State of charge estimation of lead acid battery using a kalman filter

For saving energy, lead acid battery plays an important role in photovoltaic system. Battery state of charge estimation is a key function of battery management system due to the requirement of ensuring optimum operation and safety. Therefore, for achieving a fiable operation, it is necessary to develop an accurate model for the estimation of the state of charge (SOC) of battery. In this paper, a RC equivalent circuit model has been presented. A state representation of battery has been developed. A kalman filter has been proposed to determine the SOC. The model of battery and the recursive algorithm have been implemented on Matlab-Simulink and Simpower softwares. Recovered simulation results have been compared by an experimental works applied to a lead acid battery 12V,7Ah. Obtained results show an acceptable correspondence with the experimental test. The kalman filter approach can be an useful tool for researchers to imitate the real behaviour of the battery and to ensure the accurate estimation of SOC.