Simulation Study On Train Traction Control

Traction system is the train’s power source for the normal operation, which is also the key to ensure the train fast and stable operation on railway lines. With the continuous improvement requirements for life quality of modern people, we are increasingly concerning about the safety and comfort of train travelling, which requires traction control system being further improved so that the train start and braking are guaranteed with smooth transition, and improve passengers’ comfort.The five main parts of train traction control system include traction transformers, single-phase three-level pulse rectifier, DC link, three-level inverter and AC asynchronous traction motors. Firstly, this paper has made detailed introduction about the composition and function of these five parts, respectively. And then, with regard to the control strategies of each part, this paper has compared, designed and determined them. At last, using MATLAB/Simulink simulation software, the simulation model has been established for the train traction control system, the control strategy for each part has been simulated and verified.In this paper, with regard to CRH3-type train, the research has been undertaken. The part of three-level pulse rectifier uses PWM modulation scheme, and predictive current control strategy; the inverter section part uses the space vector pulse width modulation (SVPWM) to drive the traction motor, and the traction motor is the three-phase AC induction one whose control method is vector control. By MATLAB/Simulink, the traction control system has been simulated and verified. The simulation simulates the train speed, torque and stator current wave when a train at the conditions of startup, constant-speed operation, braking and their combination. Through simulation, we can see that, at those conditions, the stator current waveform of traction motor does not fluctuate greatly, and the motor torque is basically guaranteed to be in the stable trend, which indicates that the designed traction control method in this paper can meet the stable operation of the CRH3train and consequently realize the comfort of train operation.