RT info:eu-repo/semantics/article T1 Electroluminescence Imaging Based on FFT Analysis for Outdoor Photovoltaic Module Inspection: A Self-Powered Signal Modulation Approach A1 Redondo-Plaza, Alberto A1 Velasco-Bonilla, Amy Zulema A1 Morales-Aragones, José Ignacio A1 Zorita-Lamadrid, Ángel L. A1 Alonso-Gómez, Víctor A1 Hernández-Callejo, Luis K1 Ingeniería Eléctrica K1 photovoltaics; module inspections; luminescence; electroluminescence; outdoor; solar cell failures; Fast Fourier Transformation K1 3306 Ingeniería y Tecnología Eléctricas AB Electroluminescence imaging is increasingly used in photovoltaic power plant inspections due to its effectiveness in detecting various types of failures in solar cells. This article presents a novel technique that enables the modulation of an arbitrary electroluminescence signal in PV modules using an electronic device that controls the signal by modulating an arbitrary current waveform in a photovoltaic module, utilizing the string current as its energy source. As a result, measurements do not require a power supplyand can be performed during the normal operation of a PV string. Throughout the paper, this method is compared to a more conventional approach that relies solely on a power supply to generate the current signal. Capturing a sequence of images while modulating the current with different waveforms allows the application of the Fast Fourier Transform to suppress background signals caused by sunlight, resulting in high-quality EL images. Experimental results demonstrate that the proposed method delivers imaging quality comparable to that achieved with a power supply, while effectively detecting a broad range ofsolar cell failures. Furthermore, the calculated signal-to-noise ratio for both approaches yields similar values, indicating comparable quality in quantitative terms. Finally, square wave modulation has shown slightly better performance than other waveforms, such as sinusoidal and half-sinusoidal modulation. PB MDPI SN 2076-3417 YR 2025 FD 2025-04-22 LK https://uvadoc.uva.es/handle/10324/75628 UL https://uvadoc.uva.es/handle/10324/75628 LA eng NO Applied Sciences, Abril 2025, vol 15, n.9 NO Producción Científica DS UVaDOC RD 08-jul-2025