IEC TR 62905:2018

Exposure assessment methods for wireless power transfer systems

IEC/TR 62905:2018(E) is a Technical Report. It describes general exposure assessment methods for wireless power transfer (WPT) at frequency up to 10 MHz considering thermal and stimulus effects. Exposure assessment procedures and experimental results are shown as examples such as electric vehicles (EVs) and mobile devices.
Keywords: Exposure Assessment, Wireless Power Transfer (WPT), Human Exposure

General Information

• Status: Published
• Publication Date: 05-Feb-2018
• ICS: 01 - GENERALITIES. TERMINOLOGY. STANDARDIZATION. DOCUMENTATION
• ICS: 17.220.20 - Measurement of electrical and magnetic quantities
• Technical Committee: TC 106 - Methods for the assessment of electric, magnetic and electromagnetic fields associated with human exposure
• Current Stage: PPUB - Publication issued
• Start Date: 21-Feb-2018
• Completion Date: 06-Feb-2018

Standards Content (Sample)

IEC TR 62905 ®
Edition 1.0 2018-02
TECHNICAL
REPORT
colour
inside
Exposure assessment methods for wireless power transfer systems
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IEC TR 62905 ®
Edition 1.0 2018-02
TECHNICAL
REPORT
colour
inside
Exposure assessment methods for wireless power transfer systems

INTERNATIONAL
ELECTROTECHNICAL
COMMISSION
ICS 17.220.20 ISBN 978-2-8322-5350-2

– 2 – IEC TR 62905:2018 © IEC 2018
CONTENTS
FOREWORD . 7
INTRODUCTION . 9
1 Scope . 10
2 Normative references . 10
3 Terms and definitions . 10
4 Symbols and abbreviations . 12
4.1 Physical quantities . 12
4.2 Constants . 12
4.3 Abbreviations . 12
5 Overview of WPT systems . 13
5.1 General . 13
5.2 WPT systems whose frequency range is less than 100 kHz . 13
5.3 WPT systems whose frequency range is from 100 kHz to 10 MHz . 17
6 Basic assessment methods . 20
6.1 General . 20
6.2 Basic assessment methods considering direct effect . 20
6.2.1 General . 20
6.2.2 Evaluation based on transmit power or current . 21
6.2.3 Evaluation of incident fields against reference levels . 21
6.2.4 Evaluation of incident fields against basic restrictions . 21
6.2.5 Evaluation of induced E-field and SAR against basic restrictions . 22
6.2.6 Assessment procedure . 23
6.3 Basic assessment method considering indirect effect . 23
Annex A (informative) WPT systems whose frequency range is over 10 MHz . 25
Annex B (informative) International exposure guidelines . 27
B.1 ICNIRP guidelines. 27
B.2 IEEE standards . 30
Annex C (informative) Assessment methods . 33
C.1 Exclusion based on transmit power or current . 33
C.2 Measurement of incident electromagnetic fields . 34
C.2.1 Equipment for electric field measurement . 34
C.2.2 Equipment for magnetic field measurement . 34
C.2.3 Measurement method . 35
C.3 Coupling factor . 36
C.4 Generic gradient source model . 37
C.5 Induced E-field or SAR . 40
C.5.1 Measurement . 40
C.5.2 Calculation . 41
C.6 Contact current . 43
C.6.1 Equipment . 43
C.6.2 Measurements . 45
Annex D (informative) Case studies . 46
D.1 WPT system for EV . 46
D.1.1 General . 46
D.1.2 Assessment procedures for WPT system for EV . 47
D.2 Experimental assessment results for EV . 58

D.2.1 General . 58
D.2.2 Electromagnetic field measurement results . 58
D.2.3 Contact current measurement . 60
D.3 WPT system for mobile devices . 61
D.3.1 General . 61
D.3.2 Assessment procedures for WPT system for mobile . 62
Annex E (informative) Numerical and experimental studies . 64
E.1 Exposure evaluation of WPT for EV . 64
E.1.1 Research in Japan . 64
E.1.2 Research in Korea . 68
E.2 Exposure evaluation of WPT for mobile device. 72
E.2.1 WPT system in 140 kHz band . 72
E.2.2 WPT systems in MHz band . 74
E.3 Coupling factor . 79
E.3.1 WPT system for EV . 79
E.3.2 WPT system for mobile device . 82
E.3.3 Evaluation example of CF and GGSM using a cylinder model . 83
E.4 SAR measurement . 87
E.5 Contact current . 89
E.5.1 WPT system for EV . 89
E.5.2 WPT systems for mobile (MHz) . 90
Annex F (informative) Medical implants . 92
F.1 Background. 92
F.2 Medical implant enhancement factor . 92
F.3 Numerical evaluation of medical implant enhancement factor . 97
F.3.1 General . 97
F.3.2 Numerical setup . 97
Bibliography . 99

Figure 1 – Wireless power kitchen appliances [1] . 13
(WPT kitchen island of apartment) . 14
Figure 2 – Use cases of the LCD and semiconductor product lines and kitchen WPT
systems [1] . 14
Figure 3 – Example of a WPT system for EV/PHEV [1] . 15
Figure 4 – Example of an online electric vehicle [1] . 16
Figure 5 – Technical characteristics of an online electric vehicle [1] . 16
Figure 6 – Example magnetic induction WPT system block diagram [1] . 18
Figure 7 – Example magnetic resonance WPT system block diagram [1] . 18
Figure 8 – Capacitive coupling WPT system block diagram [1] . 19
Figure 9 – Typical structure of the capacitive coupling system [1] . 19
Figure 10 – Flowchart of assessment procedure considering the direct effect . 23
Figure 11 – Two exposure situations for ungrounded and grounded metal objects . 24
Figure 12 – Flowchart of assessment procedures for indirect effects . 24
Figure C.1 – Frequency characteristics of impedance of adult male and IEC equivalent
circuit . 44
Figure C.2 – IEC equivalent circuit . 44
Figure C.3 – Example of contact current measurement equipment . 44

– 4 – IEC TR 62905:2018 © IEC 2018
Figure D.1 – Example for areas of protection, for ground mounted systems [37] . 47
Figure D.2 – Area 3 measurement position [37] . 48
Figure D.3 – Area 4 measurement position [37] . 48
Figure D.4 – Assessment flow of Part 1 . 51
Figure D.5 – Assessment flow of Part 2 .
...