ЕКСПЕРИМЕНТАЛЬНЕ ВИЗНАЧЕННЯ ПОТОКУ СОНЯЧНОГО ВИПРОМІНЮВАННЯ ІЗ ЗАСТОСУВАННЯМ ПАСПОРТНИХ ПАРАМЕТРІВ МОДУЛЯ ФОТОЕЛЕКТРИЧНИХ ПЕРЕТВОРЮВАЧІВ

Abstract

To organize natural studies of the energy characteristics of photovoltaic systems, data on the current level of solar radiation incoming to the receiver surface are required. When using standard methods for measuring of the solar radiation flux, specialized meteorological instruments or reference solar cells are applied. Such devices are quite expensive. At the same time, an ordinary serial solar cell or module can also play the role of a reference cell under the stipulation that its passport characteristics are known for some radiation intensity. In this paper, a method for determining of the solar radiation flux based on the passport parameters of photovoltaic modules under standard test conditions and the values of short-circuit current and module temperature directly measured in natural conditions is proposed. Based on the equation of the solar cell current-voltage characteristic and the linear dependence of the short-circuit current and the temperature on the light flux a mathematical expression for solar radiation flux is obtained. This expression relates solar flux to the short-circuit current under standard test conditions, the temperature coefficient of the current and the measured values of the short-circuit current and the module temperature. It is shown that proposed method for determining of the solar radiation flux is correct and can be used in practice. A convenient for practical application analytical expression has been obtained for a silicon photovoltaic module 120P/12. The expression makes it possible to determine the incited on the module surface solar flux from the measured values of the short-circuit current and the module temperature. Experimental testing of the developed method was carried out for the module 120P/12 as an example. It is shown that fluctuations in the short-circuit current from 0.73 A to 0.76 A observed during the measurements correspond to changes in the solar radiation flux in the range from 105 W/m 2 to 110 W/m 2 . Keywords: solar radiation flux, solar cell, short-circuit current, temperature, temperature coefficient of the current, standard test conditions