Real Time Li-Ion Battery Bank Parameters Estimation via Universal Adaptive Stabilization

Abstract

This paper proposes an accurate and efficient Universal Adaptive Stabilizer (UAS) based online parameters estimation technique for a 400 V Li-ion battery bank. The battery open circuit voltage, parameters modeling the transient response, and series resistance are all estimated in a single real-time test. In contrast to earlier UAS based work on individual battery packs, this work does not require prior offline experimentation or any post-processing. Real time fast convergence of parameters' estimates with minimal experimental effort enables update of battery parameters during run-time. The proposed strategy is mathematically validated and its performance is demonstrated on a 400 V, 6.6 Ah Li-ion battery bank powering an induction motor driven prototype electric vehicle (EV) traction system.

Battery State of Charge Management for an Electric Vehicle Traction System

“…The Chen and Mora (CM) circuit model is a comprehensive representation that captures the dynamic attributes of the battery's terminal voltage, and variations in battery parameters concerning SOC, and has undergone extensive experimentation over the last decade [13]. utilized in this study.…”

“…In this model, the state variable x 1 represents the battery's SOC, while x 2 corresponds to the voltage across R ts kC ts , and x 3 corresponds to voltage across R tl kC tl . The parallel combination R ts kC ts characterizes the short-term terminal voltage dynamics in response to fluctuations in discharge current, while the parallel combination R tl kC tl characterizes the long-term terminal voltage dynamics in response to variations in discharge current [13]. Eqs.…”

“…The lithium battery's E o curve was recorded through the technique described in Ref. [13]. Furthermore, MATLAB was employed to determine the variables a 1 through a 6 in Eq.…”

“…The remaining parameters of the lithium-ion battery model, as specified in Eqs. ( 6)-( 9), are acquired using the APE technique [13]. The R s constants a 19 through a 21 can be obtained by fitting Eq.…”

“…The R s constants a 19 through a 21 can be obtained by fitting Eq. ( 10) with curve R s x 1 t ðÞ ðÞ versus x 1 t ðÞ [13]. The values for parameter a 1 through a 21 are provided in Table 4 in Ref.…”