A Novel Technique for Battery Parameter Estimation Using Equivalent Circuit Models
Battery systems play an indispensable role in the adoption of electric vehicles (EVs) and hybrid electric vehicles (HEVs). Continuous monitoring of battery systems is essential to assess their condition and operational dynamics, ensuring both optimal performance and safety. Although most monitoring functionalities rely heavily on accurate knowledge of the electrical equivalent circuit model (ECM) parameters, a great portion of existing parametrization methods require laboratory setups and are conventionally unfeasible in practice. This paper proposes a novel method to estimate the parameters of the Nth-order ECM using selective harmonic injections into the battery, which can be added on top of the load or charge current through the charger or the dc-link's dc-dc converter. The proposed method is needless to an optimization algorithm and can be implemented in any low-cost controller. To investigate the performance of the proposed method, the first-order and the second-order ECMs serve as examples, which depending on the order-of the considered ECM, consecutive noises are is injected on top of the charging current to derive the impedance of the circuit and estimate the ECM parameters. The obtained results show that the proposed approach can easily estimate the parameters of first- and second-order ECMs with respectively >99.4 % and >98.7 % accuracies.
