Research On Security Control Of EMU Line Side Converter System

With the development of high speed-railway, more and more impact on high-speed rail safety and stability, such as traction-line voltage fluctuations, voltage flicker, traction-line resonance and so on, which is a serious threat to the normal operation of high-speed railway.Grid side converter working as energy exchange unit between traction-line and EMU trains, plays a crucial role in in the electric traction system. Therefore, it is necessary to study the security control of EMU line side converter system, so as to improve the stability and safety of the EMU train and traction power supply system.First, in order to ensure the EMU run normally during traction-line voltage fluctuation conditions, this paper presents two control methods of line-side converter: (1)instantaneous current control based on the rotating coordinate system; (2)short delay dq decoupling control method. The decoupling control method with short time delay ensures good static performance, and improves the dynamic performance of the traditional dq decoupling control method. The short delay dq decoupling control is the best control method, and its excellent performance is verified by comparing the simulation results.In this paper, the traction network is simplified by combining the multi conductor transmission theory and the uniform transmission line model, the harmonic transmission characteristics of traction network and the characteristics of the traction network are analyzed by the simplified traction network model. In view of the traction network resonance phenomenon may occur, this paper presents traction network resonance suppression measures based on train traction transformer auxiliary filter winding. The proposed method is more simple to achieve, lower cost, and better compensation effect compared to the traditional method. In this paper, three topologies are given:single tuned filter, double tuned filter and high pass filter, and the design method of the parameters is described in detail.At the end of this paper, the high power test platform of hybrid power train is presented to verify the superiority of the proposed line-side converter control method. The simulation model of train traction and traction-line was built to verify the correctness of the proposed parameters design method and the superiority of the resonance suppression effect.