Design Of Power Battery Management System For Subway Engineering Vehicles

Urban rail transit as the best way to solve urban traffic congestion in recent years has developed rapidly,the level of subway equipment is also rising.The air and noise pollution caused by the operation of traditional internal combustion-type engineering vehicles in subway tunnels has been a troubled problem,with the advancement of power battery technology,there have emerged power engineering vehicles that use batteries as their power source.At present,battery-powered engineering vehicles are in a period of development.the management of battery packs is still relatively simple,there is still a gap with the increasingly perfect battery management system for electric vehicles,it only detects the voltage and capacity of battery pack.For this reason,this dissertation references the power battery management technology of the electric automobile,and studies the management system of the battery of the subway engineering vehicle.This dissertation first discusses the selection of the power battery for subway engineering vehicles,and analyzes the advantages of lead-acid batteries as the power battery for locomotives.Then,the characteristics and failure modes of the lead-acid battery are analyzed,and the factors causing the failure of the lead-acid battery are evaded in the design process of the battery management system.Therefore,the designed battery management system should include necessary functions such as real-time monitoring of key battery parameters,battery state of charge estimation,battery safety protection,balanced battery management,and information exchange with the vehicle control system.The overall architecture of the battery management system is proposed based on above requirements.In particular,the single-cell voltage acquisition method of the battery pack and the equalization control method of the battery pack are demonstrated in detail,and a corresponding scheme is established.The battery management system designed consists of a main control module,multiple acquisition modules,an equalization module and a host computer display module.The main control module uses NXP's MC9S08DZ60 MCU chip,which mainly receives the cell voltage,temperature,current and alarm information from the acquisition modules,calculates the SOC,and communicates with the upper computer.Each acquisition module adopts NXP's MM9Z1₆38 battery management chip,and one module can simultaneously detect the voltage,temperature,and current of 4 cells and upload them together with alarm informationto the central control module.The main control module communicates with the acquisition modules via the CAN bus.The equalization module uses the active equalization method to balance the battery packs.In the following,the basic circuit of the main control module and the main chip of the acquisition module,the voltage,current,temperature acquisition circuit,battery equalization circuit,communication interface circuit and its corresponding software of the acquisition module are designed in detail.In order to facilitate the user to monitor the state of the battery pack in real time.Based on the Qt development environment,the upper computer display interface is designed to realize the interaction between the user and the system.In addition,the SOC of the battery pack is estimated using a combination of the Ah integration method and the open-circuit voltage method.Finally,based on the program development environment Code Warrior,BDM debugger U-Mltilink,4 lead-acid batteries and battery acquisition board,an experimental platform is set up for basic functional testing.Through the experiment,the battery single cell voltage,current,temperature and SOC are tested.The functions of estimation and equalization control can be achieved,the system designed basically can meet the design's expected goals.