Open Switch Fault Diagnosis Methods for an AC/DC Line-Side Converter

This paper provides an open switch fault diagnosis method for a voltage oriented controlled AC/DC line side converter. The technique is based on rectifier phase voltage errors calculations. For the faulted transistors localization, the average voltage errors of the rectifier are computed and their values and signs are analyzed. The proposed method is valid under the rectifier as well as the regenerative mode of the converter. Additionally, the algorithm does not generate false alarms during a healthy operation of the rectifier. Further, an assumed fault threshold, which is required for the transistor failure detection, is constant and does not depend on a grid choke inductance. The proposed method is characterized by a short diagnosis time and full effectiveness. To validate the proposed diagnostic algorithm Matlab/Simulink has been used.