Dual Kalman filter-based SoC/SoH estimator for an ultracapacitor module

This paper presents the design of a dual adaptive Kalman-filter-based state and parameter estimator of an ultracapacitor module suitable for state-of-charge (SoC) and state-of-health (SoH) estimation purposes. A lumped-parameter resistive-capacitive (RC) electrical circuit representation has been used in the design of both estimators. In the case of state estimator a second-order disturbance model has been used for charge balancing current modeling purposes, while in the case of parameter estimator, a time series model of ultracapacitor is extended with a generalized disturbance model describing balancing current effects. The effectiveness of the dual Kalman filter-based SoC/SoH estimator has been verified by means of computer simulations and experimentally on the dedicated ultracapacitor test setup.