The Research Of Harmonic Characteristics And The Methods Of Harmonic Suppression Of High-speed Railway Power Transmission

In recent years,the high-speed railway has been rapidly developed in our country.At the same time,grid power quality problems which cause by high-speed railway are more and more serious.Harmonic has serious impact on the grid power quality.It will not only cause energy waste,but also have negative impacts on other electrical equipments.The harmonic generated by high-speed railway is different from the ordinary electric locomotive.Therefore,the researches of the harmonic problems caused by the high-speed railway and the corresponding suppressing measurements have great significance.On this background,the main work of this paper is as follows:Firstly,the paper has a research on the telex system components of the high-speed EMU and their various components.have analyzed theoretically.The high-speed EMU traction system's power supply modes are studied deeply,at the same time analysis each mode's advantages and disadvantages.Secondly,the operating principle of the two-level rectifier is sudied and it matical model has been built.Then the author analyzes the rectifier control methods which can not achieve the desire control effect due to the nonlinear system.On this basis and combining the rotating coordinate system,a current decoupling control method which control DC variables instead of AC variables is provided.After that,the entire simulation model of the control system to verify the effectiveness and feasibility of the control method is built.Thirdly,harmonic generation mechanisms of high speed emu telex system are analyzed and it effect on primary equipments,secondary equipments and communication system are researched at the same time.The paper has a study on measured data of traction substation in the midland,and analyzes the characteristics of the high-speed EMU traction load.Then the simulation model of the high-speed EMU traction drive system is built in the Matlab/Simulink simulation software to analyze the simulation results of single or multiple motor car running state.Finally,the effectiveness of harmonic suppression methods by improving the structure of inverter and the control method of rectifier are researched.And the multiple carrier phase PWM rectifier technology which can reduce the AC input current harmonics and reduce the DC output voltage harmonic are verified through simulation.The inductive filtering technology used in the motor train unit is studied and the simulation model is built to verify the feasibility of the scheme and technical advantages of this program.