Dynamic modeling and characterization of ultracapacitors for electric transportation

Abstract

In order to capture real-time characteristics of ultracapacitors (UCs), especially for electric transportation applications, they need to be modeled dynamically. Dynamic models provide accurate estimation of UC charge/discharge responses to varied inputs. Dynamic models are useful in predicting the behavior of UCs under varied load conditions. Also, it is critical to build an accurate UC model, which can be used for tests in various power electronics/drive simulation toolboxes. This paper aims at constructing an accurate dynamic UC model, which can estimate the output voltage without the extraction of the model parameters. The critical parameters have been determined dynamically from characteristic equations. The complete dynamic model is fabricated and simulation responses to charging and discharging pulses have been presented. Finally, the results obtained from the dynamic model are compared with the output voltage estimation results obtained from the popular equivalent RC-branch model.