In This research, the fuzzy logic (FC) method was used to calculate the main parameters of photovoltaic cell. Some of the basic silicon solar cell parameters were measured in the laboratory. A fuzzy logic method is used to demonstrate and compared the value of the solar cell's parameters corresponding to I-V curve of this cell. The results showed that the fuzzy logic method is very suitable for comparing the optimal values of the photovoltaic cell parameters.

In the present work, our goal is to define the Cartesian product of two generalized normed spaces depending on the notion of generalized normed space. It is a background to state and prove that the Cartesian product of two complete generalized normed spaces is also a complete generalized normed space. Furthermore, the definition of the pseudo-generalized normed space is introduced and essential concepts related to this space are discussed and proved.

The purpose of this work is to present the concepts of a compact soft fuzzy metric space and totally fuzzy bounded space. The definition of a soft fuzzy metric space is first listed with its basic important properties. Then, the main theorems related to the compact soft fuzzy metric space and totally fuzzy bounded space concepts are proved. In particular, if is a soft fuzzy metric space with the property that is compact, then it is totally fuzzy bounded. Moreover, we prove the fact that a totally fuzzy bounded and a complete soft fuzzy metric space must be compact.

The fuzzy set technique has been used in order to investigate PV parameters in this paper. These parameters are determined in the laboratory practically. Then, the fuzzy set technique is applied in order to examined and analyzed the optimal data of PV parameters theoretically. The results of the parameters obtained are compared which is a simple technique for the calculations. The results showed that the proposed technique is very suitable and accurate for the investigation.