| For meeting the need of heightening speed, high-speed AC driving locomotive has become the preferred selection for developing railway in our country. Meanwhile, PWM inverters using high switching frequency device that shortens the rise time of PWM output pulse have been widely applied in high-speed AC driving locomotive. The propagation of high frequency PWM voltage wave in the cable leads to over-voltage at the terminals of the inverter-fed traction motor. At the same time, equivalent distribution parameters of high frequency circuit of the motor bring uneven voltage distribution between windings and it results in further higher electrical stress on the anterior windings, finally the failure of the windings insulation.In allusion to the problems mentioned above, firstly, the paper models the distribution parameter circuit of the cable and the high frequency circuit of motor through the transmission theory. Calculating it's parameters based on the structure and disposal of the cable. In addition, the finite element analysis is applied to analyze the electromagnetic field in the slots of the stator using ANSYS. The distribution parameters of the windings in the slots are calculated. Then, the paper analyzes mechanism of the appearance of the over-voltage at the terminals of the motor using the transmission theory, and the influencing factors on the magnitude of the over-voltage. The simulation results match basically with academic analyze, which validates simulation methods. With regard to high frequency circuit of the motor, the effect of distribution parameters on voltage distribution among windings is obtained.Based on the before-mentioned analysis, under the principle of reducing the over-voltage and improve voltage distribution, valid countermeasures to restrain the failure of motor insulation are brought forward such as inserting filters and improvement on the insulation structures of the inverter-fed traction...
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