A fault-tolerant strategy for current controlled PWM rectifier

Pulse Width Modulated (PWM) rectifiers play an important role in power conversion systems. However, open-switch faults are one of the main problems that face the operation of a PWM rectifier and its reliability. In this paper, open-switch faults in three-phase current controlled PWM rectifiers are analysed. The Space Vector Modulation (SVM) based Hysteresis Current Control (HCC) scheme is considered. The paper presents an open-switch fault-tolerant strategy for current controlled PWM rectifiers. The proposed strategy is composed of two steps. The zero vector is compensated in first step, while the active vectors are partially compensated. To reduce the distortion of the input three-phase current, the angle between the reference current and voltage vectors is nullified in the second step of the proposed fault-tolerant strategy. This step can be achieved by adjusting either the magnitude or the angle of the reference current vector of the PWM rectifier. The proposed strategy is simulated on EMTDC/PSCAD software package. Simulation results prove that the proposed fault-tolerant strategy succeeds to minimize the total harmonic distortion (THD) of the input currents during an open-switch fault.