Balancing circuit control for supercapacitor state estimation

In this paper, an original technique for monitoring the aging of supercapacitor energy storage system is proposed. The aging of supercapacitor is represented by the degradation of its internal parameters as the loss of capacitance and the increase of the Equivalent Series Resistance (ESR). This degradation is continuous until reaching the end of life criteria. The proposed approach is based on estimating the current ESR, of each storage system element with a fast control of the balancing circuit present at the terminal of each storage element. The fast control is applied for a short moment and could be applied at any storage system state with no incidence on the system. The information about this current parameter makes the state of health monitoring possible. The analysis is performed using simulation with realistic storage system models in order to demonstrate and validate the effectiveness and the accuracy of the proposed technique. The results presented covers storage system such as supercapacitor but could be also applied to batteries.