Nonlinear Modeling and Observer for Supercapacitors in Electric Vehicle Applications

Abstract

In Hybrid Electric Vehicle (HEV) the estimation of the state of charge (SOC) of storage systems is one of crucial issues. Indeed, the SOC depends on the internal voltages which are not accessible for measurement. In this paper a nonlinear observer allowing the estimation of the supercapacitor internal voltages is proposed. Using theoretical analysis and simulation it is proven that the proposed non-linear observer gives an accurate estimation of the SOC.