ISO 5712:2022

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

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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
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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
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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
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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
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on the ISO list of patent declarations received (see www.iso.org/patents).
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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
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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.
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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
m
2
coupling coefficient (k ) of the piezoelectric device.
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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
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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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