EMC Seminar Series
All about EMC Testing and Measurement Seminar – 1
Fundamentals of EMC Theoryy and Principles
p
Dr. LEUNG, Peter Sai‐Wing
梁世榮
http://www ee cityu edu hk/ pswleung/
http://www.ee.cityu.edu.hk/~pswleung/
O
Organized
i d by
b :
Department of Electronic Engineering
1
ElectroM
l
Magnetic Compatibility
bl
 The ability of an equipment or system to function
satisfactorily in its environment without introducing
i l bl electromagnetic
intolerable
l
i iinterference
f
to anything
hi
in that environment.
EMC = EME + EMI
EME=Electromagnetic Emission (Interference)
EMI=Electromagnetic Immunity (Susceptibility)
2
EMC
…A complicated and difficult subject!!!!?
 Talks in Order of Magnitudes
 Frequency
q
y from DC to daylights
y g
 magnitude µA ‐ kA; µV ‐ MV
 works on dB for order of magnitude, and log scale in frequency
 Different types of EMC requirements, methods, measurements
 Many
y different standards
3
Sources of Emission / Noise
Natural / man-made / intended emission!
4
Coupling
p g
5
Effects
ff
off EME// EM iinterference
f
Equipment to equipment
 Loss of data in digital systems or in transmission of data
 Interference to TV and radio reception
 Malfunction of medical electronic equipment
 Malfunction of automotive microprocessor control systems (braking) and
navigation equipment
 Malfunction of critical process‐control functions (e.g. oil, chemical, airports
railways)
 …….
Equipment to Human (Human Safety)
 IEEE C95.1 ‐ Standard For Safety Levels with Respect to Human Exposure to
Radio Frequency Electromagnetic Fields, 3KHz to 300GHz
 ICNIRP ‐ Guidelines limiting exposure to time‐varying Electric, Magnetic, and
Electromagnetic fields (Up to 300 GHz).
EME and EMI Testsc
7
Different characteristics of emissions
Radiated Emission‐
 Far field radiation
 near field radiation


E field source
H field source
Conducted Emission
 Different paths
….dc port, power port, communication port
Electromagnetic Coupling
8
RE CE
RE,
CE,RI,CI
RI CI
9
RE,, CE,, RI,, CI

10
RE : 40 dBµV/m ~ 0.01V/m
CE : 60 dBµV/m ~ 0.001V/m
0 001V/m
Examples of some limits in Radiated Emission
…from CISPR22
11
EMC‐ A reasonable good margin between RE
and RI, for general consideration!!
RI requirement ….3V/m
RE : 40 dBµV/m ~ 0
0.01V/m
01V/m
CI requirement ….3V
CE : 60 dBµV/m ~ 0.001V/m
Examples of some limits in Radiated Immunity
…
from IEC 61000‐6‐1 for RCLI
12
ELECTROSTATIC DISCHARGE (ESD)
A transfer of electric charge
between bodies of different
electrostatic potential in proximity or
through direct contact.
Effect:
Cause damage to electronic equipment.
13
ELECTROSTATIC DISCHARGE (ESD)
Hard failures (irreversibly)
• Junction burnout
• IC metal burnout
•Dielectric breakdown
Soft failures ( mainly digital circuits)
Transient interference ( eg. Radio)
Logic errors, System resets, Lost data, Lost program flow
14
HUMAN BODY MODEL
R
C
L
VC
C = 50 to 250 pF
R = 500 to 10k
|VC| = 0 to 30kV ( above 30V will have corona effect )
L = 50 - 200nH
First order model, TRIBOELECTRIC EFFECT
EN 61000‐4‐2
4 Testingg and measurement techniques
q
–
Electrostatic discharge immunity test
15
DISCHARGE INTO AN IDEAL GROUND
R=500
15kV
L=100nH
C=300pF
I pk
I
Ipk
I
t=0
15kV

 30 A
500
0
~ 1ns
t
16
ESD Tests
 Direct Application:
Discharge Electrodes
 Air Discharge (sparks)
EUT
 Contact Discharge
EUT
……..different electrostatic p
potential in p
proximityy or through
g direct contact.
17
ESD Generators
Some models can generate air‐
or contact discharge up to 30kV.
With different combination of
R‐C value for other
applications…
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Fast Transient/Burst
Electrical Fast Transients caused a spark in air or other gas ‐ When a circuit is
switched off, the current flowing
g is interrupted;
p
large
g di/dt is g
generated.
Arcing between the contacts; first at a low voltage and high frequency; later at a
higher voltage and lower frequency.
19
Electrical Fast Transient
Electrical Fast Transients caused a spark in air or other gas ‐ When a circuit is
switched
h d off,
ff the
h current fl
flowing is interrupted;
d llarge di/dt
d d is generated.
d
Arcing between the contacts; first at a low voltage and high frequency; later at a
hi h voltage
higher
lt
and
d llower frequency.
f
IEC 61000‐4‐4 Electromagnetic
Compatibility (EMC) ‐ Part 4‐4:
Testing and measurement techniques –
Electrical fast transient/burst immunity test.
test
20
Fast Transient/Burst
Electrical Fast Transients caused a spark in air or other gas ‐ When a circuit is
switched
h d off,
ff the
h current fl
flowing is interrupted;
d llarge di/dt
d d is generated.
d
Arcing between the contacts; first at a low voltage and high frequency; later at a
hi h voltage
higher
lt
and
d llower frequency.
f
Coupling of the EFT into electronic products occurs when power cables handling
high currents are run in close proximity to power,
power data,
data and/or I/O cables.
cables
21
Surge
g
 Sudden rises in voltage and/or current
to a connected load; standard
household equipment can be damaged
by surges of 500 volts or greater….
 Indoors, caused by major equipment,
such as your air conditioner switching
on and off.
 Outdoors, they can be caused by
lines power
incidents involving electric lines,
equipment failures. Lightning in
seasonal storms.
Electromagnetic Compatibility (EMC) — Part 4‐5:
Testing and measurement techniques — Surge
immunity test
22
23
Power frequency
q
y magnetic
g
field
Electrical power lines, wiring,
t
transformers
f
and
d household
h
h ld appliances
li
…
 Power
P
stations,
t ti
HV ttransformer
f
builder, overhead cable, railways
system….
system
Electromagnetic compatibility (EMC) —Part
Part 4
4‐8:
8: Testing and measurement
techniques — Power frequency magnetic field immunity test
24
 H  dl 
l
I  Ampere'
A
' s law;
l
H 
I
2r
I
10 
2X 1m
Electromagnetic compatibility (EMC) —Part 4‐8: Testing and measurement
techniques — Power frequency magnetic field immunity test
25
Voltage dips
dips, short interruptions
g variations
and voltage
 Electrical equipment can be affected by
voltage dips,
dips short interruptions or voltage
variations of the power supply caused by
faults in the network, in installations or by a
sudden large change of load.
Electromagnetic
El
i compatibility
ibili (EMC) — Part
P
4‐11: Testing
T i and
d measurement
techniques — Voltage dips, short interruptions and voltage variations
immunity tests
26
Voltage dips, short interruptions
and voltage variations
27
I
Immunity
i Test
T results
l
Criterion
A
Performance
Normal p
performance,, specified
p
by
y manufacturer
B
Temporary loss of function or performance degradation during test.
EUT recovers itits performance
f
without
ith t iintervention
t
ti
C
Temporary loss of function or degradation (requiring intervention)
D
Loss of function or degradation unrecoverable
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Summary
 Some concept and fundamentals on EMC.
 RE,
RE RI
RI, CE
CE, DI
DI, ESD
ESD, FT & S
S, H
H‐Field,
Fi ld V
Voltage
lt
Dip.
Electromagnetic
El
i compatibility
ibili (EMC) — Part
P
4‐11: Testing
T i and
d measurement
techniques — Voltage dips, short interruptions and voltage variations
immunity tests
29
Thank You!!
Peter Sai‐Wing LEUNG, 梁世榮
http://www.ee.cityu.edu.hk/~pswleung/
http://www ee cityu edu hk/ pswleung/
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