The Study Of The Traction Converter In Electrical Multiple Units Of Crh5

With the rapid development of our economy, there are growing demands and more control technologies for high-speed trains. To accelerate the development of high-speed trains is of great significance.This paper tightly surrounds the traction converter used in CRH5for the study. There is a detailed analysis for the structures and principles of AC-DC converters, intermediate DC link and traction inverter. Transient four-quadrant pulse rectifier direct current control,forecast direct current control and Inhibition of the third harmonic feedforward compensation strategy, the carrier phase shift technology and SPWM modulation strategy are analyzed in detail. the principle of derivation and analysis of traction inverter using the magnetic field oriented vector control strategies and the use of a variety of ways SPWM modulation strategy are depth anaiszed. Four-quadrant pulse rectifier and the simulation circut of traction inverter are built in the Matlab. The secondary pulsation problem caused by the intermediate DC link is analyzed and a feed-forward compensation method based on repeated observations is well proposed to inhibits the beat frequency current and reduce torque ripple. The effectiveness of this method by building a simulation model in Matlab/Simulink is verified.Through the four-quadrant pulse rectifier, the simulation results show that the power factor of the network side voltage and current close to1in the traction conditions and close to-1in the regenerative braking conditions, while the intermediate DC voltage be able to achieve the regulator and low input current harmonic content features. At the same time, the use of carrier phase shift technology can eliminate the network side of the secondary current harmonics and reduce harm harmonics back to the grid. The traction inverter simulation results show that with the rising of the motor speed, the traction motor achieves running in constant torque and constant flux. Simulation results show that using repeated prediction observer can effectively reduce the secondary pulse and inhibiting beat current of the motor of the intermediate DC secondary ripple problem.Finally, the single-phase rectifier low-power hardware experimental platform was built independently based on TMS320F2812. the experimental results with the transient direct current control closed-loop show the effectiveness of such strategy.