Simple and effective open switch fault diagnosis of single-phase PWM rectifier

In order to obtain lower harmonics distortion and higher power factors, single-phase pulse-width modulation (PWM) rectifiers are adopted in AC railway drive systems. Therefore, its reliability is of most importance with regard to the safe operation of the train. In this paper, a fault diagnosis method for open switch fault in single-phase PWM rectifier is proposed based on the switching system theory. It requires no additional sensor, nor extra operation states need to be set. Four observers which correspond to four kinds of open switch faults are utilized to detect and locate the faults. Real-time simulations are carried out to validate the effectiveness of this method.