Optimal SoC Estimation Considering Hysteresis Effect for Effective Battery Management in Shipboard Batteries

The energy storage is critical in shipboard systems since there is no alternate energy in case of primary energy source failure. Hence, a battery management system (BMS) is necessary to monitor the state of the battery. Since a BMS operates the battery based on its state, an accurate estimation of the state of charge (SoC) is essential. Hysteresis is predominantly present in lead–acid batteries, whose effect is generally not accounted for in existing SoC estimation methods. In this work, the effect of hysteresis on SoC estimation is considered and the differential evolution-based SoC estimation technique is applied to accurately estimate the SoC while minimizing the hysteresis effect. A dynamic charge and discharge dynamic model of a 100-Ah lead–acid battery with ship thruster load is used to study the battery hysteresis. The battery model with the proposed SoC estimation and the BMS algorithm is simulated in MATLAB/SIMULINK 2018A and is tested under different charging and discharging conditions. The proposed model is validated in a real-time testbed comprising of a 62-Ah lead–acid battery connected to a 25 HP thruster of a boat. From the test results, it has been demonstrated that the proposed estimation algorithm reduces the estimation error thereby achieving an accurate SoC.