Novel supercapacitor model parameter identification methods

Supercapacitor based energy storage system has been applied in different power level applications for years. Due to its ultra-high capacitance and capacitor characteristics, it is ideal for high power short duration circumstances, such as regenerative braking in electric vehicle, transient frequency control in power grid. For all such supercapacitor applications, an accurate model of supercapacitor is essential for analysing its behaviour under various operating conditions. Many different electrical models have been proposed to improve accuracy under different conditions, such as the three branch model, ladder model, and transmission line model. The associated parameter identification methods are also important in improving model accuracy. Different models are reviewed in this paper, and its applicable conditions for each model are discussed. Two novel parameter identification methods are proposed, which provides better accuracy in describing supercapacitor discharge behaviour with a simplified experimental test. The mathematical model and experimental comparison are provided to verify the new parameter identification method.