Fine ceramics (advanced ceramics, advanced technical ceramics) — Method for measuring the power generation characteristics of piezoelectric resonant devices for stand-alone power sources

This document specifies a method for measuring power generation characteristics to evaluate and determine the output power, mechanical quality factor, electromechanical coupling factor and output efficiency of piezoelectric resonant devices used for self-sustaining power sources. This document defines vibration-based test methods and characteristic parameters in order to accurately and practically evaluate the performance of piezoelectric resonant devices.

Céramiques techniques — Méthode de mesurage des caractéristiques de production d’énergie électrique d'un dispositif résonnant piézoélectrique pour une source d'alimentation autonome

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Publication Date
08-May-2022
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4020 - DIS ballot initiated: 5 months
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ISO 5712:2022 - Fine ceramics (advanced ceramics, advanced technical ceramics) — Method for measuring the power generation characteristics of piezoelectric resonant devices for stand-alone power sources Released:5/9/2022
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INTERNATIONAL ISO
STANDARD 5712
First edition
2022-05
Fine ceramics (advanced ceramics,
advanced technical ceramics) —
Method for measuring the power
generation characteristics of
piezoelectric resonant devices for
stand-alone power sources
Céramiques techniques — Méthode de mesurage des caractéristiques
de production d’énergie électrique d'un dispositif résonnant
piézoélectrique pour une source d'alimentation autonome
Reference number
ISO 5712:2022(E)
© ISO 2022
---------------------- Page: 1 ----------------------
ISO 5712:2022(E)
COPYRIGHT PROTECTED DOCUMENT
© ISO 2022

All rights reserved. Unless otherwise specified, or required in the context of its implementation, no part of this publication may

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Published in Switzerland
© ISO 2022 – All rights reserved
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ISO 5712:2022(E)
Contents Page

Foreword ........................................................................................................................................................................................................................................iv

Introduction .................................................................................................................................................................................................................................v

1 Scope ................................................................................................................................................................................................................................. 1

2 Normative references ..................................................................................................................................................................................... 1

3 Terms and definitions .................................................................................................................................................................................... 1

4 Measurement principle ................................................................................................................................................................................. 1

5 Apparatus .................................................................................................................................................................................................................... 2

6 Piezoelectric resonant device ................................................................................................................................................................ 3

6.1 Piezoelectric resonant device configuration ............................................................................................................... 3

6.2 Measurement of characteristic values .............................................................................................................................. 4

7 Output voltage measurement procedure and method for creating output voltage

wave form .................................................................................................................................................................................................................... 5

8 Calculation of characteristic values ................................................................................................................................................ 6

8.1 General ........................................................................................................................................................................................................... 6

8.2 Output power ........................................................................................................................................................................................... 6

8.3 Mechanical quality factor ............................................................................................................................................................. 7

8.4 Electromechanical coupling coefficient ........................................................................................................................... 7

8.5 Output efficiency .................................................................................................................................................................................. 7

9 Expression of principal constants in characteristic values ................................................................................... 8

10 Test report .................................................................................................................................................................................................................. 8

Annex A (informative) Guidelines for selection of vibration device and mounting jig ...............................10

Annex B (informative) Example of data evaluation ..........................................................................................................................13

Bibliography .............................................................................................................................................................................................................................15

iii
© ISO 2022 – All rights reserved
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ISO 5712:2022(E)
Foreword

ISO (the International Organization for Standardization) is a worldwide federation of national standards

bodies (ISO member bodies). The work of preparing International Standards is normally carried out

through ISO technical committees. Each member body interested in a subject for which a technical

committee has been established has the right to be represented on that committee. International

organizations, governmental and non-governmental, in liaison with ISO, also take part in the work.

ISO collaborates closely with the International Electrotechnical Commission (IEC) on all matters of

electrotechnical standardization.

The procedures used to develop this document and those intended for its further maintenance are

described in the ISO/IEC Directives, Part 1. In particular, the different approval criteria needed for the

different types of ISO documents should be noted. This document was drafted in accordance with the

editorial rules of the ISO/IEC Directives, Part 2 (see www.iso.org/directives).

Attention is drawn to the possibility that some of the elements of this document may be the subject of

patent rights. ISO shall not be held responsible for identifying any or all such patent rights. Details of

any patent rights identified during the development of the document will be in the Introduction and/or

on the ISO list of patent declarations received (see www.iso.org/patents).

Any trade name used in this document is information given for the convenience of users and does not

constitute an endorsement.

For an explanation of the voluntary nature of standards, the meaning of ISO specific terms and

expressions related to conformity assessment, as well as information about ISO's adherence to

the World Trade Organization (WTO) principles in the Technical Barriers to Trade (TBT), see

www.iso.org/iso/foreword.html.
This document was prepared by Technical Committee ISO/TC 206, Fine ceramics.

Any feedback or questions on this document should be directed to the user’s national standards body. A

complete listing of these bodies can be found at www.iso.org/members.html.
© ISO 2022 – All rights reserved
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ISO 5712:2022(E)
Introduction

Economic development is supported by infrastructure such as roads and railroads; however, maintaining

ageing infrastructure at a low cost is a problem. An effective monitoring system for maintaining the

health of infrastructure at a low cost is necessary, therefore a stand-alone power source is required

because of requirements such as installation location, number of items and period of use. In addition, in

the internet of things (IoT), power is needed everywhere in order for everything to be connected to the

internet, and from that perspective a stand-alone power source is expected.

A self-supporting power source is a technology that collects energy such as light, vibration and heat,

converts it into electrical energy and uses it. Power supplies for small electronic devices include those

for various mobile devices, lighting switches, automotive tire-pressure monitoring systems (TPMS) and

wireless sensor networks (sensor power supplies) that monitor infrastructure and the environment.

The use of such power supplies is expanding to active type tags used for recognition, such as radio

frequency identifiers (RFIDs). Vibratory electrical conversion using vibrational energy is considered to

be easy to use because of its high energy density after sunlight. Various power generation experiments

have already been conducted and its practical application has been accelerated. There are methods that

use piezoelectric devices and electromagnetic induction for vibration electric conversion, but methods

using ceramic piezoelectric devices are prominent because of the output voltage, device size and degree

of structural freedom. The vibrations used in power generation in daily life have a wide variety of

frequencies, and it is difficult to set conditions for obtaining an appropriate amount of power generation

with piezoelectric devices that are highly frequency-dependent. Piezoelectric device structures are

also broadly divided into cantilever (beam), plate and double-supported beam shapes, and the sizes are

diversified according to the purpose and application. It is also difficult to set conditions.

Currently, the measurement of power generation performance of piezoelectric devices for self-

supporting power supplies is performed by an arbitrary method. What device structure (e.g. size,

structure) will be used? What kind of vibration (e.g. frequency, additional mass, displacement) is applied

to the piezoelectric body? What kind of circuit configuration (e.g. output voltage, current, conversion

efficiency, measuring instrument) is standardized?

For this reason, this document was created for measuring the power generation characteristics of

piezoelectric devices for self-supporting power supplies.
© ISO 2022 – All rights reserved
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INTERNATIONAL STANDARD ISO 5712:2022(E)
Fine ceramics (advanced ceramics, advanced technical
ceramics) — Method for measuring the power generation
characteristics of piezoelectric resonant devices for stand-
alone power sources
1 Scope

This document specifies a method for measuring power generation characteristics to evaluate and

determine the output power, mechanical quality factor, electromechanical coupling factor and output

efficiency of piezoelectric resonant devices used for self-sustaining power sources.

This document defines vibration-based test methods and characteristic parameters in order to

accurately and practically evaluate the performance of piezoelectric resonant devices.

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.

ISO 20507, Fine ceramics (advanced ceramics, advanced technical ceramics) — Vocabulary

3 Terms and definitions

For the purposes of this document, the terms and definitions given in ISO 20507 and the following apply.

ISO and IEC maintain terminology databases for use in standardization at the following addresses:

— ISO Online browsing platform: available at https:// www .iso .org/ obp
— IEC Electropedia: available at https:// www .electropedia .org/
3.1
resonance frequency
frequency when output voltage reaches maximum
3.2
resonance peak width

difference in frequency between two points having a value of 1/√2 of the maximum output voltage in

an output voltage wave form
4 Measurement principle

A piezoelectric resonant device is subjected to mechanical vibration and the accompanying electrical

charge generated by the piezoelectric resonant device is measured by load resistance as an output

voltage, from which power generation characteristics are determined. The principal factors affecting

power generation characteristics are the mechanical quality factor (Q ) and the electromechanical

coupling coefficient (k ) of the piezoelectric device.
© ISO 2022 – All rights reserved
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ISO 5712:2022(E)
5 Apparatus

The equipment used for measurement and its configuration is as follows. Figure 1 shows a block

diagram of the measuring system. Calibrated apparatus shall be used for measurement.

Key
1 voltmeter 6 vibration device
2 load resistance 7 accelerometer
3 laser displacement meter 8 recorder
4 piezoelectric resonant device 9 vibration controller
5 mounting jig
Figure 1 — Block diagram of measuring system

5.1 Voltmeter, connected to the load resistance to measure the output voltage of the piezoelectric

resonant device. The input impedance of the voltmeter shall be at least ten times greater than the

output impedance of the piezoelectric resonant device. If the input impedance is too low, the impedance

should be converted at a stage prior to the voltmeter.

5.2 Load resistance, a resistance between the piezoelectric resonant device and the voltmeter used

for measuring the output voltage of the piezoelectric resonant device.

5.3 Laser displacement meter, for measuring the displacement of an object using laser light. When

an additional weight can be observed directly, a laser displacement meter is used to measure change

in the position of the additional weight, which improves precision in the measurement of acceleration

resulting from application of mechanical vibration. On this basis, installation of a laser displacement

meter is acceptable. The frequency bandwidth shall be capable of handling the applied frequency of

vibration.

5.4 Mounting jig, for mounting a piezoelectric resonant device to the vibration device. The mounting

jig shall have no natural frequency in the measurement bandwidth. The natural frequency of the

mounting jig shall be higher than the upper limit of the measurement frequency. The moment of the

piezoelectric resonant device attributable to resonance shall be absorbable. See Clause A.3 for further

information regarding the mounting jig.

5.5 Vibration device, which generates a mechanical vibration applied to the piezoelectric resonant

device. The device shall be capable of sinusoidal output and of vibrational output at frequencies and

accelerations in the ranges needed for measurement. The device should also have a feedback control

function intended to prevent a decrease in applied vibrational acceleration when the piezoelectric

© ISO 2022 – All rights reserved
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ISO 5712:2022(E)

resonant device has reached a resonant state. The vibrating device shall be provided with anti-vibration

measures. The guideline for selecting the vibration device and mounting jig is shown in Clause A.2.

5.6 Accelerometer, which measures the acceleration of the mechanical vibration applied to the

piezoelectric resonant device. Bandwidth shall be capable of handling the applied frequency of

vibration. Attachment to the piezoelectric resonant device should reference A.2.3.

5.7 Recorder, which records vibration frequency, output voltage and acceleration continually.

When an additional weight can be observed directly, the displacement of the additional weight is also

recorded.

5.8 Vibration controller, which controls the action of the vibration resonant device to prevent noise

and other such effects from changing the acceleration or frequency of applied vibration.

6 Piezoelectric resonant device
6.1 Piezoelectric resonant device configuration

The piezoelectric resonant device shall have a structure in which an additional weight is attached to the

tip of a planar material to which piezoelectric material is attached. See Figure 2 and Figure 3.

a) The piezoelectric resonant device comprises piezoelectric material, which generates an electrical

charge when subjected to a mechanical strain, planar material to which the piezoelectric material

is attached and an electrode for extracting an output voltage. See Figure 2 and Figure 3.

b) To obtain the output voltage efficiently, an additional weight which imparts acceleration to the

piezoelectric resonant device shall be installed. The form of the additional weight is of no particular

concern, provided that it does not affect vibration. The effective mass (m) of the additional weight

in Formula (7) used to calculate theoretical output power is taken as the sum of the mass of the

applied weight and the mass of the piezoelectric material during vibration.

c) The piezoelectric material shall be given a polarizing treatment in the orientation of its thickness.

d) The piezoelectric resonant device shall be fixed securely to the mounting jig with bolts or other

such means. See Figure 3.

e) The lead wire to extract the output voltage shall have a hardness and mass unaffected by vibrational

testing.

f) When a laser displacement meter is used, displacement of the piezoelectric resonant device should

be measured as far toward its tip as possible. The surface for laser irradiation should also have a

mirror finish to allow precise capture of reflected laser light.
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ISO 5712:2022(E)
Key
1 electrode 4
...

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