@inproceedings{MuellerSchulzeIsenbergetal.2010, author = {M{\"u}ller, M. and Schulze, Achim and Isenberg, J. and Hund, B. and Beyer, H.-G.}, title = {Influence of the water resistivity on the temperature coeffizients of industrial silicon solar cells and on the expected performance behavior}, series = {Proceedings of the 25th EU-PVSEC}, booktitle = {Proceedings of the 25th EU-PVSEC}, year = {2010}, language = {en} } @incollection{HinkenMilstedBocketal.2010, author = {Hinken, D. and Milsted, A. and Bock, R. and Fischer, B. and Bothe, K. and Sch{\"u}tze, M. and Isenberg, J. and Schulze, Achim and Wagner, M.}, title = {Determination of the Base-Dopant Concentration of Large-Aria Crystalline Solar Cells}, series = {IEEE Trans. Electronic Devices}, booktitle = {IEEE Trans. Electronic Devices}, publisher = {IEEE Electronic Devices Society}, address = {USA, North Carolina}, publisher = {Technische Hochschule Rosenheim}, year = {2010}, language = {en} } @article{AckermannGutewortQuinqueetal.2010, author = {Ackermann, N and Gutewort, V. and Quinque, M. and K{\"u}hne, M. and Stein v. Kamienski, E. and Schulze, Achim and Wichtendahl, R.}, title = {Final testing: a secure release gate towards module manufacturing}, series = {Photovoltaics International}, journal = {Photovoltaics International}, number = {8}, year = {2010}, language = {en} } @article{Schulze2009, author = {Schulze, Achim}, title = {Existence and stability of static shells to the Vlasov-Poisson System with a fixed central point mass}, series = {Mathematical Proceedings of the Cambridge Philosophical Society}, journal = {Mathematical Proceedings of the Cambridge Philosophical Society}, number = {146}, year = {2009}, language = {en} } @article{Schulze2008, author = {Schulze, Achim}, title = {Existence of axially symmetric solution to the Vlasov-Poisson System depending on Jacobi's Integral}, series = {Mathematical Proceedings of the Cambridge Philosophical Society}, journal = {Mathematical Proceedings of the Cambridge Philosophical Society}, number = {6/2009}, year = {2008}, language = {en} } @article{Schulze2006, author = {Schulze, Achim}, title = {Existence and stability of static shells to the Vlasov-Poisson system}, series = {Analysis}, journal = {Analysis}, number = {26}, year = {2006}, language = {en} } @inproceedings{GottschalkPflaumSchneideretal.2017, author = {Gottschalk, L. and Pflaum, D. and Schneider, S. and Schulze, Achim and Becker, F. and Queck, M. and H{\"u}ttl, B.}, title = {Evaluation of a compehensive IV- Outdoor Characterization Method for Photovoltaik Modules}, series = {Proceedings of the 33rd EU-PVSEC}, booktitle = {Proceedings of the 33rd EU-PVSEC}, year = {2017}, language = {en} } @inproceedings{TaubitzSchulzeKoentopp2016, author = {Taubitz, C. and Schulze, Achim and K{\"o}ntopp, M.B.}, title = {Potential-Induced Degradation: An improved unterstanding of mechanicm and infuence factors}, series = {Proceedings of the 32nd EU-PVSEC}, booktitle = {Proceedings of the 32nd EU-PVSEC}, year = {2016}, language = {en} } @inproceedings{WachterGottschalkSimmleretal.2016, author = {Wachter, M. and Gottschalk, L. and Simmler, M. and Schulze, Achim and Becker, F. and Sayala, M. and H{\"u}ttl, B.}, title = {Short-cicuit current measurement at clear-sky conditions on photovoltaik modules}, series = {Proceedings of the 32nd EU-PVSEC}, booktitle = {Proceedings of the 32nd EU-PVSEC}, year = {2016}, language = {en} } @inproceedings{KaiserSimmlerWachteretal.2015, author = {Kaiser, D. and Simmler, M. and Wachter, M. and Becker, F. and Sayala, M. and Kaden, T. and Schulze, Achim and H{\"u}ttl, B.}, title = {Concept for fast and precise PV Module Outdoor Characterization}, series = {Proceedings of the 31st EU-PVSEC}, booktitle = {Proceedings of the 31st EU-PVSEC}, year = {2015}, language = {en} } @inproceedings{SchulzeHuettlNeubertetal.2010, author = {Schulze, Achim and H{\"u}ttl, B. and Neubert, S. and Hund, B. and Luschitz, J. and Patzlaff, T.}, title = {2D Analysis of thin-film modules}, series = {Proceedings of the 25th EU-PVSEC}, booktitle = {Proceedings of the 25th EU-PVSEC}, year = {2010}, language = {en} } @article{SchulzeKoentoppTaubitz2020, author = {Schulze, Achim and Koentopp, M. B. and Taubitz, C.}, title = {A drift and diffusion model for PID-s in solar modules}, series = {IEEE Journal of Photovoltaics}, volume = {2020}, journal = {IEEE Journal of Photovoltaics}, publisher = {IEEE}, address = {USA}, pages = {6}, year = {2020}, abstract = {A quantitative physical model for potential induced degradation of the shunting type (PID-s) in solar modules is introduced. Based on a drift and diffusion approach for sodium ions and atoms, it gives insight into the kinetics of degradation and the corresponding regeneration. A simple drift/source term is used to describe the time-dependent flux of Na-ions towards stacking faults at the surface of the solar cell. The assumed transport mechanism for Na+ ions through the SiN-layer uses the modified Stern-Eyring rate theory but our approach can also be adapted to other mechanisms. Several PID-s and regeneration curves of one-cell solar modules at T = 49°C and T = 90°C with 1000V potential difference between modul frame and cell were measured and least-square fits of the in-situ measured parallel resistance Rsh to the model were performed giving very good accordance. Based on a few measurements, the model can predict PID-s and regeneration characteristics of solar modules under different conditions.}, language = {en} } @inproceedings{SchneiderHuettlPflaumetal.2020, author = {Schneider, S. and H{\"u}ttl, B. and Pflaum, D. and Schnell, V. and Schulze, Achim}, title = {Freifeldcharakterisierung von PV-Anlagen im Rahmen des Projektes PV- FeldLab -ein Statusbericht-}, series = {3. Regenerative Energietechnik Konferenz in Nordhausen}, booktitle = {3. Regenerative Energietechnik Konferenz in Nordhausen}, publisher = {RET.con 2020}, address = {Nordhausen}, year = {2020}, abstract = {Das Projekt PV-FeldLab verfolgt das Ziel, ein umfassendes Konzept f{\"u}r eine messtechnisch sehr pr{\"a}zise elektrische Freifeld-Charakterisierung von PV-Generatoren zu entwickeln. Es beinhaltet eine optische Untersuchung mittels drohnengest{\"u}tzter Thermografie und eine genaue elektrische Charakterisierung von PV-Anlagen im Freifeld, auch bei r{\"a}umlicher Inhomogenit{\"a}t von Bestrahlungsst{\"a}rke, Temperatur und bei variablen Aufbauwinkeln von Modulen im Strang. Die Verkn{\"u}pfung der elektrischen und optischen Messdaten erlaubt eine effiziente Untersuchung von PV-Anlagen und erm{\"o}glicht eine Pr{\"a}zisierung von Ertragsanalysen. Dieser Bericht beschreibt den ersten Projektabschnitt, in welchem der Fokus vor allem auf der Initialisierung der messtechnischen Komponenten, sowie ersten Messungen und Analysen liegt.}, language = {de} } @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{SchneiderHuettlGerstenbergetal.2019, author = {Schneider, S. and H{\"u}ttl, B. and Gerstenberg, L. and Wesselak, V. and Voswinckel, S. and Schulze, Achim}, title = {PV-FeldLab -Feldlabor f{\"u}r Vorort-Leistungsbestimmungen und Alterungsidentifikation von Photovoltaikgeneratoren}, series = {2. Regenerative Energietechnik Konferenz in Nordhausen}, booktitle = {2. Regenerative Energietechnik Konferenz in Nordhausen}, publisher = {RET.com 2019}, address = {Nordhausen}, year = {2019}, abstract = {Ziel des Projektes ist es, ein Verfahren f{\"u}r elektrische Vorort-Leistungsanalysen von Photovoltaik (PV)-Anlagen zu entwickeln. Dazu werden die elektrischen Parameter von PV-Strings lokal und global mit Hilfe eines neuen Feldlaboransatzes mit Indoor-Laborgenauigkeit vermessen. Das neue Messverfahren ist normgerecht und wird helfen, die Standardisierung von Feldmessungen weiterzuentwickeln. Im Projekt werden bekannte Messmethoden der Photovoltaik, (IR-Thermografie, I-U-String-Messung, digitale Datenverarbeitung mittels Selbstreferenzierung) zu einem innovativen Gesamtkonzept synthetisch zusammengef{\"u}hrt. Die Entwicklung des Messverfahrens wird an speziell gealterten PV-Anlagen marktbestimmender Technologien (c-Si-, CdTe-, CIGS-Muster-PV-Anlagen) vorangetrieben. So wird das Verfahren auf Erkennung spezifischer Degradationsszenarien und marginaler quantitativer Parameterver{\"a}nderungen trainiert und gesch{\"a}rft}, language = {de} } @inproceedings{SchneiderPflaumGottschalketal.2018, author = {Schneider, S. and Pflaum, D. and Gottschalk, L. and Schulze, Achim and H{\"u}ttl, B.}, title = {Laborgenaue elektrische Charakterisierungen von PV-Modulen unter Feldbedingungen}, series = {1. Regenerative Energietechnik Konferenz in Nordhausen}, booktitle = {1. Regenerative Energietechnik Konferenz in Nordhausen}, publisher = {RET.con 2018}, address = {Nordhausen}, year = {2018}, abstract = {Outdoor-I-U-Messungen an Photovoltaik- (PV) - Modulen haben den Vorteil, dass Effekte wie „light soaking" oder „light-induced degradation" unter nat{\"u}rlichen Bedingungen untersucht werden k{\"o}nnen. Solche Outdoor-Analysen k{\"o}nnen unter Anwendung des Selbstreferenzierungsalgorithmus (SRA) die Zuverl{\"a}ssigkeit von Indoor-Flasher-Messungen erreichen. Dieses neue Konzept liefert I-UEigenschaften f{\"u}r wesentlich mehr Testbedingungen als vom Standard IEC 61853 gefordert und so k{\"o}nnen Schwachlichtkurven aller relevanten elektrischen I-U-Parameter f{\"u}r bestimmte Temperaturen erzeugt werden. Wir berichten {\"u}ber experimentelle Ergebnisse einer 6-t{\"a}gigen Outdoor-Messkampagne an D{\"u}nnschicht-PV-Modulen. Wir evaluieren dar{\"u}ber hinaus die M{\"o}glichkeiten, Temperaturkoeffizienten, STC- und NOCT-Daten zu bestimmen und I-U-Kennlinien als Basis f{\"u}r Fitting-Analysen abzuleiten. Abschließend wird die Genauigkeit der neuen Outdoor-Methode untersucht.}, language = {de} } @inproceedings{HuettlHeimfarthSchulzeetal.2012, author = {H{\"u}ttl, B. and Heimfarth, J.P. and Schulze, Achim and Schelhase, S. and Hafemeister, M. and Weiler, U. and Queck, M. and Patzlaff, T. and Bauer, M. and Becker, F.}, title = {Improved JV-Analysis on CdTe Dot Cells by Controlled Series Resistance}, series = {Proc. 27th European Photovoltaic Solar Energy Conference and Exhibition}, booktitle = {Proc. 27th European Photovoltaic Solar Energy Conference and Exhibition}, publisher = {27th European Photovoltaic Solar Energy Conference and Exhibition}, year = {2012}, abstract = {CdS/CdTe thin film solar technology is one of the most promising concepts to accomplish high efficiencies and low costs in mass production. Further knowledge about electric parameters, such as serial resistances and recombination losses, is needed in order to improve in a systematic approach the module efficiency. The basic tool for device evaluation is the JV-measurement (current density - voltage) under standard test conditions. JVmeasurements result in rather direct determination of electric parameters, and detailed JV-analysis in indirect determination of some more relevant electric parameters. For thin film solar cells the usual 2-diode model and the responsible equation can be reduced to a 1-diode model due to significant recombination processes in the space charge region. However, the fit results suffer on imprecision of derived recombination currents (Jrec), and series resistance (Rs), due to their ambiguousness in fit routine. Direct and precise access of Rs by measurements fails for CdTe, due to its significant dependency on illumination levels. In this work we present a new method for precise Rs and Jrec determination of CdTe cells.}, language = {en} } @inproceedings{HuettlWachterGottschalketal.2016, author = {H{\"u}ttl, B. and Wachter, M. and Gottschalk, L. and Schulze, Achim and Becker, F.}, title = {Self Reference Algorithm for Precise Outdoor Characterization of PV Modules}, series = {PV-Days Halle 2016}, booktitle = {PV-Days Halle 2016}, publisher = {PV-Days Halle 2016}, address = {Halle}, year = {2016}, abstract = {Outdoor or just on site analyzes of photovoltaic modules can offer some advantages in comparison to indoor Lab stud-ies. In this way the electrical performance is monitored and logged under natural operating conditions in full range of irradiation and temperature. The entirety of monitored IV data allows deriving low-light characteristics of electric parameters, temperature coefficients and root cause analysis for possible degradation. We apply so-called self-reference algorithm in order to increase the accuracy of analysis. The improved precision is due to application of effective acting irradiation and effective temperature instead of externally measured data. Effective irradiation is determined in self-referencing scheme: the short circuit current of the module is assigned to the irradiation.}, language = {en} } @inproceedings{WachterGottschalkSimmleretal.2016, author = {Wachter, M. and Gottschalk, L. and Simmler, M. and Schulze, Achim and Becker, F. and Sayala, M. and H{\"u}ttl, B.}, title = {Short Circuit Current Measurements at Clear-Sky Conditions on Photovoltaic Modules: Basic for a Reliable Self-Reference Algorithm}, series = {Proc. 32nd European Photovoltaic Solar Energy Conference and Exhibition (PVSEC)}, booktitle = {Proc. 32nd European Photovoltaic Solar Energy Conference and Exhibition (PVSEC)}, publisher = {32nd European Photovoltaic Solar Energy Conference and Exhibition (PVSEC)}, year = {2016}, abstract = {Outdoor or just on site analyzes of photovoltaic modules can offer some advantages in comparison to indoor Lab studies. In this way the electrical performance is monitored and logged under natural operating conditions in full range of irradiation and temperature. The entirety of monitored IV data allows deriving low-light characteristics of electric parameters, temperature coefficients and root cause analysis for possible degradation. We apply so-called self-reference algorithm in order to increase the accuracy of analysis. The improved precision is due to application of effective acting irradiation and effective temperature instead of externally measured data. Effective irradiation is determined in self-referencing scheme: the short circuit current of the module is assigned to the irradiation. This assignment has to be calibrated, preferably at standard test conditions for irradiation. In this contribution we demonstrate a process of precise measurement of Isc under clear-sky outdoor conditions and the determination of the short circuit current for STC. The measurement method avoids errors by spectral deviations with respect to AM 1.5G spectrum, by optical reflection losses for high angles of incidence and errors by high albedo impact. In particular we investigate comparatively a CdTe module under outdoor conditions and by means a calibrated indoor Lab flasher.}, language = {en} } @inproceedings{SchulzePanuysenDaumeetal.2024, author = {Schulze, Achim and Panuysen, Markus and Daume, Darwin and Sch{\"o}nau, Maximilian}, title = {Quantitative Shade Detection for PV-Systems based on Clearsky Data}, series = {Proceedings of the 41st EU PVSEC}, booktitle = {Proceedings of the 41st EU PVSEC}, pages = {3}, year = {2024}, abstract = {In modern monitoring applications, losses from shading should be quantitatively separated from other loss mechanisms such as soiling, degradation or total failures. Based on clearsky reference data, we introduce a shading matrix which enables accurate hourly description of shading losses of PV strings over the year. This matrix can be used to improve failure detections and reference yield data in PV systems. Furthermore, a shading matrix with respect to sun position is introduced to improve the spatial understanding of shading caused by surrounding objects.}, language = {en} }