@article{HuettlGottschalkSchneideretal.2019, author = {H{\"u}ttl, Bernd and Gottschalk, L. and Schneider, S. and Pflaum, D. and Schulze, Achim}, title = {Accurate Performance Rating of Photovoltaic Modules under Outdoor Test Conditions}, series = {Solar Energy}, volume = {2019}, journal = {Solar Energy}, number = {177}, pages = {737 -- 745}, year = {2019}, abstract = {Outdoor performance analyses of photovoltaic modules can be advantageous compared to indoor investigations, as they take into account the influences of natural test conditions on the modules. However, such outdoor performance assessments usually suffer from poor accuracies due to undefined test conditions for the modules. This paper reports on a comprehensive concept for improved outdoor analysis which results in performance data with indoor laboratory precision. The approach delivers current-voltage characteristics for even more test conditions than required by the standard IEC 61853-1. Hence, curves of modules' electrical parameters above irradiance can be deduced for any temperatures. The concept allows precise determination of temperature coefficients for user-defined irradiances taking into account outdoor effects like light-soaking or light-induced degradation. The calibration and measurement uncertainty of the presented outdoor analysis method is evaluated quantitatively. For the measurements an advanced outdoor set-up was used.}, language = {en} } @inproceedings{SchoenauDaumePanhuysenetal.2024, author = {Sch{\"o}nau, Maximilian and Daume, Darwin and Panhuysen, Markus and Kreller, T. and Jachmann, J. and Schulze, Achim and H{\"u}ttl, Bernd and Landes, Dieter}, title = {Hindcasting Solar Irradiance by Machine Learning using Photovoltaic Data}, series = {Proceedings of the 41st EU PVSEC}, booktitle = {Proceedings of the 41st EU PVSEC}, pages = {5}, year = {2024}, abstract = {This work introduces an innovative approach to calculate high-accuracy solar irradiance data for effective asset management of photovoltaic plants using Machine Learning. Ground-based pyranometers are expensive and seldom maintained, while weather service providers face limitations in spatial and temporal accuracy. A novel irradiance data model is introduced, that combines satellite weather information with data from PV plants to reconstruct historical irradiance levels with high accuracy. Our method uses existing PV arrays as "virtual sensors" to capture the local operating conditions, specifically the local irradiance incident on the array. The model was developed and validated using data from 43 medium to large-scale PV plants and two high-precision irradiance sensors. Results show superior performance compared to satellite weather data. With a root mean square deviation of 71 W/m² for global horizontal irradiation and 133 W/m² for direct normal irradiation with 5-minute resolution data, the model is about three times as accurate as the satellite weather prediction. This approach offers significant advantages in spatial resolution, reliability, and cost-effectiveness over conventional irradiance data by satellites or sensors. Utilizing SMARTBLUE AG'S dense network of thousands of monitored PV plants, the proposed methodology will enable the accurate prediction of irradiance in Germany, significantly enhancing asset management capabilities for PV plants.}, language = {de} } @inproceedings{SchoenauDaumePanhuysenetal.2024, author = {Sch{\"o}nau, Maximilian and Daume, Darwin and Panhuysen, Markus and Schulze, Achim and H{\"u}ttl, Bernd and Landes, Dieter}, title = {Verbesserte Clear-Sky-Erkennung durch hybrides Maschinelles Lernen}, series = {Proceedings of the 7th Ret.Con, Nordhausen}, booktitle = {Proceedings of the 7th Ret.Con, Nordhausen}, pages = {8}, year = {2024}, abstract = {Die pr{\"a}zise Erkennung von Clear-Sky-Momenten ist f{\"u}r die {\"U}berwachung und Effizienzana-lyse von Photovoltaikanlagen von zentraler Bedeutung, da zu diesen Zeitpunkten definierte und model-lierbare Einstrahlungsverh{\"a}ltnisse herrschen. Es wird ein hybrides Modell zur verbesserten Erkennung von Clear-Sky-Momenten auf Basis von Einstrahlungsdaten vorgestellt. Hierf{\"u}r wurden zun{\"a}chst ma-nuell, dann mithilfe eines CNNs Merkmale aus den Einstrahlungsdaten gebildet. Eine Falls tudie mit Referenzdaten belegt, dass durch die Kombination dieser wissens-und datengetriebenen Methoden Clear-Sky-Momente zuverl{\"a}ssiger identifiziert werden k{\"o}nnen. Dadurch k{\"o}nnen Analysemethoden schneller und zuverl{\"a}ssiger Aussagen {\"u}ber die untersuchten PV-Anlagen treffen.}, language = {de} } @misc{SchoenauSchoenauDaumeetal.2024, author = {Sch{\"o}nau, Maximilian and Sch{\"o}nau, Elisabeth and Daume, Darwin and Panhuysen, Markus and Schulze, Achim and H{\"u}ttl, Bernd and Landes, Dieter}, title = {Improved Sampling of IV Measurements}, series = {Proceedings of the 41st EU PVSEC}, journal = {Proceedings of the 41st EU PVSEC}, publisher = {Proceedings of the 41st EU PVSEC}, doi = {10.4229/EUPVSEC2024/3AV.3.50}, pages = {3}, year = {2024}, abstract = {The measurement of IV curves is the most important characterization technique of photovoltaic devices. This work seeks to determine a fair sampling rate for IV curves. Traditional sampling methods, such as using equidistant voltage steps, result in biased data by over- and undersampling the measurement at different voltages, which affect critical evaluations such as maximum power point (MPP) determination as well as series and shunt resistance estimation. Therefore, an adaptive sampling approach based on calculating the arc length of the IV curve is proposed, aiming to distribute data points equidistantly along the curve. This method is intended to provide a more balanced representation of the measurement data across all segments of the curve. The results indicate that using this adaptive approach, the measurement points can be significantly reduced at lower voltages while maintaining essential data density at key characteristics such as the MPP, facilitating faster and more accurate assessments.}, language = {en} }