Daylight photoluminescence imaging of photovoltaic systems using
inverter-based switching
Abstract
Daylight photoluminescence imaging of crystalline silicon photovoltaic
modules is demonstrated for modules embedded in rooftop and
utility-scale systems, using inverters to electrically switch the
operating point of the array. The method enables rapid and high-quality
luminescence image acquisition during the day, unlocking efficient
performance and quality monitoring without the need to connect specific
electrical hardware or to make any modifications to the system wiring.
The principle of the measurement approach is discussed and experimental
results from a 10 kW DC residential rooftop system and
from a 149 MW DC utility-scale photovoltaic power plant
are presented. Measurements were performed using commercial inverters
without modifications to the inverter hardware or firmware. In the case
of the utility-scale power plant, the daylight photoluminescence image
acquisition of modules connected to a central inverter was obtained from
a remote piloted aircraft. Data analysis includes the conversion of
photoluminescence image data into implied voltage differences.