A Fault Tolerant Operation of 3-Phase, 5-Level CHBMLI under Open Circuit Fault Conditions

Fault detection and its restoration is the major challenge for the smooth functioning of the Multi-Level Inverter (MLI). In this paper, fault detection and its clearance scheme for an Open Circuit (OC) fault on a 3-level 5-level Cascaded H-Bridge Multi-Level Inverter (CHBMLI) has been developed and tested to improve the reliability and suitability of the system. An accurate and fast detection, isolation and bypassing of faulty bridges enhance the reliability, suitability, and acceptability of CHBMLI in any domestic, industrial drive applications. To reschedule the line voltage and current value close to the pre-fault level, a Neutral Point Shift (NPS) technique is presented in this paper. The desired output voltage is governed by Level Shift Pulse Width Modulation (LSPWM) technique. The proposed scheme is developed in MATLAB/Simulink environment and results are validated by using Opal-RT simulator. Simulation results has confirmed the performance and Opal-RT simulator results shows feasibility and applicability of the proposed scheme.