| The auxiliary power supply system of standard Electric Multiple Unit mainly supplies power for air compressor,cooling fan,oil pump / water pump motor,air conditioning system,heating,lighting,passenger information system and other important on-board auxiliary equipment,which is an important part of the power supply system of standard EMU.At present,the backup power supply of the auxiliary power supply system of the standard EMU independently developed in China is supplied by the nickel cadmium alkaline battery pack,which has some prominent problems,such as low bulk energy density,high self discharge rate,heavy metal pollution and poor service life and so on,seriously affecting the operation economy and safety of the whole system.Due to the significant advantages of lithium-ion battery over traditional alkaline battery,such as high energy density,low self-discharge rate,long cycle life,this paper carries out the exploration and research on lithium-ion battery management system aiming to the replacement of standard EMU auxiliary power supply based on the previous researches on the auxiliary power supply system of the standard EMU by our team,and studies the lithium-ion battery management system architecture suitable for standard EMU auxiliary power supply.On this basis,the accurate and reliable estimation method of lithium-ion battery state of charge and state of health is studied,and the reliable state of health management of lithium-ion battery pack for standard EMU is realized.The research contents of this paper mainly include the following three aspects:(1)Aiming at the estimation of state of charge and state of health of lithium-ion battery pack for standard EMU,an adaptive unscented Kalman filter algorithm is proposed,which achieves adaptive noise estimation based on unscented Kalman filter algorithm.The simulation results show that the state of charge and state of health estimation errors of the proposed method are1% and 2% respectively,which are 2% and 3% lower than those of the traditional unscented Kalman filter based state of charge and state of health estimation methods.(2)Based on the analysis and evaluation of the current design scheme of lithium-ion battery management system,a master-slave distributed architecture based on daisy chain communication is proposed for the lithium-ion battery management system of standard EMU auxiliary power supply substitution;and the wireless communication module is designed to realize remote data interaction,which provides the hardware basis for offline state of health estimation.The system hardware and software are designed based on the data acquisition,information communication and fault tolerance functions(3)On the basis of the above state of health estimation method and battery management system architecture design,the installation of lithium-ion battery management system for standard EMU auxiliary power supply substitution is completed and the experimental platform is set up.The core functions of the management system,such as data acquisition,fault alarm,passive balance,battery state of charge and health state estimation,are experimentally verified.The verification results show that the voltage acquisition error is±0.5V,the current acquisition error is±1%,The single voltage acquisition error is ± 2m V,and the temperature acquisition error is±1℃.The fault alarm and passive equalization function can work reliably,and the state of charge estimation error of the battery pack is 2%.After the experimental verification,a oneyear real vehicle verification of the system is carried out.Based on the collected system data,the estimation error of the state of health of the lithium-ion battery pack for the standard EMU is less than 5%.All function errors of the system meet the design requirements. |
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