Design Of Slave Control Unit Of Wireless Battery Management System Based On S9KEAZ128

The environmental and resource problems caused by the sharp increase of fuel vehicles are increasingly prominent,because of the advantages of high energy utilization rate and low pollutant emission,electric vehicles have been widely concerned.The BMS is an important device of electric vehicles,which can realize various functions such as detection of various parameters of the battery pack,balanced management of the battery pack and temperature control.Designing a high-performance BMS is of great significance for improving the service life of battery packs and ensuring the safe driving of electric vehicles.After analyzing and comparing traditional battery equivalent models,the design builds a second-order RC equivalent circuit model.The parameters are identified by HPPC discharge test,and built the simulation circuit to verify the accuracy of the model.The design use the CKF to estimate SOC,and built the simulation circuit model of SOC estimation in Matlab/Simulink to verify the accuracy and robustness of the algorithm.The design use a balancing strategy based on SOC and terminal voltage,which can effectively improve the balancing efficiency.The connection and laying of traditional wired BMS communication lines are more difficult,the location of the fault point is difficult to determine when the line fails,and the layout is not convenient for subsequent optimization.Select nRF2401 RF chip to build a wireless communication module for communication between central unit and management unit,which effectively overcomes the above shortcomings.After completing the hardware circuit construction,use the uVision keil MDK to write the program of each sub module,and verify whether the code is correct.Experimental data shows that the battery management unit of the BMS can complete the accurate detection of battery parameters,and can interact with the battery central unit through the nRF2401 wireless communication circuit.In case of abnormal conditions such as over temperature of battery pack,the battery management unit can send alarm information in time.After optimization of estimation principle,the average error of SOC estimation can be controlled within 3%.Adopt the improved equilibrium strategy,the standard deviation of cell voltage level off to zero.