Input Current-Based Diagnosis Scheme for Power Transistor Open-Circuit Faultin Traction Converter

In this paper, a novel method for fault diagnosis and location of traction converter for AC/DC drive is presented. This scheme compares the input current of the system under normal and fault condition. The fault state is obtained by the distinction and the fault location is identified by the fault diagnosis table. The diagnosis variable is the polarity of current error, eliminating the complicated calculations and avoiding the influence of load variation on the current. The fault detection device is simple, which can be directly included in the existing converter system without any increase of system complexity. The digital signal of fault diagnosis is achieved by using simple hardware, which significantly improves the ease of maintenance on the traction converter . The proposed method has a short diagnosis time, and it took only two fundamental periods to determine the diagnostic results. The simulation model is established in Matlab/Simulink software platform, and the effectiveness of the fault diagnosis method is verified by experiments.