Research On Rectifer Of DC Traction Power Supply System For The Urban Rail Transit

With the development of the national economy and the increase of the traffic, as a new traffic facility, urban rail transportation is used more and more widely. The next few years will become the significant time of the development of the urban rail transportation. The research on Harmonic Suppression of DC Traction Power Supply System for the Urban Rail Transit is becoming the researching hotspot on international and native.There are two-kind ways on Harmonic Suppression of DC Traction Power Supply System for the Urban Rail transportation: one is used passive Harmonic Suppression which is in using, such as installed filter-device in network side; Another is used active Harmonic Suppression, which adopted multiphase rectifier to increase pulses at the DC side. At present, widely use of 12-pulse rectifier set even equivalent 24-pulse rectifier set. However the good application of high power factor rectifier in other fields, to replace uncontrollable rectifier in urban rail transportation to be possible, so decrease harmonic produce from headstream.Firstly,to promote the widely use of 24-pulse rectifier set, the paper discusses the principle of multiple superposition of three-phase rectifier. Due to harmonic pollution in the urban rail transportation rectifier unit 12 phase,24 phase rectifier, using voltage source PWM rectifier instead of traditional rectifiers are put forward in this paper.This paper analyzed the principle of PWM rectifier in detail, then deduced the mathematical model of three-phase PWM voltage source rectifiers(VSR), from manipulative angle standpoint, using voltages pace-vector PWM modulation's(SPWM) direct current control ways , adopting the double-loop control for three-phase PWM voltage source rectifiers,then deduced three-phase PWM rectifiers which based on SVPWM and its theory and computing steps are described in detail. At the same time, using MATLAB simulation model to modeling and simulation on this system.,also deduced the engineering design method of the parameters of the main circuit of three-phase PWM rectifiers, which based on the SPWM control method. It used the designed parameters of the current circle and the voltage modulation and it also used the parameters of the main system units into the system simulation model. It built up a simulation on the Power Supply System for the Urban Rail Transit, and compared the result of the simulation with the result of the simulation of the traditional 12-pulse, 24-pulse rectifier. As the result it is indicated the voltages pace-vector PWM rectifiers have many excellent characteristics such as undistorted sinusoidal current waveform, unity power factor, and bi-directional energy flow and low harmonic disturbance. And the simulation base on a real environment of DC traction power supply system for urban mass transit is done, testified the control ways and the way for designing parameters of the system are all useful, and also testified that the use of three-phase VSR in DC traction power supply system for urban mass transit is available.