Design And Realization Of DEMU Traction System Ground Debugging Test-bed

The DEMU project is carried out by CNR Changchun Railway Vehicles Co.Ltd and Beijing Jiaotong University. Developing traction converter and auxiliary converter for train that meets requirement is the work of laboratory. AC drive test rigs with equivalent power are needed to provide good test site for the research of high power AC drive systems. So this dissertation designs a twin inverter-motor reciprocal power-fed AC drive test system for DEMU.Firstly, this dissertation introduces the research background and significance of DEMU. Then the development of AC drive technology of electric traction is introduced. The necessity of test system is also discussed.According to the requirement of testing DEMU, two high voltage DC power supplies and a25kV50Hz power supply for network side converter are designed. Because single-phase power frequency of traction power supply system is a three-phase unbalanced load for electric power system. A balancing conversion device is designed to solve the problem of imbalance.Then, the dissertation introduces the vector control, including key issues such as coordinate conversion, magnetic field orientation, voltage decoupling, flux calculation, SVPWM and so on. Motor control block diagram of vector control is established and the dynamic and static performance of control system is verified in MATLAB.Finally, this paper introduces the existing AC drive test rig including their respective advantages and disadvantages. In this paper, the structure of the test bench is identified as a twin inverter-motor reciprocal power-fed AC drive test system.And then the joint control strategy based on speed closed-loop of the traction motor, torque closed-loop of load motor is proposed. The dynamic and static performance of control system is verified in MATLAB at last.Simulation and test results show that twin inverter-motors reciprocal power-fed system using the above control strategy has good static performance, good performance of speed and load torque adjustment and the availability of the train traction and braking condition simulation.