Machine learning-driven SoC estimation for Li-Ion batteries using optimized nonlinear predictive modelling
摘要
State of Charge (SoC) needs to be SoC needs to be accurately measured in order to guarantee the safety, reliability, and functionality of electric powered systems including electric vehicles and energy storage units especially when the Lithium-Ion (Li-Ion) battery is involved. The nonlinear and time varying characteristics of the Li-Ion batteries pose challenges to conventional SoC estimation methods, which provide lower accuracy with changing load profiles and change in environmental conditions. In order to address such constraints, this paper presents a hybrid SoC estimation model, combining a Nonlinear Auto-Regressive Moving Average with exogenous inputs (NARMAX) model and an Adaptive Sunflower Optimization Algorithm (ASOA). The algorithm uses Principal Component Analysis (PCA) to decrease the number of dimensions and find significant features between measurements of voltage, current, and temperature in order to obtain the appropriate variables and derived indicators. The modelling process of the NARMAX-ASOA methodology will improve the precision of modelling as it can consider the complex interdependences throughout the time and parameters within the model are optimally optimized. The results demonstrate the effectiveness of the proposed solution of the performance evaluation, which are the root mean square error (RMSE) 1.12, the mean absolute error (MAE) 0.87, the mean absolute percentage error (MAPE) 1.53, and the