Urban Rail Transit Power Supply System Modeling And Harmonic Suppression

Urban rail transit is an important part of urban transportation infrastructure.The power supply system of rail transit plays a very important role in its safe and reliable operation.At the same time,it is also a part of the urban power system,so the frequent starting and braking of trains will cause constant changes in the parameters of the power supply system,and produce harmonic interference,which has a negative impact on the power supply system.Therefore,it is of great significance to study the power supply system and harmonic suppression of urban rail transit.In this paper,the models and harmonic suppression of urban rail power supply system are studied,the research includes:Firstly,the development history and research status of urban rail transit power supply system at home and abroad,are comprehensively analyzed and summarized,besides the existing power supply system structure,model and harmonic suppression methods are compared.Secondly,The urban rail transit power supply system and the basic principles and characteristics of train operation are analyzed in detail,which provides a theoretical basis for building the simulation model.Thirdly,the simulation models of power supply part and locomotive part of urban rail transit power supply system are constructed respectively based on MATLAB/Simulink module library,the simulation results are as follows:1)The power supply part can output 1500 V DC power;2)The locomotive part can start and stop normally.Fourthly,the whole simulation models of single train and multi-train are established respectively,the simulation results are as follows: 1)The operation process of the locomotive under four operating conditions,such as starting,pulling,coasting and braking,is simulated in the whole simulation model of single train with the method of vector control,and the DC bus voltage of the power supply part is stable in the range of 1000 V-1600 V,so the model is reasonable and the operation result is reliable;2)The train running conditions under different working conditions are simulated,such as: time sharing start up,multiple trains running in the same time period,in the whole simulation model of Multi-train,besides fluctuations of voltage and current and corresponding harmonic distributions are analyzed.Fifthly,on the basis of analyzing the causes of harmonic generation,a chopper controller module is constructed to suppress harmonics,and harmonic components of multiple trains are effectively controlled.The simulation result shows that harmonic content of 1500 k V DC bus decreases by 31.64%,The traction substation has a harmonic content below 1.6%,and that the scheme proposed by this paper has the effect of stabilizing voltage and restraining harmonic component.The above research results provide a theoretical and experimental basis for the construction and operation of urban rail transit power supply system,and it has certain reference value for the design of power supply system.