The Research Of Cophase Traction Power Supply Control System

Electrified railway has large capacity, low running cost, long service life, environmental protection and energy saving advantages, make the development construction of electrified railway become inevitable trend. Determines its position and functions of the traction power supply system to meet the requirements of electric locomotive traction performance on one hand, on the other hand can not cause adverse effect to the public power grid. However the traditional electrified railway traction power supply system exists many problems:single-phase locomotive load will inevitably cause a negative sequence current in three-phase public power grid; Locomotive as the sensibility of nonlinear load, will bring three-phase power grid reactive power, harmonic pollution; The traditional phase sequence rotation, segmented split-phase power supply way makes the electric split-phase link is indispensable. Aiming at the existing problem of electrified railway traction power supply system, carried out extensive research both at home and abroad, including in phase power supply is a fundamental solution. Papers around the new cophase power supply topology and the corresponding control strategy study.This paper proposes a new type of cophase power supply topology without traction transformer. The topology input side to connect the public power grid, the output side directly to power supply catenary, adopt the way of the power electronic transform completed the public grid three-phase electric energy conversion function of single-phase catenary. Due to the volatility of train load, randomness, in order to improve the dynamic performance, establish without traction transformer with the small signal model of the power supply device, and proposed the amount of disturbance voltage and current double closed-loop feed-forward control strategy; In the output side of the control, adopts double voltage closed loop method, and using carrier phase shift technique, the output quality of catenary voltage; Line capacitor voltage balance control strategy, improve the speed of the bus bar balance and balance effect.In view of the cophase power supply mode combined with traction transformer, puts forward a new kind of topology. The topology using high-frequency multiwinding transformer, and connecting with the V/x type traction transformer, implementation in phase power supply. Traction transformer is proved theoretically equilibrium conditions, combined with V/x is given in phase of traction transformer power supply device of instruction current calculation method; Set up the high frequency and high frequency of multiwinding transformer H bridge physical model, and use the model to establish the relationship between the output power and output voltage phase Angle; Independent busbar voltage balance control strategy based on power balance, and the strategies and combined with active transfers, formed a complete cophase power supply device control strategy.The two topology based on PSIM simulation environment, the paper combined with the corresponding control strategies are simulated, the simulation results verify the proposed two kinds of topology and its control strategy is effective, and no traction transformer in experimental platform for experimental verification cophase power supply system, provides a new train of thought for the research of cophase power supply.