PV Cell Model by Single-diode Electrical Equivalent Circuit

This paper models PV cells as a single-diode electrical equivalent circuit. It extracts the parameters of the equivalent circuit through Thevenin-Norton transformation at three remarkable operation points such as open circuit condition, short circuit condition, and maximum power operating condition where the voltage and current are commonly provided by manufacturers. Since the slopes of the PV cell characteristic I-V curve at those operating points are associated with series resistance and shunt resistance of the electrical equivalent circuit, equivalent resistance at maximum power operation point, gradients of these three slops can be used as the boundary conditions to solve the unknown values of PV cell equivalent circuit. With this regards, this paper provides complete set of simultaneous equations to solve any type of PV cell models as single-diode equivalent circuit named by K-algorithm. Proposed method is advantageous as it not only describes the I-V curve of initial PV cell products that manufacturers ensure by the characteristic datasheets, but also properly describes the deformed I-V characteristic curve of practically aged PV cells by just measuring the voltage and current values of at three remarkable operating points.