Measurement of EDLC Equivalent Circuit Constants based on Energy Method

Abstract

To improve the accuracy of measurement method for EDLC's equivalent circuit constants of internal resistance R and capacitance C, an energy based method is developed in this paper. The most important feature of the method is that we focus on the voltage V_c not at circuit terminal but at capacitance element and, using V_c and differential capacitance, estimate the discharge energy of U. This enables us to determine the energy loss at resistance I²Rt and then the effective values of R and C from I²Rt and U respectively. Through the theoretical discussions and test results, we confirm the effectiveness of the proposed method.