Pub Date : 2012-06-03DOI: 10.1109/PVSC.2012.6317605
K. Ghosh, C. Tracy, S. Goodnick, S. Bowden
The transport of photogenerated minority carriers (photocarriers) across the heterointerface of amorphous silicon (a-Si) and crystalline silicon (c-Si) in a-Si/c-Si heterostructure solar cell is shown in this work to critically depend on the non-Maxwellian energy distribution function of those carriers impinging on the heterointerface. A theoretical model is presented that integrates the effect of the high electric field inversion region upon energy distribution function of the impinging carriers with the transmission probability of those carriers across the heterointerface. The transport of the photocarriers across the high electric field inversion region is simulated by the full solution of the Boltzmann transport equation by Monte Carlo technique while the transmission probability of carriers across the heterointerface is calculated through the percolation path technique. The results are discussed under two different condition of band bending; strongly inverted and weakly inverted c-Si surface. The results comparing different conditions of band bending show that the energy distribution of the carriers impinging on the heterointerface is non-Maxwellian and the integrated photocarrier collection increases with the strength of the inversion field since the carrier population is weighted towards higher energy where the transmission probability through the barrier is higher. Thus we demonstrate that hot carriers play an important role in heterostructure cell operation.
{"title":"Effect of band bending and band offset in the transport of minority carriers across the ordered/disordered interface of a-Si/c-Si heterojunction solar cell","authors":"K. Ghosh, C. Tracy, S. Goodnick, S. Bowden","doi":"10.1109/PVSC.2012.6317605","DOIUrl":"https://doi.org/10.1109/PVSC.2012.6317605","url":null,"abstract":"The transport of photogenerated minority carriers (photocarriers) across the heterointerface of amorphous silicon (a-Si) and crystalline silicon (c-Si) in a-Si/c-Si heterostructure solar cell is shown in this work to critically depend on the non-Maxwellian energy distribution function of those carriers impinging on the heterointerface. A theoretical model is presented that integrates the effect of the high electric field inversion region upon energy distribution function of the impinging carriers with the transmission probability of those carriers across the heterointerface. The transport of the photocarriers across the high electric field inversion region is simulated by the full solution of the Boltzmann transport equation by Monte Carlo technique while the transmission probability of carriers across the heterointerface is calculated through the percolation path technique. The results are discussed under two different condition of band bending; strongly inverted and weakly inverted c-Si surface. The results comparing different conditions of band bending show that the energy distribution of the carriers impinging on the heterointerface is non-Maxwellian and the integrated photocarrier collection increases with the strength of the inversion field since the carrier population is weighted towards higher energy where the transmission probability through the barrier is higher. Thus we demonstrate that hot carriers play an important role in heterostructure cell operation.","PeriodicalId":6318,"journal":{"name":"2012 38th IEEE Photovoltaic Specialists Conference","volume":"03 1","pages":"000221-000226"},"PeriodicalIF":0.0,"publicationDate":"2012-06-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"86347898","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}
Pub Date : 2012-06-03DOI: 10.1109/PVSC.2012.6318167
Yang Shen, Mool C. Gupta
Capacitance of P3HT(poly (3-hexylthiophene-2,5-diyl)):PCBM ([6,6]-phenyl C61-butyric acid methyl ester) bulk heterojunction solar cell was measured at different biases and different temperatures (25°C and 130°C). The capacitance was found to vary with bias voltages, and showed different trends with temperature, but the peak capacitance values and positions did not vary much. Mott-Schottky relation was used to model the behavior of capacitance in reverse bias. The capacitance of pure P3HT showed a different trend as compare to the P3HT:PCBM blend. The peak position did not vary, but the peak values decrease with temperature. Permittivity of P3HT was then calculated and the temperature dependence of exciton binding energy was revealed. The active layer thickness effect on the series resistance was also examined. The results show two regions, the slope quickly changes after certain thickness. Further investigation of electrical prosperities will provide insight on the origin of open circuit voltage and charge transport mechanism.
{"title":"Investigation of electrical characteristics of P3HT:PCBM organic solar cells","authors":"Yang Shen, Mool C. Gupta","doi":"10.1109/PVSC.2012.6318167","DOIUrl":"https://doi.org/10.1109/PVSC.2012.6318167","url":null,"abstract":"Capacitance of P3HT(poly (3-hexylthiophene-2,5-diyl)):PCBM ([6,6]-phenyl C61-butyric acid methyl ester) bulk heterojunction solar cell was measured at different biases and different temperatures (25°C and 130°C). The capacitance was found to vary with bias voltages, and showed different trends with temperature, but the peak capacitance values and positions did not vary much. Mott-Schottky relation was used to model the behavior of capacitance in reverse bias. The capacitance of pure P3HT showed a different trend as compare to the P3HT:PCBM blend. The peak position did not vary, but the peak values decrease with temperature. Permittivity of P3HT was then calculated and the temperature dependence of exciton binding energy was revealed. The active layer thickness effect on the series resistance was also examined. The results show two regions, the slope quickly changes after certain thickness. Further investigation of electrical prosperities will provide insight on the origin of open circuit voltage and charge transport mechanism.","PeriodicalId":6318,"journal":{"name":"2012 38th IEEE Photovoltaic Specialists Conference","volume":"1 1","pages":"002770-002774"},"PeriodicalIF":0.0,"publicationDate":"2012-06-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"82816232","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}
Pub Date : 2012-06-03DOI: 10.1109/PVSC.2012.6317659
K. Stika, S. Pélisset, S. Schreiber, F. de Borman Chautems, P. Dafniotis, Laure‐Emmanuelle Perret‐Aebi, C. Ballif
The role of surface analysis, specifically XPS (X-ray Photoelectron Spectroscopy) and SIMS (Secondary Ion Mass Spectrometry) has been explored to broaden our understanding of TCO / encapsulant interactions focusing on TCO resistivity evolution. Peel laminates of PVB, Ionomer and EVA encapsulants with LPCVD boron doped ZnO were exposed to Damp Heat and removed at different points in the aging cycle for analysis. Distinct response patterns were observed for the different encapsulant families and selected ionomers were found to be most effective at protecting and maintaining the conductivity of the TCO. Trends in interfacial ion enrichment as a function of damp heat exposure were determined by a combination of XPS and SIMS to provide the necessary quantitation, sensitivity and surface specificity. In this study, the transition from a cohesive peel within the encapsulant toward an adhesive peel between the TCO and encapsulant layers provided an important point of comparison. Depth profiling to determine the distribution of mobile species throughout the thickness of the TCO added yet another dimension to our understanding of TCO / encapsulant interactions.
{"title":"Transparent conductive oxide / encapsulant interface characterization following Damp Heat exposure","authors":"K. Stika, S. Pélisset, S. Schreiber, F. de Borman Chautems, P. Dafniotis, Laure‐Emmanuelle Perret‐Aebi, C. Ballif","doi":"10.1109/PVSC.2012.6317659","DOIUrl":"https://doi.org/10.1109/PVSC.2012.6317659","url":null,"abstract":"The role of surface analysis, specifically XPS (X-ray Photoelectron Spectroscopy) and SIMS (Secondary Ion Mass Spectrometry) has been explored to broaden our understanding of TCO / encapsulant interactions focusing on TCO resistivity evolution. Peel laminates of PVB, Ionomer and EVA encapsulants with LPCVD boron doped ZnO were exposed to Damp Heat and removed at different points in the aging cycle for analysis. Distinct response patterns were observed for the different encapsulant families and selected ionomers were found to be most effective at protecting and maintaining the conductivity of the TCO. Trends in interfacial ion enrichment as a function of damp heat exposure were determined by a combination of XPS and SIMS to provide the necessary quantitation, sensitivity and surface specificity. In this study, the transition from a cohesive peel within the encapsulant toward an adhesive peel between the TCO and encapsulant layers provided an important point of comparison. Depth profiling to determine the distribution of mobile species throughout the thickness of the TCO added yet another dimension to our understanding of TCO / encapsulant interactions.","PeriodicalId":6318,"journal":{"name":"2012 38th IEEE Photovoltaic Specialists Conference","volume":"100 1","pages":"000470-000473"},"PeriodicalIF":0.0,"publicationDate":"2012-06-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"88987945","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}
Pub Date : 2012-06-03DOI: 10.1109/PVSC.2012.6317772
Tseng-Jung Chang, Te-Yu Wei, S. H. Chen, Li-Wei Cheng
A new approach for performance improvement of laser doped selective emitter cells with dual dielectric passivation layers was demonstrated. Taking advantage of recovery of laser induced defects and emitter passivation of dual dielectric layer, a new scheme has been implemented to laser doped selective emitter cells. With this dual layer structure, it is shown that both of the lightly doped and laser treated areas get higher photoluminescence response and the open circuit voltage increases from 636mV to 640mV, compared to conventional single dielectric passivation layer. The slightly optical loss is a trade-off on this kind of dual-layered passivation due to non-optimum refraction match for light trapping, but this can be compensated by better internal quantum response. Laser doped selective emitter cells with dual-layered passivation scheme show 18.8% efficiency in average with 0.3%abs efficiency gain, compared to single layer passivated cells.
{"title":"Novel dual-layered passivation approach for 18.8% efficiency laser doped selective emitter cells","authors":"Tseng-Jung Chang, Te-Yu Wei, S. H. Chen, Li-Wei Cheng","doi":"10.1109/PVSC.2012.6317772","DOIUrl":"https://doi.org/10.1109/PVSC.2012.6317772","url":null,"abstract":"A new approach for performance improvement of laser doped selective emitter cells with dual dielectric passivation layers was demonstrated. Taking advantage of recovery of laser induced defects and emitter passivation of dual dielectric layer, a new scheme has been implemented to laser doped selective emitter cells. With this dual layer structure, it is shown that both of the lightly doped and laser treated areas get higher photoluminescence response and the open circuit voltage increases from 636mV to 640mV, compared to conventional single dielectric passivation layer. The slightly optical loss is a trade-off on this kind of dual-layered passivation due to non-optimum refraction match for light trapping, but this can be compensated by better internal quantum response. Laser doped selective emitter cells with dual-layered passivation scheme show 18.8% efficiency in average with 0.3%abs efficiency gain, compared to single layer passivated cells.","PeriodicalId":6318,"journal":{"name":"2012 38th IEEE Photovoltaic Specialists Conference","volume":"15 1","pages":"001006-001009"},"PeriodicalIF":0.0,"publicationDate":"2012-06-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"88998795","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}
Pub Date : 2012-06-03DOI: 10.1109/PVSC.2012.6317639
S. Shumate, H. Mohammed, D. Hutchings, H. Naseem
Thin-film silicon solar cells remain a promising technology to approach wafer-based efficiencies at thin-film costs. Epitaxial growth of silicon cells on seed layers has been a prominent approach with demonstrated efficiencies. However, cost-effective seed layers on glass or other low-cost substrates still remain one of the biggest road blocks to the success of this technology. Top-down aluminum induced crystallization (TAIC) has been developed to produce large-grain silicon seed layers on glass. Initial cells have been fabricated by Hot-Wire CVD at the National Renewable Energy Laboratory (NREL). The seed layers with grain-gaps show poor electrical characteristics comparable to reported cells grown on wafer templates with defect densities around 2 × 106 cm-3. New seed layers without grain gaps have been developed and are in queue for cell fabrication.
{"title":"Large-grain polysilicon seed layers on glass for epitaxial silicon solar cells","authors":"S. Shumate, H. Mohammed, D. Hutchings, H. Naseem","doi":"10.1109/PVSC.2012.6317639","DOIUrl":"https://doi.org/10.1109/PVSC.2012.6317639","url":null,"abstract":"Thin-film silicon solar cells remain a promising technology to approach wafer-based efficiencies at thin-film costs. Epitaxial growth of silicon cells on seed layers has been a prominent approach with demonstrated efficiencies. However, cost-effective seed layers on glass or other low-cost substrates still remain one of the biggest road blocks to the success of this technology. Top-down aluminum induced crystallization (TAIC) has been developed to produce large-grain silicon seed layers on glass. Initial cells have been fabricated by Hot-Wire CVD at the National Renewable Energy Laboratory (NREL). The seed layers with grain-gaps show poor electrical characteristics comparable to reported cells grown on wafer templates with defect densities around 2 × 106 cm-3. New seed layers without grain gaps have been developed and are in queue for cell fabrication.","PeriodicalId":6318,"journal":{"name":"2012 38th IEEE Photovoltaic Specialists Conference","volume":"42 1","pages":"000371-000376"},"PeriodicalIF":0.0,"publicationDate":"2012-06-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"91525289","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}
Pub Date : 2012-06-03DOI: 10.1109/PVSC.2012.6318187
J. Farah
OptiCOMP Networks is developing a new method for manufacturing thin, lightweight, flexible, portable high efficiency III-V PV modules that can be folded and rolled for space and terrestrial applications. Multi-junction inverted (IMM3J) and non-inverted cells are lifted off the Ge or GaAs growth wafer and transferred to inexpensive flexible polyimide permanent carrier substrate. The lift-off happens in fraction of a second. OptiCOMP uses proprietary materials and bonding techniques. No expensive ion implantation or slow chemical etching of a sacrificial layer is needed. Several cells are integrated on a common blanket polymeric sheet and interconnected by soldering copper ribbons. Both sides of the epi-layer can be contacted from the top side of the wafer. This eliminates the need for copper cladded polymeric substrates and reduces weight. The cells were fully encapsulated using transparent spray-on polyimide layer which replaces the cover glass. The thickness and CTE of the blanket polyimide layer were chosen to stress-balance the structure so that it remains flat in spite of 300°C temperature variations in orbit. The entire solar cell structure is less than 250 μm thick and achieves a specific power ratio of 340 W/kg. The base wafer is reused to grow another epi-layer and the cycle repeated. The cost of substrate materials is about 40% of the cost of the finished cell. OptiCOMP's process will result in savings in raw materials up to 30% of the cost of the cell and will enable terrestrial applications.
{"title":"Dry-epitaxial lift-off, integration, interconnect and encapsulation of foldable/rollable high efficiency solar cell modules","authors":"J. Farah","doi":"10.1109/PVSC.2012.6318187","DOIUrl":"https://doi.org/10.1109/PVSC.2012.6318187","url":null,"abstract":"OptiCOMP Networks is developing a new method for manufacturing thin, lightweight, flexible, portable high efficiency III-V PV modules that can be folded and rolled for space and terrestrial applications. Multi-junction inverted (IMM3J) and non-inverted cells are lifted off the Ge or GaAs growth wafer and transferred to inexpensive flexible polyimide permanent carrier substrate. The lift-off happens in fraction of a second. OptiCOMP uses proprietary materials and bonding techniques. No expensive ion implantation or slow chemical etching of a sacrificial layer is needed. Several cells are integrated on a common blanket polymeric sheet and interconnected by soldering copper ribbons. Both sides of the epi-layer can be contacted from the top side of the wafer. This eliminates the need for copper cladded polymeric substrates and reduces weight. The cells were fully encapsulated using transparent spray-on polyimide layer which replaces the cover glass. The thickness and CTE of the blanket polyimide layer were chosen to stress-balance the structure so that it remains flat in spite of 300°C temperature variations in orbit. The entire solar cell structure is less than 250 μm thick and achieves a specific power ratio of 340 W/kg. The base wafer is reused to grow another epi-layer and the cycle repeated. The cost of substrate materials is about 40% of the cost of the finished cell. OptiCOMP's process will result in savings in raw materials up to 30% of the cost of the cell and will enable terrestrial applications.","PeriodicalId":6318,"journal":{"name":"2012 38th IEEE Photovoltaic Specialists Conference","volume":"45 1","pages":"002868-002873"},"PeriodicalIF":0.0,"publicationDate":"2012-06-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"83083231","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}
Pub Date : 2012-06-03DOI: 10.1109/PVSC.2012.6317834
V. Herbort, R. von Schwerin, B. Compton, L. Brecht, H. te Heesen
The quality and performance of the components of a photovoltaic (PV) power plant has an effect on its energy yield. Therefore, it is sensible to select the best performing components in order to get maximized energy yield. But for example the performance of PV modules is often only known at standard test conditions (STC) which are most of the time artificially created in laboratories. Measurement data of over 24,000 PV plants deployed at sites located in Central Europe has been captured for 2009 and 2010. This data was checked by routines in order to provide sufficient data quality. Then it was transformed to STC in order to compare the empiric results of components' performance. This transformation was done using temperature data and plant configuration data e.g. inverter efficiency. With this approach a quasi performance ratio can calculated which allows fair comparism of PV modules and module types under real-life conditions.
{"title":"Insolation dependent solar module performance evaluation from PV monitoring data","authors":"V. Herbort, R. von Schwerin, B. Compton, L. Brecht, H. te Heesen","doi":"10.1109/PVSC.2012.6317834","DOIUrl":"https://doi.org/10.1109/PVSC.2012.6317834","url":null,"abstract":"The quality and performance of the components of a photovoltaic (PV) power plant has an effect on its energy yield. Therefore, it is sensible to select the best performing components in order to get maximized energy yield. But for example the performance of PV modules is often only known at standard test conditions (STC) which are most of the time artificially created in laboratories. Measurement data of over 24,000 PV plants deployed at sites located in Central Europe has been captured for 2009 and 2010. This data was checked by routines in order to provide sufficient data quality. Then it was transformed to STC in order to compare the empiric results of components' performance. This transformation was done using temperature data and plant configuration data e.g. inverter efficiency. With this approach a quasi performance ratio can calculated which allows fair comparism of PV modules and module types under real-life conditions.","PeriodicalId":6318,"journal":{"name":"2012 38th IEEE Photovoltaic Specialists Conference","volume":"30 1","pages":"001274-001277"},"PeriodicalIF":0.0,"publicationDate":"2012-06-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"83850257","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}
Pub Date : 2012-06-03DOI: 10.1109/PVSC.2012.6317805
Kee Soon Wang, D. Lin, Xinrui An, L. Mai, E. Mitchell, S. Wenham
The practical realization of high efficiency laser-doped semiconductor fingers (SCF) silicon solar cell is inhibited by high contact resistance. By plating the SCF with metal, a new SCF cell concept known as the “Advanced SCF” (AdvSCF) cell that can resolve the contact resistance problem is presented. In the first AdvSCF cells demonstrated in this work, the nickel (Ni) plating coverage across the cell was found to be non-uniform with Ni voids mostly concentrated around the busbar. This was found to be avoidable by ensuring that the spin-on phosphoric acid dopant layer was uniformly thick across the whole cell area and especially at the busbar. With uniform Ni plating coverage achieved, in a batch of 6 AdvSCF cells, an average batch efficiency of 18.40 % was achieved with the highest at 18.82 %. This was achieved without any experimental optimization of the front grid design or other cell properties, implying that there is potential to achieve significantly higher efficiency levels.
{"title":"18.8 % efficient laser-doped semiconductor fingers screen-printed silicon solar cell with light-induced plating","authors":"Kee Soon Wang, D. Lin, Xinrui An, L. Mai, E. Mitchell, S. Wenham","doi":"10.1109/PVSC.2012.6317805","DOIUrl":"https://doi.org/10.1109/PVSC.2012.6317805","url":null,"abstract":"The practical realization of high efficiency laser-doped semiconductor fingers (SCF) silicon solar cell is inhibited by high contact resistance. By plating the SCF with metal, a new SCF cell concept known as the “Advanced SCF” (AdvSCF) cell that can resolve the contact resistance problem is presented. In the first AdvSCF cells demonstrated in this work, the nickel (Ni) plating coverage across the cell was found to be non-uniform with Ni voids mostly concentrated around the busbar. This was found to be avoidable by ensuring that the spin-on phosphoric acid dopant layer was uniformly thick across the whole cell area and especially at the busbar. With uniform Ni plating coverage achieved, in a batch of 6 AdvSCF cells, an average batch efficiency of 18.40 % was achieved with the highest at 18.82 %. This was achieved without any experimental optimization of the front grid design or other cell properties, implying that there is potential to achieve significantly higher efficiency levels.","PeriodicalId":6318,"journal":{"name":"2012 38th IEEE Photovoltaic Specialists Conference","volume":"81 1","pages":"001149-001153"},"PeriodicalIF":0.0,"publicationDate":"2012-06-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"79195105","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}
Pub Date : 2012-06-03DOI: 10.1109/PVSC.2012.6317860
R. Wandhare, V. Agarwal
The intermittent but complimentary nature of solar photovoltaic and wind mill generated power explored a new area of research for the hybrid PV/wind systems. This paper proposes a novel strategy for the control of power conditioning units to minimize the disturbances on the output power from the hybrid system, integrated with PV and wind turbine, in spite of highly intermittent nature of these sources. The proposed scheme balances the wide variation of power yield from wind and/or PV system and provides sufficient margin to the other sources (e.g. hydro, steam turbine, etc.) connected to the system to take over, so that to maintain power balance throughout the operation. The presented strategy makes use of high energy density ultracapacitor to absorb the effect of intermittent solar radiation and widely varying wind velocity. The MPPT associated with these sources remains unaffected and does not hamper overall generation from the system. The DC link of the conventional back to back topology of the wind farm is integrated with the PV panels with their MPPT trackers. The control strategy uses an inner fast current control loop and an outer slow voltage correcting loop for both the grid side VSI and the ultracapacitor converter. Simulation results are presented in the support of effectiveness of the proposed technique. A prototype is developed with the available 1.5kW PV installation, 1.2kW emulated wind turbine and ultracapacitor bank to validate some aspect of the proposed strategy.
{"title":"A control strategy to reduce the effect of intermittent solar radiation and wind velocity in the hybrid photovoltaic/wind SCIG system without losing MPPT","authors":"R. Wandhare, V. Agarwal","doi":"10.1109/PVSC.2012.6317860","DOIUrl":"https://doi.org/10.1109/PVSC.2012.6317860","url":null,"abstract":"The intermittent but complimentary nature of solar photovoltaic and wind mill generated power explored a new area of research for the hybrid PV/wind systems. This paper proposes a novel strategy for the control of power conditioning units to minimize the disturbances on the output power from the hybrid system, integrated with PV and wind turbine, in spite of highly intermittent nature of these sources. The proposed scheme balances the wide variation of power yield from wind and/or PV system and provides sufficient margin to the other sources (e.g. hydro, steam turbine, etc.) connected to the system to take over, so that to maintain power balance throughout the operation. The presented strategy makes use of high energy density ultracapacitor to absorb the effect of intermittent solar radiation and widely varying wind velocity. The MPPT associated with these sources remains unaffected and does not hamper overall generation from the system. The DC link of the conventional back to back topology of the wind farm is integrated with the PV panels with their MPPT trackers. The control strategy uses an inner fast current control loop and an outer slow voltage correcting loop for both the grid side VSI and the ultracapacitor converter. Simulation results are presented in the support of effectiveness of the proposed technique. A prototype is developed with the available 1.5kW PV installation, 1.2kW emulated wind turbine and ultracapacitor bank to validate some aspect of the proposed strategy.","PeriodicalId":6318,"journal":{"name":"2012 38th IEEE Photovoltaic Specialists Conference","volume":"28 1","pages":"001399-001404"},"PeriodicalIF":0.0,"publicationDate":"2012-06-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"79272772","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}
Pub Date : 2012-06-03DOI: 10.1109/PVSC.2012.6317606
H. Guthrey, S. Johnston, Fei Yan, B. Gorman, M. Al‐Jassim
Photoluminescence (PL) imaging is widely used to identify defective regions within mc-Si PV cells. Recent PL imaging investigations of defect band luminescence (DBL) in mc-Si have revealed a perplexing phenomenon. Namely, the reversal of the DBL intensity in various regions of mc-Si PV material upon the application of a SiNx:H anti-reflective coating (ARC). Regions with low DBL intensity before ARC application often exhibit high DBL intensity afterwards, and the converse is also true. PL imaging alone cannot explain this effect. We have used high resolution cathodoluminescence (CL) spectroscopy and electron beam induced current (EBIC) techniques to elucidate the origin of the DBL intensity reversal. Multiple sub-bandgap energy levels were identified that change in peak position and intensity upon the application of the ARC. Using this data, in addition to EBIC contrast information, we provide an explanation for the DBL intensity reversal based on the interaction of the detected energy levels with the SiNx:H ARC application. Multiple investigations have suggested that this is a global problem for mc-Si PV cells. Our results have the potential to provide mc-Si PV producers a pathway to increased efficiencies through defect mitigation strategies.
{"title":"Defect band luminescence intensity reversal as related to application of anti-reflection coating on mc-Si PV Cells","authors":"H. Guthrey, S. Johnston, Fei Yan, B. Gorman, M. Al‐Jassim","doi":"10.1109/PVSC.2012.6317606","DOIUrl":"https://doi.org/10.1109/PVSC.2012.6317606","url":null,"abstract":"Photoluminescence (PL) imaging is widely used to identify defective regions within mc-Si PV cells. Recent PL imaging investigations of defect band luminescence (DBL) in mc-Si have revealed a perplexing phenomenon. Namely, the reversal of the DBL intensity in various regions of mc-Si PV material upon the application of a SiNx:H anti-reflective coating (ARC). Regions with low DBL intensity before ARC application often exhibit high DBL intensity afterwards, and the converse is also true. PL imaging alone cannot explain this effect. We have used high resolution cathodoluminescence (CL) spectroscopy and electron beam induced current (EBIC) techniques to elucidate the origin of the DBL intensity reversal. Multiple sub-bandgap energy levels were identified that change in peak position and intensity upon the application of the ARC. Using this data, in addition to EBIC contrast information, we provide an explanation for the DBL intensity reversal based on the interaction of the detected energy levels with the SiNx:H ARC application. Multiple investigations have suggested that this is a global problem for mc-Si PV cells. Our results have the potential to provide mc-Si PV producers a pathway to increased efficiencies through defect mitigation strategies.","PeriodicalId":6318,"journal":{"name":"2012 38th IEEE Photovoltaic Specialists Conference","volume":"95 1","pages":"000227-000230"},"PeriodicalIF":0.0,"publicationDate":"2012-06-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"79460307","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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