A Comparison of Different Methods for Battery and Supercapacitor Modeling

In future vehicles (e.g. fuel cell vehicles, hybrid electric vehicles), the electrical system will have an important impact on the mechanical systems in the car (e.g. powertrain, steering). Furthermore, this coupling will become increasingly important over time. In order to develop effective designs and appropriate control systems for these systems, it is important that the plant models capture the detailed physical behavior in the system. This paper will describe models of two electrical components, a battery and a supercapacitor, which have been modeled in two ways: (i) modeling the plant and controller using block diagrams in Simulink and (ii) modeling the plant and controller in Dymola followed by compiling this model to an S-function for simulation in Simulink. Both the battery and supercapacitor model are based on impedance spectroscopy measurements and can be used for highly dynamic simulations. The developed models will be discussed and comparisons between the two modeling techniques (i), (ii) and measurement data will be made. This paper shows that using Modelica, the modeling language used by Dymola to describe physical components, leads to increased model flexibility and faster model development. Furthermore, a Dymola generated plant model runs faster than the equivalent Simulink model when exported into the Simulink environment and run in conjunction with a Simulink controller model.