RT info:eu-repo/semantics/doctoralThesis
T1 Non-invasive electroluminescence and photoluminescence imaging through module-level electronics in photovoltaic power plants
A1 Redondo Plaza, Alberto Gregorio
A2 Universidad de Valladolid. Escuela de Doctorado
K1 Energías renovables
K1 Photovoltaic
K1 Fotovoltáica
K1 Power electronics
K1 Electrónica de potencia
K1 Electroluminescence
K1 Electroluminiscencia
K1 Photoluminescence
K1 Fotoluminiscencia
K1 33 Ciencias Tecnológicas
AB Photovoltaic technology has experienced a rapid increase in global capacity in recent years, becoming one of the renewable technologies with the highest growth potential. Proper maintenance and operation of PV power plants require module inspection techniques to detect faults and analyse degradation, which could reduce power output or pose safety risks. Among the most common inspection methods for field-deployed modules are current–voltage curve tracing, infrared thermography, and luminescence imaging. Luminescence imaging (electroluminescence and photoluminescence) is particularly valuable, as it reveals the inner structure of solar cells, enabling fault detection and performance analysis, although its integration in PV plants is limited by practical constraints.Conventional luminescence imaging relies on EL signal acquisition in dark conditions, requiring module disconnection, external power supplies, and nighttime measurements. These requirements make it invasive, time-consuming, and logistically complex, unsuitable for inspecting thousands of modules. Novel approaches overcome these limitations by enabling measurements under daylight without disconnection, typically through modulation of electroluminescence or photoluminescence signals and post-processing to remove sunlight signal. This thesis explores a technique based on module-level electronic devices to enhance signal modulation.For this purpose, an electronic architecture has been designed and validated, enabling the modulation of both electroluminescence and photoluminescence signals. By installing this device in each module where modulation is required, non-invasive electroluminescence and photoluminescence imaging can be achieved. Moreover, these measurements do not require external energy sources such as power supplies, and image acquisition can be performed during daytime while the photovoltaic power plant operates under normal conditions.In addition, different approaches for processing image sequences acquired during luminescence signal modulation have been explored. First, time-domain processing has been studied using two strategies: a synchronous strategy, which requires continuous communication between the electronic device that modulates the signal and the camera that captures the images, allowing direct labelling of each picture according to its emission state; and an asynchronous strategy, which does not require continuous communication but instead relies on an algorithm to automatically classify the images. Secondly, frequency-domain processing based on the Fast Fourier Transform has been successfully validated, enabling background removal when the luminescence signal is modulated using any periodic waveform.Finally, photoluminescence signal modulation has been integrated into the topology of a module-level PV optimizer. In addition, current–voltage curve tracing has also been incorporated. Taken together, a module-level electronic device with extended functionalities and only minor hardware modifications has been developed and validated. The device integrates maximum power point tracking alongside non-invasive photoluminescence modulation and non-invasive current-voltage curve tracing, two inspection techniques that are conventionally invasive.
YR 2025
FD 2025
LK https://uvadoc.uva.es/handle/10324/81927
UL https://uvadoc.uva.es/handle/10324/81927
LA eng
NO Escuela de Doctorado
DS UVaDOC
RD 21-ene-2026