Improving the Tolerance of Power Semiconductor Switches Failure in an Active Rectifier Based on Cascaded H-bridge Multilevel Converter

In this paper, a new method based on model predictive control with a finite control set is proposed for the cascaded H-bridge converter-based active rectifier to control the converter under switch fault conditions. The purpose of the fault-tolerant method is to guarantee the continuous operation of the converter after switch(es) open-circuit failure. After the occurrence of an open circuit fault in the switches, by using the system model, the presented model predictive approach enables the operation of the converter despite the presence of a faulty cell. The proposed method sets the dc voltages of dc-link capacitors at the reference value under balanced and unbalanced dc loads and keeps the current drawn from the grid at a good quality. The performance of the proposed method has been evaluated through simulations based on the seven-level cascaded H-bridge converter in the MATLAB/SIMULINK environment.