Voltage Space Vector Equivalent Substitution Fault-Tolerance Control for Cascaded H-Bridge Multilevel Inverter with Current-Tracking

Abstract

A novel fault-tolerant control method based on the equivalent substitution of voltage space vector for cascaded H-bridge multilevel inverter with current-tracking is proposed in this paper. With this method, the fault effects on the voltage vector of each sector of the cascaded inverter is analyzed first. Then, an algorithm to substitute the voltage vector in fault state is developed. In the fault state, if the voltage vector selected by the original algorithm cannot be used normally, the redundant voltage vector with the position coincidence is preferentially selected for equivalent substitution. If there is no redundant coincidence vector, select the other vector whose position and effect are closest to it. Compared with the commonly used N + 1 redundancy method, this method does not require the spare cascaded units and can be applied to any class cascaded H-bridge multilevel inverter with current-tracking to improve its reliability. Finally, the effectiveness of the proposed method is validated by simulation and experiment results.