A comparative study of equivalent circuit models of ultracapacitors for electric vehicles

This paper comparatively examines three types of equivalent circuit models for ultracapacitors. They are the classic model, the multi-stage ladder model and the dynamic model. These models are consciously selected from the state-of-the-art lumped models reported in the literature. A test rig is developed and used to load the ultracapacitor and to collect the test data. The genetic algorithm (GA) is employed to extract the optimal model parameters based on the Hybrid Pulse Power Characterization (HPPC) test. The performance of these models is evaluated and compared by measuring the model complexity, accuracy, and robustness against "unseen" data collected in the Dynamic Stress Test (DST) and a self-designed pulse test (SDP). The validation results show that the dynamic model has the best overall performance. (C) 2014 Elsevier B.V. All rights reserved.