Ride-Through of Semiconductor Switch Open-Circuit Failure in Cross Switched Multilevel Inverter with Back-Up Cell Using Model Predictive Control Method

The increasing trend in the use of multilevel converters for high-power applications has emphasized the significance of reliability and fault tolerance in these systems. In this research, Model Predictive Control (MPC) has been developed to generate the switching commands for the cross-switched inverter. The performance of the inverter is investigated under conditions where an open-circuit fault occurs in any of its switches. Additionally, an approach has been proposed to enhance the utilization of the capacity of the inverter in post-fault operation. For this purpose, first, a fault detection method is presented to identify the open-switch fault by measuring the deviation of measured voltage from the reference voltage. Then, by defining fault indices and monitoring their conditions during one cycle after fault detection, the faulty switch is also identified. This method uses the minimum number of voltage and current sensors. Also, to achieve the maximum possible output voltage under post-fault conditions, it is proposed to embed a cross-switched cell with capacitive links in the converter structure as an auxiliary cell. Finally, the accuracy and effectiveness of the proposed methods are verified through the simulation of a nine-level cross-switched inverter in the MATLAB/SIMULINK environment.