SVM-Based Fault-Tolerant Control for a Cascaded H-Bridge Multilevel Converter under Multiple Open-Circuit Switch Faults

Abstract:
To improve the operation ability of the cascaded H-bridge multilevel converter (CHBMC) under multiple open-circuit (OC) faults, this paper has explored a space vector modulation (SVM)-based fault-tolerant control method. Based on the selectable vector range in the postfault conditions, the assigned output vector for each power cell is modified to reduce the current harmonics and to maintain the DC voltage balancing as much as possible with the smooth voltage level transitions. Moreover, the level number of total port voltage is not affected by the multiple OC faults, thereby balancing the voltage stresses on the switches of the different power cells. Simulation and experimental results have shown the applicability of the proposed method.