Research On Single-Phase Injection Type Hybrid Active Filter Used For Harmonic Elimination Of Electric Railway

The leetrifiedrail way is the trendofrail way transport development for its Prominent advantages.But, the hamronic and reactive components produeed by eleetrieal loeomotive not only caues added losses and reduce the utilization artio of the traction transformer,but, also influence the stability and sceurity of eleetrical power system.So, hamronic control and reactive component compensation about traction power system attract lots of interests.In order to inhibit harmonics real-time and effectively, people proposes various solutions: passive power filter,active power filter and hybrid active power filter technology. Active power filter technology has some advantages of little effect by the grid impedance,be dynamic tracking,general power quality compensation compare with the passive power filter, it play a leading role in contralling pollution of power supply systems. Papers gives the harmonic detection method of electrified railway From both the detection accuracy and speed of dynamic response. Then, analyzes the control problems of hybrid active power filter, includs the control strategy of active power filter, control mode of current tracking control circuit, control of capacitor voltage DC side,and gives appropriate control methods.Traction power supply system is a high-power single-phase rectifier load, while the cost of active power filter and the capacity is proportional,it is uneconomic if inhibits harmonics of traction power supply system by using a separate active power filters.Thus, papers introduces a single-phase into the hybrid active power filter to inhibit harmonics, by increasing fundamental resonant circuit to further reduce the capacity of active filter section between active and passive links,as a results,it reduces the cost, improves filter performance of the system and enhances stability, plays a important role in improving the functions of dynamic and tracking compensation, achieves better compensation effect.Finally, it establishs a system model and does simulation analysis by simulink of MATLAB power system simulation software. It verifies the single-phase injection hybrid active power filter is feasible in the harmonic control of traction power supply system by simulation data,graphical analysis and cost comparisons of the passive filter,shunt active filters,series and parallel hybrid active filter and the single-phase injection hybrid active power filter which the paper introduces.