Research On EMU Grid-side Converter Without LC Resonant Branch Network

With the rapid development of nationwide urbanization, there is a growing demand for intercity transportation. EMU becomes the preferred intercity transport with its flexible marshalling approach and excellent speed performance. LC filter circuit in EMU traction converters can increase weight, loss and reduce system power density. This thsis is supported by National Key Technologies R&D Program for the "12th Five-year Plan"—"Research on Hybrid EMU Key Technology and Typical Equipment Development", this thesis research on EMU grid-side converter without LC resonant branch network. This thsis proposes the control method of grid-side converter without LC resonant branch network, and the feasibility and effectiveness of the proposed method are verified by simulation and experiment.This thsis researches on EMU grid-network side converter system, introduces the topology model of grid-side converter using single-phase two level voltage type PWM rectifier, establishes a mathematical model of rotating coordinate system based on the research of control methods, and gives the control diagram. To elicit no LC resonant branch grid-side converter DC side hardware design method, this thesis introduces the LC resonance branch of grid side converter DC side hardware design, including the design of DC capacitor support resonant branch, by designing the parameters,this thsis calculates the power loss of the LC resonance circuit. Finally, the simulation verified the correctness of the calculation of loss.Based on the analysis of the two pulse generation mechanism of the DC side of the grid-side converter, the influence of the non LC resonant circuit on the network side current is studied. The DC voltage dynamic compensation and notch filter two LC resonant branch network side converter control method based on detailed and gives concrete realization means for notch filter method, gives a method of discretization in digital system. Finally, the simulation results of the two control methods mentioned are verified by Matlab/Simulink, and the advantages and disadvantages of the two methods are compared.This thsis researches on no LC resonant circuit of grid-side converter DC side secondary ripple suppression method, a design method of LC resonant circuit of grid-side converter DC intermediate support capacitor and verifies the correctness of the method to the existing two no LC resonant circuit in CRH EMU DC capacitor support actual parameters is introduced. Secondly, the influence of the multi carrier moving relative to the DC side current of the grid side converter is analyzed, and the parameter range of the design of the DC supporting capacity is given. At last, it summarizes the advantages and disadvantages of two methods, which are the suppression of DC voltage fluctuation and the control of grid side converter, to solve the problem of the effect of non LC resonant branch on the grid-side converter.This project builds the ground experimental platform of grid-side converter, the LC resonant circuit network side converter control experiments are carried out to verify the proposed method. The simulation results are agreed with the foregoing theoretical analysis of experimental results, verify the validity of the control method proposed in this thesis.