Methodology for Studying the Current-Voltage Characteristics of Solar Cells in Artificial Conditions

The efficiency and productivity of converting solar energy into electricity using photovoltaic converters is significantly affected by the ambient temperature. That is, the ability of a photovoltaic cell to convert sunlight into electricity is most significantly affected by the operating temperature of the cell. And as a result, this affects the energy efficiency of solar-based power supply systems. Temperature has the greatest effect on the short-circuit current and open-circuit voltage of a photovoltaic cell. With increasing temperature, the open-circuit voltage can decrease significantly, and the short-circuit current increases slightly. However, the overall change in these parameters leads to a decrease in the maximum output power of the photovoltaic cell. Currently, there are no universal methods for regulating the impact of ambient temperature on photovoltaic systems. Therefore, for the correct design and installation of photovoltaic systems, it is necessary to pre-model their operation, ensuring the maximum possible range of optimal temperatures. During modeling, it is advisable to study the current-voltage characteristics and spectral characteristics of the photovoltaic cell. The purpose of the article is to analyze the methods and means of constructing and studying the current-voltage characteristics of silicon photovoltaic cells under different conditions of changing illumination and ambient temperature. To achieve this goal, the article proposes a structure for a measuring instrument installation for studying the current-voltage characteristics of photovoltaic cells in laboratory conditions. The installation should include: a solar radiation simulator, a cryostat, a calibrator-multimeter, a temperature controller, and a personal computer with appropriate software. Using a solar radiation simulator, the surface of the photovoltaic cell must be irradiated with different intensities and illumination. In this case, adjustments can be made using spectral filters. During simulation, measurements must be constantly performed for the entire current-voltage characteristic. The presence of a temperature control system (cryostat) in the circuit makes it possible to provide conditions for changing the ambient temperature. In addition, the installation includes a device for smoothly adjusting the distance between the sample and the solar radiation simulator. A calibrator-multimeter is used to generate and measure current, voltage, and resistance. The article presents a diagram of the heterostructure of a silicon photovoltaic cell. Since the current-voltage characteristic of a photovoltaic cell has an s-shaped bend, which creates a potential barrier between the zones of the main charge carriers, during modeling it is necessary to achieve such optimal values of temperature and illumination at which the height of the potential barrier will change and, as a result, it will be possible to get rid of the s-shaped bend of the current-voltage characteristic of the photovoltaic cell. The results of such modeling can later be used in the design at the initial stage of installation of power supply systems based on solar energy.