Markus Babin, Ingvar Haukur Jóhannsson, Michael Linde Jakobsen, Sune Thorsteinsson
While colored photovoltaics are gaining popularity in the market for building-integrated photovoltaics (BIPV), several specific properties are not accounted for in standard PV performance models. This work shows how relying on the coloration efficiency alone can lead to significant errors regarding module temperatures. By comparing measured temperature data from a test installation featuring BIPV façade elements in multiple colors, little correlation is found between total optical losses (reflection and absorption losses) and module temperature. Instead, better correlation is found with total reflectance. This is attributed to the light absorbed in the pigment-based colored layers contributing to module heating, whereas reflected light does not. This is especially relevant for colors with high lightness, such as gray or beige, for which reflection losses are dominating absorption losses. When modelling colored BIPV products, it is therefore recommended to only consider reflection losses for the irradiance contributing to module heating, while continuing to also include absorption losses for the effective irradiance used in electrical performance modelling.
{"title":"Experimental evaluation of the impact of pigment-based colored interlayers on the temperature of BIPV modules","authors":"Markus Babin, Ingvar Haukur Jóhannsson, Michael Linde Jakobsen, Sune Thorsteinsson","doi":"10.1051/epjpv/2023028","DOIUrl":"https://doi.org/10.1051/epjpv/2023028","url":null,"abstract":"While colored photovoltaics are gaining popularity in the market for building-integrated photovoltaics (BIPV), several specific properties are not accounted for in standard PV performance models. This work shows how relying on the coloration efficiency alone can lead to significant errors regarding module temperatures. By comparing measured temperature data from a test installation featuring BIPV façade elements in multiple colors, little correlation is found between total optical losses (reflection and absorption losses) and module temperature. Instead, better correlation is found with total reflectance. This is attributed to the light absorbed in the pigment-based colored layers contributing to module heating, whereas reflected light does not. This is especially relevant for colors with high lightness, such as gray or beige, for which reflection losses are dominating absorption losses. When modelling colored BIPV products, it is therefore recommended to only consider reflection losses for the irradiance contributing to module heating, while continuing to also include absorption losses for the effective irradiance used in electrical performance modelling.","PeriodicalId":42768,"journal":{"name":"EPJ Photovoltaics","volume":"160 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"135659832","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
The determination of module temperature in a photovoltaic (PV) system is a crucial factor in PV modelling and the assessment of system health status. However, the scarcity of on-site temperature measurements poses a challenge, and existing PV temperature models encounter difficulties in accurately estimating temperatures in systems characterized by unique structural or locational attributes. This paper introduces a novel approach that enables the calibration of PV temperature models without relying on direct temperature measurements. Referred to as blind calibration, this method eliminates the requirement for temperature measurements, thus offering a promising solution to the aforementioned challenges. The method is validated using three datasets, demonstrating accurate PV temperature ( T PV ) estimation with mean absolute errors below 2 °C. The findings highlight the suitability of the proposed approach for various PV system types, while acknowledging limitations regarding certain system configurations.
{"title":"Blind PV temperature model calibration","authors":"Anastasios Kladas, Bert Herteleer, Jan Cappelle","doi":"10.1051/epjpv/2023021","DOIUrl":"https://doi.org/10.1051/epjpv/2023021","url":null,"abstract":"The determination of module temperature in a photovoltaic (PV) system is a crucial factor in PV modelling and the assessment of system health status. However, the scarcity of on-site temperature measurements poses a challenge, and existing PV temperature models encounter difficulties in accurately estimating temperatures in systems characterized by unique structural or locational attributes. This paper introduces a novel approach that enables the calibration of PV temperature models without relying on direct temperature measurements. Referred to as blind calibration, this method eliminates the requirement for temperature measurements, thus offering a promising solution to the aforementioned challenges. The method is validated using three datasets, demonstrating accurate PV temperature ( T PV ) estimation with mean absolute errors below 2 °C. The findings highlight the suitability of the proposed approach for various PV system types, while acknowledging limitations regarding certain system configurations.","PeriodicalId":42768,"journal":{"name":"EPJ Photovoltaics","volume":"101 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"135107165","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Eve Krassowski, B. Jaeckel, M. Pander, D. Dassler, S. Malik
It was previously shown that the Laser Enhanced Contact Optimization (LECO) Process is a promising boost for PERC and TOPCon cell manufacturing enhancement. In this contribution, a method is developed to assess the long-term stability of industrial LECO treated PERC cells in a module compound. Therefore, extended accelerated aging tests as well as outdoor measurements were performed on modules comprising LECO treated cells as well as untreated references. It is described, how data can be evaluated to separate typical, known aging and degradation effects from presumable LECO specific effects. The results of this work show that test modules comprising LECO treated cells did not show a different behavior in the accelerated aging or degradation compared to the reference. The same conclusion was found for thermal cycling and damp heat tests, both far in excess of IEC requirements, as well as in a sequential test sequence. In addition, their outdoor performance with local and integral measurements has been evaluated. We can conclude that for the tested PERC cells, aging and degradation effects appeared, but none of them could be attributed to the LECO process. Hence, improvements in the efficiency and/or yield on cell level due to LECO can be translated to the module or even system level considering typical aging and degradation behavior, independently of a prior LECO process.
{"title":"Assessing the long-term stability of laser enhanced contact optimization (LECO) treated PERC cells in PV modules by extended indoor and outdoor durability tests","authors":"Eve Krassowski, B. Jaeckel, M. Pander, D. Dassler, S. Malik","doi":"10.1051/epjpv/2023004","DOIUrl":"https://doi.org/10.1051/epjpv/2023004","url":null,"abstract":"It was previously shown that the Laser Enhanced Contact Optimization (LECO) Process is a promising boost for PERC and TOPCon cell manufacturing enhancement. In this contribution, a method is developed to assess the long-term stability of industrial LECO treated PERC cells in a module compound. Therefore, extended accelerated aging tests as well as outdoor measurements were performed on modules comprising LECO treated cells as well as untreated references. It is described, how data can be evaluated to separate typical, known aging and degradation effects from presumable LECO specific effects. The results of this work show that test modules comprising LECO treated cells did not show a different behavior in the accelerated aging or degradation compared to the reference. The same conclusion was found for thermal cycling and damp heat tests, both far in excess of IEC requirements, as well as in a sequential test sequence. In addition, their outdoor performance with local and integral measurements has been evaluated. We can conclude that for the tested PERC cells, aging and degradation effects appeared, but none of them could be attributed to the LECO process. Hence, improvements in the efficiency and/or yield on cell level due to LECO can be translated to the module or even system level considering typical aging and degradation behavior, independently of a prior LECO process.","PeriodicalId":42768,"journal":{"name":"EPJ Photovoltaics","volume":"1 1","pages":""},"PeriodicalIF":2.5,"publicationDate":"2023-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"57828630","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Julia Vincent, Venkata Ramana Posa, Ali Khouzam, P. Logerais, Mustapha El Yaakoubi, A. Labouret
This study presents the results of severe accelerated tests carried out on four encapsulated amorphous silicon (a-Si) mini-modules. All the a-Si mini-modules were exposed to a 85 °C and 85% relative humidity damp heat (DH) prolonged treatment for 5000 h representing five times the duration specified by the IEC 61215 standard for qualification tests. For two of the four mini-modules, the DH test was preceded by a severe UV preconditioning, by applying 30 times the dose of 15 kWh/m2 at a temperature of 50 °C as prescribed by the IEC 61215 standard, in order to enhance the degradation during the following DH test and to reduce the overall testing time. I–V curves were plotted with a time step of 100 h under standard test conditions (STC) using a class A solar simulator and a source meter in order to monitor the degradation throughout both the tests. A visual inspection with photographic capturing was also performed at each stage to detect the apparent defects. Corrosion observed after 2000 h owing to the ingress of humidity is explained here by two possible infiltration paths in the layers of the mini-modules. Delamination occurred after 5000 h for the PV mini-modules which underwent the extended DH test. After 5000 h of damp heat testing, the degradation of the maximal power (Pmax) was found to be slightly accelerated for the a-Si mini-modules that were previously exposed to a severe UV preconditioning, with a value reaching 80% of its initial value, whereas, for the others only subjected to the prolonged DH test, the maximal power remained above 80% of its initial value. In all cases, the mini-modules seemed highly reliable with no failure after 5000 h of accelerated testing, and, based on an equivalent time of 20 years for 1000 h of accelerated test, they would exhibit a limited degradation rate of 0.2%/year in outdoor field conditions.
{"title":"Analysis of the degradation of amorphous silicon mini-modules under a severe sequential UV/DH test","authors":"Julia Vincent, Venkata Ramana Posa, Ali Khouzam, P. Logerais, Mustapha El Yaakoubi, A. Labouret","doi":"10.1051/epjpv/2023014","DOIUrl":"https://doi.org/10.1051/epjpv/2023014","url":null,"abstract":"This study presents the results of severe accelerated tests carried out on four encapsulated amorphous silicon (a-Si) mini-modules. All the a-Si mini-modules were exposed to a 85 °C and 85% relative humidity damp heat (DH) prolonged treatment for 5000 h representing five times the duration specified by the IEC 61215 standard for qualification tests. For two of the four mini-modules, the DH test was preceded by a severe UV preconditioning, by applying 30 times the dose of 15 kWh/m2 at a temperature of 50 °C as prescribed by the IEC 61215 standard, in order to enhance the degradation during the following DH test and to reduce the overall testing time. I–V curves were plotted with a time step of 100 h under standard test conditions (STC) using a class A solar simulator and a source meter in order to monitor the degradation throughout both the tests. A visual inspection with photographic capturing was also performed at each stage to detect the apparent defects. Corrosion observed after 2000 h owing to the ingress of humidity is explained here by two possible infiltration paths in the layers of the mini-modules. Delamination occurred after 5000 h for the PV mini-modules which underwent the extended DH test. After 5000 h of damp heat testing, the degradation of the maximal power (Pmax) was found to be slightly accelerated for the a-Si mini-modules that were previously exposed to a severe UV preconditioning, with a value reaching 80% of its initial value, whereas, for the others only subjected to the prolonged DH test, the maximal power remained above 80% of its initial value. In all cases, the mini-modules seemed highly reliable with no failure after 5000 h of accelerated testing, and, based on an equivalent time of 20 years for 1000 h of accelerated test, they would exhibit a limited degradation rate of 0.2%/year in outdoor field conditions.","PeriodicalId":42768,"journal":{"name":"EPJ Photovoltaics","volume":"1 1","pages":""},"PeriodicalIF":2.5,"publicationDate":"2023-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"57828874","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Malte Klitzke, J. Schön, R. H. van Leest, G. Bissels, E. Vlieg, M. Schachtner, F. Dimroth, D. Lackner
In this work an inverted metamorphic four junction (IMM4J) solar cell with 30.9% conversion efficiency in beginning of life conditions under the AM0 (1367 W/m2) spectrum is presented. Additionally, our newest improved IMM3J cell, consisting of Ga0.51In0.49P/GaAs/Ga0.73In0.27As subcells, with 30.6% efficiency is also shown. The IMM4J solar cells consist of Al0.05Ga0.46In0.49P/Al0.14Ga0.86As/Ga0.89In0.11As/Ga0.73In0.27As subcells and are epitaxially grown by metal organic vapor phase epitaxy (MOVPE) on a GaAs substrate. These IMM solar cells achieve power-to-mass ratios of 3 W/g or more, which is more than three times higher than standard germanium based triple or four junction space solar cells. The losses in comparison to the simulated near-term potential efficiency of 33.8% for the IMM4J are analyzed in detail. Furthermore, the irradiation behavior for 1 MeV electron fluences of 1 × 1014 e−/cm2 and 2.5 × 1014 e−/cm2 for the IMM4J cells was investigated. A roadmap to further develop this concept towards an IMM5J with a realistic begin of life (BOL) efficiency potential of 35.9% under AM0 is presented.
{"title":"Ultra-lightweight and flexible inverted metamorphic four junction solar cells for space applications","authors":"Malte Klitzke, J. Schön, R. H. van Leest, G. Bissels, E. Vlieg, M. Schachtner, F. Dimroth, D. Lackner","doi":"10.1051/epjpv/2022024","DOIUrl":"https://doi.org/10.1051/epjpv/2022024","url":null,"abstract":"In this work an inverted metamorphic four junction (IMM4J) solar cell with 30.9% conversion efficiency in beginning of life conditions under the AM0 (1367 W/m2) spectrum is presented. Additionally, our newest improved IMM3J cell, consisting of Ga0.51In0.49P/GaAs/Ga0.73In0.27As subcells, with 30.6% efficiency is also shown. The IMM4J solar cells consist of Al0.05Ga0.46In0.49P/Al0.14Ga0.86As/Ga0.89In0.11As/Ga0.73In0.27As subcells and are epitaxially grown by metal organic vapor phase epitaxy (MOVPE) on a GaAs substrate. These IMM solar cells achieve power-to-mass ratios of 3 W/g or more, which is more than three times higher than standard germanium based triple or four junction space solar cells. The losses in comparison to the simulated near-term potential efficiency of 33.8% for the IMM4J are analyzed in detail. Furthermore, the irradiation behavior for 1 MeV electron fluences of 1 × 1014 e−/cm2 and 2.5 × 1014 e−/cm2 for the IMM4J cells was investigated. A roadmap to further develop this concept towards an IMM5J with a realistic begin of life (BOL) efficiency potential of 35.9% under AM0 is presented.","PeriodicalId":42768,"journal":{"name":"EPJ Photovoltaics","volume":"1 1","pages":""},"PeriodicalIF":2.5,"publicationDate":"2022-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"57828029","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Aleksandra Bojar, D. Regaldo, J. Alvarez, D. Alamarguy, V. Donchev, S. Georgiev, P. Schulz, J. Kleider
In this study we analysed halide perovskite films deposited directly on crystalline silicon by means of two set-ups using different operating modes of the surface photovoltage (SPV) methods, i.e., the Kelvin probe force microscopy (KPFM) and the metal-insulator-semiconductor (MIS) technique. The KPFM allowed to visualize surface potential distribution on a microscale while MIS technique allowed to study SPV spectral dependence. We studied wavelength dependent SPV of these samples, which allowed us to effectively vary the probe depth in the sample and discern the contribution from each interface to the overall effect measured under white light illumination. Depending on where the photocarriers are generated, different SPV signals are observed: at the perovskite/Si interface, the signal depends on Si doping type, while at the surface the SPV is always negative indicating downward surface band bending. This is confirmed by analysing SPV phase measured in the AC MIS mode. In addition, distinction between slow and fast processes contributing to measured SPV was possible. It has been observed, that with decreasing the illumination wavelength, the processes causing SPV become slower, which can indicate that high energy photons not only generate electronic photocarriers but can also induce chemical changes with creation of defects or ionic species that also modify the measured SPV.
{"title":"Surface photovoltage characterisation of metal halide perovskite on crystalline silicon using Kelvin probe force microscopy and metal-insulator-semiconductor configuration","authors":"Aleksandra Bojar, D. Regaldo, J. Alvarez, D. Alamarguy, V. Donchev, S. Georgiev, P. Schulz, J. Kleider","doi":"10.1051/epjpv/2022016","DOIUrl":"https://doi.org/10.1051/epjpv/2022016","url":null,"abstract":"In this study we analysed halide perovskite films deposited directly on crystalline silicon by means of two set-ups using different operating modes of the surface photovoltage (SPV) methods, i.e., the Kelvin probe force microscopy (KPFM) and the metal-insulator-semiconductor (MIS) technique. The KPFM allowed to visualize surface potential distribution on a microscale while MIS technique allowed to study SPV spectral dependence. We studied wavelength dependent SPV of these samples, which allowed us to effectively vary the probe depth in the sample and discern the contribution from each interface to the overall effect measured under white light illumination. Depending on where the photocarriers are generated, different SPV signals are observed: at the perovskite/Si interface, the signal depends on Si doping type, while at the surface the SPV is always negative indicating downward surface band bending. This is confirmed by analysing SPV phase measured in the AC MIS mode. In addition, distinction between slow and fast processes contributing to measured SPV was possible. It has been observed, that with decreasing the illumination wavelength, the processes causing SPV become slower, which can indicate that high energy photons not only generate electronic photocarriers but can also induce chemical changes with creation of defects or ionic species that also modify the measured SPV.","PeriodicalId":42768,"journal":{"name":"EPJ Photovoltaics","volume":"1 1","pages":""},"PeriodicalIF":2.5,"publicationDate":"2022-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"57828315","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
The transition to a low carbon society will not be possible without a major shift to renewables. Up to now the world is not set for a clear downward turn in emissions because most of the energy infrastructure continues to work in a business-as-usual scenario. With its strong reduction in LCOE, PV is at the forefront of new energy technologies to be a key contributor for change. PV bene fi ts range from local energy production to large power plants. In combination with other technologies, it expands its added value not only to cities, including buildings and mobility, but also to agriculture, water desalination and hydrogen production. According to the International Energy Agen-cy, solar is now the cheapest form of electricity generation and will be the most important renewable energy in the world.
{"title":"EU PVSEC 2021: state of the art and developments for photovoltaics at the forefront","authors":"R. Kenny, J. Serra","doi":"10.1051/epjpv/2022011","DOIUrl":"https://doi.org/10.1051/epjpv/2022011","url":null,"abstract":"The transition to a low carbon society will not be possible without a major shift to renewables. Up to now the world is not set for a clear downward turn in emissions because most of the energy infrastructure continues to work in a business-as-usual scenario. With its strong reduction in LCOE, PV is at the forefront of new energy technologies to be a key contributor for change. PV bene fi ts range from local energy production to large power plants. In combination with other technologies, it expands its added value not only to cities, including buildings and mobility, but also to agriculture, water desalination and hydrogen production. According to the International Energy Agen-cy, solar is now the cheapest form of electricity generation and will be the most important renewable energy in the world.","PeriodicalId":42768,"journal":{"name":"EPJ Photovoltaics","volume":"1 1","pages":""},"PeriodicalIF":2.5,"publicationDate":"2022-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"57828256","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Mattia da Lisca, J. P. Connolly, J. Alvarez, K. Mekhazni, N. Vaissière, J. Decobert, J. Kleider
Solar cells are complex devices, being constituted of many layers and interfaces. The study and the comprehension of the mechanisms that take place at the interfaces is crucial for efficiency improvement. This paper applies Kelvin probe force microscopy (KPFM) to study materials and interfaces with nanometer scale imaging of the surface potential in the dark and under illumination. KPFM measurements are highly sensitive to surface states and to the experimental measurement environment influencing the atomic probe operating conditions. Therefore, in order to develop a quantitative understanding of KPFM measurements, we have prepared a dedicated structured sample with alternating layers of InP:S and InP:Fe whose doping densities were determined by secondary-ion mass spectroscopy. We have performed KPFM measurements and shown that we can spatially resolve 20 nm thick InP layers, notably when performed under illumination which is well-known to reduce the surface band-bending.
{"title":"Revealing of InP multi-layer stacks from KPFM measurements in the dark and under illumination","authors":"Mattia da Lisca, J. P. Connolly, J. Alvarez, K. Mekhazni, N. Vaissière, J. Decobert, J. Kleider","doi":"10.1051/epjpv/2022017","DOIUrl":"https://doi.org/10.1051/epjpv/2022017","url":null,"abstract":"Solar cells are complex devices, being constituted of many layers and interfaces. The study and the comprehension of the mechanisms that take place at the interfaces is crucial for efficiency improvement. This paper applies Kelvin probe force microscopy (KPFM) to study materials and interfaces with nanometer scale imaging of the surface potential in the dark and under illumination. KPFM measurements are highly sensitive to surface states and to the experimental measurement environment influencing the atomic probe operating conditions. Therefore, in order to develop a quantitative understanding of KPFM measurements, we have prepared a dedicated structured sample with alternating layers of InP:S and InP:Fe whose doping densities were determined by secondary-ion mass spectroscopy. We have performed KPFM measurements and shown that we can spatially resolve 20 nm thick InP layers, notably when performed under illumination which is well-known to reduce the surface band-bending.","PeriodicalId":42768,"journal":{"name":"EPJ Photovoltaics","volume":"1 1","pages":""},"PeriodicalIF":2.5,"publicationDate":"2022-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"57828324","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Under non-uniform operating conditions, photovoltaic (PV) generators may have several maximum power points (MPP) and voltage of the global MPP (GMPP) may vary quickly over a wide voltage range which may cause problems for tracking of the GMPP. Since highly varying GMPP voltage causes fluctuation of the inverter reference voltage, it would be beneficial to operate the PV system in a more predictable and straightforward manner by keeping the operating point of the inverter all the time close to the nominal MPP voltage. This article presents an experimental study of a scenario in which the MPP closest to the nominal MPP voltage (CMPP) is always the operating point instead of the GMPP. The analysis was based on 1,296,000 measured current–voltage curves of three different PV strings located at Tampere, Finland. 12 days of full-time measurements were analysed for each of the studied strings consisting of 6, 17 and 23 series-connected NAPS NP190GK PV modules. Furthermore, the effects of inverter sizing on the operating point behaviour of the strings were studied. The results show that the wide operating voltage range of the GMPP can be significantly reduced by operating at the CMPP at a cost of negligible energy losses. Energy losses due to power curtailment were much larger than energy losses due to operation at the CMPP instead of the GMPP.
{"title":"Analysis of the operation of PV strings at the MPP closest to the nominal MPP voltage instead of the global MPP based on measured current–voltage curves","authors":"K. Lappalainen, S. Valkealahti","doi":"10.1051/epjpv/2022001","DOIUrl":"https://doi.org/10.1051/epjpv/2022001","url":null,"abstract":"Under non-uniform operating conditions, photovoltaic (PV) generators may have several maximum power points (MPP) and voltage of the global MPP (GMPP) may vary quickly over a wide voltage range which may cause problems for tracking of the GMPP. Since highly varying GMPP voltage causes fluctuation of the inverter reference voltage, it would be beneficial to operate the PV system in a more predictable and straightforward manner by keeping the operating point of the inverter all the time close to the nominal MPP voltage. This article presents an experimental study of a scenario in which the MPP closest to the nominal MPP voltage (CMPP) is always the operating point instead of the GMPP. The analysis was based on 1,296,000 measured current–voltage curves of three different PV strings located at Tampere, Finland. 12 days of full-time measurements were analysed for each of the studied strings consisting of 6, 17 and 23 series-connected NAPS NP190GK PV modules. Furthermore, the effects of inverter sizing on the operating point behaviour of the strings were studied. The results show that the wide operating voltage range of the GMPP can be significantly reduced by operating at the CMPP at a cost of negligible energy losses. Energy losses due to power curtailment were much larger than energy losses due to operation at the CMPP instead of the GMPP.","PeriodicalId":42768,"journal":{"name":"EPJ Photovoltaics","volume":"1 1","pages":""},"PeriodicalIF":2.5,"publicationDate":"2022-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"57827493","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Koffi F. Ahanogbe, J. Alvarez, A. Jaffré, J. P. Connolly, M. Gueunier‐Farret, E. Fourmond, Seif El-Whibi, A. Fave, P. Carroy, Z. Djebbour, J. Kleider
Electroluminescence allows rapid characterization of an entire photovoltaic solar cell and visualization of defects at the micrometer scale. Here we focus on the optoelectronic properties of silicon interdigitated back contact cells characterized by electroluminescence. The spatially resolved electroluminescence helps us control the quality of interdigitated back contact structures used in silicon bottom subcells in a three-terminal tandem perovskite on silicon solar cell. Local variations in minority carrier diffusion length, surface recombination velocity and, the impact of resistive and optical losses were analyzed by electroluminescence mapping. In addition, we quantify the radiative saturation current density and the radiative open circuit voltage using the electroluminescence spectrum of the cell. This step allows us to accurately assess the performance limits induced in the device due to the non-radiative recombination.
{"title":"Electroluminescence analysis of silicon interdigitated back contact solar cells with a front surface selective band offset barrier","authors":"Koffi F. Ahanogbe, J. Alvarez, A. Jaffré, J. P. Connolly, M. Gueunier‐Farret, E. Fourmond, Seif El-Whibi, A. Fave, P. Carroy, Z. Djebbour, J. Kleider","doi":"10.1051/epjpv/2022015","DOIUrl":"https://doi.org/10.1051/epjpv/2022015","url":null,"abstract":"Electroluminescence allows rapid characterization of an entire photovoltaic solar cell and visualization of defects at the micrometer scale. Here we focus on the optoelectronic properties of silicon interdigitated back contact cells characterized by electroluminescence. The spatially resolved electroluminescence helps us control the quality of interdigitated back contact structures used in silicon bottom subcells in a three-terminal tandem perovskite on silicon solar cell. Local variations in minority carrier diffusion length, surface recombination velocity and, the impact of resistive and optical losses were analyzed by electroluminescence mapping. In addition, we quantify the radiative saturation current density and the radiative open circuit voltage using the electroluminescence spectrum of the cell. This step allows us to accurately assess the performance limits induced in the device due to the non-radiative recombination.","PeriodicalId":42768,"journal":{"name":"EPJ Photovoltaics","volume":"1 1","pages":""},"PeriodicalIF":2.5,"publicationDate":"2022-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"57828305","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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