Advanced dynamic simulation of supercapacitors considering parameter variation and self-discharge

In this paper, dynamic simulation of the equivalent circuit model of the supercapacitor, taking into account the parameter variations and self-discharge, is discussed. Self-discharge is modeled with equivalent impedance including a constant phase element (CPE), and the parameter variations depending on the voltage are reflected. Since it is difficult to directly simulate the ZARC element (R-CPE parallel circuit) with a circuit simulation tool such as the professional simulation program with integrated circuit emphasis (PSPICE), equivalent transformation to three R-C parallel circuits is introduced in the simulation. The accuracy of simulation with the model is then verified through a comparison with results of an experiment. The comparison shows that the model using a CPE is effective in representing the dynamic characteristics and self-discharge of supercapacitors. Accordingly, it proves that the method proposed in this study can be useful in developing systems that include supercapacitors, and can be applied in an integrated simulation of a supercapacitor and a power electronic system.