This paper proposes a new method to modeling a power inverter of grid-connected photovoltaic system
by using a nonlinear system identification technique based on the Hammerstein–Weiner model. In this
method, the system is considered as a black box of which it is not necessary to know structures and
parameters inside. A nonlinear system identification, which is composed of nonlinear blocks and linear
blocks, has been processed and synthesized yielding the modeling from only measured inputs and outputs
of the system. An inverter of a grid-connected photovoltaic system has been tested and its model
determined. Results on modeling the voltage, current and power waveforms have accuracies of 98.13%,
95.02% and 91.05% respectively. The mathematical model being the representation of the system can
be analyzed and provide characteristics on controllability, stability, power quality, power flow.