Research On Traction Experiment System Of Subway Vehicle

With advances in technology and expansion of city, especially in large cities, urbanrail transit is playing a growing role and is prefered by citizens. Thus, the localizition ofurban rail transit technology is urgent. As the core of urban rail transit system, vehicletraction system becomes difficult and key in the localiziton process. Reference to tractionsystems of Shanghai Metro Line2and numerous other lines, an traction system inproportion of1to1is designed. The system includes a12-pulse transformer, a rectifier,aDC loop, an inverter, four190KW traction motors, three inertia flywheels, steel benchdamper motor and damping motor control inverter. In this paper, the subway vehicletraction system realizes data acquisition of motor speed and torque with NI card and SCM.The data is delivered to PC through Bus or serial, after which the control action is achieved.The study contents are as follow:1. AC and DC power supply for urban rail transit is analyzed, which is a theoreticalbasis of designing test system. Load resistance is analyzed, and the load mathematicalmodel is established, which provides theoretical basis for setting up the test bench.2. Based on the theoretical analysis, an model of three-level inverter vector controlsystem of the induction motor is established in Matlab/Simulink. The curve of outputvoltage of three-level inverter is obtained, from which the control performance of tractionmotor is showed.3. Reference to technical materials about traction systems of Shanghai Metro Line2and numerous other lines, hardware design and selection for traction motor, control devices,load system and interia system(three-level flywheel) is completed. An test bench of vehicletraction is built.4. Based on the Virtual Instrument Technology, the program including control paneland backgroud code is designed in LabVIEW. Runing on SCM and NI acquisition card, theprogram can capture the speed, current and voltage of traction motor, and control the speed of traction motor and torque of load motor. The load torque for traction motor is derivedfrom velocity and line resistance during runing. Adding load resistance timely for tractionmotor is fulfilled by closed-loop control on torque of load motor.5. An experiment on the simulated traction system is carried out in conditions of lightload, full load and overload. Much data under different conditons is acquired. The data ofexperiment results in different loads can be imported into Origin and showed in curves,which is convenient for comparative analysis of various conditions.