Takagi–Sugeno Observer Design for Remaining Useful Life Estimation of Li-Ion Battery System Under Faults

Among the existing estimation schemes of a battery state of charge, most deal with an assumption that the faults will never occur in the system. Nevertheless, faults may have a crucial impact on the state of charge estimation accuracy. The paper proposes a novel observer design to estimate the state of charge and the remaining useful life of a Li-ion battery system under voltage and current measurement faults. The approach starts with converting the battery system into the descriptor Takagi–Sugeno form, where the state includes the original states along with the voltage and current measurement faults. Moreover, external disturbances are bounded by an ellipsoid based on the so-called Quadratic Boundedness approach, which ensures the system stability. The second-order Resistor-Capacitor equivalent circuit model is considered to verify the performance and correctness of the proposed observer. Subsequently, a real battery model is designed with experimental data of the Li-ion 18650 battery delivered from the NASA benchmark. Another experiment deals with an automated guided vehicle fed with a battery of which the remaining useful life is estimated. Finally, the results are compared with another estimation scheme based on the same benchmark.