An approach for SOC estimation based on sliding mode observer and fractional order equivalent circuit model of lithium-ion batteries

A state of charge (SOC) estimation method based on sliding mode observer (SMO) and fractional order equivalent circuit model (FOECM) of lithium-ion batteries is presented. A fractional order equivalent circuit model was applied to model the lithium-ion battery and the sliding mode observers were designed to compensate the errors and uncertainties which are caused by the model in modeling. The convergence of the sliding mode observer is guaranteed by the Lyapunov inequality equation. The results of simulation experiment for the presented approach show the proposed method can estimate the SOC efficiently and accurately with good performance.