Pub Date : 1996-05-13DOI: 10.1109/PVSC.1996.564076
A. Aberle, T. Lauinger, S. Bowden, S. Wegener, G. Betz
SUNALYZER, a powerful yet cost-effective solar cell I-V tester is introduced. The costs of the optical components are kept at tolerable levels by means of a halogen lamp array. In combination with a computerized height adjuster, this lamp system allows the measurement of a set of illuminated I-V curves covering the intensity range from 0.1 to 4 Suns. Furthermore, the dark I-V curve is measured over a current range of up to 8 orders of magnitude. From these measurements, an analysis subroutine accurately determines the solar cell's series resistance R/sub s.light/ and R/sub s.dark/ as well as the diode ideality factor n and the saturation current density J/sub 0/ as a function of the external current density. Furthermore, design modifications are described which allow for speedy, fully automated illuminated I-V measurements, as required for testing and sorting purposes in solar cell production lines.
{"title":"SUNALYZER-a powerful and cost-effective solar cell I-V tester for the photovoltaic community","authors":"A. Aberle, T. Lauinger, S. Bowden, S. Wegener, G. Betz","doi":"10.1109/PVSC.1996.564076","DOIUrl":"https://doi.org/10.1109/PVSC.1996.564076","url":null,"abstract":"SUNALYZER, a powerful yet cost-effective solar cell I-V tester is introduced. The costs of the optical components are kept at tolerable levels by means of a halogen lamp array. In combination with a computerized height adjuster, this lamp system allows the measurement of a set of illuminated I-V curves covering the intensity range from 0.1 to 4 Suns. Furthermore, the dark I-V curve is measured over a current range of up to 8 orders of magnitude. From these measurements, an analysis subroutine accurately determines the solar cell's series resistance R/sub s.light/ and R/sub s.dark/ as well as the diode ideality factor n and the saturation current density J/sub 0/ as a function of the external current density. Furthermore, design modifications are described which allow for speedy, fully automated illuminated I-V measurements, as required for testing and sorting purposes in solar cell production lines.","PeriodicalId":410394,"journal":{"name":"Conference Record of the Twenty Fifth IEEE Photovoltaic Specialists Conference - 1996","volume":"35 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1996-05-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"115293643","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 : 1996-05-13DOI: 10.1109/PVSC.1996.564308
J. Yang, X. Xu, A. Banerjee, S. Guha
We have achieved a new world record stable efficiency of 11.8% for amorphous silicon alloy solar cells using a spectrum-splitting, triple-junction structure. In addition to our previously reported key factors leading to high performance multijunction solar cells, we have improved the current matching among the component cells. We have designed the triple structure such that the top cell, which usually exhibits the highest fill factor, remains to be the current-limiting cell in the degraded state. One critical requirement for achieving the desired current matching without sacrificing the triple cell current is to obtain a high quality narrow bandgap bottom cell capable of producing sufficient red current. Details on this narrow bandgap amorphous silicon germanium alloy cell as well as stability data on the triple-junction cell are presented.
{"title":"Progress in triple-junction amorphous silicon alloy solar cells with improved current mismatch in component cells","authors":"J. Yang, X. Xu, A. Banerjee, S. Guha","doi":"10.1109/PVSC.1996.564308","DOIUrl":"https://doi.org/10.1109/PVSC.1996.564308","url":null,"abstract":"We have achieved a new world record stable efficiency of 11.8% for amorphous silicon alloy solar cells using a spectrum-splitting, triple-junction structure. In addition to our previously reported key factors leading to high performance multijunction solar cells, we have improved the current matching among the component cells. We have designed the triple structure such that the top cell, which usually exhibits the highest fill factor, remains to be the current-limiting cell in the degraded state. One critical requirement for achieving the desired current matching without sacrificing the triple cell current is to obtain a high quality narrow bandgap bottom cell capable of producing sufficient red current. Details on this narrow bandgap amorphous silicon germanium alloy cell as well as stability data on the triple-junction cell are presented.","PeriodicalId":410394,"journal":{"name":"Conference Record of the Twenty Fifth IEEE Photovoltaic Specialists Conference - 1996","volume":"22 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1996-05-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"116683984","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 : 1996-05-13DOI: 10.1109/PVSC.1996.564379
M. Nowlan, S. Hogan, J. Patterson, S. Sutherland, J. Murach, W. Breen, G. Darkazalli
The objective of this work is to reduce the cost and improve the quality of terrestrial photovoltaic (PV) modules by developing automated high-throughput (5 MW/yr) processes for interconnecting crystalline silicon solar cells. A new automated processing system was developed for high-throughput, high-yield solar cell interconnection. The results of extensive processing evaluations with a range of different commercially produced cells are reported. Process yields typically exceeded 98%. No degradation in cell performance was observed. Modules made from cell strings fabricated with the new assembly system were subjected to accelerated environmental testing per IEC 1215 and IEEE 1262 standards. Testing consisted of thermal cycling, thermal and humidity-freeze cycling, and damp heat soaking. All modules passed these qualification tests, with an average power loss of only 2.3%.
{"title":"Processing evaluations of an automated high-throughput system for interconnecting crystalline silicon solar cells","authors":"M. Nowlan, S. Hogan, J. Patterson, S. Sutherland, J. Murach, W. Breen, G. Darkazalli","doi":"10.1109/PVSC.1996.564379","DOIUrl":"https://doi.org/10.1109/PVSC.1996.564379","url":null,"abstract":"The objective of this work is to reduce the cost and improve the quality of terrestrial photovoltaic (PV) modules by developing automated high-throughput (5 MW/yr) processes for interconnecting crystalline silicon solar cells. A new automated processing system was developed for high-throughput, high-yield solar cell interconnection. The results of extensive processing evaluations with a range of different commercially produced cells are reported. Process yields typically exceeded 98%. No degradation in cell performance was observed. Modules made from cell strings fabricated with the new assembly system were subjected to accelerated environmental testing per IEC 1215 and IEEE 1262 standards. Testing consisted of thermal cycling, thermal and humidity-freeze cycling, and damp heat soaking. All modules passed these qualification tests, with an average power loss of only 2.3%.","PeriodicalId":410394,"journal":{"name":"Conference Record of the Twenty Fifth IEEE Photovoltaic Specialists Conference - 1996","volume":"13 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1996-05-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"123845403","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 : 1996-05-13DOI: 10.1109/PVSC.1996.563956
J. Lammasniemi, K. Tappura, R. Jaakkola, A. Kazantsev, K. Rakennus, P. Uusimaa, M. Pessa
Ga/sub 0.51/In/sub 0.49/P solar cells and GaAs tunnel diodes were grown by gas-source molecular beam epitaxy. The effect of various window layer materials, such as Al/sub 0.51/In/sub 0.49/P, Al/sub 0.8/Ga/sub 0.2/As and ZnSe were studied for n-on-p Ga/sub 0.51/In/sub 0.49/P cells. The best carrier collection was obtained with Al/sub 0.51/In/sub 0.49/P window and with graded doping in emitter and base layers. A total-area AM0 efficiency of 14.0% for 2/spl times/2 cm/sup 2/ area has been measured for this cell. The GaAs tunnel diodes were grown with Be-doping for p-type and Si-doping for n-type material. Specific resistance of 0.09 m/spl Omega/cm/sup 2/ and peak tunneling current of 200 A/cm/sup 2/ were obtained for the best GaAs tunnel diodes. In addition, tunneling effect in a n++Ga/sub 0.51/In/sub 0.49/P/p++GaAs diode was observed.
{"title":"Molecular beam epitaxy grown GaInP top cells and GaAs tunnel diodes for tandem applications","authors":"J. Lammasniemi, K. Tappura, R. Jaakkola, A. Kazantsev, K. Rakennus, P. Uusimaa, M. Pessa","doi":"10.1109/PVSC.1996.563956","DOIUrl":"https://doi.org/10.1109/PVSC.1996.563956","url":null,"abstract":"Ga/sub 0.51/In/sub 0.49/P solar cells and GaAs tunnel diodes were grown by gas-source molecular beam epitaxy. The effect of various window layer materials, such as Al/sub 0.51/In/sub 0.49/P, Al/sub 0.8/Ga/sub 0.2/As and ZnSe were studied for n-on-p Ga/sub 0.51/In/sub 0.49/P cells. The best carrier collection was obtained with Al/sub 0.51/In/sub 0.49/P window and with graded doping in emitter and base layers. A total-area AM0 efficiency of 14.0% for 2/spl times/2 cm/sup 2/ area has been measured for this cell. The GaAs tunnel diodes were grown with Be-doping for p-type and Si-doping for n-type material. Specific resistance of 0.09 m/spl Omega/cm/sup 2/ and peak tunneling current of 200 A/cm/sup 2/ were obtained for the best GaAs tunnel diodes. In addition, tunneling effect in a n++Ga/sub 0.51/In/sub 0.49/P/p++GaAs diode was observed.","PeriodicalId":410394,"journal":{"name":"Conference Record of the Twenty Fifth IEEE Photovoltaic Specialists Conference - 1996","volume":"55 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1996-05-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"130156059","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 : 1996-05-13DOI: 10.1109/PVSC.1996.564049
F. Schuurmans, A. Schonecker, J. Eikelboom, W. Sinke
The crystal-orientation dependence of the surface recombination velocity for silicon nitride coated silicon wafers is investigated and compared with thermal oxides. A qualitative very similar orientation dependence of S/sub eff,d/(/spl Delta/n) for thermal oxide and PECVD nitride coated p-Si wafers etched in diluted HF is found with S/sub eff,d/(/spl Delta/n) (100)<[110]<(111). The type of HF-etch (diluted or buffered HF) prior to deposition has a large influence on S/sub eff,d/ for the nitride coated p-Si wafers. For the nitride coated n-Si wafers etched in diluted HF no orientation dependence of S/sub eff,d/ is observed.
{"title":"Crystal-orientation dependence of surface recombination velocity for silicon nitride passivated silicon wafers","authors":"F. Schuurmans, A. Schonecker, J. Eikelboom, W. Sinke","doi":"10.1109/PVSC.1996.564049","DOIUrl":"https://doi.org/10.1109/PVSC.1996.564049","url":null,"abstract":"The crystal-orientation dependence of the surface recombination velocity for silicon nitride coated silicon wafers is investigated and compared with thermal oxides. A qualitative very similar orientation dependence of S/sub eff,d/(/spl Delta/n) for thermal oxide and PECVD nitride coated p-Si wafers etched in diluted HF is found with S/sub eff,d/(/spl Delta/n) (100)<[110]<(111). The type of HF-etch (diluted or buffered HF) prior to deposition has a large influence on S/sub eff,d/ for the nitride coated p-Si wafers. For the nitride coated n-Si wafers etched in diluted HF no orientation dependence of S/sub eff,d/ is observed.","PeriodicalId":410394,"journal":{"name":"Conference Record of the Twenty Fifth IEEE Photovoltaic Specialists Conference - 1996","volume":"10 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1996-05-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"127753300","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 : 1996-05-13DOI: 10.1109/PVSC.1996.564322
Hong Zhu, S. Fonash
Two different approaches to reduce the influence of the solar cell interface have been explored using the authors' AMPS (Analysis of Microelectronics and Photonic Structures) computer program. The two particular approaches they considered both focus on shaping the field at the p layer/absorber interface between a-SiC:H and a-Si:H to enhance p-i-n solar cell performance and in both cases they assume this can be done without introducing any new defects at the interface. The two approaches examined are: (1) the bandgap grading buffer layer; and (2) the doped buffer layer.
{"title":"Study of buffer layer design in single junction solar cells","authors":"Hong Zhu, S. Fonash","doi":"10.1109/PVSC.1996.564322","DOIUrl":"https://doi.org/10.1109/PVSC.1996.564322","url":null,"abstract":"Two different approaches to reduce the influence of the solar cell interface have been explored using the authors' AMPS (Analysis of Microelectronics and Photonic Structures) computer program. The two particular approaches they considered both focus on shaping the field at the p layer/absorber interface between a-SiC:H and a-Si:H to enhance p-i-n solar cell performance and in both cases they assume this can be done without introducing any new defects at the interface. The two approaches examined are: (1) the bandgap grading buffer layer; and (2) the doped buffer layer.","PeriodicalId":410394,"journal":{"name":"Conference Record of the Twenty Fifth IEEE Photovoltaic Specialists Conference - 1996","volume":"91 ","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1996-05-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"134224912","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 : 1996-05-13DOI: 10.1109/PVSC.1996.564236
A. Rohatgi, S. Narasimha, S. Kamra, P. Doshi, C. Khattak, K. Emery, H. Field
Solar cells with efficiencies as high as 18.6% (1 cm/sup 2/ area) have been achieved by a process which involves impurity gettering and effective back surface passivation on 0.65 /spl Omega/-cm multicrystalline silicon (mc-Si) grown by the heat exchanger method (HEM). This represents the highest reported solar cell efficiency on mc-Si to date. PCD analysis revealed that the bulk lifetime (/spl tau//sub b/) in HEM samples after phosphorus gettering can be as high as 135 /spl mu/s. This increases the impact of the back surface recombination velocity (S/sub b/) on the solar cell performance. By incorporating a deeper aluminum BSF, the S/sub b/ for solar cells in this study was lowered from 10000 cm/s to 2000 cm/s on HEM mc-Si. This combination of high /spl tau//sub b/ and moderately low S/sub b/ resulted in the record high efficiency mc-Si solar cell. Model calculations indicate that lowering S/sub b/ further can raise the efficiency of untextured HEM mc-Si solar cells above 19.0%, thus closing the efficiency gap between good quality, untextured single crystal and mc-Si solar cells.
{"title":"Record high 18.6% efficient solar cell on HEM multicrystalline material","authors":"A. Rohatgi, S. Narasimha, S. Kamra, P. Doshi, C. Khattak, K. Emery, H. Field","doi":"10.1109/PVSC.1996.564236","DOIUrl":"https://doi.org/10.1109/PVSC.1996.564236","url":null,"abstract":"Solar cells with efficiencies as high as 18.6% (1 cm/sup 2/ area) have been achieved by a process which involves impurity gettering and effective back surface passivation on 0.65 /spl Omega/-cm multicrystalline silicon (mc-Si) grown by the heat exchanger method (HEM). This represents the highest reported solar cell efficiency on mc-Si to date. PCD analysis revealed that the bulk lifetime (/spl tau//sub b/) in HEM samples after phosphorus gettering can be as high as 135 /spl mu/s. This increases the impact of the back surface recombination velocity (S/sub b/) on the solar cell performance. By incorporating a deeper aluminum BSF, the S/sub b/ for solar cells in this study was lowered from 10000 cm/s to 2000 cm/s on HEM mc-Si. This combination of high /spl tau//sub b/ and moderately low S/sub b/ resulted in the record high efficiency mc-Si solar cell. Model calculations indicate that lowering S/sub b/ further can raise the efficiency of untextured HEM mc-Si solar cells above 19.0%, thus closing the efficiency gap between good quality, untextured single crystal and mc-Si solar cells.","PeriodicalId":410394,"journal":{"name":"Conference Record of the Twenty Fifth IEEE Photovoltaic Specialists Conference - 1996","volume":"264 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1996-05-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"115205356","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 : 1996-05-13DOI: 10.1109/PVSC.1996.564028
C. Honsberg, S. Ghozati, A. Ebong, Y. Tang, S. Wenham
Floating junction (FJ) passivation is a relatively recent passivation scheme which has both experimentally and theoretically demonstrated superior passivation than either oxide or back surface field passivation. In addition, it is suited not only to high efficiency laboratory cells, but also to commercial solar cells. The improvement in surface passivation for commercial cells is an especially critical issue in achieving lower cost solar cells through reducing substrate thickness while simultaneously increasing efficiency. Despite the many advantages of FJ passivation, its applicability has been limited by the apparent inability to translate the excellent modelling results into actual solar cells. The objective of this paper is to present a complete analysis of FJ passivation and to demonstrate a method by which the problems with FJ passivation can be eliminated. Experimental evidence as well as theoretical modelling demonstrates that a solar cell with an optimized rear FJ is insensitive to parasitic effects.
{"title":"Elimination of parasitic effects in floating junction rear surface passivation for solar cells","authors":"C. Honsberg, S. Ghozati, A. Ebong, Y. Tang, S. Wenham","doi":"10.1109/PVSC.1996.564028","DOIUrl":"https://doi.org/10.1109/PVSC.1996.564028","url":null,"abstract":"Floating junction (FJ) passivation is a relatively recent passivation scheme which has both experimentally and theoretically demonstrated superior passivation than either oxide or back surface field passivation. In addition, it is suited not only to high efficiency laboratory cells, but also to commercial solar cells. The improvement in surface passivation for commercial cells is an especially critical issue in achieving lower cost solar cells through reducing substrate thickness while simultaneously increasing efficiency. Despite the many advantages of FJ passivation, its applicability has been limited by the apparent inability to translate the excellent modelling results into actual solar cells. The objective of this paper is to present a complete analysis of FJ passivation and to demonstrate a method by which the problems with FJ passivation can be eliminated. Experimental evidence as well as theoretical modelling demonstrates that a solar cell with an optimized rear FJ is insensitive to parasitic effects.","PeriodicalId":410394,"journal":{"name":"Conference Record of the Twenty Fifth IEEE Photovoltaic Specialists Conference - 1996","volume":"149 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1996-05-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"115545352","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 : 1996-05-13DOI: 10.1109/PVSC.1996.564340
B. Crone, A. Payne, S. Wagner
A 200 /spl mu/m thick fully glass-encapsulated a-Si:H solar cell is demonstrated. The cell structure is 75 /spl mu/m glass foil superstrate/a-Si,N:H diffusion barrier/specular ZnO:Al/a-Si:H pin solar cell/Al. The solar cell is encapsulated with 50 /spl mu/m ethylene vinyl acetate (EVA) and another 75 /spl mu/m glass foil. The current-voltage characteristics of a 0.24 cm/sup 2/ cell measured under AM1.5 (100 mW/cm/sup 2/) light give V/sub OC/=0.83 V, J/sub SC/=11.1 mA/cm/sup 2/, and FF=0.61, for an initial efficiency of 5.6%.
{"title":"200 /spl mu/m thick encapsulated amorphous silicon solar cells","authors":"B. Crone, A. Payne, S. Wagner","doi":"10.1109/PVSC.1996.564340","DOIUrl":"https://doi.org/10.1109/PVSC.1996.564340","url":null,"abstract":"A 200 /spl mu/m thick fully glass-encapsulated a-Si:H solar cell is demonstrated. The cell structure is 75 /spl mu/m glass foil superstrate/a-Si,N:H diffusion barrier/specular ZnO:Al/a-Si:H pin solar cell/Al. The solar cell is encapsulated with 50 /spl mu/m ethylene vinyl acetate (EVA) and another 75 /spl mu/m glass foil. The current-voltage characteristics of a 0.24 cm/sup 2/ cell measured under AM1.5 (100 mW/cm/sup 2/) light give V/sub OC/=0.83 V, J/sub SC/=11.1 mA/cm/sup 2/, and FF=0.61, for an initial efficiency of 5.6%.","PeriodicalId":410394,"journal":{"name":"Conference Record of the Twenty Fifth IEEE Photovoltaic Specialists Conference - 1996","volume":"9 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1996-05-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"115563434","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 : 1996-05-13DOI: 10.1109/PVSC.1996.564389
A. Kitamura, F. Yamamoto, H. Matsuda, K. Akhmad, Y. Hamakawa
Since power output of a PV system is DC and the commercial grid carriers AC, in any linked system, attention is paid to prevent direct mixture of these two currents. Usually alternating and direct currents mix through the inverter, and because of the great variety in types and specifications, phenomena may be extremely complex. To observe the basic phenomena, demonstration tests were conducted in which direct coupling of PV arrays and the grid have been performed. PV arrays' short circuit current is relatively weak, so the effect on transformers are not so substantial as in the case of a storage battery system linkage. After a certain time exciting current appears, and grows, on the AC side of the transformer. Consequently, with increase of the exciting current when DC and AC powers are mixed, higher harmonic currents appear on the AC side. Breakdown phenomenon on the array side is different depending on whether AC injection happens during an active power generating period, or a passive one and also the existence, or lack, of by-pass diodes or blocking diodes is significant. Blocking diodes prevent larger AC currents from flowing through the solar cells, whereas by-pass diodes let those currents get around the blocking diodes.
{"title":"Test results on DC injection phenomenon of grid connected PV system at Rokko test center","authors":"A. Kitamura, F. Yamamoto, H. Matsuda, K. Akhmad, Y. Hamakawa","doi":"10.1109/PVSC.1996.564389","DOIUrl":"https://doi.org/10.1109/PVSC.1996.564389","url":null,"abstract":"Since power output of a PV system is DC and the commercial grid carriers AC, in any linked system, attention is paid to prevent direct mixture of these two currents. Usually alternating and direct currents mix through the inverter, and because of the great variety in types and specifications, phenomena may be extremely complex. To observe the basic phenomena, demonstration tests were conducted in which direct coupling of PV arrays and the grid have been performed. PV arrays' short circuit current is relatively weak, so the effect on transformers are not so substantial as in the case of a storage battery system linkage. After a certain time exciting current appears, and grows, on the AC side of the transformer. Consequently, with increase of the exciting current when DC and AC powers are mixed, higher harmonic currents appear on the AC side. Breakdown phenomenon on the array side is different depending on whether AC injection happens during an active power generating period, or a passive one and also the existence, or lack, of by-pass diodes or blocking diodes is significant. Blocking diodes prevent larger AC currents from flowing through the solar cells, whereas by-pass diodes let those currents get around the blocking diodes.","PeriodicalId":410394,"journal":{"name":"Conference Record of the Twenty Fifth IEEE Photovoltaic Specialists Conference - 1996","volume":"35 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1996-05-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"114335862","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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