Modeling of series-connected photovoltaic cells

This paper proposes a new model for series-connected photovoltaic (PV) cells, using a modified one-diode equivalent-circuit model. The PV modules comprise many series-connected cells to generate more electrical power. This modified model starts with the conventional one-diode equivalent-circuit (parallel-connected current source with a diode and a shunt resistance which are connected in series with a series resistance and a load) of PV cells and then proposes a new way of connecting the aforementioned circuit elements. The advantage of the presented modified model, is that it can model the series-connected PV cells by a new representation of one-diode equivalent-circuit. To validate the results of the modified model, similar input variables are applied to the conventional and the presented models. The current/voltage (I/V) characteristics are then calculated from both models and compared. The results show that the difference between the calculated I/V characteristics using the two models is much less than 1 percent. The presented approach can thus, be very useful for researchers or engineers to quickly and easily determine the performance of PV modules.