Non-linear, hybrid terminal behavioral modeling of a dc-based nanogrid system

This paper addresses the two-port network behavioral modeling of the power converters for renewable energy sources that feature non-linear static behavior. Based on the Hammerstein´s approach, two models, non-linear dc and linear ac are both run simultaneously in the simulation while the dynamic model is constantly being updated with the operating point values from the static model, in order to include non-linear static behavior. The goal here is to develop a procedure for the terminal identification, so-called black-box modeling approach when engineers do not have an access to the internal structure, control and dynamics of the converters, but through appropriate measurements can extract needed information useful later for the system level simulations and stability analysis. The hybrid models of the source, interface and load converters have been shown in this paper, as well as the system-level verification with an average model.