Offset-free ECM based SOC estimation using H-infinity observer

In battery management system (BMS), the sampled current signals are always contaminated by colored noises, which make the accurate battery state of charge (SOC) estimation hardly be achieved. Existing methods for current noise processing are too complex to be adopted in engineering applications. By augmenting the model states with current bias, this paper presents an offset-free equivalent circuit model (ECM) based H-infinity observer to weaken the colored noise for accurate SOC estimation, the SOC estimation convergence accuracy and observer robustness can be effectively improved, and the simulation results validate its effectiveness.