A simple lumped-equivalent circuit of a photovoltaic panel for transient simulations

An equivalent circuit of a photovoltaic (PV) panel for transient analysis is proposed in this paper. The circuit is based on a conventional equivalent circuit consisting of a photo current and a non-linear resistor for expressing DC characteristic of the PV panel. The transient characteristic is modeled by linear lumped-elements additional to the model. The equivalent internal inductance of the panel is theoretically derived by reducing a multi-phase inductance matrix. The parameters of the lumped circuit are derived from a measured transient responses of a voltage and a current at a short-circuit fault. A program estimating the circuit parameters from the measured result is developed in this paper. In the program the equivalent circuit is divided into two for avoiding instability and for reducing the calculation time. The circuit parameters are obtained by iterative approximations for each circuit. The proposed equivalent circuit can express a high frequency characteristic as well as DC characteristic.