Research And Design Of Multi-channel Data Acquisition System For Lithium Battery Packs Control

With economic development and social progress,the number of cars all over the world is increasing sharply,resulting the environmental pollution problems becoming more serious.Electric vehicle has received widespread attention because of its green environmental protection.As the power source,battery pack plays an important part of electric vehicles.A stable and reliable power management system can be safety and reliability,and improve the service life and cost savings.As an important guarantee for the safe operation of electric vehicles,the power management system is an important data acquisition system with high precision,high speed,and high real-time.In this thesis,a multi-channel data acquisition system is proposed for real-time monitoring of lithium battery packs based on Kalman filter algorithm to realize dynamic estimation of battery state of charge.The system is mainly composed of four parts,including analog-digital(AD)signal conversion subsystem and so on,which can realize the collection,processing,calculation and transmission of multi-channel signals.The AD conversion subsystem simultaneously converts the analog signal parameters of voltage and temperature of multiple lithium batteries and outputs them in the form of data.The data acquisition and calculation subsystem based on FPGA is the core,which is responsible for configuring each part of each AD conversion subsystem for data acquisition,eliminating the data error through the internal filter module and performing range conversion and the operation is finally output to the ARM host computer subsystem through the FSMC bus.The ARM host computer subsystem sends out the instructions according to the data analysis results,and transmits it to the charging and discharging control subsystem through the SPI communication module of the data collection and calculation subsystem to control the batteries charging or not,thus completing the monitoring of the battery pack.Finally,the overall implementation and debugging of the data acquisition subsystem system is completed.Debugging and test results show that all modules in the system are operating normally with small resource occupancy.Randomly,26 sets of 128 test sets are selected and compared with reference data.The results show that the accuracy is close to 100%.Based on the study of the Kalman filter battery charging algorithm,a multichannel data acquisition system architecture is proposed and designed which realizes temperature and voltage multiplexing.This architecture completes the filtering,sorting and maximum value of multi-channel data based on hardware The calculation also introduces the voltage scaling factor parameter,which solves the problem of different ranges in the process of collecting multiple different types of data.The system can be widely used in an efficient charge and discharge management system for multi-lithium battery packs such as electric vehicles.