Photovoltaic devices - Part 1: Measurement of photovoltaic current-voltage characteristics

IEC 60904-1:2020 describes procedures for the measurement of current-voltage characteristics (I-V curves) of photovoltaic (PV) devices in natural or simulated sunlight. These procedures are applicable to a single PV solar cell, a sub-assembly of PV solar cells, or a PV module. This document is applicable to non-concentrating PV devices for use in terrestrial environments, with reference to (usually but not exclusively) the global reference spectral irradiance AM1.5 defined in IEC 60904-3.
This third edition cancels and replaces the second edition published in 2006. The main changes with respect to the previous edition are as follows:
- Updated scope to include all conditions.
- Added terms and definitions.
- Reorganised document to avoid unnecessary duplication.
- Added data analysis clause.
- Added informative annexes (area measurement, PV devices with capacitance, dark I-V curves and effect of spatial non-uniformity of irradiance).

Dispositifs photovoltaïques - Partie 1: Mesurage des caractéristiques courant-tension des dispositifs photovoltaïques

l’IEC 60904-1:2020 décrit les procédures pour le mesurage des caractéristiques/courant-tension (courbes I-V) des dispositifs photovoltaïques (PV) sous éclairement solaire naturel ou simulé. Ces procédures sont applicables aux cellules solaires individuelles PV, aux sous-ensembles de cellules solaires PV ou aux modules PV. Le présent document s’applique aux dispositifs PV sans concentration destinés à être utilisés dans des environnements terrestres, en référence (habituellement mais pas exclusivement) à l’éclairement énergétique spectral de référence global AM1.5 défini dans l’IEC 60904-3.
Cette troisième édition annule et remplace la deuxième édition parue en 2006. Les principales modifications par rapport à l'édition précédente sont les suivantes:
- Mise à jour du domaine d’application pour inclure toutes les conditions.
- Ajout d’un article "Termes et définitions".
- Réorganisation du document pour éviter les doublons inutiles.
- Ajout d’un article "Analyse des données".
- Ajout d’annexes informatives (mesurage de la surface, dispositifs PV à capacité, courbes I-V dans l’obscurité et effet de la non-uniformité spatiale de l’éclairement énergétique).

General Information

Status
Published
Publication Date
24-Sep-2020
Current Stage
PPUB - Publication issued
Completion Date
25-Sep-2020
Ref Project

Buy Standard

Standard
IEC 60904-1:2020 - Photovoltaic devices - Part 1: Measurement of photovoltaic current-voltage characteristics
English and French language
67 pages
sale 15% off
Preview
sale 15% off
Preview

Standards Content (sample)

IEC 60904-1
Edition 3.0 2020-09
INTERNATIONAL
STANDARD
NORME
INTERNATIONALE
colour
inside
Photovoltaic devices –
Part 1: Measurement of photovoltaic current-voltage characteristics
Dispositifs photovoltaïques –
Partie 1: Mesurage des caractéristiques courant-tension des dispositifs
photovoltaïques
IEC 60904-1:2020-09(en-fr)
---------------------- Page: 1 ----------------------
THIS PUBLICATION IS COPYRIGHT PROTECTED
Copyright © 2020 IEC, Geneva, Switzerland

All rights reserved. Unless otherwise specified, no part of this publication may be reproduced or utilized in any form

or by any means, electronic or mechanical, including photocopying and microfilm, without permission in writing from

either IEC or IEC's member National Committee in the country of the requester. If you have any questions about IEC

copyright or have an enquiry about obtaining additional rights to this publication, please contact the address below or

your local IEC member National Committee for further information.

Droits de reproduction réservés. Sauf indication contraire, aucune partie de cette publication ne peut être reproduite

ni utilisée sous quelque forme que ce soit et par aucun procédé, électronique ou mécanique, y compris la photocopie

et les microfilms, sans l'accord écrit de l'IEC ou du Comité national de l'IEC du pays du demandeur. Si vous avez des

questions sur le copyright de l'IEC ou si vous désirez obtenir des droits supplémentaires sur cette publication, utilisez

les coordonnées ci-après ou contactez le Comité national de l'IEC de votre pays de résidence.

IEC Central Office Tel.: +41 22 919 02 11
3, rue de Varembé info@iec.ch
CH-1211 Geneva 20 www.iec.ch
Switzerland
About the IEC

The International Electrotechnical Commission (IEC) is the leading global organization that prepares and publishes

International Standards for all electrical, electronic and related technologies.
About IEC publications

The technical content of IEC publications is kept under constant review by the IEC. Please make sure that you have the

latest edition, a corrigendum or an amendment might have been published.

IEC publications search - webstore.iec.ch/advsearchform Electropedia - www.electropedia.org

The advanced search enables to find IEC publications by a The world's leading online dictionary on electrotechnology,

variety of criteria (reference number, text, technical containing more than 22 000 terminological entries in English

committee,…). It also gives information on projects, replaced and French, with equivalent terms in 16 additional languages.

and withdrawn publications. Also known as the International Electrotechnical Vocabulary

(IEV) online.
IEC Just Published - webstore.iec.ch/justpublished

Stay up to date on all new IEC publications. Just Published IEC Glossary - std.iec.ch/glossary

details all new publications released. Available online and 67 000 electrotechnical terminology entries in English and

once a month by email. French extracted from the Terms and Definitions clause of

IEC publications issued since 2002. Some entries have been

IEC Customer Service Centre - webstore.iec.ch/csc collected from earlier publications of IEC TC 37, 77, 86 and

If you wish to give us your feedback on this publication or CISPR.
need further assistance, please contact the Customer Service
Centre: sales@iec.ch.
A propos de l'IEC

La Commission Electrotechnique Internationale (IEC) est la première organisation mondiale qui élabore et publie des

Normes internationales pour tout ce qui a trait à l'électricité, à l'électronique et aux technologies apparentées.

A propos des publications IEC

Le contenu technique des publications IEC est constamment revu. Veuillez vous assurer que vous possédez l’édition la

plus récente, un corrigendum ou amendement peut avoir été publié.
Recherche de publications IEC - Electropedia - www.electropedia.org

webstore.iec.ch/advsearchform Le premier dictionnaire d'électrotechnologie en ligne au

La recherche avancée permet de trouver des publications IEC monde, avec plus de 22 000 articles terminologiques en

en utilisant différents critères (numéro de référence, texte, anglais et en français, ainsi que les termes équivalents dans

comité d’études,…). Elle donne aussi des informations sur les 16 langues additionnelles. Egalement appelé Vocabulaire

projets et les publications remplacées ou retirées. Electrotechnique International (IEV) en ligne.

IEC Just Published - webstore.iec.ch/justpublished Glossaire IEC - std.iec.ch/glossary

Restez informé sur les nouvelles publications IEC. Just 67 000 entrées terminologiques électrotechniques, en anglais

Published détaille les nouvelles publications parues. et en français, extraites des articles Termes et Définitions des

Disponible en ligne et une fois par mois par email. publications IEC parues depuis 2002. Plus certaines entrées

antérieures extraites des publications des CE 37, 77, 86 et
Service Clients - webstore.iec.ch/csc CISPR de l'IEC.
Si vous désirez nous donner des commentaires sur cette
publication ou si vous avez des questions contactez-nous:
sales@iec.ch.
---------------------- Page: 2 ----------------------
IEC 60904-1
Edition 3.0 2020-09
INTERNATIONAL
STANDARD
NORME
INTERNATIONALE
colour
inside
Photovoltaic devices –
Part 1: Measurement of photovoltaic current-voltage characteristics
Dispositifs photovoltaïques –
Partie 1: Mesurage des caractéristiques courant-tension des dispositifs
photovoltaïques
INTERNATIONAL
ELECTROTECHNICAL
COMMISSION
COMMISSION
ELECTROTECHNIQUE
INTERNATIONALE
ICS 27.160 ISBN 978-2-8322-8814-6

Warning! Make sure that you obtained this publication from an authorized distributor.

Attention! Veuillez vous assurer que vous avez obtenu cette publication via un distributeur agréé.

® Registered trademark of the International Electrotechnical Commission
Marque déposée de la Commission Electrotechnique Internationale
---------------------- Page: 3 ----------------------
– 2 – IEC 60904-1:2020 © IEC 2020
CONTENTS

FOREWORD ........................................................................................................................... 4

1 Scope .............................................................................................................................. 6

2 Normative references ...................................................................................................... 6

3 Terms and definitions ...................................................................................................... 7

4 General requirements ...................................................................................................... 8

4.1 General ................................................................................................................... 8

4.2 Measurements ........................................................................................................ 9

4.3 Stabilisation .......................................................................................................... 10

4.4 Equivalence to steady-state performance .............................................................. 10

4.5 Reporting conditions ............................................................................................. 10

4.6 Translation from test conditions to reporting conditions ......................................... 11

5 Apparatus ...................................................................................................................... 11

6 Measurements in natural sunlight .................................................................................. 12

6.1 General ................................................................................................................. 12

6.2 Test procedure ...................................................................................................... 13

7 Measurement in simulated sunlight ................................................................................ 14

7.1 General ................................................................................................................. 14

7.2 Test procedure ...................................................................................................... 15

8 Data analysis ................................................................................................................. 16

8.1 Translation from test conditions to reporting conditions ......................................... 16

8.2 Extracting I-V curve parameters ............................................................................ 17

8.3 Evaluating measurement uncertainty..................................................................... 17

9 Test report ..................................................................................................................... 18

Annex A (informative) Device area measurement ................................................................. 19

A.1 General ................................................................................................................. 19

A.2 Definition of device area ....................................................................................... 19

A.2.1 General ......................................................................................................... 19

A.2.2 Total area (A ) ............................................................................................... 19

A.2.3 Aperture area (A ) ....................................................................................... 19

A.2.4 Designated illumination area (A ) ................................................................ 19

A.3 Area measurement of PV devices ......................................................................... 19

Annex B (informative) Measurement of current-voltage characteristics for PV devices

with capacitance ................................................................................................................... 22

B.1 General ................................................................................................................. 22

B.2 Definitions............................................................................................................. 22

B.3 Relative error due to capacitance .......................................................................... 22

B.4 Methodologies to suppress the measurement error ............................................... 24

B.4.1 General ......................................................................................................... 24

B.4.2 Measurement at steady-state conditions ........................................................ 24

B.4.3 Measurement at quasi-steady-state conditions .............................................. 25

B.4.4 Common methods for characterisation of capacitive PV devices .................... 25

B.5 Report................................................................................................................... 26

B.6 Reference documents ........................................................................................... 26

Annex C (informative) Measurement of photovoltaic current-voltage characteristics

without illumination (dark I-V)................................................................................................ 28

---------------------- Page: 4 ----------------------
IEC 60904-1:2020 © IEC 2020 – 3 –

C.1 General ................................................................................................................. 28

C.2 Apparatus ............................................................................................................. 29

C.3 Procedure ............................................................................................................. 29

C.3.1 General ......................................................................................................... 29

C.3.2 Dark I-V curve measurements ........................................................................ 30

Annex D (informative) Influence of spatial non-uniformity of irradiance on I-V curve

parameters ........................................................................................................................... 31

D.1 General ................................................................................................................. 31

D.2 Reference documents ........................................................................................... 32

Bibliography .......................................................................................................................... 33

Figure 1 – Schematic current-voltage characteristic (I-V curve) depicting typical I-V

curve parameters short-circuit current (I ), open-circuit voltage (V ), maximum
sc oc
power (P ), voltage at maximum power (V ) and current at maximum power
max Pmax

(I )................................................................................................................................... 8

Pmax

Figure 2 – Schematic power-voltage characteristic (P-V curve) depicting typical I-V

curve parameters open-circuit voltage (V ), maximum power (P ) and voltage at
oc max

maximum power (V ) ....................................................................................................... 9

Pmax

Figure A.1 – PV module (rectangular) ................................................................................... 20

Figure A.2 – PV module of different geometries (pentagon, trapezoid) .................................. 20

Figure A.3 – PV cell (cut corners) ......................................................................................... 21

Figure A.4 – PV cell (rounded corners, circle) ....................................................................... 21

Figure B.1 – Equivalent circuit diagram for device exhibiting a capacitance effect ................. 23

Figure B.2 – Three I-V curves (steady-state, forward sweep and reverse sweep)

showing the effect of device capacitance on the curve shape ................................................ 23

Figure B.3 – Deviation of maximum power (P ) determined from I-V curve due to
max

the effect of device capacitance with respect to steady-state result as a function of

sweep rate ............................................................................................................................ 24

Figure C.1 – I-V characteristics without illumination (dark I-V curve) ..................................... 28

Figure C.2 – I-V characteristics under illumination (I-V curve) ............................................... 29

Figure D.1 – Monte-Carlo simulation of a 60-cell PV module with high shunt cell type ......... 32

---------------------- Page: 5 ----------------------
– 4 – IEC 60904-1:2020 © IEC 2020
INTERNATIONAL ELECTROTECHNICAL COMMISSION
____________
PHOTOVOLTAIC DEVICES –
Part 1: Measurement of photovoltaic current-voltage characteristics
FOREWORD

1) The International Electrotechnical Commission (IEC) is a worldwide organization for standardization comprising

all national electrotechnical committees (IEC National Committees). The object of IEC is to promote international

co-operation on all questions concerning standardization in the electrical and electronic fields. To this end and

in addition to other activities, IEC publishes International Standards, Technical Specifications, Technical Reports,

Publicly Available Specifications (PAS) and Guides (hereafter referred to as “IEC Publication(s)”). Their

preparation is entrusted to technical committees; any IEC National Committee interested in the subject dealt with

may participate in this preparatory work. International, governmental and non-governmental organizations liaising

with the IEC also participate in this preparation. IEC collaborates closely with the International Organization for

Standardization (ISO) in accordance with conditions determined by agreement between the two organizations.

2) The formal decisions or agreements of IEC on technical matters express, as nearly as possible, an international

consensus of opinion on the relevant subjects since each technical committee has representation from all

interested IEC National Committees.

3) IEC Publications have the form of recommendations for international use and are accepted by IEC National

Committees in that sense. While all reasonable efforts are made to ensure that the technical content of IEC

Publications is accurate, IEC cannot be held responsible for the way in which they are used or for any

misinterpretation by any end user.

4) In order to promote international uniformity, IEC National Committees undertake to apply IEC Publications

transparently to the maximum extent possible in their national and regional publications. Any divergence between

any IEC Publication and the corresponding national or regional publication shall be clearly indicated in the latter.

5) IEC itself does not provide any attestation of conformity. Independent certification bodies provide conformity

assessment services and, in some areas, access to IEC marks of conformity. IEC is not responsible for any

services carried out by independent certification bodies.

6) All users should ensure that they have the latest edition of this publication.

7) No liability shall attach to IEC or its directors, employees, servants or agents including individual experts and

members of its technical committees and IEC National Committees for any personal injury, property damage or

other damage of any nature whatsoever, whether direct or indirect, or for costs (including legal fees) and

expenses arising out of the publication, use of, or reliance upon, this IEC Publication or any other IEC Publications.

8) Attention is drawn to the Normative references cited in this publication. Use of the referenced publications is

indispensable for the correct application of this publication.

9) Attention is drawn to the possibility that some of the elements of this IEC Publication may be the subject of patent

rights. IEC shall not be held responsible for identifying any or all such patent rights.

International Standard IEC 60904-1 has been prepared by IEC technical committee 82: Solar

photovoltaic energy systems.

This third edition cancels and replaces the second edition published in 2006. This edition

constitutes a technical revision.
The main changes with respect to the previous edition are as follows:
• Updated scope to include all conditions.
• Added terms and definitions.
• Reorganised document to avoid unnecessary duplication.
• Added data analysis clause.

• Added informative annexes (area measurement, PV devices with capacitance, dark I-V

curves and effect of spatial non-uniformity of irradiance).
---------------------- Page: 6 ----------------------
IEC 60904-1:2020 © IEC 2020 – 5 –
The text of this International Standard is based on the following documents:
FDIS Report on voting
82/1760/FDIS 82/1786/RVD

Full information on the voting for the approval of this International Standard can be found in the

report on voting indicated in the above table.

This document has been drafted in accordance with the ISO/IEC Directives, Part 2.

A list of all parts of IEC 60904 series, under the general title Photovoltaic devices, can be found

on the IEC website.

The committee has decided that the contents of this document will remain unchanged until the

stability date indicated on the IEC website under "http://webstore.iec.ch" in the data related to

the specific document. At this date, the document will be
• reconfirmed,
• withdrawn,
• replaced by a revised edition, or
• amended.

IMPORTANT – The 'colour inside' logo on the cover page of this publication indicates

that it contains colours which are considered to be useful for the correct understanding

of its contents. Users should therefore print this document using a colour printer.

---------------------- Page: 7 ----------------------
– 6 – IEC 60904-1:2020 © IEC 2020
PHOTOVOLTAIC DEVICES –
Part 1: Measurement of photovoltaic current-voltage characteristics
1 Scope

This part of IEC 60904 describes procedures for the measurement of current-voltage

characteristics (I-V curves) of photovoltaic (PV) devices in natural or simulated sunlight. These

procedures are applicable to a single PV solar cell, a sub-assembly of PV solar cells, or a PV

module. They are applicable to single-junction mono-facial PV devices. For other device types,

reference is made to the respective documents, in particular for multi-junction devices to

IEC 60904-1-1 and for bifacial devices to IEC TS 60904-1-2. Additionally informative annexes

are provided concerning area measurement of PV devices (Annex A), PV devices with

capacitance (Annex B), measurement of dark current-voltage characteristics (dark I-V curves)

(Annex C) and effects of spatial non-uniformity of irradiance (Annex D).

NOTE The methods provided in this document can also be used as guidance for taking I-V curves of PV arrays. For

on-site measurement refer to IEC 61829.

This document is applicable to non-concentrating PV devices for use in terrestrial environments,

with reference to (usually but not exclusively) the global reference spectral irradiance AM1.5

defined in IEC 60904-3. It may also be applicable to PV devices for use under concentrated

irradiation if the application uses direct sunlight and reference is instead made to the direct

reference spectral irradiance AM1.5d in IEC 60904-3.

The purposes of this document are to lay down basic requirements for the measurement of I-V

curves of PV devices, to define procedures for different measuring techniques in use and to

show practices for minimising measurement uncertainty. It is applicable to the measurement of

I-V curves in general. I-V measurements can have various purposes, such as calibration (i.e.

traceable measurement with stated uncertainty, usually performed at standard test conditions)

of a PV device under test against a reference device, performance measurement under various

conditions (e.g. for device temperature and irradiance) such as those required by IEC 60891

(for determination of temperature coefficients or internal series resistance), by IEC 61853-1

(power rating of PV devices) or by IEC 60904-10 (for determination of output’s linear

dependence and linearity with respect to a particular test parameter). I-V measurements are

also important in industrial environments such as PV module production facilities, and for testing

in the field. Further guidance on I-V measurements in production facilities is provided in

IEC TR 60904-14.

The actual requirements (e.g. for the class of solar simulator) depend on the end-use. Other

standards referring to IEC 60904-1 can stipulate specific requirements. Where those

requirements are in conflict with this document, the specific requirements take precedence.

2 Normative references

The following documents are referred to in the text in such a way that some or all of their content

constitutes requirements of this document. For dated references, only the edition cited applies.

For undated references, the latest edition of the referenced document (including any

amendments) applies.

IEC 60891, Photovoltaic devices – Procedures for temperature and irradiance corrections to

measured I-V characteristics
IEC 60904-2, Photovoltaic devices – Part 2: Requirements for reference devices
---------------------- Page: 8 ----------------------
IEC 60904-1:2020 © IEC 2020 – 7 –

IEC 60904-3, Photovoltaic devices – Part 3: Measurement principles for terrestrial photovoltaic

(PV) solar devices with reference spectral irradiance data

IEC 60904-4, Photovoltaic devices – Part 4: Photovoltaic reference devices – Procedures for

establishing calibration traceability

IEC 60904-5, Photovoltaic devices – Part 5: Determination of the equivalent cell temperature

(ECT) of photovoltaic (PV) devices by the open-circuit voltage method

IEC 60904-7, Photovoltaic devices – Part 7: Computation of the spectral mismatch correction

for measurements of photovoltaic devices

IEC 60904-9, Photovoltaic devices – Part 9: Solar simulator performance requirements

IEC 60904-10, Photovoltaic devices – Part 10: Methods of linearity measurement

IEC TR 60904-14, Photovoltaic devices – Part 14: Guidelines for production line measurements

of single-junction PV module maximum power output and reporting at standard test conditions

IEC 61215 (all parts), Terrestrial photovoltaic (PV) modules – Design qualification and type

approval
IEC TS 61836, Solar photovoltaic energy systems – Terms, definitions and symbols

IEC 61853-1, Photovoltaic (PV) module performance testing and energy rating – Part 1:

Irradiance and temperature performance measurements and power rating

IEC TR 63228, Measurement protocols for photovoltaic devices based on organic, dye-

sensitized or perovskite materials

ISO 9060, Solar energy – Specification and classification of instruments for measuring

hemispherical solar and direct solar radiation
3 Terms and definitions

For the purposes of this document, the terms and definitions given in IEC TS 61836 and the

following apply.

ISO and IEC maintain terminological databases for use in standardization at the following

addresses:
• IEC Electropedia: available at http://www.electropedia.org/
• ISO Online browsing platform: available at http://www.iso.org/obp
3.1
sweep rate
temporal rate of change of the voltage applied to the measured PV device
Note 1 to entry: The term ramp rate is also used interchangeably.
3.2
sweep direction

direction of change of applied voltage during I-V measurements; a positive sweep rate is

referred to as forward or direct sweep (I to V direction), while a negative sweep rate is

sc oc
referred to as reverse or backward sweep (V to I direction)
oc sc
---------------------- Page: 9 ----------------------
– 8 – IEC 60904-1:2020 © IEC 2020
3.3
time delay

time interval between the change of voltage applied to PV device and the measurement of PV

device current
4 General requirements
4.1 General

For illustration purposes a schematic current-voltage characteristic (I-V curve) is shown in

Figure 1 and the corresponding power-voltage characteristic (P-V curve) in Figure 2.

Figure 1 – Schematic current-voltage characteristic (I-V curve) depicting typical I-V

curve parameters short-circuit current (I ), open-circuit voltage (V ), maximum power

sc oc
(P ), voltage at maximum power (V ) and current at maximum power (I )
max Pmax Pmax
---------------------- Page: 10 ----------------------
IEC 60904-1:2020 © IEC 2020 – 9 –
Figure 2 – Schematic power-voltage characteristic (P-V curve) depicting
typical I-V curve parameters open-circuit voltage (V ), maximum power (P )
oc max
and voltage at maximum power (V
Pmax
4.2 Measurements

a) When the measurements are intended to be reported at standard test conditions (see 4.5)

the in-plane average irradiance during measurement shall be between 800 W∙m and
1 200 W∙m to minimise errors arising from large corrections.

b) Temperature sensors should be located so as to detect as closely as possible the

temperature of the respective device cell junction. If a temperature gradient between the

sensor and the cell junction is suspected, an appropriate contribution to the measurement

uncertainty should be included. Consideration should also be given to any possible non-

uniformity of temperature across either device, particularly for PV modules, where the

temperature of individual cells can vary due to their electrical characteristics, particularly

when the module is illuminated under short-circuit conditions. The Equivalent Cell

Temperature (ECT) method specified in IEC 60904-5 can be useful in dealing with either a

temperature gradient or temperature non-uniformity. The cooling effect from airflow (for

example due to wind during outdoor measurement or due to air conditioning of the room for

indoor measurements) on the temperature sensors should be considered in the uncertainty

of the temperature measurement.

c) The active surface of the device under test shall be coplanar within ±2° with the active

surface of the reference device.

d) Voltages and currents shall be measured using independent leads from the terminals of the

device under test and keeping them as short as possible. If the device under test is a module,

a subassembly or an encapsulated solar cell, the 4-wire connection should start at the

terminals or connectors. If the device under test is a bare PV cell, the 4-wire connection

should start at the cell bus bars. The connection method for bare cells (i.e. provided without

connectors) should be carefully evaluated. Differences can occur if soldered tabs are used

compared with non-soldered methods such as bars having contact springs or conductive

plates having a large-area contact with the cell back contact. Non-soldered methods can

result in higher fill factors than are observed in the module. The contacting method should

be appropriate to the intended use of the cell or of the measurement. The contact method

used (bare cells) or the contact point (modules) for 4-wire connection shall be stated in the

report. For bare solar cells without busbars or cells with low surface conductivity such as

multi-busbar cells, 4-wire connection should start at the contacting s
...

Questions, Comments and Discussion

Ask us and Technical Secretary will try to provide an answer. You can facilitate discussion about the standard in here.