Enhanced State-of-Charge Estimation for Lithium-Ion Batteries Using a Fractional-Order Sliding Mode Observer

In order to estimate the state-of-charge (SoC) of lithium-ion batteries, this study presents a fractional-order sliding mode (SM) observer. Due to nonlinearities and uncertainty in the dynamical models of these power sources, a precise estimation of their state of charge (SoC) necessitates the implementation of an effective and nonlinear observer. In their performance, the sliding mode observers exhibit chattering behaviors and extended convergence time. However, the proposed fractional order sliding mode observer addresses these issues by providing reduced chattering and convergence time. Next, we select a suitable control rule based on the principles of Lyapunov stability theory to guarantee a decrease in the Lyapunov function. In order to create the intended FNTSM observer, we take into account an equivalent circuit model (ECM) for the battery, which incorporates uncertainty. We validated the stability and effectiveness of the developed technique using simulation results.