDI block in which the faulty switch is detected and it is substituted with a backup auxiliary switch. The open circuit fault is inspected, and the results are analyzed using Simulation in MATLAB/Simulink environment. In case of fault tolerance, additional backup auxiliary switches are added so as to compensate for the fault. Therefore, the fault-tolerant 31-level inverter circuit transforms into 16 switches, four diodes, and 4 DC sources. All the switches employed in the proposed structure are unidirectional; thus, using less no of components to achieve 31 31-level fault-tolerant multilevel inverters with increased reliability and low cost is proposed. Also, the power quality is analyzed by evaluating the Total Harmonic Distortion (THD) for all cases with and without fault. The feasibility of the circuit is examined through Simulation. From the results, it is evident that the proposed circuit can resist the single and multiple switch faults.