Temperature-Irradiance Matrix and Determination of Temperature Coefficients of a Monocrystalline PV Module

Abstract

Photovoltaic (PV) modules performance testing and energy rating as described in IEC 61853-1 standard depend on electrical performance parameters (short-circuit current, open-circuit voltage, maximum-power) of PV modules as a function of temperature and irradiance. In this work, in order to precisely determine the effects of temperature on the electrical parameters of a monocrystalline PV module, the temperature controlled, xenon light based solar simulator system with irradiance attenuating masks was used. This solar simulator, according to the IEC 60904-9 standard in terms of spectral match, spatial non-uniformity and temporal instability has A+A+A+ classes which are two times better than the standard requirements for a solar simulator to be used in PV module measurements. Moreover, the thermal chamber used in this work is a closed type chamber with fast opening door for not allowing the distortion of temperature uniformity over the surface of PV modules under test. Within about 2 m × 2 m area within 15 °C to 75 °C temperature interval, the temperature uniformity obtained for this system is less than 1.0 °C which is almost two times better tha n the IEC 60891 standard requirements (±2.0 °C ). The temperature and irradiance dependent measurements of the electrical performance parameters of a mono-crystalline PV module at various irradiance levels and the evaluation of its temperature coefficients [ α (% °C - 1 ), β (% °C - 1 ) and δ (% °C - 1 )] were done by implementing the interpolation method described in IEC 60891 standard.