EN IEC 62969-3:2018

Semiconductor devices - Semiconductor interface for automotive vehicles - Part 3: Shock driven piezoelectric energy harvesting for automotive vehicle sensors

IEC 62969-3:2018 describes terms, definitions, symbols, configurations, and test methods that can be used to evaluate and determine the performance characteristics of mechanical shock driven piezoelectric energy harvesting devices for automotive vehicle sensor applications. This document is also applicable to energy harvesting devices for motorbikes, automobiles, buses, trucks and their respective engineering subsystems applications without any limitations of device technology and size.

Halbleiterbauelemente - Halbleiterschnittstelle für Automobile - Teil 3: Stoßgeführtes piezoelektrisches Energie-Harvesting bei Sensoren für Automobile

Dispositifs à semiconducteurs - Interface à semiconducteurs pour les véhicules automobiles - Partie 3: Récupération de l’énergie piézoélectrique produite par les chocs pour les capteurs de véhicules automobiles

L’IEC 62969-3:2018 décrit les termes, définitions, symboles, configurations et les méthodes d’essai pouvant être utilisés pour apprécier et déterminer les caractéristiques de performance des dispositifs de récupération de l’énergie piézoélectrique produite par des chocs mécaniques pour des applications mettant en œuvre des capteurs de véhicules automobiles. Le présent document est également applicable aux dispositifs de récupération d’énergie pour les motos, les automobiles, les bus, les camions ainsi que leurs applications d’ingénierie aux sous-systèmes, sans restriction concernant la technologie et la taille des dispositifs.

Polprevodniški elementi - Polprevodniški vmesnik za motorna vozila - 3. del: Zajemanje energije s piezoelektričnimi zaznavali za motorna vozila (IEC 62969-3:2018)

Ta del standarda IEC 62969 opisuje izraze, definicije, simbole, konfiguracije in preskusne metode, ki jih je mogoče uporabiti za vrednotenje in ugotavljanje delovnih značilnosti piezoelektričnih naprav za zajemanje energije za uporabo v zaznavalih za motorna vozila.
Ta dokument se uporablja tudi za naprave za zajemanje energije za motorna kolesa, avtomobile, avtobuse, tovornjake in njihovo uporabo v inženirskih podsistemih brez omejitev glede na tehnologijo in velikost naprave.

General Information

• Status: Published
• Publication Date: 21-Jun-2018
• Withdrawal Date: 10-Jun-2021
• ICS: 31.080.99 - Other semiconductor devices
• Technical Committee: CLC/SR 47 - Semiconductor devices
• Drafting Committee: IEC/TC 47 - IEC_TC_47
• Current Stage: 6060 - Document made available - Publishing
• Start Date: 22-Jun-2018
• Completion Date: 22-Jun-2018
• Ref Project: SIST EN IEC 62969-3:2018 - Semiconductor devices - Semiconductor interface for automotive vehicles - Part 3: Shock driven piezoelectric energy harvesting for automotive vehicle sensors (IEC 62969-3:2018)

Standards Content (Sample)

SLOVENSKI STANDARD
SIST EN IEC 62969-3:2018
01-september-2018
3ROSUHYRGQLãNLHOHPHQWL3ROSUHYRGQLãNLYPHVQLN]DPRWRUQDYR]LODGHO
=DMHPDQMHHQHUJLMHVSLH]RHOHNWULþQLPL]D]QDYDOL]DPRWRUQDYR]LOD,(&


Semiconductor devices - Semiconductor interface for automotive vehicles - Part 3: Shock

driven piezoelectric energy harvesting for automotive vehicle sensors (IEC 62969-

3:2018)
Ta slovenski standard je istoveten z: EN IEC 62969-3:2018
ICS:
31.080.01 Polprevodniški elementi Semiconductor devices in
(naprave) na splošno general
43.040.10 (OHNWULþQDLQHOHNWURQVND Electrical and electronic
RSUHPD equipment
SIST EN IEC 62969-3:2018 en

2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.

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SIST EN IEC 62969-3:2018
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SIST EN IEC 62969-3:2018
EUROPEAN STANDARD EN IEC 62969-3
NORME EUROPÉENNE
EUROPÄISCHE NORM
June 2018
ICS 31.080.99
English Version
Semiconductor devices - Semiconductor interface for automotive
vehicles - Part 3: Shock driven piezoelectric energy harvesting
for automotive vehicle sensors
(IEC 62969-3:2018)

Dispositifs à semiconducteurs - Interface à Halbleiterbauelemente - Halbleiterschnittstelle für

semiconducteurs pour les véhicules automobiles - Automobile - Teil 3: Stoßgeführtes piezoelektrisches

Partie 3: Récupération de l'énergie piézoélectrique produite Energie-Harvesting bei Sensoren für Automobile

par les chocs pour les capteurs de véhicules automobiles (IEC 62969-3:2018)
(IEC 62969-3:2018)

This European Standard was approved by CENELEC on 2018-06-11. CENELEC members are bound to comply with the CEN/CENELEC

Internal Regulations which stipulate the conditions for giving this European Standard the status of a national standard without any alteration.

Up-to-date lists and bibliographical references concerning such national standards may be obtained on application to the CEN-CENELEC

Management Centre or to any CENELEC member.

This European Standard exists in three official versions (English, French, German). A version in any other language made by translation

under the responsibility of a CENELEC member into its own language and notified to the CEN-CENELEC Management Centre has the

same status as the official versions.

CENELEC members are the national electrotechnical committees of Austria, Belgium, Bulgaria, Croatia, Cyprus, the Czech Republic,

Denmark, Estonia, Finland, Former Yugoslav Republic of Macedonia, France, Germany, Greece, Hungary, Iceland, Ireland, Italy, Latvia,

Lithuania, Luxembourg, Malta, the Netherlands, Norway, Poland, Portugal, Romania, Serbia, Slovakia, Slovenia, Spain, Sweden,

Switzerland, Turkey and the United Kingdom.
European Committee for Electrotechnical Standardization
Comité Européen de Normalisation Electrotechnique
Europäisches Komitee für Elektrotechnische Normung
CEN-CENELEC Management Centre: Rue de la Science 23, B-1040 Brussels

© 2018 CENELEC All rights of exploitation in any form and by any means reserved worldwide for CENELEC Members.

Ref. No. EN IEC 62969-3:2018 E
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SIST EN IEC 62969-3:2018
EN IEC 62969-3:2018
European foreword

The text of document 47/2461/FDIS, future edition 1 of IEC 62969-3, prepared by IEC/TC 47

"Semiconductor devices" was submitted to the IEC-CENELEC parallel vote and approved by

CENELEC as EN IEC 62969-3:2018.
The following dates are fixed:
(dop) 2019-03-11
• latest date by which the document has to be
implemented at national level by
publication of an identical national
standard or by endorsement
• latest date by which the national (dow) 2021-06-11
standards conflicting with the
document have to be withdrawn

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

patent rights. CENELEC shall not be held responsible for identifying any or all such patent rights.

Endorsement notice

The text of the International Standard IEC 62969-3:2018 was approved by CENELEC as a European

Standard without any modification.

In the official version, for Bibliography, the following notes have to be added for the standards indicated:

IEC 62047-5:2011 NOTE Harmonized as EN 62047-5:2011 (not modified).
IEC 62047-7:2011 NOTE Harmonized as EN 62047-7:2011 (not modified).
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SIST EN IEC 62969-3:2018
EN IEC 62969-3:2018
Annex ZA
(normative)
Normative references to international publications
with their corresponding European publications

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.

NOTE 1 Where an International Publication has been modified by common modifications, indicated by (mod), the relevant

EN/HD applies.

NOTE 2 Up-to-date information on the latest versions of the European Standards listed in this annex is available here:

www.cenelec.eu.
Publication Year Title EN/HD Year
IEC 60749-5 - Semiconductor devices - Mechanical and EN 60749-5 -
climatic test methods -
Part 5: Steady-state temperature humidity
bias life test
IEC 60749-10 - Semiconductor devices - Mechanical and EN 60749-10 -
climatic test methods -
Part 10: Mechanical shock
IEC 60749-12 - Semiconductor devices - Mechanical and EN IEC 60749-12 -
climatic test methods -
Part 12: Vibration, variable frequency
IEC 62830-1 - Semiconductor devices - Semiconductor - -
devices for energy harvesting and
generation -
Part 1: Vibration based piezoelectric
energy harvesting
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SIST EN IEC 62969-3:2018
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SIST EN IEC 62969-3:2018
IEC 62969-3
Edition 1.0 2018-05
INTERNATIONAL
STANDARD
NORME
INTERNATIONALE
colour
inside
Semiconductor devices – Semiconductor interface for automotive vehicles –
Part 3: Shock driven piezoelectric energy harvesting for automotive vehicle
sensors
Dispositifs à semiconducteurs – Interface à semiconducteurs pour les véhicules
automobiles –
Partie 3: Récupération de l’énergie piézoélectrique produite par les chocs pour
les capteurs de véhicules automobiles
INTERNATIONAL
ELECTROTECHNICAL
COMMISSION
COMMISSION
ELECTROTECHNIQUE
INTERNATIONALE
ICS 31.080.99 ISBN 978-2-8322-5685-5

Warning! Make sure that you obtained this publication from an authorized distributor.

Attention! Veuillez vous assurer que vous avez obtenu cette publication via un distributeur agréé.

® Registered trademark of the International Electrotechnical Commission
Marque déposée de la Commission Electrotechnique Internationale
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SIST EN IEC 62969-3:2018
– 2 – IEC 62969-3:2018 © IEC 2018
CONTENTS

FOREWORD ........................................................................................................................... 4

INTRODUCTION ..................................................................................................................... 6

1 Scope .............................................................................................................................. 7

2 Normative references ...................................................................................................... 7

3 Terms and definitions ...................................................................................................... 7

3.1 General terms ......................................................................................................... 8

3.2 Piezoelectric transducer .......................................................................................... 9

3.3 Characteristic parameters ..................................................................................... 10

4 Essential ratings and characteristic parameters ............................................................. 11

4.1 Identification and type ........................................................................................... 11

4.2 Limiting values and operating conditions ............................................................... 11

4.3 Additional information ........................................................................................... 12

5 Test method .................................................................................................................. 12

5.1 General ................................................................................................................. 12

5.2 Electrical characteristics ....................................................................................... 13

5.2.1 Test procedure .............................................................................................. 13

5.2.2 Capacitance .................................................................................................. 14

5.2.3 Natural frequency .......................................................................................... 14

5.2.4 Damping ratio ................................................................................................ 15

5.2.5 Output voltage ............................................................................................... 15

5.2.6 Output current ............................................................................................... 16

5.2.7 Output power ................................................................................................. 16

5.2.8 Optimal load impedance ................................................................................ 17

5.2.9 Maximum output power .................................................................................. 17

5.3 Mechanical characteristics .................................................................................... 18

5.3.1 Test procedure .............................................................................................. 18

5.3.2 Temperature range ........................................................................................ 19

5.3.3 Shock magnitude ........................................................................................... 20

5.3.4 Temperature and humidity testing .................................................................. 20

5.3.5 Mechanical reliability (shock) testing ............................................................. 20

Annex A (informative) Mechanical shock pulses ................................................................... 21

Annex B (informative) Electromechanical coupling ............................................................... 23

B.1 Compliance and coupling coefficient relation......................................................... 23

B.2 Young’s modulus and coupling coefficient relation ................................................ 23

Bibliography .......................................................................................................................... 24

Figure 1 – Shock driven energy harvester using cantilever with piezoelectric film .................. 8

Figure 2 – Conceptual diagram of shock driven piezoelectric energy harvester ...................... 9

Figure 3 – Equivalent circuit of shock driven piezoelectric energy harvester ........................ 10

Figure 4 – Measurement procedure of shock driven piezoelectric energy harvester .............. 13

Figure 5 – Test setup for the electrical characteristics of shock driven piezoelectric

energy harvester ................................................................................................................... 14

Figure 6 – Output waveform and its frequency component of a shock driven

piezoelectric energy harvester .............................................................................................. 15

Figure 7 – Output voltages of shock excited piezoelectric energy harvester at various

external loads ....................................................................................................................... 16

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SIST EN IEC 62969-3:2018
IEC 62969-3:2018 © IEC 2018 – 3 –

Figure 8 – Output currents of shock driven piezoelectric energy harvester at various

output voltages ..................................................................................................................... 16

Figure 9 – Output power of shock driven piezoelectric energy harvester at various

external loads ....................................................................................................................... 17

Figure 10 – Output power and voltage of shock driven piezoelectric energy harvester at

various shock amplitudes ...................................................................................................... 18

Figure 11 – Block diagram of a test setup for evaluating the reliability of shock driven

piezoelectric energy harvester .............................................................................................. 19

Figure A.1 – Comparison of general shock patterns and shock pattern from automobile ....... 21

Figure A.2 – Impact (or shock) recorded by an electronic impact recorder ............................ 22

Table 1 – Specification parameters for shock driven piezoelectric energy harvesters ............ 11

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SIST EN IEC 62969-3:2018
– 4 – IEC 62969-3:2018 © IEC 2018
INTERNATIONAL ELECTROTECHNICAL COMMISSION
____________
SEMICONDUCTOR DEVICES –
SEMICONDUCTOR INTERFACE FOR AUTOMOTIVE VEHICLES –
Part 3: Shock driven piezoelectric energy harvesting
for automotive vehicle sensors
FOREWORD

1) The International Electrotechnical Commission (IEC) is a worldwide organization for standardization comprising

all national electrotechnical committees (IEC National Committees). The object of IEC is to promote

international co-operation on all questions concerning standardization in the electrical and electronic fields. To

this end and in addition to other activities, IEC publishes International Standards, Technical Specifications,

Technical Reports, Publicly Available Specifications (PAS) and Guides (hereafter referred to as “IEC

Publication(s)”). Their preparation is entrusted to technical committees; any IEC National Committee interested

in the subject dealt with may participate in this preparatory work. International, governmental and non-

governmental organizations liaising with the IEC also participate in this preparation. IEC collaborates closely

with the International Organization for Standardization (ISO) in accordance with conditions determined by

agreement between the two organizations.

2) The formal decisions or agreements of IEC on technical matters express, as nearly as possible, an international

consensus of opinion on the relevant subjects since each technical committee has representation from all

interested IEC National Committees.

3) IEC Publications have the form of recommendations for international use and are accepted by IEC National

Committees in that sense. While all reasonable efforts are made to ensure that the technical content of IEC

Publications is accurate, IEC cannot be held responsible for the way in which they are used or for any

misinterpretation by any end user.

4) In order to promote international uniformity, IEC National Committees undertake to apply IEC Publications

transparently to the maximum extent possible in their national and regional publications. Any divergence

between any IEC Publication and the corresponding national or regional publication shall be clearly indicated in

the latter.

5) IEC itself does not provide any attestation of conformity. Independent certification bodies provide conformity

assessment services and, in some areas, access to IEC marks of conformity. IEC is not responsible for any

services carried out by independent certification bodies.

6) All users should ensure that they have the latest edition of this publication.

7) No liability shall attach to IEC or its directors, employees, servants or agents including individual experts and

members of its technical committees and IEC National Committees for any personal injury, property damage or

other damage of any nature whatsoever, whether direct or indirect, or for costs (including legal fees) and

expenses arising out of the publication, use of, or reliance upon, this IEC Publication or any other IEC

Publications.

8) Attention is drawn to the Normative references cited in this publication. Use of the referenced publications is

indispensable for the correct application of this publication.

9) Attention is drawn to the possibility that some of the elements of this IEC Publication may be the subject of

patent rights. IEC shall not be held responsible for identifying any or all such patent rights.

International Standard IEC 62969-3 has been prepared by IEC technical committee 47:

Semiconductor devices.
The text of this International Standard is based on the following documents:
FDIS Report on voting
47/2461/FDIS 47/2480/RVD

Full information on the voting for the approval of this International Standard 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.

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SIST EN IEC 62969-3:2018
IEC 62969-3:2018 © IEC 2018 – 5 –

A list of all parts in the IEC 62969 series, published under the general title Semiconductor

devices – Semiconductor interface for automotive vehicles, can be found on the IEC website.

The committee has decided that the contents of this document will remain unchanged until the

stability date indicated on the IEC website under "http://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.

IMPORTANT – The 'colour inside' logo on the cover page of this publication indicates

that it contains colours which are considered to be useful for the correct

understanding of its contents. Users should therefore print this document using a

colour printer.
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SIST EN IEC 62969-3:2018
– 6 – IEC 62969-3:2018 © IEC 2018
INTRODUCTION
The IEC 62969 series is composed of four parts as follow:

• IEC 62969-1, Semiconductor devices – Semiconductor interface for automotive vehicles –

Part 1: General requirements of power interface for automotive vehicle sensors

• IEC 62969-2, Semiconductor devices – Semiconductor interface for automotive vehicles –

Part 2: Efficiency evaluation methods of wireless power transmission using resonance for

automotive vehicle sensors

• IEC 62969-3, Semiconductor devices – Semiconductor interface for automotive vehicles –

Part 3: Shock driven piezoelectric energy harvesting for automotive vehicle sensors

• IEC 62969-4 , Semiconductor devices – Semiconductor interface for automotive vehicles

– Part 4: Evaluation method of data interface for automotive vehicle sensors

The IEC 62969 series covers power and data interfaces for sensors in automotive vehicles.

The first part covers general requirements of test conditions such as temperature, humidity,

vibration, etc for automotive sensor power interface. This part also includes various electrical

performances of power interface such as voltage drop from power source to automotive

sensors, noises, voltage level, etc. The second part covers “Efficiency evaluation methods of

wireless power transmission using resonance for automotive vehicle sensors “. The third part

covers “Shock driven piezoelectric energy harvesting for automotive vehicle sensors”. The

fourth part covers “Evaluation methods of data interface for automotive vehicle sensors”.

___________
To be published
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SIST EN IEC 62969-3:2018
IEC 62969-3:2018 © IEC 2018 – 7 –
SEMICONDUCTOR DEVICES –
SEMICONDUCTOR INTERFACE FOR AUTOMOTIVE VEHICLES –
Part 3: Shock driven piezoelectric energy harvesting
for automotive vehicle sensors
1 Scope

This part of IEC 62969 describes terms, definitions, symbols, configurations, and test

methods that can be used to evaluate and determine the performance characteristics of

mechanical shock driven piezoelectric energy harvesting devices for automotive vehicle

sensor applications.

This document is also applicable to energy harvesting devices for motorbikes, automobiles,

buses, trucks and their respective engineering subsystems applications without any limitations

of device technology and size.
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 60749-5, Semiconductor devices – Mechanical and climatic test methods – Part 5:

Steady-state temperature humidity bias life test

IEC 60749-10, Semiconductor devices – Mechanical and climatic test methods – Part 10:

Mechanical shock

IEC 60749-12, Semiconductor devices – Mechanical and climatic test methods – Part 12:

Vibration, variable frequency

IEC 62830-1, Semiconductor devices – Semiconductor devices for energy harvesting and

generation – Part 1: Vibration based piezoelectric energy harvesting
3 Terms and definitions

For the purposes of this document, the terms and definitions given in IEC 62830-1 and the

following apply.

ISO and IEC maintain terminological databases for use in standardization at the following

addresses:
• IEC Electropedia: available at http://www.electropedia.org/
• ISO Online browsing platform: available at http://www.iso.org/obp
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– 8 – IEC 62969-3:2018 © IEC 2018
3.1 General terms
3.1.1
shock

sudden acceleration or deceleration resulting in transient physical excitation; characterized by

the peak acceleration, the duration, and the shape of the shock pulse (rectangular, half-sine,

sawtooth, etc.)

Note 1 to entry: The fundamental frequency of the automotive vehicle shock is varied from 0,5 Hz to 20 Hz.

Note 2 to entry: Mechanical shock pulses are sinusoidal, rectangular, half-sine, sawtooth, etc. waves. Detailed

explanation of mechanical shock pulses with an analysis of shock amplitude and duration/frequency of automobile

and conventional shaker have been included in Annex A (informative).
3.1.2
shock driven energy harvester

generator that responds to the applied mechanical shock, transforms shock into vibration

(mechanical oscillation), and converts the vibration to the electricity

Note 1 to entry: The generated power depends on the characteristics of applied shock and, mechanical and

electrical characteristics of the generator itself.

Note 2 to entry: Shock energy harvester to convert shock to electricity by using piezoelectric transducers is

comprised of inertial mass, spring, and piezoelectric transducer as shown in Figure 1. The piezoelectric transducer

contains two electrodes and a piezoelectric film. Vibration is induced in response to the applied shock that

introduces a reciprocating motion to the mass. The spring which suspends the mass is bended and the bending of

spring introduces tensile and compression of piezoelectric film. The top and bottom electrodes of piezoelectric film

harvest generated charges from the piezoelectric effect.

Note 3 to entry: Shock driven energy harvester is represented as shown in Figure 2. It is configured by mass,

spring, damping, and piezoelectric transducer. The piezoelectric transducer is generally viewed as damping.

Electrodes
Piezoelectric film
Output
Spring
Mass
Fixed base
Shock
IEC
Key
Configuration of energy harvester Components to operate a energy harvester

Mass Inertial mass to induce mechanical Shock Transient physical excitation supplied

oscillation responding to applied shock to vibrate the mass of energy
harvester
Spring To couple the induced vibration to the R External load
mass by suspending it
Piezoelectric Body layer of piezoelectric transducer for
film energy harvester
Figure 1 – Shock driven energy harvester using cantilever
with piezoelectric film
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SIST EN IEC 62969-3:2018
IEC 62969-3:2018 © IEC 2018 – 9 –
Spring
Piezoelectric
transducer
Mass
Damping
Shock
IEC
Key
Configuration of energy harvester Components to operate an energy harvester

Damping Reduction of the acceleration of Piezoelectric Power generator via piezoelectric

oscillation of mass transducer effect
Figure 2 – Conceptual diagram of shock driven piezoelectric
energy harvester
3.2 Piezoelectric transducer
3.2.1
piezoelectric effect

phenomenon in which a mechanical deformation produces an electric polarization of

piezoelectric material, and conversely an electric polarization produces a mechanical

deformation
[SOURCE: IEC 60050-121:1998, 121-12-86, modified]
3.2.2
piezoelectric charge constant

polarization generated per unit of mechanical stress applied to a piezoelectric material

Note 1 to entry: The first subscript to d indicates the direction of polarization generated in the material when the

electric field, is zero or, alternatively, is the direction of the applied field strength. The second subscript is the

direction of the applied stress or the induced strain, respectively. d : induced strain in direction Z-axis per unit

electric field applied in direction Z-axis. d : induced strain in direction X-axis per unit electric field applied in

direction Z-axis.
3.2.3
electromechanical coupling coefficient

value to describe the conversion rate of electrical energy to mechanical form or vice versa

Note 1 to entry: The coefficient is a combination of elastic, dielectric and piezoelectric constants which appears

naturally in the expression of piezoelectric transducer as following
k= (1)
1/2
(sε)
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SIST EN IEC 62969-3:2018
– 10 – IEC 62969-3:2018 © IEC 2018
where
d is the piezoelectric charge constant
s is elastic compliance (inverse of Young's modulus) at constant electric field
ε is permittivity of the piezoelectric material at constant stress

Note 2 to entry: The relationship of electromechanical coupling coefficient with compliance and Young’s modulus

have been elaborated in Annex B (informative).
3.3 Characteristic parameters
3.3.1
equivalent circuit

arrangement of ideal circuit elements that has circuit parameters, electrically equivalent to

those of a shock driven piezoelectric energy harvester

Note 1 to entry: Shock driven piezoelectric energy harvester can be divided into mechanical and electrical parts

as shown in Figure 3. The mechanical part consists of series elements m, k , b , and transformer (coupling

sp m

element between mechanical and electrical parts)- where m, k , and b represent the effective mass, spring

sp m

constant of spring, damping, respectively; and piezoelectric effect to convert mechanically induced strain to

electrical charge density with coupling coefficient k. The electrical part is comprised of parallel connected C , R,

and transformer- where C and R represent the capacitance between two electrodes of piezoelectric transducer and

external load.
k b
m sp m
A(t) R
Mechanical part Electrical part
IEC
Key
Mechanical part Electrical part
m effective mass C capacitance of piezoelectric
transducer
k spring constant R external load
b damping coefficient
A(t) induced vibration in response to the
applied shock
Figure 3 – Equivalent circuit of shock driven
piezoelectric energy harvester
[SOURCE: IEC 60050-521:2002, 521-05-35, modified]
3.3.2
natural frequency

free vibration frequency of the mass-spring-damping system of the energy harvester to

generate largest output power
ω = (2)
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IEC 62969-3:2018 © IEC 2018 – 11 –
3.3.3
damped natural frequency

frequency of free vibration of the mass-spring-damping system of the energy harvester

incorporating damping in response to the shock excitation
ω =ω 1−ζ (3)
d n

where ζ is the damping ratio determined by logarithmic decrement of output voltage waveform,

normalized from electrical and mechanical damping.
3.3.4
shock excitation amplitude

acceleration amplitude of the random applied shock to the energy harvester for maximum

duration as measured on the enclosure over which the energy harvester will not sustain

permanent damage though not necessarily functioning within the specified tolerances

4 Essential ratings and characteristic parameters
4.1 Identification and type

The shock driven energy harvester shall be clearly and durably marked in the order given

below:
a) year and week (or month) of manufacture;
b) manufacture’s name or trade mark;
c) terminal id
...