School of Engineering Bypass Diode Tester - MyWWW ZHAWbauf/pv/talks/5DO_12_6_ppt_D.Schaer_Portable... · Bypass Diode Tester D. Schär, F.P. Baumgartner Zurich University of Applied

IEFE Institute of Energy Systems and Fluid-Engineering

School of Engineering

Zurick University of Applied Sciences

Portable LED Flasher with Implemented Bypass Diode Tester

D. Schär, F.P. Baumgartner Zurich University of Applied Sciences




Why testing PV outdoor fields?

• to prove the power of the PV Generator – natural sunlight method: depends on weather situation – sun simulator: low uncertainty of Pn

– IR thermography: no actual measurement of Pn

• Remark: – the proper functioning of

all bypass diodes is very important

29.09.2014 D. Schär, F. P. Baumgartner, EUPVSEC 5DO.12.6, Portable LED Flasher 25.09.2014 2

source: InfraTec




Sun simulators applications

Stationary Xenon Flasher Mobile Flasher (Xenon) e.g. EKZ ZHAW Swiss Mobile Flasher Bus

Portable LED Flasher presented in this talk (3840 LEDs)

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ce: i

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ofer

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• Benefits Portable Flasher: – Bypass Diode Test (also just before end of warranty time) – 2 persons > 200 Modules / day – Result immediately available – Measure during night no yield loss – Measuring independent of solar radiation




Why bypass diodes?

• Bypass diodes safe the solar cell against overheating


60°C

25°C

Bypass diodes are not working (source: IEA Task 13 Report March 2014)

Bypass diodes are working only 60°C




Why bypass diode measurements?

• Damage of bypass diodes through – Overheating – Static high voltages – Lightning currents – Connection problems

• Of 1272 modules 47% with defect bypass diodes (source: IEA Task 13 Report March 2014)





I-V curve at 3 different illuminated sectors 3 bypass diodes ok





I-V curve at 3 different illuminated sectors 1 bypass diode defect


x




I-V curve at 3 different illuminated sectors 2 bypass diodes defect


x x




Bypass Diode Measurement: 3 measurement periods


Area 1 Area 2 Area 3 measurement period 1/3

1000 W/m2 1000 W/m2 1000 W/m2 Measure regular I-V curve

measurement period 2/3 1000 W/m2 800 W/m2 600 W/m2

measurement period 3/3 600 W/m2 800 W/m2 1000 W/m2




Bypass Diode Measurement: case example - measurement period 1/3



1000 W/m2 1000 W/m2 1000 W/m2 Target: Measure regular I-V curve

x x






x x


1000 W/m2 800 W/m2 600 W/m2

1 step:






x x


600 W/m2 800 W/m2 1000 W/m2

2 steps:




Bypass diodes: damage detection


measurement measurement defect period 2/3 period 3/3 3 3 - 3 1 BD1 2 2 BD2 1 3 BD3 2 1 BD1, BD2 1 2 BD2, BD3 1 1 BD1, BD3 or BD1, BD2, BD3

numbers (1,2 and 3): number of steps in the I-V curve




Standard IV Measurement


Deviation Portable LED Flasher / Swiss Mobile Flasher

Sunways SM 210 U

0.10%

LDK 250P-20 1.10% Pevafersa IP-170

-0.19%

Swiss Mobile Flasher

Portable LED Flasher




Why low light measurements?


Carigiet, ZHAW, see Poster 5CV.2.34




Low light measurement: efficiency vs. irradiance


polycrystalline module, 230Wp STC polycrystalline module, 260Wp STC




Portable LED Flasher: characteristics

LED flasher characteristics developed at the University of Applied Sciences ZHAW Active optical area 2m x 1.27m Total dimensions and weight 2.21m x 1.50m x 0.10m, 50kg Number of LEDs 2400 blue and 1440 IR

(455nm and 850nm) Power of the LEDs Are able to generate 2.8 times the ISCSTC

of a crystalline module (blue only: 1.2 times, IR only: 1.6 times)

Number of subsections 20, each controllable in intensity of blue and IR LEDs separately

Flash duration 10ms, but expandable to several 100ms AC Supply 115/230 VAC, 230W Measurement programs Standard I-V, bypass diode, low light,

spectral characteristics 29.09.2014 D. Schär, F. P. Baumgartner, EUPVSEC 5DO.12.6, Portable LED Flasher 25.09.2014 17




Conclusion

LED Flasher, first successful tests One instrument measures 4 module characteristics, without dismantling the module in the field – Nominal power 1sec – Bypass diode test 2sec – Low light efficiency 9sec – Indication of spectral characteristics

ZHAW University is open for cooperation to further development of the system





Thank you for your attention! Daniel Schär [email protected] Franz Baumgartner [email protected]


Side view of the LED Flasher in operation

Documents

School of Engineering Bypass Diode Tester - MyWWW ZHAWbauf/pv/talks/5DO_12_6_ppt_D.Schaer_Portable... · Bypass Diode Tester D. Schär, F.P. Baumgartner Zurich University of Applied