Rational Approximation of a Three-Phase Photovoltaic System via TD-VF and NL-VF

This paper presents the rational approximation of a three-phase photovoltaic (PV) system via the time-domain vector fitting (TD-VF) and nonlinear vector fitting (NL-VF) techniques. A significant feature of both methods is that the transfer function is unknown, and input/output variables are sufficient data for the transfer function's dynamics characterization. The accuracy and robustness of both techniques are compared via an example. It is shown that NL-VF is an effective alternative to TD-VF for rationally identifying a system with nonlinear components, such as a PV generator.