【PVPMC】Toyota-Kenji-车顶光伏性能建模综述

Performance Modeling of the Car-roof PV - OverviewKenji Araki1, Yasuyuki Ota2, and Masafumi Yamaguchi11Toyota Technological Institute, cpvkenjiaraki@toyota-ti.ac.jp, Nagoya, Japan2University of Miyazaki, Miyazaki, Japan Testing car-roof PV: Three issues Accurate performance measurement in indoor STC Mauro PRAVETTONI et al., SNEC 2019 Scientific ConferenceAccurate product testing (STC/SOC) Fair modeling in energy yield on the car Durability and safety Scientific contents in today’s presentation•Testing a curved PV moduleDevelopment a protocol for repeatable measurement•Modeling solar irradiance on the car-roofDynamic installationShading influencePartial shading Curved PV is often overestimated. Example of the radius of curvature of the car-roof Reference: Accurate performance measurement in indoor STC, Mauro PRAVETTONI et al., SNEC 2019 Scientific ConferencedFor typical solar simulators, the range of the working distance d may be a bigger issue. Curved PV is illuminated in testing out of the aperture areaPin = A  Irr Pin: Input energyA : Aperture areaIrr: IrradianceRay outside the aperture illuminates the curved PV, and input energy will be underestimated.  Overestimation of performance The virtual position of the aperture may be the geometrical gravity of the curve profile. Inconsistency in “area”, projected area vs. total areaFlattened module (tested)CurvedTotal area (area used for test)Projected area (area for module operation) Local cosine loss and self-shading loss are inherent, but enhanced in the outdoor operationThis means testing angular performance is essential to curved PV (car-roof PV).Illumination direction in testing Illumination direction in operation Typical illumination of the curved PV in outdoor operation Curve correction factor f1 is the coving factor, or in another way, geometrical curve correction factor corresponding to the ratio of the projected area by surface area), f2 is the irradiance ratio due to the local cosine loss and self-shading loss, in other words, optical curve correction factor. f 3 is the correction of uneven expansion of the curved module. Round-robin of the car-roof PVScope: Standard measurement method for the curved car-roof PV panel.Purpose:Identification of the measurement errors in measurement.Improvement of the measurement method by testing labs.Plan:Operated by IEC TC82. To be started in April, 2020.We are about to investigate preliminary protocols using flexible Si modules by JET and AIST. https://www.kurumaerabi.com/car_mag/list/6690/ Minimum requirement of the solar simulator 1.0 1.1 1.2 1.3 1.4 1.5Ratio of the width/depth of the uniform illumination area relative to the procected width/depth of the curved PV panel010 203040Angle of divergence (deg) 2 5 10Contor of the (max-min)/(mean) of flux illuminating onto the curved panel (%)BackgroundThe minimum requirement of the solar simulator (standard type) shown in the last meeting was too strict for testing laboratory equipped with instruments to normal PV modules.RelaxationFlux (not irradiance) onto the ¼ of Si cell region is less than ± 1% after correction of illumination level at the plane of the center of gravity of the surface.(Illuminated Area) 10 % more (module length)AND (Angle of divergence) 30° Ultimate solution: Collimated solar simulator For more information, visit http://solaraddedvalue.com/en/category/productos/helios-3198/ Mathematical solution by Dr. Tayagaki, AIST The curve correction factor may be approximated byT Tayagaki, K Araki, M Yamaguchi, T Sugaya, IEEE Journal of Photovoltaics 9 (6), 1721-1726 Solar irradiation of the car-roof is complicated but can be modeled. Solar resource monitoring around the car-body by University of Miyazaki Why is 5-axis measurement important?• “One sensor on the car-roof” does not have sufficient DOF to validate the outdoor irradiance model.• 3-D evaluation including angular weighting is crucial to the module design.• Shading effect locally varies, for example, less shading in y direction than x direction. One sensor monitoring cannot detect such car-specific solar environment. Car-roof PV modelingReference Car-roof Coving factor: 0.97Equivalent R: 3.5 m Validation of the model - IntensityAnnually MonthlyDaily Validation of the model – Angular distribution 0%1%2%3%4%5%6%7%8% 0 15 30 45 60 75 90Weighted percentage Incident angle (deg) ModelMeasurement Note: Validation was done by the weighted histogram of the incident angle of the main beam. Inherent error is expected to the higher incident angle corresponding overcast conditions (incident angle of the main beam becomes indetermination. Not only geometrical parameter (1)Curve correction factor is affected by the angular distribution of the irradiation, thus varies by place. Not only geometrical parameter (2)Uneven distribution of the solar irradiance due to curved surface, dynamic shading and partial shading Significant mismatching lossUnpredictable and complicated by string and variation of shape designsCombination of Graph theory and Monte Carlo simulation is investigated Design recommendation by the knowledge in the solar modeling. Relative to GHI, incl. curve-correction Rough estimation (1/3)Power marginDepending on the driving zones (latitude, climates), 20 % power margin is recommended by the reduction of the effective irradiance on the car-roof. Rough estimation (2/3)Urban drivingPartial shading probability (mismatching loss) substantially increases in the urban driving. Use of the cut cells (thus increasing string number) is inevitable. 1/2 cut, 4 strings 1/8 cut, 16 strings1/4 cut, 8 strings Rough estimation (3/3)Partial shadings1/6 or more cut is recommended for suppressing partial-shading loss to 10%. Lets study togetherAs resources increase, substantial greenhouse gas reduction will be achieved quickly.20 years ahead → 10 years ahead → 5 years aheadAcknowledgement A part of this research is based on NEDO entrusted research “research and development of ultrahigh efficiency · low cost III-V compound solar cell module“. I thank the people concerned.For this proposal, we received a hot discussions at various conferences. I am thankful to CPV guys and PV masters of high spirit.Regarding in-vehicle PV and peripheral technologies, I repeatedly discussed with Toyota Motor Corporation, Miyazaki University and Nagaoka University of Technology. Again thank you once again, next time I will delicious delicacies in Nagoya. 26