Kalman filtering state of charge estimation for battery management system based on a stochastic fuzzy neural network battery model

Extended Kalman filtering is an intelligent and optimal means for estimating the state of a dynamic system. In order to use extended Kalman filtering to estimate the state of charge (SOC), we require a mathematical model that can accurately capture the dynamics of battery pack. In this paper, we propose a stochastic fuzzy neural network (SFNN) instead of the traditional neural network that has filtering effect on noisy input to model the battery nonlinear dynamic. Then, the paper studies the extended Kalman filtering SOC estimation method based on a SFNN model. The modeling test is realized on an 80 Ah Ni/MH battery pack and the Federal Urban Driving Schedule (FUDS) cycle is used to verify the SOC estimation method. The maximum SOC estimation error is 0.6% compared with the real SOC obtained from the discharging test.

► A novel extended Kalman Filtering SOC estimation method based on a stochastic fuzzy neural network (SFNN) battery model is proposed.
► The SFNN which has filtering effect on noisy input can model the battery nonlinear dynamic with high accuracy.
► A robust parameter learning algorithm for SFNN is studied so that the parameters can converge to its true value with noisy data.
► The maximum SOC estimation error based on the proposed method is 0.6%.