IEC 60904-7:2019
(Main)Photovoltaic devices - Part 7: Computation of the spectral mismatch correction for measurements of photovoltaic devices
Photovoltaic devices - Part 7: Computation of the spectral mismatch correction for measurements of photovoltaic devices
IEC 60904-7:2019 describes the procedure for correcting the spectral mismatch error introduced in the testing of a photovoltaic device, caused by the mismatch between the test spectrum and the reference spectrum (e.g. AM1.5 spectrum) and by the mismatch between the spectral responsivities (SR) of the reference device and of the device under test and therewith reduce the systematic uncertainty. This procedure is valid for single-junction devices but the principle may be extended to cover multi-junction devices. The purpose of this document is to give guidelines for the correction of the spectral mismatch error, should there be a spectral mismatch between the test spectrum and the reference spectrum as well as between the reference device SR and the device under test SR. The calculated spectral mismatch correction is only valid for the specific combination of test and reference devices measured with a particular test spectrum. This fourth edition cancels and replaces the third edition published in 2008. The main technical changes with respect to the previous edition are as follows:
- For better compatibility and less redundancy, the clause “Determination of test spectrum” refers to IEC 60904-9.
- The spectral mismatch factor is called SMM instead of MM to enable differentiation to the angular mismatch factor AMM and spectral angular mismatch factor SAMM.
- Formulae for the derivation and application of the spectral mismatch factor SMM are added.
- Links to new standards are given, e.g. concerning multi-junction devices.
- Corrected wording (responsivity instead of response and irradiance instead of intensity).
Dispositifs photovoltaïques - Partie 7: Calcul de la correction de désadaptation des réponses spectrales dans les mesures de dispositifs photovoltaïques
L'IEC 60904-7:2019 décrit la procédure pour corriger l'erreur de mesure spectrale introduite dans l'essai d'un dispositif photovoltaïque, due d'une part à la désadaptation du spectre pour l'essai et du spectre de référence (par exemple, spectre AM1.5), et d'autre part à la désadaptation entre les sensibilités spectrales (SS) du dispositif de référence et du dispositif soumis à essai, et ainsi réduire l'incertitude systématique. Cette procédure est valable pour les dispositifs à jonction unique, mais le principe peut être étendu aux dispositifs multijonctions. Le but du présent document est de donner des lignes directrices pour la correction de l'erreur de mesure spectrale se traduisant par une désadaptation à la fois du spectre pour l'essai et du spectre de référence, ainsi que des sensibilités spectrales (SS) du dispositif de référence et celles du dispositif soumis à essai. La correction calculée de désadaptation des réponses spectrales n'est valable que pour la combinaison spécifique des dispositifs d'essai et de référence mesurés à l'aide d'un spectre d'essai particulier. La Norme internationale IEC 60904-7 a été établie par le comité d'études 82 de l'IEC: Systèmes de conversion photovoltaïque de l'énergie solaire. Les modifications techniques principales par rapport à l'édition précédente sont les suivantes:
- pour davantage de compatibilité et moins de redondance, l'article "Détermination du spectre pour l'essai" fait référence à l'IEC 60904-9;
- le facteur de désadaptation des réponses spectrales est appelé SMM plutôt que MM afin de permettre la différenciation avec le facteur de désadaptation angulaire AMM et le facteur de désadaptation angulaire spectral SAMM;
- les formules correspondant à la dérivée et à l'application du facteur de désadaptation spectral SMM sont ajoutées;
- des références à de nouvelles normes sont données, par exemple concernant les dispositifs multijonctions;
- des formulations ont été corrigées ("sensibilité" remplace "réponse" et "éclairement" remplace "intensité").
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Photovoltaic devices –
Part 7: Computation of the spectral mismatch correction for measurements of
photovoltaic devices
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International Standards for all electrical, electronic and related technologies.
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IEC 60904-7 ®
Edition 4.0 2019-08
REDLINE VERSION
INTERNATIONAL
STANDARD
colour
inside
Photovoltaic devices –
Part 7: Computation of the spectral mismatch correction for measurements of
photovoltaic devices
INTERNATIONAL
ELECTROTECHNICAL
COMMISSION
ICS 27.160 ISBN 978-2-8322-7329-6
– 2 – IEC 60904-7:2019 RLV © IEC 2019
CONTENTS
FOREWORD . 3
1 Scope . 5
2 Normative references . 5
3 Terms and definitions . 6
Apparatus . 7
4 Description of method . 7
5 Determination of spectral response responsivity . 7
6 Determination of test spectrum . 9
7 Determination of the spectral mismatch factor . 9
7.1 General . 10
7.2 Simplified formula for a thermopile detector (pyranometer) . 12
8 Report . 9
Bibliography .
INTERNATIONAL ELECTROTECHNICAL COMMISSION
____________
PHOTOVOLTAIC DEVICES –
Part 7: Computation of the spectral mismatch correction
for measurements of photovoltaic devices
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.
This redline version of the official IEC Standard allows the user to identify the changes
made to the previous edition. A vertical bar appears in the margin wherever a change
has been made. Additions are in green text, deletions are in strikethrough red text.
– 4 – IEC 60904-7:2019 RLV © IEC 2019
International Standard IEC 60904-7 has been prepared by IEC technical committee 82: Solar
photovoltaic energy systems.
This fourth edition cancels and replaces the third edition published in 2008. It constitutes a
technical revision.
The main technical changes with respect to the previous edition are as follows:
• For better compatibility and less redundancy, the clause “Determination of test spectrum”
refers to IEC 60904-9.
• The spectral mismatch factor is called SMM instead of MM to enable differentiation to the
angular mismatch factor AMM and spectral angular mismatch factor SAMM.
• Formulae for the derivation and application of the spectral mismatch factor SMM are
added.
• Links to new standards are given, e.g. concerning multi-junction devices.
• Corrected wording (responsivity instead of response and irradiance instead of intensity).
The text of this International Standard is based on the following documents:
FDIS Report on voting
82/1590/FDIS 82/1605/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, published 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.
PHOTOVOLTAIC DEVICES –
Part 7: Computation of the spectral mismatch correction
for measurements of photovoltaic devices
1 Scope and object
This part of IEC 60904 describes the procedure for correcting the bias spectral mismatch
error introduced in the testing of a photovoltaic device, caused by the mismatch between the
test spectrum and the reference spectrum (e.g. AM1.5 spectrum) and by the mismatch
between the spectral responses responsivities (SR) of the reference cell device and of the
device under test specimen and therewith reduce the systematic uncertainty. The procedure
applies only to photovoltaic devices linear in SR as defined in IEC 60904-10. This procedure
is valid for single-junction devices but the principle may be extended to cover multi-junction
devices.
The purpose of this document is to give guidelines for the correction of measurement bias the
spectral mismatch error, should there be a spectral mismatch betweenthe test spectrum and
the reference spectrum as well as between the reference device SR and the device under test
specimen SR. The calculated spectral mismatch correction is only valid for the specific
combination of test and reference devices measured with a particular test spectrum.
Since a PV device has a wavelength-dependent response spectral responsivity, its
performance is significantly affected by the spectral distribution of the incident radiation,
which in natural sunlight varies with several factors such as location, weather, time of year,
time of day, orientation of the receiving surface, etc., and with a solar simulator varies with its
type and conditions. If the irradiance is measured with a thermopile-type radiometer (that is
not spectrally selective) or with a PV reference solar cell device (IEC 60904-2), the spectral
irradiance distribution of the incoming light must be known to make the necessary corrections
to obtain the performance of the PV device under the reference solar spectral irradiance
distribution defined in IEC 60904-3.
If a reference PV device or a thermopile type detector is used to measure the irradiance, then,
following the procedure given in this document, it is possible to calculate the spectral
mismatch correction necessary to obtain the short-circuit current of the test PV device under
test under the reference solar spectral irradiance distribution in IEC 60904-3 or any other
reference spectrum. If the reference PV device has the same relative spectral response
responsivity as the test PV device under test then the reference device automatically takes
into account deviations of the real light measured spectral irradiance distribution from the
standard reference spectral irradiance distribution, and no further correction of spectral bias
mismatch errors is necessary. In this case, location and weather conditions are not critical
when the reference device method is used for outdoor performance measurements provided
both reference cell and test PV device have the same relative spectral response under natural
sunlight. Also, for identical relative SRs, the spectral classification of the simulator is not
critical for indoor measurements with solar simulators.
If the performance of a PV device is measured using a known spectral irradiance distribution,
its short-circuit current at any other spectral irradiance distribution can be computed using the
spectral response responsivity of the PV test device under test.
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
– 6 – IEC 60904-7:2019 RLV © IEC 2019
cited applies. For undated references, the latest edition of the referenced document (including
any amendmen
...
IEC 60904-7 ®
Edition 4.0 2019-08
INTERNATIONAL
STANDARD
NORME
INTERNATIONALE
Photovoltaic devices –
Part 7: Computation of the spectral mismatch correction for measurements of
photovoltaic devices
Dispositifs photovoltaïques –
Partie 7: Calcul de la correction de désadaptation des réponses spectrales dans
les mesures de dispositifs photovoltaïques
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
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copyright or have an enquiry about obtaining additional rights to this publication, please contact the address below or
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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
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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.
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IEC 60904-7 ®
Edition 4.0 2019-08
INTERNATIONAL
STANDARD
NORME
INTERNATIONALE
Photovoltaic devices –
Part 7: Computation of the spectral mismatch correction for measurements of
photovoltaic devices
Dispositifs photovoltaïques –
Partie 7: Calcul de la correction de désadaptation des réponses spectrales dans
les mesures de dispositifs photovoltaïques
INTERNATIONAL
ELECTROTECHNICAL
COMMISSION
COMMISSION
ELECTROTECHNIQUE
INTERNATIONALE
ICS 27.160 ISBN 978-2-8322-7219-0
– 2 – IEC 60904-7:2019 © IEC 2019
CONTENTS
FOREWORD . 3
1 Scope . 5
2 Normative references . 5
3 Terms and definitions . 6
4 Description of method . 6
5 Determination of spectral responsivity . 8
6 Determination of test spectrum . 8
7 Determination of the spectral mismatch factor . 8
7.1 General . 8
7.2 Simplified formula for a thermopile detector (pyranometer) . 10
8 Report . 10
INTERNATIONAL ELECTROTECHNICAL COMMISSION
____________
PHOTOVOLTAIC DEVICES –
Part 7: Computation of the spectral mismatch correction
for measurements of photovoltaic devices
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 60904-7 has been prepared by IEC technical committee 82: Solar
photovoltaic energy systems.
This fourth edition cancels and replaces the third edition published in 2008. It constitutes a
technical revision.
The main technical changes with respect to the previous edition are as follows:
• For better compatibility and less redundancy, the clause “Determination of test spectrum”
refers to IEC 60904-9.
• The spectral mismatch factor is called SMM instead of MM to enable differentiation to the
angular mismatch factor AMM and spectral angular mismatch factor SAMM.
• Formulae for the derivation and application of the spectral mismatch factor SMM are
added.
• Links to new standards are given, e.g. concerning multi-junction devices.
– 4 – IEC 60904-7:2019 © IEC 2019
• Corrected wording (responsivity instead of response and irradiance instead of intensity).
The text of this International Standard is based on the following documents:
FDIS Report on voting
82/1590/FDIS 82/1605/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, published 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.
PHOTOVOLTAIC DEVICES –
Part 7: Computation of the spectral mismatch correction
for measurements of photovoltaic devices
1 Scope
This part of IEC 60904 describes the procedure for correcting the spectral mismatch error
introduced in the testing of a photovoltaic device, caused by the mismatch between the test
spectrum and the reference spectrum (e.g. AM1.5 spectrum) and by the mismatch between
the spectral responsivities (SR) of the reference device and of the device under test and
therewith reduce the systematic uncertainty. This procedure is valid for single-junction
devices but the principle may be extended to cover multi-junction devices.
The purpose of this document is to give guidelines for the correction of the spectral mismatch
error, should there be a spectral mismatch between the test spectrum and the reference
spectrum as well as between the reference device SR and the device under test SR. The
calculated spectral mismatch correction is only valid for the specific combination of test and
reference devices measured with a particular test spectrum.
Since a PV device has a wavelength-dependent spectral responsivity, its performance is
significantly affected by the spectral distribution of the incident radiation, which in natural
sunlight varies with several factors such as location, weather, time of year, time of day,
orientation of the receiving surface, etc., and with a solar simulator varies with its type and
conditions. If the irradiance is measured with a thermopile-type radiometer (that is not
spectrally selective) or with a PV reference device (IEC 60904-2), the spectral irradiance
distribution of the incoming light must be known to make the necessary corrections to obtain
the performance of the PV device under the reference spectral irradiance distribution defined
in IEC 60904
...
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