The Research Of Test Technology For Mutual-fed Ground Traction System

Research, development and production of high power AC drive system need drive test system. Thorough research on the structure, control characteristics and energy optimization of AC drive test system has the important theory significance and application value for high power AC drive system test platform and domestic AC traction system.In this paper, based on the research on the development of Metro locomotive asynchronous traction test platform, the equivalent relation of dual motor shaft coupled mathematical model and the mathematical model of real metro AC traction system is analyzed. Based on study of the working principle of the testing platform. A DC link AC motor control strategy is proposed. The energy balance conditions are analysis, and the "dual inverter-motor " shaft coupled type asynchronous traction test platform is designed.In the LabVIEW graphical programming environment, the asynchronous traction test platform closed-loop debugging is designed. The debugging process by observed repeated step response to optimize closed loop parameters. By testing of single motor speed closed loop and the dual motor closed loop system and parameters optimization, the relationship of motor speed error and torque is thoroughly studied. Finally, by optimizing the speed closed-loop PI parameters and torque loop PI parameters to complete the dual-motor speed, torque independent closed loop experiments. Based on this constant load and constant speed test, the dynamic process of metro is simulated. Observation on the stator frequency error of two motors and the motor feedback speed and torque changes prove the correctness of the design.Constant load vary speed process and constant speed vary load process experiments show that: DC-link traction test system based on the the VVVF control of dual inverter has good steady-state performance and dynamic adjust capacity of speed and load torque control to simulate actual subway operation process.Finally, based on the real-time simulation of dSPACE system, a real-time test system is designed. By through comparison of various cases of motor phase current waveform and voltage waveform, the experimental results show that the operation of the system, consistent with the theoretical analysis.