Linear circuit-oriented model of photovoltaic array using optimization algorithm

Output voltage -current (I-V) characteristic of the photovoltaic arrays is nonlinear. In equivalent circuit model, this nonlinear nature is applied by diodes. In this paper, a new modelling method for the electrical equivalent circuit of photovoltaic cell is presented. Nonlinear characteristic of I-V output in this method is approximated by parallel branches made by linear circuit elements. The number of branches is variable, so that increased number of branches will reduce the approximation. An optimization algorithm is used to determine the parameters of elements in the equivalent circuit. The algorithm enables the simulation software to not only optimize the parameters in the circuit, but also apply the effects of changing temperature and radiation on the model. The above modelling has been implemented in MATLAB software, and numerical simulation has also been done to evaluate the accuracy and precision of performance, of which the results are presented in detail.