IEC 60891:2021

IEC 60891 ®
Edition 3.0 2021-10
INTERNATIONAL
STANDARD
NORME
INTERNATIONALE
Photovoltaic devices – Procedures for temperature and irradiance corrections to
measured I-V characteristics
Dispositifs photovoltaïques – Procédures pour les corrections en fonction de la
température et de l'éclairement à appliquer aux caractéristiques I-V mesurées

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IEC 60891 ®
Edition 3.0 2021-10
INTERNATIONAL
STANDARD
NORME
INTERNATIONALE
Photovoltaic devices – Procedures for temperature and irradiance corrections

to measured I-V characteristics

Dispositifs photovoltaïques – Procédures pour les corrections en fonction de la

température et de l'éclairement à appliquer aux caractéristiques I-V mesurées

INTERNATIONAL
ELECTROTECHNICAL
COMMISSION
COMMISSION
ELECTROTECHNIQUE
INTERNATIONALE
ICS 27.160 ISBN 978-2-8322-1036-0

– 2 – IEC 60891:2021 © IEC 2021
CONTENTS
FOREWORD . 4
1 Scope . 6
2 Normative references . 6
3 Terms and definitions, symbols and abbreviated terms . 7
4 Correction procedures . 8
4.1 General . 8
4.2 Correction procedure 1 . 11
4.3 Correction procedure 2 . 12
4.4 Correction procedure 3 . 14
4.4.1 General . 14
4.4.2 Correction for the irradiance and temperature from two measured I-V
curves . 14
4.4.3 Correction to various irradiances and temperatures from three I-V
curves . 17
4.4.4 Correction to various irradiances and temperatures from four measured
I-V curves . 17
4.5 Correction procedure 4 . 18
5 Determination of temperature coefficients . 20
5.1 General . 20
5.2 Apparatus . 20
5.3 Procedure in natural or steady-state simulated sunlight . 22
5.4 Procedure with a pulsed solar simulator . 23
5.5 Calculation of temperature coefficients . 23
6 Determination of internal series resistance R and R′ . 24
S S
6.1 General . 24
6.2 Determination of R in correction procedures 1 and 4 . 25
S
6.3 Determination of B and B in correction procedure 2 . 27
1 2
6.4 Determination of R′ in correction procedure 2 . 28
S
6.5 Determination of R in correction procedure 4 . 30
S
7 Determination of the curve correction factor κ and κ′ . 31
7.1 General . 31
7.2 Procedure . 31
8 Reporting . 32
Annex A (informative) Alternative procedures for series resistance determination . 34
A.1 General . 34
A.2 Differential resistance at V against inverse irradiance method . 34
OC
Bibliography . 35

Figure 1 – Example of the correction of the I-V characteristics by formulae (10) and
(11) . 16
Figure 2 – Schematic diagram of the relation of G and T which can be chosen in the
3 3
simultaneous correction for irradiance and temperature, for a fixed set of T , G , T ,
1 1 2
and G by formulae (12) and (13) . 16
Figure 3 – Schematic diagram of the processes for correcting the I-V characteristics to
various ranges of irradiance and temperature based on three measured
characteristics . 17
Figure 4 – Schematic diagram of the processes for correcting the I-V characteristics to
various ranges of irradiance and temperature based on four measured characteristics . 18
Figure 5 – Example positions for measuring the temperature of the test module behind
the cells . 21
Figure 6 – Determination of internal series resistance . 26
Figure 7 – Determination of internal series resistance when the corrected I-V

characteristics intersect . 27
Figure 8 – Determination of irradiance correction factors B and B and internal series
1 2
resistance, R′ . 29
S
Figure 9 – Determination of internal series resistance of a PV module from a single I-V
curve . 31
Figure 10 – Determination of curve correction factor . 32
Figure A.1 – Determination of internal series resistance . 34

Table 1 – Overview of correction procedures for irradiance corrections (i.e. T = T ) . 9
1 2
Table 2 – Overview of correction procedures for temperature corrections (i.e. G = G ) . 10
1 2
– 4 – IEC 60891:2021 © IEC 2021
INTERNATIONAL ELECTROTECHNICAL COMMISSION
____________
PHOTOVOLTAIC DEVICES – PROCEDURES FOR TEMPERATURE AND
IRRADIANCE CORRECTIONS TO MEASURED I-V CHARACTERISTICS

FOREWORD
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