IEC TS 63156:2021

IEC TS 63156 ®
Edition 1.0 2021-02
TECHNICAL
SPECIFICATION
Photovoltaic systems – Power conversion equipment performance – Energy
evaluation method
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IEC TS 63156 ®
Edition 1.0 2021-02
TECHNICAL
SPECIFICATION
Photovoltaic systems – Power conversion equipment performance – Energy

evaluation method
INTERNATIONAL
ELECTROTECHNICAL
COMMISSION
ICS 27.160 ISBN 978-2-8322-9303-4

– 2 – IEC TS 63156:2021 © IEC 2021
CONTENTS
FOREWORD . 3
INTRODUCTION . 5
1 Scope . 6
2 Normative references . 6
3 Terms and definitions . 6
4 Workflow of energy conversion efficiency evaluation method . 10
4.1 General . 10
4.2 Flow of energy conversion efficiency evaluation test . 11
4.3 Flow of energy conversion efficiency calculation . 12
5 Energy efficiency measurement conditions . 13
5.1 Energy efficiency test circuit . 13
5.2 Test conditions . 14
6 Static energy conversion efficiency evaluation . 14
7 Dynamic energy conversion efficiency evaluation . 14
8 Weighted energy conversion efficiency calculation . 14
Annex A (informative) Rate of change of irradiance . 15
A.1 Analysis of irradiance profile . 15
A.2 Rate of change of irradiance . 18
Annex B (informative) Static energy conversion efficiency test sequence . 19
Annex C (informative) Dynamic energy conversion efficiency test sequence . 20
Annex D (informative) Weighted energy conversion efficiency . 22
Bibliography . 23

Figure 1 – Flowchart of energy conversion efficiency evaluation test . 11
Figure 2 – Flowchart of energy conversion efficiency calculation . 12
Figure 3 – Power conversion equipment test circuits . 13
Figure A.1 – Example of irradiance profile . 17
−2 −1
Figure A.2 – Histogram of the irradiance in Figure A.1 (< 2 W•m •s ) . 17
−2 −1
Figure A.3 – Histogram of rate of change of irradiance (>2 W•m •s ) . 18
Figure C.1 – Test sequence for fluctuations between medium and high irradiation
intensities . 20

Table 1 – Weighted energy conversion efficiency . 14
Table A.1 – Weighted factor ratios for F . 18
n=1 to 7
Table A.2 – Weighted factor ratios for J , J , etc. . 18
1 2
Table B.1 – Static energy efficiency . 19
Table C.1 – Dynamic energy efficiency test with input power from 30 % to 100 % . 21
Table C.2 – Dynamic energy efficiency data . 21
Table D.1 – Static energy conversion efficiency . 22
Table D.2 – Dynamic energy conversion efficiency . 22
Table D.3 – Weighted total conversion efficiency . 22

INTERNATIONAL ELECTROTECHNICAL COMMISSION
____________
PHOTOVOLTAIC SYSTEMS –
POWER CONVERSION EQUIPMENT PERFORMANCE –
ENERGY EVALUATION METHOD
FOREWORD
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The main task of IEC technical committees is to prepare International Standards. In exceptional
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• the required support cannot be obtained for the publication of an International Standard,
despite repeated efforts, or
• the subject is still under technical development or where, for any other reason, there is the
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Technical Specifications are subject to review within three years of publication to decide
whether they can be transformed into International Standards.
IEC TS 63156, which is a Technical Specification, has been prepared by IEC technical
committee 82: Solar photovoltaic energy systems.

– 4 – IEC TS 63156:2021 © IEC 2021
The text of this Technical Specification is based on the following documents:
Draft TS Report on voting
82/1755/DTS 82/1801A/RVDTS
Full information on the voting for the approval of this Technical Specification 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.
The committee has decided that the contents of this document will remain unchanged until the
stability date indicated on the IEC website under 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.
INTRODUCTION
The performance of a photovoltaic power generation system is influenced by various factors,
such as meteorological conditions, installation environment (e.g. shade sources, soiling),
design, and so on. The performance of a power conversion equipment is one of the significant
indices for evaluating the performance of a PV system. IEC 61683 and IEC 62891 describe
procedures for measuring the static (constant) conversion efficiency of power conversion
equipment and MPPT efficiency, respectively. However, the standards do not define conversion
efficiency under dynamic changes in factors such as meteorological changes, installation
environment changes or temporal changes.
The CEC efficiency test protocol and EN 50530 define dynamic performance tests and
procedures partially, but do not define a calculation procedure for evaluating the quantity of
energy produced by a PV system. IEC TS 61724-3 describes a procedure for measuring and
analysing the energy production of a specific photovoltaic system relative to the production
expected for the same system from actual weather conditions for a certain period, but does not
define the procedure for measuring the performance of power conversion equipment under
actual environments.
Since there are areas where meteorological conditions, especially irradiance, change greatly
and could affect the performance of power conversion equipment, a performance evaluation
method under dynamic conditions needs to be defined. This document describes the procedure
for evaluating the dynamic performance and energy production efficiency of power conversion
equipment in a particular location using site-specific solar profiles.

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PHOTOVOLTAIC SYSTEMS –
POWER CONVERSION EQUIPMENT PERFORMANCE –
ENERGY EVALUATION METHOD
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