SOC Estimation Research Based On AEKF For Lithium-ion Battery

The resource-saving and environment-friendly electric vehicle is the advance position and technical commanding point in the process of global technological revolution and industrial transformation.Now,the power density and operation life of battery in electric vehicle are the key factors and technical bottleneck,which limit the development of the electric vehicle.In the driving process of electric vehicle,the battery was charged or discharged intermittently with the complex road condition.The state of charge(SOC)was hard to estimate due to the nonlinearity mathematics model.Considering the influence of complex noise interference in the electric vehicle,the adaptive extended kalman filter(AEKF)was proposed for the SOC estimation of battery,which could optimize the operation,improve the utiliztion and extend the operation life of a battery.Firstly,the state space equation of LiFePO4 was built based on DP equivalent circuit model with two order filter.Then,this paper focused on the SOC estimation of battery with the method of AEKF,and simulation modeling and analysis were studied for this proposed method.In the last,the experiment research was proceed in the battery test bench.The experiment data shows that the changing voltage of battery can be followed accurately,and SOC of battery converges to the true value with any initial value.Using the DP equivalent circuit model,the parameters and SOC of battery were estimated based on AEKF.Considering the influence of complex noise interference in electric vehicle for AEKF,the adaptive filter theory was adopted,which decreased the noise interference for Extended Kalman Filter.Therefore,with the rising demand of power density and operation life in electric vehicle,the SOC estimation method in electric vehicle was explored.The research of this paper has very important application value,and it will be very helpful for expanding electric vehicle theory.