1
Outdoor Module Characterization Methods:
Power Matrix, Angle of Incidence and
Spectral Mismatch Correction
Mani G. Tamiz...
Motivation
Qualification PLUS
A New ANSI/TUV-R Standard
• As the PV Industry matures, PV Reliability is
becoming more impo...
TÜV Rheinland PTL, a Standards Developing Organization (SDO) for the
American National Standards Institute (ANSI), has now...
4
Outline
 Pmax matrix generation standards
 Outdoor methods to generate Pmax matrix
 M e t h o d 1 : S a n d i a m e t...
5
Pmax Matrix Generation Standards:
UL 4730 and IEC 61853
Key to improve accuracy:
• Avoid/minimize extrapolation
• Avoid/...
UL 4730: 5 Test Conditions
www.solarABCs.org
UL 4730 standard is based on the
following Solar ABCs report
7
www.solarABCs.org
IEC 61853-1: 23 Test Conditions
IEC 61730-1 standard is validated in the
following Solar ABCs report
8
Pmax Matrix Generation:
Method 1
9
Pmax Matrix Generation:
Sandia method – Automated 2-axis tracker based
I-V
curve
tracer
Pyranometer
Reference Cell
Modul...
Irradiance
W/m2
15 C 25 C 50 C 75C
1200 358.1 341.7 301.0 260.6
1100 328.6 313.6 276.1 239.0
1000 299.0 285.3 251.2 217.4
...
11
Pmax Matrix Generation:
Method 2
12
Manual 2-Axis Tracking
(Cool the module; Take I-V as it warms up)
Mesh screens to change irradiance
Pmax Matrix Generat...
13
1, 2 & 3 = IEC 60891 procedures; 4 = NREL procedure
Pmax Matrix Generation:
Using IEC 60891 models and results (example...
14
Pmax Matrix Generation:
Method 3
Outdoor Method 4: Matrix Generation Using Fixed Tilt Modules (or
Grid Tied Arrays)
15
• Monitor (6 minutes): MPPT, POA irr...
16
Angle of Incidence (AOI) Effect
AOI Setup:
Five Module Technologies
(Superstrate: Glass; Interface: air/glass)
AOI Effect on Cleaned Modules:
Practically no AOI difference between technologies
as the interface (air/glass) is the same...
Soiling level: A – Heavy, B – Medium-Heavy, C – Medium, D –Light, E – Cleaned
Sample Name (Soiling Level) Critical Angle (...
20
Spectral Mismatch Error
21
Source: Sandia
Reference spectrum ~ Outdoor Test Spectrum
Test spectra (AMa=2.46 and Ama=4.70) are ONLY SLIGHTLY DIFFER...
Reference spectrum # Test Spectrum
Test spectrum is VERY DIFFERENT from the reference spectrum
Red line = Reference spectr...
23
0%
10%
20%
30%
40%
50%
60%
70%
80%
90%
100%
January
February
March
April
May
June
July
August
September
October
Novembe...
24
where:
M = spectral mismatch parameter;
E(λ) = spectral irradiance (Wm-2/nm);
E0(λ) = reference spectral irradiance (Wm...
Spectral Response Depends on the Technology
If the reference cell technology (e.g. c-Si) is not matched with the test tech...
26
Source: Newport Corporation, Application Note 51
Spectral Mismatch Factor for Simulated Light (Xe-arc lamp)
If the refe...
27
0.940
0.960
0.980
1.000
1.020
1.040
1.060
7:00 8:00 9:00 10:00 11:00 12:00 13:00 14:00 15:00 16:00 17:00 18:00
Spectral...
• Pmax Matrix Generation
Three outdoor methods presented
First two methods are used by TUV Rheinland PTL
• Angle of Inci...
Thanks for your attention!
Mani G. TamizhMani
gtamizhmani@us.tuv.com
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2014 PV Performance Modeling Workshop: Outdoor Module Characterization Methods: Power Matrix, Angle of Incidence and Spectral Mismatch Correction:

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2014 PV Performance Modeling Workshop: Outdoor Module Characterization Methods: Power Matrix, Angle of Incidence and Spectral Mismatch Correction
Mani Tamizh, TUV Rheinland PTL, ASU PRL

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2014 PV Performance Modeling Workshop: Outdoor Module Characterization Methods: Power Matrix, Angle of Incidence and Spectral Mismatch Correction:

  1. 1. 1 Outdoor Module Characterization Methods: Power Matrix, Angle of Incidence and Spectral Mismatch Correction Mani G. TamizhMani TUV Rheinland PTL Arizona State University PRL Presented at the 2014 Sandia PV Performance Modeling Workshop, Santa Clara, CA. May 5, 2014 Published by Sandia National Laboratories with the Permission of the Author. gtamizhmani@us.tuv.com
  2. 2. Motivation Qualification PLUS A New ANSI/TUV-R Standard • As the PV Industry matures, PV Reliability is becoming more important o Project developers want to make bankable investments • PV customers are asking for tests that “go beyond” the standard qualification test (IEC 61215). Note: “Qualification PLUS” testing is expected to be adopted by the California Energy Commission in the near future.
  3. 3. TÜV Rheinland PTL, a Standards Developing Organization (SDO) for the American National Standards Institute (ANSI), has now initiated the development of two new American National Standards: • ANSI / TUV-R 71732-01:201X: Qualification PLUS (Q+) Testing for PV Modules - Test and Sampling Requirements • ANSI / TUV-R 71733-01:201X: Quality Management System (QMS) Requirements for PV Manufacturing TUV Rheinland is now seeking industry participation in the respective standards’ working groups. Stakeholders include manufacturers of PV Modules, Project Investors and Developers, Utility Companies, PV Consumers, Incentive Programs as well as Engineering and Insurance Companies. To get involved, please click here. http://education.tuv.com/join-ansi-working-groups/ Seeking Members for the ANSI Working Group (WG)
  4. 4. 4 Outline  Pmax matrix generation standards  Outdoor methods to generate Pmax matrix  M e t h o d 1 : S a n d i a m e t h o d b a s e d o n a n a u t o m a t e d 2 - a x i s t r a c k e r ( u s e d a t T U V R h e i n l a n d P T L )  M e t h o d 2 : M e s h s c r e e n m e t h o d b a s e d o n a m a n u a l 2 - a x i s t r a c k e r ( u s e d a t T U V R h e i n l a n d P T L )  M e t h o d 3 : M P P T m e t h o d b a s e d o n a f i x e d t i l t a r r a y m e t h o d  Angle of incidence effect  C l e a n a n d s o i l e d m o d u l e s u s i n g o u t d o o r m e t h o d  Spectral mismatch error  S p e c t r a l m i s m a t c h e r r o r c a l c u l a t i o n f o r o u t d o o r m e t h o d  Conclusions
  5. 5. 5 Pmax Matrix Generation Standards: UL 4730 and IEC 61853 Key to improve accuracy: • Avoid/minimize extrapolation • Avoid/minimize long range translation
  6. 6. UL 4730: 5 Test Conditions www.solarABCs.org UL 4730 standard is based on the following Solar ABCs report
  7. 7. 7 www.solarABCs.org IEC 61853-1: 23 Test Conditions IEC 61730-1 standard is validated in the following Solar ABCs report
  8. 8. 8 Pmax Matrix Generation: Method 1
  9. 9. 9 Pmax Matrix Generation: Sandia method – Automated 2-axis tracker based I-V curve tracer Pyranometer Reference Cell Module Thermocouple 2 Thermocouple 1 Automatic 2-axis tracker Automated 2-axis tracking (take I-Vs daylong) J. Granata et al., IEEE PVSC 2011
  10. 10. Irradiance W/m2 15 C 25 C 50 C 75C 1200 358.1 341.7 301.0 260.6 1100 328.6 313.6 276.1 239.0 1000 299.0 285.3 251.2 217.4 800 239.5 228.5 201.1 173.9 600 179.6 171.3 150.6 130.0 400 119.3 113.7 99.7 86.0 300 89.1 84.9 74.3 63.9 200 58.9 56.0 48.9 42.0 100 28.9 27.4 23.7 20.2 Module Cell Temperature 10 Pmax Matrix Generation: Using Sandia model and results (example)Efficiencydoesnotremainthesame! Shortrangetranslationforaccuratematrixgenerationisrequired!
  11. 11. 11 Pmax Matrix Generation: Method 2
  12. 12. 12 Manual 2-Axis Tracking (Cool the module; Take I-V as it warms up) Mesh screens to change irradiance Pmax Matrix Generation: Mesh screen method – Manual 2-axis tracker based Karen Paghasian et al., IEEE PVSC 2011 Two reference cells
  13. 13. 13 1, 2 & 3 = IEC 60891 procedures; 4 = NREL procedure Pmax Matrix Generation: Using IEC 60891 models and results (example) Efficiency does not remain the same! Short range translation for accurate matrix generation is required!
  14. 14. 14 Pmax Matrix Generation: Method 3
  15. 15. Outdoor Method 4: Matrix Generation Using Fixed Tilt Modules (or Grid Tied Arrays) 15 • Monitor (6 minutes): MPPT, POA irradiance and Module temperature • If one module used: Many days of monitoring required • If two or more identical modules used: Only few days of monitoring required • A combination of back-insulated, mesh screen-filtered modules can also be used to reduce the number of monitoring days Source: K. Koka et al., IEEE Photovoltaic Specialists Conference, June 2011
  16. 16. 16 Angle of Incidence (AOI) Effect
  17. 17. AOI Setup: Five Module Technologies (Superstrate: Glass; Interface: air/glass)
  18. 18. AOI Effect on Cleaned Modules: Practically no AOI difference between technologies as the interface (air/glass) is the same for all
  19. 19. Soiling level: A – Heavy, B – Medium-Heavy, C – Medium, D –Light, E – Cleaned Sample Name (Soiling Level) Critical Angle (3% and above loss) Sample E (Cleaned) 57o Sample D (Light; 1.7 g/m2 ) 42o Sample C (Medium; 2.7 g/m2 ) 38o Sample B (Medium Heavy; 4.9 g/m2 ) 37o Sample A (Heavy; 11.8 g/m2 ) 20o Source: J.J. Joseph et al. SPIE, San Diego, August 2014 (accepted) AOI Effect on Soiled Modules: AOI loss increases as the soiling density increases
  20. 20. 20 Spectral Mismatch Error
  21. 21. 21 Source: Sandia Reference spectrum ~ Outdoor Test Spectrum Test spectra (AMa=2.46 and Ama=4.70) are ONLY SLIGHTLY DIFFERENT from the reference spectrum (Ama=1.5)
  22. 22. Reference spectrum # Test Spectrum Test spectrum is VERY DIFFERENT from the reference spectrum Red line = Reference spectrum Black line = Xe-arc lamp spectrum If matched reference technology is NOT used to measure the irradiance level, the performance measurement error (spectral mismatch error) will be very HIGH (see later).
  23. 23. 23 0% 10% 20% 30% 40% 50% 60% 70% 80% 90% 100% January February March April May June July August September October November December Reference MeasuredSpectral-BandIrradiance(%) Month Analysis of Full Year Spectrum 900-1100nm 800-900nm 700-800nm 600-700nm 500-600nm 400-500nm Source: ASU-PRL On clear sunny days during solar window (9am-3pm): Less than 5% deviation from reference spectrum (Mesa, Arizona) Even if matched reference technology is NOT used to measure the irradiance level, the performance measurement error (spectral mismatch error) will be very SMALL (see later). Reference spectrum ~ Outdoor Test Spectrum
  24. 24. 24 where: M = spectral mismatch parameter; E(λ) = spectral irradiance (Wm-2/nm); E0(λ) = reference spectral irradiance (Wm-2/nm); Rr(λ) = spectral response of reference cell (A/W); Rt(λ) = spectral response of photovoltaic device (A/W). Spectral mismatch factor (M) = Current correction factor M= E λ R λ dλ b a E λ Rr λ dλ d c × E0 λ Rr λ dλ d c E0 λ Rt λ dλ b a M = 1 if the reference device is matched with the test device M = 1 if test spectrum is matched with the reference spectrum
  25. 25. Spectral Response Depends on the Technology If the reference cell technology (e.g. c-Si) is not matched with the test technology (e.g. CdTe), then it is imperative either to experimentally match the test spectrum or to mathematically correct for the spectral mismatch error.
  26. 26. 26 Source: Newport Corporation, Application Note 51 Spectral Mismatch Factor for Simulated Light (Xe-arc lamp) If the reference cell technology (e.g. c-Si) is not matched with the test technology (e.g. CdTe), the spectral mismatch error can NOT be ignored.
  27. 27. 27 0.940 0.960 0.980 1.000 1.020 1.040 1.060 7:00 8:00 9:00 10:00 11:00 12:00 13:00 14:00 15:00 16:00 17:00 18:00 SpectralMismatchFactor Time (hh:mm ) Spectral Mismatch Factor for May 25, '09 A191 (Mono-Si) is the reference device A191 (Mono-Si) A209 (CdTe) A187 (Mono-Si) A203 (Poly-Si) A210 (GaAs) -5% Limit +5% Limit Spectral Mismatch Factor for Natural Sunlight (Daily) Even if the reference cell technology (e.g. c-Si) is not matched with the test technology (e.g. CdTe), the spectral mismatch error will be very small because the test spectrum is practically matched with the reference spectrum!
  28. 28. • Pmax Matrix Generation Three outdoor methods presented First two methods are used by TUV Rheinland PTL • Angle of Incidence Effect Practically identical for all technologies if clean-glass superstrate is used AOI loss increases as the soiling density increases • Spectral Mismatch Error Negligibly small if natural sunlight is used with the matched reference cell technology Conclusions
  29. 29. Thanks for your attention! Mani G. TamizhMani gtamizhmani@us.tuv.com

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