Study On Active Compensation Device Of The Electrified Railway Based On Adaptive Harmonic Detection

In recent years,with the development of non-linear power electronic equipment,it has been widely used in electric railways.Taking non-linear load electric locomotive as an example,when it is connected to the power grid,large harmonic and reactive components will be generated and the grid voltage becomes fluctuating and asymmetric,which pose a serious threat to the safe operation of the traction power supply system and the public power grid.In order to solve this problem,an electric railway active compensation device based on adaptive theory harmonic detection was designed.The simulation results show that real-time compensation of harmonics and reactive current can be achieved.First of all,the paper described current research background and significance.according to the characteristics of the electric railway in China,a method of rectifying parallel hybrid active compensation was preliminarily formulated.Secondly,by consulting a large amount of related data and literature,the definitions and standards of harmonics were described.A mathematical model of main harmonic source of electric railway was built with MATLAB/Simulink software,and then analyzing the harmonic characteristics of traction power supply system and proving the necessity of harmonic control.Thirdly,the harmonic current detection algorithm and control strategy of the electric railway active compensation device were studied.By analyzing and comparing several commonly used detection algorithms,the adaptive harmonic detection method with good robustness and simple parameter design was selected.In order to improve the contradiction between dynamic response and detection accuracy,a modified adaptive harmonic detection method was adopted which can improve detection accuracy as well as ensure rapidity.By comparing the simulation results before and after improvement,we found that the improved detection method is faster and more accurate,so that it is more suitable for complex railway conditions in China.Finally,the overall simulation of the hybrid active compensation device was built to simulation compare the differences between before inputting the compensation device,only inputting the passive power filter and the hybrid active compensation device was input.After that,the hardware and software design of the hybrid APF was performed.An experimental prototype was built and verified in the laboratory,whose results were basically consistent with the simulation results.Therefore the correctness and feasibility of the hybrid active compensation device designed in this paper were then comprehensively proved.