Simulation Research On Auxiliary Power Supply System Of China Standard EMU

With the rapid development of railway industry in China,the number and operation mileage of Electric Multiple Unit(EMU)allocated by various railway bureaus are increasing continuously.Domestically developed China standard EMU plays an important role in railway transportation.This proposes higher requirements for the design and development level of vehicle manufacturers.It has become an impending problem for all manufacturers to solve that how to rapidly design high-performance trains that satisfy the demands according to different requirements.The auxiliary design based on computer simulation provides a solution to this problem,which has become an important research direction at present.The power supply capacity and quality of Auxiliary power supply system(APSS),an essential part of EMU,directly affect the safety and stability of EMU.Recently,various research institutes have carried out extensive and profound research on its internal single components,which use MATLAB~?and other simulation software for modeling and simulation analysis.However,the simulation of a single component usually fails to reflect the collaborative and associated states among the system modules,which is also inconvenient to realize the overall design and rapid verification of the system.Therefore,this work focuses on studying the overall simulation technology of the system,which takes the APSS of China standard EMU as the research object.By introducing the modular design thought,the computer overall simulation platform of EMU's APSS has been designed,sequentially providing computer simulation basis for the rapid design and performance verification of the EMU's APSS.In this paper,the overall structure,working control logic and the characteristics of each single module of APSS have been firstly studied to form the overall framework of the simulation platform.Based on the component of system,the single modules,such as auxiliary inverter,charger and battery modules,are respectively learned from aspects of topology model and working principle.The mathematical model of auxiliary converter under different coordinate system has been established and the parameters of the three-phase LC filter has been designed to restrain the high harmonic.Additionally,the working principle of the charger has been analyzed and then dynamic model of the large signal and the small signal of the post-class whole bridge two electrical level DC/DC converter has been deduced,providing theoretical support for the research of key control technology in the overall simulation of APSS.Secondly,the overall simulation control technology of APSS has been studied,which realizes the joint simulation of each part of the system.In order to solve the cooperative working problem of multiple auxiliary converters,the double closed-loop decoupling control strategy of single auxiliary converter has been established on the foundation of the mathematical model under d-q rotating coordinate system.By analyzing the mechanism of circulation generated by multiple auxiliary converters in parallel,the droop control method with virtual impedance has been adopted to solve the problem of unequal power distribution in traditional droop control and to improve the current-sharing characteristics of the system.In order to solve the problem of step charging by connecting the charger to the battery bank,a control strategy has been designed to reach the requirements of constant current and constant voltage charging in the five stages of the battery bank.Finally,based on the overall simulation study of the APSS,the computer simulation platform of the APSS has been designed.According to the real operating conditions of the Chinese standard EMU,the system has been integrally simulated and analyzed through the simulation platform.Compared between the input and output of the system components under the same operating conditions of the real EMU,it showes that the simulation platform is feasible.The overall simulation platform of the APSS can be further applied in the design of the novel vehicle's APSS,so as to provide reference for the subsequent field application and maintenance work.