H∞ Filter-based Online Battery State-of-Charge Estimator for Pure Electric Vehicles

The development of an online battery SOC estimator using an H-infinity filter for pure electric vehicles equipped with a Lead Acid battery pack is presented. The procedure followed in the computation of the battery parameters is discussed along with the methods used in the selection of the H-infinity filter parameters. A simulation based H-infinity estimator is presented together with a hardware based estimator. An analysis of the results is shown in the later sections showing a hardware estimator capable of providing outputs with errors as low as +/- 6%. Finally, a discussion on the limitations of the hardware estimator together with a few recommendations for improvement is presented.