A state of charge estimator for rechargeable batteries that operate under variable and repetitive charging and discharging conditions is proposed. The estimator is based on a state-space dynamic model of the battery which is obtained by modeling the kinetic of reactions and the diffusion phenomena. The state variables are the oxygen pressure, the concentrations of nickel active material and the concentrations of metal hydride active material. NiMH (Nickel-Metal Hydride) batteries are fabricated in sealed maintenance-free cells that do not allow the insertion of measurement probes, and the only possible measurement are current and voltage at the terminals of the battery. Such measurements are typically affected by noise and therefore an extended Kaiman filter is used as an estimator. By using the terminal current and voltage measurements, the concentrations are estimated in chemical species which are averaged on the thickness of the active material in order to obtain the state of charge of the battery. The estimator is tested on experimental data derived from typical operating conditions of from a 6.5 Ah NiMH batteries used in automotive hybrid vehicle.
State of charge Kalman filter estimator for automotive batteries
Kalman-Filter für die Schätzung des Aufladungszustandes von Automobilbatterien
Control Engineering Practice ; 14 , 3 ; 267-275
2006
9 Seiten, 12 Bilder, 15 Quellen
Article (Journal)
English
State of Charge Kalman Filter Estimator for Automotive NiMH Batteries
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