Application diversity and power level of proton exchange membrane (PEM) fuel cells are growing continuously. Therefore, suitable models and software tools are needed to study fuel cell behaviour in connection to electric energy systems. These models calculate the output voltage of fuel cell systems based on their output current, in real-time. Suitable fitting of the model to a specific PEM fuel cell system is crucial to calculate fuel cell system’s output voltage based on its output current (load current).
The present paper demonstrates a simple approach to fit an electrical circuit to PEM fuel cell systems demonstrating their dynamic performance. This approach uses a simple polynomial model fitting to estimate circuit parameters based on the output voltage and current. Using the polynomial model, circuit parameters can be adjusted to generate a defined dynamic output voltage. A simple three-element (RL) circuit has been chosen to find its parameters using the proposed approach.