The accurate estimation of the state of charge (SOC) for lithium-ion batteries’ performance prediction and durability evaluation is of paramount importance, which is significant to ensure reliability and stability for electric vehicles. The SOC estimation approaches based on big data collection and offline adjustment could result in imprecision for SOC estimation under various driving conditions at different temperatures. In the traditional GM(1,1), the initialization condition and the identifying parameter could not be changed as soon as they are confirmed. Aiming at the requirements of battery SOC estimation with non-linear characteristics of a dynamic battery system, the paper presents a method of battery state estimation based on Metabolic Even GM(1,1) to expand battery state data and introduce temperature factors in the estimation process to make SOC estimation more accurate. The latest information data used in the optimized rolling model is introduced through the data cycle updating. The experimental results show that the optimized MEGM(1,1) effectively considers the influence of initial data, and has higher accuracy than the traditional GM(1,1) model in the application of data expansion. Furthermore, it could effectively solve the problem of incomplete battery information and battery capacity fluctuation, and the dynamic performance is satisfactory to meet the requirements of fast convergence. The SOC estimation based on the presented strategy for power batteries at different temperatures could reach the goal of the overall error within 1% under CLTC conditions with well robustness and accuracy.

The shield multiconductor cable has been widely utilized in smart power grid with the characteristics of compact structure, low loss, high current carrying capacity and less environmental pollution. To achieve the accurate estimation of shield multiconductor cable for electromagnetic application, the partial element equivalent circuit (PEEC) topology with high-frequency parasitic parameters is established, and the distributed parameter model with Γ topology is proposed to describe the dynamic transmission features. The skin and proximity effect of shield cable can affect current distribution density, and the trivial solution with insufficient model estimation accuracy will result in the fitting residuals. Thus the R-L ladder based on N -branch topology is analyzed, and the vector fitting iteration strategy achieves the accurate approximation and fast convergence for the estimation model. Considering the continual charging and discharging characteristics caused by high-frequency dv/dt and di/dt , Neumann Law and Mirror theory are employed to derive the partial capacitance of shield multiconductor cable model. Finally, the simulation and test results with the presented cable model for conducted EMI assessment are performed on the test bench, the reliability of the parameter estimation is experimentally verified and its effect on high-frequency conducted interference is accurately characterized.