Estimating the state of charge of lithium batteries based on fractional-order sliding-mode observer

This paper considers estimating the state-of-charge (SOC) for lithium-ion batteries, that utilizes a fractional-order (FO) sliding-mode observer (SMO) is investigated. The capacity loss and deterioration resistance can be estimated by the FO SMO. Based on Mittag-Leffler stability theory, the FO SMO is designed and analyzed. The convergence property about FO SMO is shown by utilizing the Lyanunov-Krasovskii function. A key analysis technique is enabled by proposed a fundamental boundedness lemma. The proposed method is easily applied to SOC in order to illustrate robust control properties against system´s errors. The simulation examples are used to illustrate effectiveness of the proposed control scheme.