Frequency-domain approach to calculate steady-state of a stand-alone photovoltaic system

This paper presents a frequency-domain (FD) approach to calculate the steady-state of a stand-alone photovoltaic (PV) system. The PV array is represented as a Thévenin equivalent for stationary conditions, simplifying its nonlinear performance. The boost converter (BC), which acts as voltage regulator and performs maximum power point tracking (MPPT), is modeled as a FD equivalent based on the matrix representation of the discrete Fourier transform (DFT). Switching actions of the BC are accounted for by partitioning the DFT transformation matrix according to the switching-on and switching-off times. MPPT is performed via an iterative process using the duty ratio of the BC as the feedback variable. The proposed approach achieves fast computation of the periodic steady-state compared to traditional time domain modeling methods. An illustrative example is presented and validated using the PSCAD software.