This data set contains Matlab files for calculating the frequency response function of the complex model described in the dissertation Nonlinear Frequency Response Method for Process Identification and Forced Periodic Operation Analysis: Application on Proton Exchange Membrane Water Electrolysis by Tamara Miličić. The model was also published in a journal article by Miličić et. al., Processes, 2022, 10, 2417, doi: 10.3390/pr10112417, and the frequency response functions were discussed in a journal article by Miličić et al., Chemical Engineering Journal, 2024, 496, 153889, doi: 10.1016/j.cej.2024.153889.