In order to estimate the charge of battery exactly when the charging or discharging current with nonlinear uncertainty,an adaptive nonlinear damping based observer was proposed.With an adaptive parameter,the observer estimates the state of charge and the uncertainty in the current simultaneously.The proposed observer can well dominate the effects of the uncertainty caused by the voltage fluctuations,actuator failure or sensor measurement noise,etc on the estimation of charge.It was proved that the estimation errors are uniformly bounded.Furthermore,with well designed parameter,the estimation errors can reach arbitrarily small values.Simulation results illustrated the effectiveness of the proposed robust daptive battery charge observer.
