Flexible Fractional Supercapacitor Model Analyzed in Time Domain

Supercapacitors have been rapidly adopted to replace batteries in many instances from power tools to automotive and aviation. Designing systems incorporating supercapacitors necessitate an accurate model of supercapacitor to maintain system efficiency. However, due to varying impedance property of supercapacitor, modeling becomes critical with likelihood of introducing errors. This work proposes an enhanced model to predict the system dynamics under various initial state of charge in supercapacitors. The proposed flexible model is suitable to represent actual supercapacitor impedance without prior assumption on the model structure. The use of one model to cover the other various impedance structures is simple and possible to estimate accurate supercapacitor’s impedance. Selection of impedance structure is self-regulated to improve the accuracy with minimum variables. To illustrate the variable structure fractional model, experimental results are shown with three different values of supercapacitors from three different manufacturers.