IEC 63245-2:2022

IEC 63245-2 ®
Edition 1.0 2022-12
INTERNATIONAL
STANDARD
NORME
INTERNATIONALE
colour
inside
Spatial wireless power transfer based on multiple magnetic resonances –
Part 2: Reference model
Transfert d’énergie sans fil dans l’espace reposant sur des résonances
magnétiques multiples –
Partie 2: Modèle de référence
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IEC 63245-2 ®
Edition 1.0 2022-12
INTERNATIONAL
STANDARD
NORME
INTERNATIONALE
colour
inside
Spatial wireless power transfer based on multiple magnetic resonances –

Part 2: Reference model
Transfert d’énergie sans fil dans l’espace reposant sur des résonances

magnétiques multiples –
Partie 2: Modèle de référence
INTERNATIONAL
ELECTROTECHNICAL
COMMISSION
COMMISSION
ELECTROTECHNIQUE
INTERNATIONALE
ICS 29.240.99; 35.200 ISBN 978-2-8322-6305-1

– 2 – IEC 63245-2:2022 © IEC 2022
CONTENTS
FOREWORD . 3
INTRODUCTION . 5
1 Scope . 6
2 Normative references . 6
3 Terms, definitions, and abbreviated terms . 6
3.1 Terms and definitions . 6
3.2 Abbreviated terms . 7
4 Overview of spatial wireless power transfer based on multiple magnetic
resonances . 7
5 Reference model . 8
5.1 Overview. 8
5.2 Components of an SWPT-MMR system . 9
5.2.1 Power source . 9
5.2.2 Capacitor . 9
5.2.3 Inverter . 10
5.2.4 Transmitter coils . 12
5.2.5 Communication module . 14
Bibliography . 15

Figure 1 – Conceptual image of SWPT-MMR [IEC 63245-1] . 8
Figure 2 – The reference model of an SWPT-MMR system . 8
Figure 3 – Example configuration of an SWPT-MMR system with power sources . 9
Figure 4 – Configuration on an SWPT-MMR system with transmitter coils connected to
capacitors . 10
Figure 5 – Configuration of an SWPT-MMR system with an inverter controlling a phase
of magnetic field formed on transmitter coils connected in parallel . 11
Figure 6 – Configuration of an SWPT-MMR system with an inverter controlling a phase
of magnetic field formed on transmitter coils connected in series . 11
Figure 7 – An example of an SWPT-MMR system with two transmitter coils . 12
Figure 8 – An example of an SWPT-MMR system with two pairs of transmitter coils . 13

Table 1 – Power source-related requirements defined in IEC 63245-1 . 9
Table 2 – Capacitor-related requirements defined in IEC 63245-1 . 10
Table 3 – Inverter-related requirements defined in IEC 63245-1 . 12
Table 4 – Transmitter coil-related requirements defined in IEC 63245-1 . 13
Table 5 – Communication module-related requirements defined in IEC 63245-1 . 14

INTERNATIONAL ELECTROTECHNICAL COMMISSION
_____________
SPATIAL WIRELESS POWER TRANSFER
BASED ON MULTIPLE MAGNETIC RESONANCES –

Part 2: Reference model
FOREWORD
1) The International Electrotechnical Commission (IEC) is a worldwide organization for standardization comprising
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IEC 63245-2 has been prepared by technical area 15: Wireless Power Transfer, of IEC technical
committee 100: Audio, video and multimedia systems and equipment. It is an International
Standard.
The text of this International Standard is based on the following documents:
Draft Report on voting
100/3839/FDIS 100/3864/RVD
Full information on the voting for its approval can be found in the report on voting indicated in
the above table.
The language used for the development of this International Standard is English.
A list of all parts in the IEC 63245 series, published under the general title Spatial wireless
power transfer based on multiple magnetic resonances, can be found on the IEC website.

– 4 – IEC 63245-2:2022 © IEC 2022
This document was drafted in accordance with ISO/IEC Directives, Part 2, and developed in
accordance with ISO/IEC Directives, Part 1 and ISO/IEC Directives, IEC Supplement, available
at www.iec.ch/members_experts/refdocs. The main document types developed by IEC are
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The committee has decided that the contents of this document will remain unchanged until the
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• reconfirmed,
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• amended.
IMPORTANT – The "colour inside" logo on the cover page of this document indicates that it
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INTRODUCTION
The IEC 63245 series (Spatial wireless power transfer based on multiple magnetic resonances,
SWPT-MMR) provides requirements and a reference model for implementing spatial wireless
power transfer systems. The IEC 63245 series consists of the following parts:
– Part 1: Requirements, and
– Part 2: Reference model
IEC 63245-1 describes requirements of SWPT-MMR.
IEC 63245-2 (this document) describes the reference model of SWPT-MMR.

– 6 – IEC 63245-2:2022 © IEC 2022
SPATIAL WIRELESS POWER TRANSFER
BASED ON MULTIPLE MAGNETIC RESONANCES –

Part 2: Reference model
1 Scope
This document specifies a reference model for spatial wireless power transfer based on multiple
magnetic resonances (SWPT-MMR), which is a type of non-radiative wireless power transfer
(WPT). The document contains an overview of SWPT-MMR and a reference model.
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 63245-1:2021, Spatial wireless power transfer based on multiple magnetic resonances –
Part 1: Requirements
3 Terms, definitions, and abbreviated terms
For the purposes of this document, the following terms and definitions apply.
ISO and IEC maintain terminology databases for use in standardization at the following
addresses:
• IEC Electropedia: available at https://www.electropedia.org/
• ISO Online browsing platform: available at https://www.iso.org/obp
3.1 Terms and definitions
3.1.1
null point
point or area in the charging zone where the magnetic field cancels out almost entirely or is
below a certain specified minimum
[SOURCE: IEC 63245-1:2021, 3.1.1]
3.1.2
quiet zone
magnetic field having an equalized energy density corresponding to each of the magnetic fields
formed on the transmitter coils
[SOURCE: IEC 63245-1:2021, 3.1.2]

3.1.3
spatial wireless power transfer
concept of wireless power transfer between multiple sources and multiple receiving devices
which are placed at a distance within a spatial space
Note 1 to entry: "Spatial" means that receiving devices will take various positions and postures, and will lead to
variable transfer efficiency including almost zero percent. This situation can occur when receiving devices are placed
far apart from power source and freely rearranged.
[SOURCE: IEC 62827-3:2016, 3.1.2, modified – "placed at a certain distance in various
positions and postures within a space" has been replaced with " which are placed at a distance
within a spatial space"]
3.1.4
spatial wireless power transfer system
group implementing spatial wireless power transfer in which the power source can deliver power
and data to the power-receiving device
Note 1 to entry: In special cases, a spatial wireless power transfer system can consist of only a single power source
and only a single power-receiving device.
Note 2 to entry: Spatial wireless power transfer system includes the case in which a power source has the ability to
access a power-receiving device through a relay from other power sources when the power source attempts to deliver
data to the receiving device. In this document, "data" means control and management data for wireless power transfer.
[SOURCE: IEC 62827-3:2016, 3.1.3]
3.1.5
transmitter coil
component of a wireless power transmitter that converts electric current to magnetic flux
[SOURCE: IEC 63006:2019, 3.48]
3.2 Abbreviated terms
SWPT spatial wireless power transfer
SWPT-MMR spatial wireless power transfer based on multiple magnetic resonances
WPT wireless power transfer
4 Overview of spatial wireless power transfer based on multiple magnetic
resonances
A spatial wireless power transfer (SWPT) system delivers the electronic power to one or more
receivers within a specific space. As a specific implementation of SWPT, spatial wireless power
transfer based on multiple magnetic resonances (SWPT-MMR) includes multiple magnetic
resonances to generate the specific space, namely a charging zone. In the charging zone,
electric power is transferred to one or more receivers regardless of the position and the direction
of the receiver(s). Figure 1 shows a conceptual image of SWPT-MMR.

– 8 – IEC 63245-2:2022 © IEC 2022

Figure 1 – Conceptual image of SWPT-MMR [IEC 63245-1]
5 Reference model
5.1 Overview
The reference model of an SWPT-MMR system provides essential components of an
SWPT-MMR system. Every essential component is based on the requirements of SWPT-MMR
defined in IEC 63245-1. Thus, the reference model defined in this document shall comply with
IEC 63245-1. Figure 2 shows the reference model of an SWPT-MMR system.

Figure 2 – The reference model of an SWPT-MMR system

5.2 Components of an SWPT-MMR system
5.2.1 Power source
As an essential component of a power transfer system, an SWPT-MMR system shall have at
least one power source configured to supply a current to all the transmitter coils. Figure 3 shows
an example configuration of an SWPT-MMR system with two power sources. Table 1 lists the
requirements related to power source, which IEC 63245-1 defines.

Figure 3 – Example configuration of an SWPT-MMR system with power sources
Table 1 – Power source-related requirements defined in IEC 63245-1
Tag Description
REQ-ZONE1 It is required that an SWPT-MMR system be capable of generating a 3D charging zone.
REQ-PROC1 It is recommended that an SWPT-MMR system follow the basic charging procedure
comprised of a standby state, charging zone generation, optimization, power transmission,
and transmission termination.
5.2.2 Capacitor
To reduce the size of transmitter coils or reduce resonance frequencies of transmitter coils, an
SWPT-MMT system shall have one or more capacitors that are in between each transmitter coil
and the power source connected to each transmitter coil. Figure 4 shows an example
configuration of an SWPT-MMR system with transmitter coils connected to capacitors. Table 3
lists the requirements related to the capacitors and which are defined in IEC 63245-1.

– 10 – IEC 63245-2:2022 © IEC 2022

Figure 4 – Configuration on an SWPT-MMR system
with transmitter coils connected to capacitors
Table 2 – Capacitor-related requirements defined in IEC 63245-1
Tag Description
REQ-ZONE1 It is required that an SWPT-MMR system be capable of generating a 3D charging zone.
REQ-ZONE2 It is required that an SWPT-MMR system be capable of generating a quiet zone indicating a
magnetic field having an equalized energy density in the charging zone
REQ-ZONE3 It is required that an SWPT-MMR system be capable of controlling multiple transmitter coils
to generate multiple quiet zones.
REQ-ZONE4 It is required that an SWPT-MMR system be capable of dealing with null points in a charging
zone.
REQ-PROC1 It is recommended that an SWPT-MMR system follow the basic charging procedure
comprised of standby state, charging zone generation, optimization, power transmission,
and transmission termination.
REQ-FREQ1 It is required that an SWPT-MMR system be capable of adjusting resonance frequencies of
the transmitting coils.
REQ-FREQ2: It is required that the transmitting coils of a SWPT-MMR system use the same resonance
frequency.
REQ-FREQ3 It is recommended that an SWPT-MMR system be capable of selecting the resonance
frequency that results in the most efficiency in power transfer.

5.2.3 Inverter
An SWPT-MMR system shall have an inverter to control the phase of a magnetic field formed
on transmitter coils. Figure 5 and Figure 6 show two different example configurations of an
SWPT-MMR system with an inverter included in a power source. The phase of the current
adjusted by the inverter is determined by the angle between the pairs of transmitter coils. When
an SWPT-MMR system has two pairs of transmitter coils that are orthogonally placed, one pair
of transmitter coils is supplied the current that is phase shifted by 90° relative to the other. By
supplying the current with the adjusted phase to the pairs of transmitter coils, a rotating
magnetic field will be formed in the charging zone. Table 3 lists the requirements related to the
inverter and which are defined in IEC 63245-1.

Figure 5 – Configuration of an SWPT-MMR system with an inverter controlling a phase
of magnetic field formed on transmitter coils connected in parallel

Figure 6 – Configuration of an SWPT-MMR system with an inverter controlling a phase
of magnetic field formed on transmitter coils connected in series

– 12 – IEC 63245-2:2022 © IEC 2022
Table 3 – Inverter-related requirements defined in IEC 63245-1
Tag Description
REQ-ZONE1 It is required that an SWPT-MMR system be capable of generating a 3D charging zone.
It is required that an SWPT-MMR system be capable of generating a quiet zone indicating a
REQ-ZONE2
magnetic field having an equalized energy density in the charging zone.
REQ-ZONE3 It is required that an SWPT-MMR system be capable of controlling multiple transmitter coils
to generate multiple quiet zones.
REQ-ZONE4 It is required that an SWPT-MMR system be capable of dealing with null points in a charging
zone.
REQ-PROC1 It is recommended that an SWPT-MMR system follow the basic charging procedure
comprised of standby state, charging zone generation, optimization, power transmission,
and transmission termination.
REQ-CUR1 It is required that an SWPT-MMR system be capable of supplying currents to at least two
pairs of transmitting coils.
REQ-CUR2 It is required that an SWPT-MMR system supply an in-phase current or an out-of-phase
current to each pair of transmitter coils when the SWPT-MMR system has multiple pairs of
transmitter coils.
REQ-CUR3 It is required that an SWPT-MMR system be capable of controlling the phase of the current
supplied to all the transmitting coils included in the wireless charging zone.
REQ-CUR4 It is required that an SWPT-MMR system be capable of controlling a phase of the current
supplied to all the transmitting coils based on the induced current formed on the receiver coil
using the current supplied to all the transmitter coils in the charging zone.

5.2.4 Transmitter coils
An SWPT-MMR system has multiple transmitter coils to generate a quiet zone and to avoid
having null points. The size or shape of the SWPT-MMR system determines the number of
transmitter coils. The system has two transmitter coils when the system is pocket-shaped.
Figure 7 shows an example of a pocket-shaped SWPT-MMR system. The pocket-shaped
SWPT-MMR system allows WPT to a receiver facing any transmitter coil. Table 4 lists the
requirements related to transmitter coils and which are defined in IEC 63245-1.

Figure 7 – An example of an SWPT-MMR system with two transmitter coils
An larger SWPT-MMR system can have four transmitter coils, which allows WPT to one or more
receivers in any position or in any angle. Figure 8 shows an example of an SWPT-MMR system
with a larger space.
Figure 8 – An example of an SWPT-MMR system with two pairs of transmitter coils
Table 4 – Transmitter coil-related requirements defined in IEC 63245-1
Tag Description
REQ-ZONE1 It is required that an SWPT-MMR system be capable of generating a 3D charging zone.
REQ-ZONE2 It is required that an SWPT-MMR system be capable of generating a quiet zone indicating
a magnetic field having an equalized energy density in the charging zone
REQ-ZONE3 It is required that an SWPT-MMR system be capable of controlling multiple transmitter
coils to generate multiple quiet zones.
It is required that an SWPT-MMR system be capable of dealing with null points in a
REQ-ZONE4
charging zone.
REQ-ZONE5 It is recommended that an SWPT-MMR system be capable of generating multiple quiet
zones in different directions.
REQ-PROC1 It is recommended that an SWPT-MMR system follow the basic charging procedure
comprised of a standby state, charging zone generation, optimization, power transmission,
and transmission termination.
REQ-COIL1 It is required that an SWPT-MMR system have at least a pair of transmitter coils for
generating a quiet zone on one axis.
REQ-COIL2 It is required that an SWPT-MMR system have at least two pairs of transmitter coils for
handling null points occurred on each axis of quiet zone.
REQ-COIL3 It is required that an SWPT-MMR system be capable of accommodating transmitter coils
placed at various locations in the system.
REQ-COIL4 It is required that an SWPT-MMR system have a pair of transmitter coils arranged to face
each other in the charging zone.
REQ-COIL5 It is required that an SWPT-MMR system have at least one pair of transmitter coils, which
are connected in parallel or in series.
REQ-COIL6 It is required that an SWPT-MMR system have at least one power supplier.
REQ-CUR1 It is required that an SWPT-MMR system be capable of supplying currents to the at least
two pairs of transmitting coils.
REQ-CUR2 It is required that an SWPT-MMR system supply an in-phase current or an out-of-phase
current to each pair of transmitter coils when the SWPT-MMR system has multiple pairs of
transmitter coils.
It is required that an SWPT-MMR system be capable of controlling the phase of the current
REQ-CUR3
supplied to all the transmitting coils included in the wireless charging zone.

– 14 – IEC 63245-2:2022 © IEC 2022
Tag Description
REQ-CUR4 It is required that an SWPT-MMR system be capable of controlling a phase of the current
supplied to the plurality of transmitting coils based on the induced current formed on the
receiver coil using the current supplied to all the transmitter coils in the charging zone.
REQ-FREQ1 It is required that an SWPT-MMR system be capable of adjusting resonance frequencies of
the transmitting coils.
REQ-FREQ2: It is required that the transmitting coils of a SWPT-MMR system use the same resonance
frequency.
REQ-FREQ3 It is recommended that an SWPT-MMR system be capable of selecting the resonance
frequency that results in the most efficiency in power transfer.

5.2.5 Communication module
For co
...