Characterisation of spectral and angular effects on photovoltaic modules for energy rating

This thesis presents work aimed at the development of practical and simplified methods for advanced characterisation of PV modules while reducing energy yield estimation uncertainties, focusing on the spectral and angular effects. In this work, practical characterisation method to measure the spectral response (SR) curve of PV modules have been developed based on the polychromatic method. Improvement of the method have been achieved through the development of new measurement setup and detail evaluation of the polychromatic fitting algorithm. Set of coloured plate with unique transmission profiles supplemented with a smaller number of optical bandwidth filters used in the measurement setup resulted in high throughput irradiance (the lowest is measured at 150 W/m2). High uniformity of the throughput irradiance over the measurement plane contribute to low uncertainty in the measurement of short-circuit current where the highest estimated uncertainty lays within the uncertainty margin for the STC measurement, at 2.5%. Measurement of optical/electrical of device under test with associated uncertainty are combined with the fitting algorithm through the Monte-carlo simulation method. The uncertainty in the final determination of SR characteristic gave the value of 7%, with about ±10% agreement between the SR curves obtained through the polychromatic method to the conventional monochromatic method. The measurement of angular response developed in this method employed the indoor measurement setup with the additional turn table attachment. The evaluation of divergent light of the non-ideal light source and the accuracy in angle adjustment of the turn table have been quantified and incorporated into the angular response measurement as uncertainties. Partial illumination method are applied for a reliable extraction of operating current in the measurement of PV modules with the uncertainty estimated at 1%. 4% variation in the measurement of angular dependency of various PV devices at high tilt angle have been realised which translate to about 1.5% difference in the simulated annual energy performance. The application of the same simulator in the development of spectral and angular response measurement in this work creates the potential for the angle-dependent spectral response characterisation on module scale. This have been realised through a simulation. Low uncertainty in energy yield is important as this indicate the risk in the investment of PV project. Detail evaluation with accuracy and uncertainty analysis of the works to be described will further improve the uncertainty in the measurement of spectral and angular response of PV modules, hence better accuracy in the assessment of energy yield can be achieved

Validation of spectral response polychromatic method measurement of full size photovoltaic modules using outdoor measured data

This paper presents the validation of a polychromatic method of spectral response measurement applied to full size mono-crystalline silicon photovoltaic modules using outdoor measured data. The difference between short-circuit current modelled from the measured spectral response and outdoor spectral irradiance and the directly-measured current is below 5% which confirms the validity of the spectral response curve obtained using the polychromatic measurement method

Spectral response measurements of photovoltaic devices using a pulsed source solar simulator

This paper presents a method for spectral response determination of photovoltaic devices using a commercially available pulsed source solar simulator and broadband filters. A fitting algorithm which is an iterative process is developed to model the spectral response curve. The method is tested on two different technologies of photovoltaic modules and the result shows that a fair agreement between the modelled and calibrated spectral response could be achieved with the improvement in the quality of measurement