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Dr. Kenji Araki
Toyota Technological Institute

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0 CPV
0 Optical Design
0 PV
0 Monte Carlo methods
0 VIPV

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Research article
Published: 24 September 2020 in Progress in Photovoltaics: Research and Applications
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Silicon space solar cells are currently attracting attention again for their relatively low‐cost feature with sufficient performance, and they are expected to resume into the space market especially by short‐term mission spacecraft designers. In this paper, efficiency potential of crystalline Si space solar cells is analyzed by considering external radiative efficiency (ERE), voltage and fill factor losses. Crystalline Si space solar cells have efficiency potential of more than 26% by realizing ERE of 20% from about 0.2% and normalized resistance of less than 0.05 from around 0.15. Nonradiative recombination and resistance losses in Si space solar cells are also discussed. Radiation degradation of Si space solar cells is also analyzed. Advanced Si solar cells such as passivated emitter, hetero‐junction, and back contact solar cells are expected to use as space solar cells. Potential of advanced Si solar cells for space applications is discussed from point view of radiation degradation.

ACS Style

Masafumi Yamaguchi; Kan‐Hua Lee; Kenji Araki; Nobuaki Kojima; Yasuki Okuno; Mitsuru Imaizumi. Analysis for nonradiative recombination loss and radiation degradation of Si space solar cells. Progress in Photovoltaics: Research and Applications 2020, 29, 98 -108.

AMA Style

Masafumi Yamaguchi, Kan‐Hua Lee, Kenji Araki, Nobuaki Kojima, Yasuki Okuno, Mitsuru Imaizumi. Analysis for nonradiative recombination loss and radiation degradation of Si space solar cells. Progress in Photovoltaics: Research and Applications. 2020; 29 (1):98-108.

Chicago/Turabian Style

Masafumi Yamaguchi; Kan‐Hua Lee; Kenji Araki; Nobuaki Kojima; Yasuki Okuno; Mitsuru Imaizumi. 2020. "Analysis for nonradiative recombination loss and radiation degradation of Si space solar cells." Progress in Photovoltaics: Research and Applications 29, no. 1: 98-108.

Journal article
Published: 27 May 2020 in Applied Physics Express
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ACS Style

Daisuke Sato; Kenji Araki; Tatsuya Takamoto; Hiroyuki Juso; Noboru Yamada; Taizo Masuda; Masafumi Yamaguchi. Nearly 30%-efficient low-concentration static photovoltaic modules with IMM triple-junction solar cells. Applied Physics Express 2020, 1 .

AMA Style

Daisuke Sato, Kenji Araki, Tatsuya Takamoto, Hiroyuki Juso, Noboru Yamada, Taizo Masuda, Masafumi Yamaguchi. Nearly 30%-efficient low-concentration static photovoltaic modules with IMM triple-junction solar cells. Applied Physics Express. 2020; ():1.

Chicago/Turabian Style

Daisuke Sato; Kenji Araki; Tatsuya Takamoto; Hiroyuki Juso; Noboru Yamada; Taizo Masuda; Masafumi Yamaguchi. 2020. "Nearly 30%-efficient low-concentration static photovoltaic modules with IMM triple-junction solar cells." Applied Physics Express , no. : 1.

Journal article
Published: 07 April 2020 in Applied Sciences
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The outdoor field test of the 4-terminal on Si tandem photovoltaic module (specifically, InGaP/GaAs on Si) was investigated and a performance model, considering spectrum change affected by fluctuation of atmospheric parameters, was developed and validated. The 4-terminal on Si tandem photovoltaic module had about 40% advantage in seasonal performance loss compared with standard InGaP/GaAs/InGaAs 2-terminal tandem photovoltaic module. This advantage increases (subarctic zone < temperate zone < subtropical zone). The developed and validated model used an all-climate spectrum model and considered fluctuation of atmospheric parameters. It can be applied every type of on-Si tandem solar cells.

ACS Style

Kenji Araki; Hiroki Tawa; Hiromu Saiki; Yasuyuki Ota; Kensuke Nishioka; Masafumi Yamaguchi. The Outdoor Field Test and Energy Yield Model of the Four-Terminal on Si Tandem PV Module. Applied Sciences 2020, 10, 2529 .

AMA Style

Kenji Araki, Hiroki Tawa, Hiromu Saiki, Yasuyuki Ota, Kensuke Nishioka, Masafumi Yamaguchi. The Outdoor Field Test and Energy Yield Model of the Four-Terminal on Si Tandem PV Module. Applied Sciences. 2020; 10 (7):2529.

Chicago/Turabian Style

Kenji Araki; Hiroki Tawa; Hiromu Saiki; Yasuyuki Ota; Kensuke Nishioka; Masafumi Yamaguchi. 2020. "The Outdoor Field Test and Energy Yield Model of the Four-Terminal on Si Tandem PV Module." Applied Sciences 10, no. 7: 2529.

Preprint
Published: 30 March 2020
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The outdoor field test of the 4-terminal on Si tandem photovoltaic module (specifically, InGaP/GaAs on Si) was investigated and performance model, considering spectrum change affected by fluctuation of atmospheric parameters, was developed and validated. The 4-terminal on Si tandem photovoltaic module had about 40 % advantage in seasonal performance loss compared with standard InGaP/GaAs/InGaAs 2-terminal tandem photovoltaic module. This advantage is expanded in (subarctic zone) < (temperate zone) < (subtropical zone). The developed and validated model used all-climate spectrum model and considered fluctuation of atmospheric parameters, and can be applied every type of on-Si tandem solar cells.

ACS Style

Kenji Araki; Hiroki Tawa; Hiromu Saiki; Yasuyuki Ota; Kensuke Nishioka; Masafumi Yamaguchi. The Outdoor Field Test and Energy Yield Model of the Four-terminal on Si Tandem PV Module. 2020, 1 .

AMA Style

Kenji Araki, Hiroki Tawa, Hiromu Saiki, Yasuyuki Ota, Kensuke Nishioka, Masafumi Yamaguchi. The Outdoor Field Test and Energy Yield Model of the Four-terminal on Si Tandem PV Module. . 2020; ():1.

Chicago/Turabian Style

Kenji Araki; Hiroki Tawa; Hiromu Saiki; Yasuyuki Ota; Kensuke Nishioka; Masafumi Yamaguchi. 2020. "The Outdoor Field Test and Energy Yield Model of the Four-terminal on Si Tandem PV Module." , no. : 1.

Article
Published: 27 January 2020 in Applied Sciences
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The energy yield of vehicle-integrated photovoltaics (VIPV) differs from that of standard photovoltaics (PV). It is mainly by the difference of the solar irradiance onto the car roof and car bodies as well as its curved shape. Both meaningful and practical modeling and measurement of solar irradiance for VIPV need to be established, rather than the extension of the current technologies. The solar irradiance is modeled by a random distribution of shading objects and car orientation with the correction of the curved surface of the PV modules. The measurement of the solar irradiance onto the car roof and car body is done using five pyranometers in five local axes on the car for one year. The measured dynamic solar irradiance onto the car body and car roof is used for validation of the solar irradiance model in the car.

ACS Style

Kenji Araki; Yasuyuki Ota; Masafumi Yamaguchi. Measurement and Modeling of 3D Solar Irradiance for Vehicle-Integrated Photovoltaic. Applied Sciences 2020, 10, 872 .

AMA Style

Kenji Araki, Yasuyuki Ota, Masafumi Yamaguchi. Measurement and Modeling of 3D Solar Irradiance for Vehicle-Integrated Photovoltaic. Applied Sciences. 2020; 10 (3):872.

Chicago/Turabian Style

Kenji Araki; Yasuyuki Ota; Masafumi Yamaguchi. 2020. "Measurement and Modeling of 3D Solar Irradiance for Vehicle-Integrated Photovoltaic." Applied Sciences 10, no. 3: 872.

Journal article
Published: 19 January 2020 in Applied Sciences
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Because semiconductors absorb wavelengths dependent on the light absorption coefficient, photovoltaic (PV) energy output is affected by the solar spectrum. Therefore, it is necessary to consider the solar spectrum for highly accurate PV output estimation. Bird’s model has been used as a general spectral model. However, atmospheric parameters such as aerosol optical depth and precipitable water have a constant value in the model that only applies to clear days. In this study, atmospheric parameters were extracted using the Bird’s spectrum model from the measured global spectrum and the seasonal fluctuation of atmospheric parameters was examined. We propose an overcast spectrum model and calculate the all-weather solar spectrum from clear to overcast sky through linear combination. Three types of PV modules (fixed Si, two-axis tracking Si, and fixed InGaP/GaAs/InGaAs triple-junction solar cells) were installed at the University of Miyazaki. The estimated performance ratio (PR), which takes into account incident angle and spectral variations, was consistent with the measured PR. Finally, the energy yield of various PVs installed across Japan was successfully estimated.

ACS Style

Hiroki Tawa; Hiromu Saiki; Yasuyuki Ota; Kenji Araki; Tatsuya Takamoto; Kensuke Nishioka. Accurate Output Forecasting Method for Various Photovoltaic Modules Considering Incident Angle and Spectral Change Owing to Atmospheric Parameters and Cloud Conditions. Applied Sciences 2020, 10, 703 .

AMA Style

Hiroki Tawa, Hiromu Saiki, Yasuyuki Ota, Kenji Araki, Tatsuya Takamoto, Kensuke Nishioka. Accurate Output Forecasting Method for Various Photovoltaic Modules Considering Incident Angle and Spectral Change Owing to Atmospheric Parameters and Cloud Conditions. Applied Sciences. 2020; 10 (2):703.

Chicago/Turabian Style

Hiroki Tawa; Hiromu Saiki; Yasuyuki Ota; Kenji Araki; Tatsuya Takamoto; Kensuke Nishioka. 2020. "Accurate Output Forecasting Method for Various Photovoltaic Modules Considering Incident Angle and Spectral Change Owing to Atmospheric Parameters and Cloud Conditions." Applied Sciences 10, no. 2: 703.

Preprint
Published: 15 January 2020
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The energy yield of the Vehicle-integrated photovoltaic (VIPV) differs from that of the standard photovoltaics (PV). It is mainly by the difference of the solar irradiance onto the car-roof and car-bodies as well as its curved-shape. Both meaningful and practical modeling and measurement of the solar irradiance for VIPV are needed to be newly established, not the extension of the current technologies. The solar irradiance was modeled by a random distribution of the shading objects and car-orientation with the correction of the curved surface of the PV modules. The measurement of the solar irradiance onto the car-roof and car-body was done using five pyranometers in five local axes on the car for one year. The measured dynamic solar irradiance onto the car-body and car-roof was used for validation of the solar irradiance model in the car.

ACS Style

Kenji Araki; Yasuyuki Ota; Masafumi Yamaguchi. Measurement and Modeling of the 3-D Solar Irradiance for Vehicle-Integrated Photovoltaic. 2020, 1 .

AMA Style

Kenji Araki, Yasuyuki Ota, Masafumi Yamaguchi. Measurement and Modeling of the 3-D Solar Irradiance for Vehicle-Integrated Photovoltaic. . 2020; ():1.

Chicago/Turabian Style

Kenji Araki; Yasuyuki Ota; Masafumi Yamaguchi. 2020. "Measurement and Modeling of the 3-D Solar Irradiance for Vehicle-Integrated Photovoltaic." , no. : 1.

Journal article
Published: 29 October 2019 in Applied Sciences
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The highest-efficiency solar cell in the efficiency race does not always give the best annual energy yield in real world solar conditions because the spectrum is always changing. The study of radiative coupling of concentrator solar cells implies that efficiency could increase by recycling the radiative recombination generated by the surplus current in the upper junction. Such a configuration is called a super-multi-junction cell. We expand the model in the concentrator solar cell to a non-concentrating installation. It is shown that this super-multi-junction cell configuration is robust and can keep maximum potential efficiency (50% in realistic spectrum fluctuation) for up to 10 junctions. The super-multi-junction cell is also robust in the bandgap engineering of each junction. Therefore, a future multi-junction may not be required for tuning the bandgap to match the standard solar spectrum, as well as relying upon artificial technologies such as epitaxial lift-off (ELO), wafer-bonding, mechanical-stacking, and reverse-growth, but merely uses upright and lattice-matching growth technologies. We present two challenging techniques; one is the optical cap layer that may be the directional photon coupling layer in the application of the photonics technologies, and another is the high-quality epitaxial growth with almost 100% radiative efficiency.

ACS Style

Kenji Araki; Yasuyuki Ota; Hiromu Saiki; Hiroki Tawa; Kensuke Nishioka; Masafumi Yamaguchi. Super-Multi-Junction Solar Cells—Device Configuration with the Potential for More Than 50% Annual Energy Conversion Efficiency (Non-Concentration). Applied Sciences 2019, 9, 4598 .

AMA Style

Kenji Araki, Yasuyuki Ota, Hiromu Saiki, Hiroki Tawa, Kensuke Nishioka, Masafumi Yamaguchi. Super-Multi-Junction Solar Cells—Device Configuration with the Potential for More Than 50% Annual Energy Conversion Efficiency (Non-Concentration). Applied Sciences. 2019; 9 (21):4598.

Chicago/Turabian Style

Kenji Araki; Yasuyuki Ota; Hiromu Saiki; Hiroki Tawa; Kensuke Nishioka; Masafumi Yamaguchi. 2019. "Super-Multi-Junction Solar Cells—Device Configuration with the Potential for More Than 50% Annual Energy Conversion Efficiency (Non-Concentration)." Applied Sciences 9, no. 21: 4598.

Preprint
Published: 14 October 2019
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The highest efficiency solar cell won in the efficiency race does not always give the most excellent annual energy yield in the real world solar condition that the spectrum is ever-changing. The study of the radiative coupling of the concentrator solar cells implied that the efficiency could increase by the recycle of the radiative recombination generated by the surplus current in upper junction. Such configuration is called by a super-multi-junction cell. We expanded the model in the concentrator solar cell to non-concentrating installation. It was shown that this super-multi-junction cell configuration was found robust and can keep the maximum potential efficiency (50 % in realistic spectrum fluctuation) up to 10 junctions. The super-multi-junction cell is also robust in the bandgap engineering of each junction. Therefore, the future multi-junction may not be needed to tune the bandgap for matching the standard solar spectrum, as well as relying upon artificial technologies like ELO (Epitaxial lift-off), wafer-bonding, mechanical-stacking, and reverse-growth, but merely uses up-right and lattice-matching growth technologies. We have two challenging techniques; one is the optical cap layer that may be the directional photon coupling layer in the application of the photonics technologies, and another is the high-quality epitaxial growth with almost 100 % of the radiative efficiency.

ACS Style

Kenji Araki; Yasuyuki Ota; Hiromu Saiki; Hiroki Tawa; Kensuke Nishioka; Masafumi Yamaguchi. Super-Multi-Junction Solar Cell, Device Configuration with the Potential of More Than 50 % of the Annual Energy Conversion Efficiency (Non-Concentration). 2019, 1 .

AMA Style

Kenji Araki, Yasuyuki Ota, Hiromu Saiki, Hiroki Tawa, Kensuke Nishioka, Masafumi Yamaguchi. Super-Multi-Junction Solar Cell, Device Configuration with the Potential of More Than 50 % of the Annual Energy Conversion Efficiency (Non-Concentration). . 2019; ():1.

Chicago/Turabian Style

Kenji Araki; Yasuyuki Ota; Hiromu Saiki; Hiroki Tawa; Kensuke Nishioka; Masafumi Yamaguchi. 2019. "Super-Multi-Junction Solar Cell, Device Configuration with the Potential of More Than 50 % of the Annual Energy Conversion Efficiency (Non-Concentration)." , no. : 1.

Journal article
Published: 23 September 2019 in IEEE Journal of Photovoltaics
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We investigate the impact of nonplanar panels on power generation in the case of photovoltaic panels mounted on vehicles. The power generation of nonplanar photovoltaic panels on vehicles is analyzed using the numerical geometric model, comprising the incident angle distribution of irradiation. We calculated power generated by the photovoltaic panels equipped on the roof, side, and tilted surfaces of vehicles, showing that even the panels on the side, which are fitted vertically to the ground, generate more than a quarter of the total power as that generated by the panel horizontal to the ground. Furthermore, we evaluated the curve correction factor that reflects the relative power generation of nonplanar panels with respect to the reference flat panels on vehicles. The geometrical model reproduces a simple relationship between the curve correction factor and effective surface ratio between the nonplanar and reference flat panels. Our findings indicate that the curve correction factor is useful to estimate power generation for nonplanar photovoltaic devices on vehicles; this provides a guiding principle for designing nonplanar photovoltaic devices for vehicles.

ACS Style

Takeshi Tayagaki; Kenji Araki; Masafumi Yamaguchi; Takeyoshi Sugaya. Impact of Nonplanar Panels on Photovoltaic Power Generation in the Case of Vehicles. IEEE Journal of Photovoltaics 2019, 9, 1721 -1726.

AMA Style

Takeshi Tayagaki, Kenji Araki, Masafumi Yamaguchi, Takeyoshi Sugaya. Impact of Nonplanar Panels on Photovoltaic Power Generation in the Case of Vehicles. IEEE Journal of Photovoltaics. 2019; 9 (6):1721-1726.

Chicago/Turabian Style

Takeshi Tayagaki; Kenji Araki; Masafumi Yamaguchi; Takeyoshi Sugaya. 2019. "Impact of Nonplanar Panels on Photovoltaic Power Generation in the Case of Vehicles." IEEE Journal of Photovoltaics 9, no. 6: 1721-1726.

Conference paper
Published: 26 August 2019 in 15th International Conference on Concentrator Photovoltaic Systems (CPV-15)
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We demonstrated a static (non-tracking) low concentration photovoltaic module that employs a new design paradigm that mixes two different types of the lens arrays. This design approach brings the annual optical collection efficiency closer to the theoretical upper limit but with high manufacturability and scalability, because this design paradigm gives more degree of freedom to optimize the overall efficiencies. We demonstrated that the module with the hybrid lens array is 2-%(absolute) more efficient than its single lens array counterparts at on-axis illumination. Also, the good match of the modeled and experimental incident-angle dependent module efficiency confirms the robustness of our fabrication process, showing the promise of achieving high annual collection efficiency of this module.

ACS Style

Kan-Hua Lee; Sato Daisuke; Kenji Araki; Noboru Yamada; Masafumi Yamaguchi. Demonstration of the performance static low-concentration module using hybrid lens arrays. 15th International Conference on Concentrator Photovoltaic Systems (CPV-15) 2019, 2149, 070009 .

AMA Style

Kan-Hua Lee, Sato Daisuke, Kenji Araki, Noboru Yamada, Masafumi Yamaguchi. Demonstration of the performance static low-concentration module using hybrid lens arrays. 15th International Conference on Concentrator Photovoltaic Systems (CPV-15). 2019; 2149 (1):070009.

Chicago/Turabian Style

Kan-Hua Lee; Sato Daisuke; Kenji Araki; Noboru Yamada; Masafumi Yamaguchi. 2019. "Demonstration of the performance static low-concentration module using hybrid lens arrays." 15th International Conference on Concentrator Photovoltaic Systems (CPV-15) 2149, no. 1: 070009.

Conference paper
Published: 26 August 2019 in 15th International Conference on Concentrator Photovoltaic Systems (CPV-15)
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With this car-roof PV, 70 % of passenger’s may be able to run by solar energy. The potential of the market size is 50 GW/year. However, it is not an easy task to meet the requirement of the main component of EV and the creation of the massive market. It is also apparent that the market will be small as far as we only try to apply the conventional crystalline Si cells. The CPV technology with high power conversion efficiency and capable of coloring and covering on the three-dimensional curved surface is suitable for this market. The static CPV is useful for this application with a better collection of diffused sunlight. One of the problems is the spectrum mismatching. However, this issue is easily solved by adjustment of the bandgap of the bottom cell.

ACS Style

Kenji Araki; Daisuke Sato; Taizo Masuda; Kan-Hua Lee; Noboru Yamada; Masafumi Yamaguchi. Why and how does car-roof PV create 50 GW/year of new installations? Also, why is a static CPV suitable to this application? 15th International Conference on Concentrator Photovoltaic Systems (CPV-15) 2019, 2149, 050003 .

AMA Style

Kenji Araki, Daisuke Sato, Taizo Masuda, Kan-Hua Lee, Noboru Yamada, Masafumi Yamaguchi. Why and how does car-roof PV create 50 GW/year of new installations? Also, why is a static CPV suitable to this application? 15th International Conference on Concentrator Photovoltaic Systems (CPV-15). 2019; 2149 (1):050003.

Chicago/Turabian Style

Kenji Araki; Daisuke Sato; Taizo Masuda; Kan-Hua Lee; Noboru Yamada; Masafumi Yamaguchi. 2019. "Why and how does car-roof PV create 50 GW/year of new installations? Also, why is a static CPV suitable to this application?" 15th International Conference on Concentrator Photovoltaic Systems (CPV-15) 2149, no. 1: 050003.

Conference paper
Published: 26 August 2019 in 15th International Conference on Concentrator Photovoltaic Systems (CPV-15)
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Qualification standards are one the driving forces for the commercialization and production of the Concentrator Photovoltaic (CPV) technology. After several years of preparation the Committee Draft of IEC 62787 has been finally submitted. The new standard IEC 62787 (Concentrator photovoltaic (CPV) solar cells and cell-on-carrier (CoC) assemblies – Qualification) fills the gap between the IEC TS 62789:2014 (Photovoltaic concentrator cell documentation) and the IEC 62108 Ed 2 (Concentrator photovoltaic (CPV) modules and assemblies - Design qualification and type approval). In the present article, apart from analyzing the objective, main guidelines, the innovative characteristics, and the life estimation from several tests of the qualification standard is also explained.

ACS Style

Neftali Nuñez; Manuel Vazquez; Roland Schilling; Kenji Araki; Carlos Algora. Present status and main guidelines of IEC 62787: “Concentrator photovoltaic (CPV) solar cells and cell-on-carrier (CoC) assemblies – qualification”. 15th International Conference on Concentrator Photovoltaic Systems (CPV-15) 2019, 2149, 090002 .

AMA Style

Neftali Nuñez, Manuel Vazquez, Roland Schilling, Kenji Araki, Carlos Algora. Present status and main guidelines of IEC 62787: “Concentrator photovoltaic (CPV) solar cells and cell-on-carrier (CoC) assemblies – qualification”. 15th International Conference on Concentrator Photovoltaic Systems (CPV-15). 2019; 2149 (1):090002.

Chicago/Turabian Style

Neftali Nuñez; Manuel Vazquez; Roland Schilling; Kenji Araki; Carlos Algora. 2019. "Present status and main guidelines of IEC 62787: “Concentrator photovoltaic (CPV) solar cells and cell-on-carrier (CoC) assemblies – qualification”." 15th International Conference on Concentrator Photovoltaic Systems (CPV-15) 2149, no. 1: 090002.

Conference paper
Published: 26 August 2019 in 15th International Conference on Concentrator Photovoltaic Systems (CPV-15)
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It is well known that CPV is sensitive to the spectrum change, and its high-performance is often discouraged by the spectrum mismatching loss by the seasonal change of the atmospheric parameters. We found multiple methods could improve the robustness to the spectrum sensitivity, including enhancing luminescence coupling and fine-tuning to the bottom-bandgap matched to local atmospheric conditions (water absorption).

ACS Style

Kenji Araki; Yasuyuki Ota; Kan-Hua Lee; Kensuke Nishioka; Masafumi Yamaguchi. Improvement of the spectral sensitivity of CPV by enhancing luminescence coupling and fine-tuning to the bottom-bandgap matched to local atmospheric conditions. 15th International Conference on Concentrator Photovoltaic Systems (CPV-15) 2019, 2149, 060001 .

AMA Style

Kenji Araki, Yasuyuki Ota, Kan-Hua Lee, Kensuke Nishioka, Masafumi Yamaguchi. Improvement of the spectral sensitivity of CPV by enhancing luminescence coupling and fine-tuning to the bottom-bandgap matched to local atmospheric conditions. 15th International Conference on Concentrator Photovoltaic Systems (CPV-15). 2019; 2149 (1):060001.

Chicago/Turabian Style

Kenji Araki; Yasuyuki Ota; Kan-Hua Lee; Kensuke Nishioka; Masafumi Yamaguchi. 2019. "Improvement of the spectral sensitivity of CPV by enhancing luminescence coupling and fine-tuning to the bottom-bandgap matched to local atmospheric conditions." 15th International Conference on Concentrator Photovoltaic Systems (CPV-15) 2149, no. 1: 060001.

Conference paper
Published: 26 August 2019 in 15th International Conference on Concentrator Photovoltaic Systems (CPV-15)
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CPV incorporates a wide variety of technologies and options. The application of these technologies, however, is not limited to CPV only. The basic approach of the standardization for CPV is thus expanding the scope to a broader range of technologies. The knowledge gained through our activities is contributing to standardizations in PV technologies like, e.g. standards for trackers. In this regard, the standardization activities for CPV is also moving to new fields of applications.

ACS Style

Kenji Araki; Carlos Algora; Gerald Siefer; Kensuke Nishioka; Ralf Leutz; Sam Carter; Shitao Wang; Steve Askins; Liang Ji; George Kelly. Standardization of the CPV technology in 2019 – The path to new CPV technologies. 15th International Conference on Concentrator Photovoltaic Systems (CPV-15) 2019, 2149, 090001 .

AMA Style

Kenji Araki, Carlos Algora, Gerald Siefer, Kensuke Nishioka, Ralf Leutz, Sam Carter, Shitao Wang, Steve Askins, Liang Ji, George Kelly. Standardization of the CPV technology in 2019 – The path to new CPV technologies. 15th International Conference on Concentrator Photovoltaic Systems (CPV-15). 2019; 2149 (1):090001.

Chicago/Turabian Style

Kenji Araki; Carlos Algora; Gerald Siefer; Kensuke Nishioka; Ralf Leutz; Sam Carter; Shitao Wang; Steve Askins; Liang Ji; George Kelly. 2019. "Standardization of the CPV technology in 2019 – The path to new CPV technologies." 15th International Conference on Concentrator Photovoltaic Systems (CPV-15) 2149, no. 1: 090001.

Conference paper
Published: 01 August 2019 in 2019 18th International Conference on Optical Communications and Networks (ICOCN)
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It is known that multi-junction solar cells are sensitive to the spectrum change [1]-[2], and its high-performance is often discouraged by the spectrum mismatching loss by the seasonal change of the atmospheric parameters [3]-[4]. It implies that the highest efficiency solar cell in the standard testing condition does not always promise the most excellent annual energy yield in the real world solar condition that the spectrum is ever-changing. We found the ultimate solution of the seasonal loss will be autonomous compensation of the carrier imbalance by the radiative coupling among junctions due to radiative recombination [5]. We call it a super-multi-junction solar cell. The annual operation of the super-multi-junction solar cell was simulated by the validated operation model of the photovoltaic module using multi-junction solar cells. It was shown that the super-multi-junction architecture was found robust up to 6 junctions. The robust high-efficiency solar cell can be the right candidate of the vehicle-integrated photovoltaic that run a majority of electric vehicles on solar energy.

ACS Style

Kenji Araki; Yasuyuki Ota; Kan-Hua Lee; Kensuke Nishioka; Masafumi Yamaguchi. Super-Multi-Junction Solar Cells, a New Configuration of the Robust and High-Efficiency Solar Cell and Its Application – Operation Model Based on the Annual Monitoring of the Multi-Junction PV Modules. 2019 18th International Conference on Optical Communications and Networks (ICOCN) 2019, 1 -3.

AMA Style

Kenji Araki, Yasuyuki Ota, Kan-Hua Lee, Kensuke Nishioka, Masafumi Yamaguchi. Super-Multi-Junction Solar Cells, a New Configuration of the Robust and High-Efficiency Solar Cell and Its Application – Operation Model Based on the Annual Monitoring of the Multi-Junction PV Modules. 2019 18th International Conference on Optical Communications and Networks (ICOCN). 2019; ():1-3.

Chicago/Turabian Style

Kenji Araki; Yasuyuki Ota; Kan-Hua Lee; Kensuke Nishioka; Masafumi Yamaguchi. 2019. "Super-Multi-Junction Solar Cells, a New Configuration of the Robust and High-Efficiency Solar Cell and Its Application – Operation Model Based on the Annual Monitoring of the Multi-Junction PV Modules." 2019 18th International Conference on Optical Communications and Networks (ICOCN) , no. : 1-3.

Journal article
Published: 19 July 2019 in IEEE Access
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Equivalent circuit network simulation is widely used in modeling solar cells in three dimensions. However, the computational time and numerical instability increases dramatically when the number of circuit element increases. This problem is exacerbated by increasing the number of junctions in the solar cells. We propose a downsampling algorithm to reduce the time complexity but retain reasonable accuracy within the appropriate parameter space of multi-junction solar cells. We also publish a full-featured software that implements this algorithm and the full circuit network simulation along with this paper.

ACS Style

Kan-Hua Lee; Kenji Araki; Masafumi Yamaguchi. A Mesh Downsampling Algorithm for Equivalent Circuit Network Simulation of Multi-Junction Solar Cells. IEEE Access 2019, 7, 97208 -97215.

AMA Style

Kan-Hua Lee, Kenji Araki, Masafumi Yamaguchi. A Mesh Downsampling Algorithm for Equivalent Circuit Network Simulation of Multi-Junction Solar Cells. IEEE Access. 2019; 7 ():97208-97215.

Chicago/Turabian Style

Kan-Hua Lee; Kenji Araki; Masafumi Yamaguchi. 2019. "A Mesh Downsampling Algorithm for Equivalent Circuit Network Simulation of Multi-Junction Solar Cells." IEEE Access 7, no. : 97208-97215.

Conference paper
Published: 01 June 2019 in 2019 IEEE 46th Photovoltaic Specialists Conference (PVSC)
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We demonstrated a static (non-tracking) low concentration photovoltaic module that employs a new design paradigm that mixes two different types of the lens arrays. This design approach brings the annual optical collection efficiency closer to the theoretical upper limit but with high manufacturability and scalability, because this design paradigm give more degree of freedom to optimize the overall efficiencies. We demonstrated that the module with the hybrid lens array is 2%(absolute) more efficient than its single lens array counterparts at on-axis illumination. Also, the good match of the modeled and experimental incident-angle dependent module efficiency confirms the robustness of our fabrication process, showing the promise of achieving high annual collection efficiency of this module.

ACS Style

Kan-Hua Lee; Daisuke Sato; Kenji Araki; Noboru Yamada; Masafumi Yamaguchi. Demonstration of High Efficiency Static Low-Concentration Photovoltaic Module Using Hybrid Lens Arrays. 2019 IEEE 46th Photovoltaic Specialists Conference (PVSC) 2019, 0255 -0259.

AMA Style

Kan-Hua Lee, Daisuke Sato, Kenji Araki, Noboru Yamada, Masafumi Yamaguchi. Demonstration of High Efficiency Static Low-Concentration Photovoltaic Module Using Hybrid Lens Arrays. 2019 IEEE 46th Photovoltaic Specialists Conference (PVSC). 2019; ():0255-0259.

Chicago/Turabian Style

Kan-Hua Lee; Daisuke Sato; Kenji Araki; Noboru Yamada; Masafumi Yamaguchi. 2019. "Demonstration of High Efficiency Static Low-Concentration Photovoltaic Module Using Hybrid Lens Arrays." 2019 IEEE 46th Photovoltaic Specialists Conference (PVSC) , no. : 0255-0259.

Conference paper
Published: 01 June 2019 in 2019 IEEE 46th Photovoltaic Specialists Conference (PVSC)
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Solar panels used for EV charging stations and car-roof PV are often partially shaded and lead to substantial energy loss. It is known that this mismatching loss can be reduced by increasing the number of parallel strings. First, a probability model was developed using a one-year solar irradiance monitoring around the car body in 5 directions. The developed model successfully matched to the measured solar resource in each direction and succeeded to quantify the probability of the partial shading on the car. Another related issue of the inherent mismatching loss of the car-roof PV is non-uniform illumination caused by the curved shape of the panel. This can also be modeled by ray-tracing simulation. Then, we calculated the PV output affected by mismatching due to various sunlight patterns and partial shade patterns by Monte Carlo method. It was found that the average efficiency asymptotically approached 1 - 1 / N (N is the number of strings). We also examined the relationship between partial shade quantity and power generation loss in a 30 kW solar system array and verified the above model.

ACS Style

Kenji Araki; Kan-Hua Lee; Taizo Masuda; Yoshitaka Hayakawa; Noboru Yamada; Yasuyuki Ota; Masafumi Yamaguchi. Rough and Straightforward Estimation of the Mismatching Loss by Partial Shading of the PV Modules Installed on an Urban Area or Car-Roof. 2019 IEEE 46th Photovoltaic Specialists Conference (PVSC) 2019, 1218 -1225.

AMA Style

Kenji Araki, Kan-Hua Lee, Taizo Masuda, Yoshitaka Hayakawa, Noboru Yamada, Yasuyuki Ota, Masafumi Yamaguchi. Rough and Straightforward Estimation of the Mismatching Loss by Partial Shading of the PV Modules Installed on an Urban Area or Car-Roof. 2019 IEEE 46th Photovoltaic Specialists Conference (PVSC). 2019; ():1218-1225.

Chicago/Turabian Style

Kenji Araki; Kan-Hua Lee; Taizo Masuda; Yoshitaka Hayakawa; Noboru Yamada; Yasuyuki Ota; Masafumi Yamaguchi. 2019. "Rough and Straightforward Estimation of the Mismatching Loss by Partial Shading of the PV Modules Installed on an Urban Area or Car-Roof." 2019 IEEE 46th Photovoltaic Specialists Conference (PVSC) , no. : 1218-1225.

Conference paper
Published: 01 June 2019 in 2019 IEEE 46th Photovoltaic Specialists Conference (PVSC)
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Curved photovoltaic, typically using flexible one receives different irradiation from the sunlight. The energy yield is often overestimated by ignoring local cosine loss and other losses related to the curvature of the PV surface. Although the formula to some extent varies by the type of the curved surface, it is modeled by the curve-correction factor from the flat-plate conditions. The curve correction factor is calculated either geometrical calculation or the numerical ray-tracing simulation. In these proceedings, the one by Monte Carlo method (Ray-tracing simulation) is discussed. First, the incident angle the sunlight affected by the orientation (random orientation if necessary), shading by surrounding structures (randomly distributed), climate pattern, and both direct and diffused sunlight from a regional database, was calculated. Second, the absorbed flux onto the curved module surface was calculated using random rays by the above distribution of the sunlight. Third, the regional influences onto the energy generation of the curved PV panel were discussed. The energy yield of the curved PV drops significantly by the increase of the curvature and incident angle distribution affected by latitude, climate pattern, and shading environment.

ACS Style

Kenji Araki; Yasuyuki Ota; Kan-Hua Lee; Noboru Yamada; Masafumi Yamaguchi. Curve Correction of the Energy Yield by Flexible Photovoltaics for VIPV and BIPV Applications Using a Simple Correction Factor. 2019 IEEE 46th Photovoltaic Specialists Conference (PVSC) 2019, 1584 -1591.

AMA Style

Kenji Araki, Yasuyuki Ota, Kan-Hua Lee, Noboru Yamada, Masafumi Yamaguchi. Curve Correction of the Energy Yield by Flexible Photovoltaics for VIPV and BIPV Applications Using a Simple Correction Factor. 2019 IEEE 46th Photovoltaic Specialists Conference (PVSC). 2019; ():1584-1591.

Chicago/Turabian Style

Kenji Araki; Yasuyuki Ota; Kan-Hua Lee; Noboru Yamada; Masafumi Yamaguchi. 2019. "Curve Correction of the Energy Yield by Flexible Photovoltaics for VIPV and BIPV Applications Using a Simple Correction Factor." 2019 IEEE 46th Photovoltaic Specialists Conference (PVSC) , no. : 1584-1591.