abstract
- © 2021 IEEE.This paper presents a reference model estimator for the state of charge of a battery based on a Thevenin equivalent electrical circuit model. State-of-charge estimation is essential in battery management systems across devices to plan operating times, charge profiles, and supply profile from battery to the load. The presented estimator is intended for an online application and uses the current and voltage at the battery terminals to perform the estimation. The battery is connected to a step-down converter of an extended conversion ratio that operates in closed loop with the objective of maintaining a DC constant voltage across a load. A control consisting of a current control loop and a voltage control loop is used to regulate the output voltage of the converter. The controller guarantees closed-loop stability and provides damped behavior and zero steady-state error for constant output voltage references. Numerical results are presented to evaluate the estimator based on the reference model.