Abstract：Usually，the DC side of the traction rectifier requires a series LC resonant circuit to filter out the

pulsating component of 2 times the grid frequency. When the resonant inductor on the DC side had a short-circuit

fault，the pulsating component would be transferred to the motor side，the problems such as torque ripple and noise would occur in traction motor. Therefore，aimed at the short-circuit fault of traction rectifier resonant inductor，the corresponding method of fault diagnosis and fault-tolerant control was proposed. First，on the basis of establishing the mathematical model of traction rectifier and analyzing the second harmonic generation mechanism，the fault diagnosis method based on notch detector was introduced. Secondly，the fault-tolerant control algorithm of combining voltage dynamic compensation with low-pass filter was proposed. Finally，the proposed fault diagnosis and fault-tolerant control method was studied by simulation. The results show that the fault can be found accurately and quickly by the fault diagnosis method，the second harmonic content of the output voltage on the DC side also can be reduced effectively by the fault-tolerant control algorithm and improve system stability in case of failure.

      Key words：traction rectifiers；resonant inductance；voltage compensation；low-pass filter；fault diagnosis

and fault-tolerant control