Study On Dc Traction Power Supply Of High Quality For Urban Mass Transit

Eliminating harmonic pollution and improving power factor are a very important task in the field of power electronics. Due to the prodigious proportion of medium and big electronic equipment in power line, the research of three-phase PWM rectifier is becoming the researching hotspot on international and native. So it is significant to bring it to the DC traction power supply system for urban mass transit.Firstly, to promote the widely use of 24-pulse rectifier set, the paper discusses the principle of multiple superposition of three-phase rectifier.On the basis of deriving the VSR' s mathematical model, the MATLAB simulation model is achieved, the VSR' s control ways are summarized and their features are pointed out.The control, based on active and reactive current, as a kind of direct current control strategy, is selected by comparing with other ways in this paper. The voltage space vector is selected as the PWM method, its theory and computing steps are described in detail. And then discusses two control ways based on SVPWM. One is the current decouple control, another way is current predicted control. The novel control tactic, based on predicted current, has a more simple structure and less variables, therefore it would be easier to achieve optimum response that use this way than other ways.The whole simulation module of control system is built up under the powerful MATLAB/SIMULINK platform, it can precisely reflect the system properties, and it makes the control tactics selecting and parameter confirmation become easier. And the closed loop 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.