EMC Seminar Series
All about EMC Testing and Measurement Seminar – 1
Fundamentals of EMC Theory and Principles
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Dr. LEUNG, Peter Sai‐Wing 梁世榮
http://www ee cityu edu hk/ pswleung/
http://www.ee.cityu.edu.hk/~pswleung/
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Organized
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b :
Department of Electronic Engineering
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ElectroM
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Magnetic Compatibility
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 The ability of an equipment or system to function satisfactorily in its environment without introducing i l bl l
intolerable electromagnetic interference
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to anything hi in that environment.
EMC = EME + EMI
EME=Electromagnetic Emission (Interference)
EMI=Electromagnetic Immunity (Susceptibility)
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EMC
…A complicated and difficult subject!!!!?
 Talks in Order of Magnitudes
 Frequency from DC to daylights
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 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 different standards
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Sources of Emission / Noise
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Natural / man-made / intended emission!
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Coupling
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Effects of EME/ EM interference
ff
f
/
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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
EME and EMI Testsc
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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
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RE CE RI CI
RE, CE,RI,CI
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RE, CE, RI, CI
, , ,

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RE : 40 dBµV/m ~ 0.01V/m
CE : 60 dBµV/m 0 001V/m
CE : 60 dBµV/m ~ 0.001V/m
Examples of some limits in Radiated Emission
…from CISPR22
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EMC‐ A reasonable good margin between RE and RI, for general consideration!!
and RI, for general consideration!!
RI requirement ….3V/m
RE : 40 dBµV/m 0 01V/m
RE : 40 dBµV/m ~ 0.01V/m
CI requirement ….3V
CE : 60 dBµV/m ~ 0.001V/m
Examples of some limits in Radiated Immunity
Examples of some limits in Radiated Immunity … from IEC 61000‐6‐1 for RCLI
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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.
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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
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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 Testing and measurement techniques –
g
q
Electrostatic discharge immunity test
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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
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ESD Tests
 Direct Application:
Discharge Electrodes
 Air Discharge (sparks)
EUT
 Contact Discharge
EUT
……..different electrostatic potential in proximity
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y or through direct contact.
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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
Fast Transient/Burst
Electrical Fast Transients caused a spark in air or other gas ‐ When a circuit is switched off, the current flowing is interrupted; large di/dt
g
p
g
is generated. g
Arcing between the contacts; first at a low voltage and high frequency; later at a higher voltage and lower frequency.
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Electrical Fast Transient
Electrical Fast Transient
Electrical Fast Transients caused a spark in air or other gas ‐ When a circuit is switched off, the current flowing is interrupted; large di/dt
h d ff h
fl
d l
d d is generated. d
Arcing between the contacts; first at a low voltage and high frequency; later at a hi h lt d l
higher voltage and lower frequency.
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IEC 61000‐4‐4 Electromagnetic Compatibility (EMC) ‐ Part 4‐4: Testing and measurement techniques –
Electrical fast transient/burst immunity test.
Electrical fast transient/burst immunity test
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Fast Transient/Burst
Fast Transient/Burst
Electrical Fast Transients caused a spark in air or other gas ‐ When a circuit is switched off, the current flowing is interrupted; large di/dt
h d ff h
fl
d l
d d is generated. d
Arcing between the contacts; first at a low voltage and high frequency; later at a hi h lt d l
higher voltage and lower frequency.
f
Coupling of the EFT into electronic products occurs when power cables handling high currents are run in close proximity to power data and/or I/O cables
high currents are run in close proximity to power, data, and/or I/O cables.
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Surge
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 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 incidents involving electric lines power incidents involving electric lines, power equipment failures. Lightning in seasonal storms. Electromagnetic Compatibility (EMC) — Part 4‐5: Testing and measurement techniques Surge Testing and measurement techniques —
immunity test
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Power frequency magnetic field
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Electrical power lines, wiring, t
transformers and household appliances f
d h
h ld li
…
 Power stations, HV transformer P
t ti
HV t
f
builder, overhead cable, railways system….
system
Electromagnetic compatibility (EMC) Part 4 8: Testing and measurement Electromagnetic compatibility (EMC) —Part 4‐8: Testing and measurement techniques — Power frequency magnetic field immunity test
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 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
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Voltage dips, short interruptions Voltage
dips short interruptions
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and voltage variations
 Electrical equipment can be affected by voltage dips, short interruptions or voltage voltage 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 compatibility (EMC) —
El
i ibili (EMC) Part 4‐11: Testing and measurement P T i d techniques — Voltage dips, short interruptions and voltage variations immunity tests
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Voltage dips, short interruptions and voltage variations
and voltage variations
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I
Immunity Test results
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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
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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, RI, CE, DI, ESD, FT & S, H‐Field, Voltage RE RI CE DI ESD FT & S H Fi ld V lt Dip.
Electromagnetic compatibility (EMC) —
El
i ibili (EMC) Part 4‐11: Testing and measurement P T i d techniques — Voltage dips, short interruptions and voltage variations immunity tests
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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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