EMC Europe 2016 Wrocla · EMC Europe 2016 Wroclaw ... Understanding the Physics of Electromagnetic...

1

UNIVERSITY OF TWENTE.TELECOMMUNICATION ENGINEERING.

EMC Europe 2016 Wroclaw International Symposium and Exhibition on Electromagnetic CompatibSeptember 5-9, 2016, Wroclaw, Poland

Kees PostLambda Engineering [email protected]

Frits [email protected]

EMC for LARGE Installations

EMC Europe 2016, Wroclaw, Poland 2

Contents

EMC for LARGE installations

1 Introduction to Electromagnetic Compatibility (EMC)

Essential Requirements and Standardization

2 The physics of Electromagnetic Interference (EMI)

How does it work and how to measure it?

3 Electromagnetic Phenomena

Electromagnetic Environmental Effects (E3)

4 Measures against interference coupling

Building Electromagnetic Environments (divide & conquer)

5 Compatibility of Large Systems

Organization of EMC and Reducing Complexity

6 Conclusions and recommendations

The research leading to these results has receivedfunding from the European Union on the basis ofDecision No 912/2009/EC, and identified in theEuropean Metrology Research Program (EMRP)as Joint Research Project (JRP) IND60 EMC,Improved EMC test methods in industrial environments.Additional funding was received from the EMRPparticipating countries

UNIVERSITY OF TWENTE.TELECOMMUNICATION ENGINEERING.

Lambda Engineering B.V.

Acknowledgements

2


Introduction


“The ability of the System to Operate according to its Specificationsin its Intended Electromagnetic Environment” [IMMUNITY]

“Without generating Unacceptable Electromagnetic Disturbancesinto that Environment” [EMISSION]

Definition of EMC

Sou

rce:

You

Tub

e


Three Criteria for EMC

1. No (intolerable) emissions into the environment

2. Operate satisfactorily in its EM environment

So

urce

:Y

ouT

ube


3. Not cause interference with itself3. Not cause interference with itself

3


Systems Perspective: Performance Criteria


what happens when immunity threshold levels are approached?

ASystem continues to work according to specificationDegradation not acceptableGenerally applies to all interference with a continuous nature

BTemporary degradation acceptable, auto recovery.Usually applies to sporadic interferenceto a non-critical function.

C Degradation acceptable. Recovery after manual RESET.e.g. at mains interruptions. Only for non-critical functions. A

n U

NS

AF

Esi

tuat

ion

is n

ever

acc

epta

ble

!


The necessary elements for an interference situation

EMI, ElectroMagnetic Interference model: source – victim and coupling path

Source Victimcoupling path

Coupling path: always electrical interconnections

to tiny.

EmissionSusceptibility

(Immunity)

Very large….

this can be demonstrated using: a noise generator a radio receiver and some cables

Effects appearat any scale

(relative to wavelength)


4


EMC characteristics

emission

environment

immunity

interference

I

interference

I



EMC characteristics of LARGE installations

SMPS, variable speed drives(frequency converters, servo drives)

Switched applications (electrical motors, pneumatics, hydraulics)

Measurement and control

Datacommunication (fieldbus, ethernet)

EM

SO

UR

CE

01011010001

EM

SU

SC

EP

TO

R

EMC?EMC for LARGE installations

5


frequency

Disturbance levelvoltage (LF) field (HF)

residential

residential immunityEN-IEC 61000-6-1

residentieal emissionEN-IEC 61000-6-3

EMC margin

emission

susceptibility(immunity

industrial immunityEN-IEC 61000-6-2

industrial emissionEN-IEC 61000-6-4

industrial

Generic standards

EMC as per the requirements



Disturbence levelvoltage (LF) field (HF)

frequency

emission

emission limit (as per the standard)

immunity(as per the standard)

susceptibility

Lack of EMC: EMI = EM Interference


6


Neccesity of EMC margin

Large number of apparatus

Deviations in EM levels, gaps in technical standards

Different environments

Different installation practices

Very high EMC margin

WarningThis product complies with the requirements in accordance with product standard IEC 61800-3. In a domestic environment, this product may cause radio interference, in which case supplementary mitigation measures may be required.

WARNING: Screened cables must be used with this equipment in order to comply with the EMC Directive 2004/108/EC regulations



Understanding the Physics of Electromagnetic Effects

passive components and their (ideal) behavior in the time domain

RResistor

VR

IR

·

described by(behavioral model)

Ohm’s Law

LCoil

VL

IL

·

described by

CCapacitor

VC

IC

described by

·


7


Ideal Components do not Exist

all components have, so called, “parasitics”


RResistor C

Capacitor

LCoil


Any current needs a magnetic field!

field of the return conductor is identical but opposite (if geometry is identical)


H = Magnetic Field [A/m] - H

Ir

rH

2

Biot Savart’s Law:

8


Current carrying conductor always exhibits H‐field

minimize fields by aligning conductors (not possible for twin wires)



Special Cable Geometries

COAX produces less fields than twin wires (under conditions)


I

I

ONLY if shield currentuniformly distributed

over 360°

Special care when mountingconnectors or glands!

9


Special Cable Geometries

make sure, current over shield can be uniformly distributed over 360°


I

I

ONLY if shield currentuniformly distributed

over 360°

Source: Smythe W.R.“Static and Dynamic Electricity”p. 278. McGraw Hill, 1950

EMC gland with provision for 360° contact


“Pig‐tails” Destroy Good Coax Properties

effect of geometry changes: fields outside interconnections; CM currents


whencompared…

“Coax is betterthan

twin wires”Coax

Twinwires

Pig-tail destroys cable symmetry

Fields aregenerated

10


Induction in a Single Wire

current in a conductor is only possible when a magnetic field exists


50

coax cable

single wire

1. Waveform for fast edge

A B

A

B

signal integrity =no distortion onthe signal line



current in a conductor is only possible when magnetic field exists


50

coax cable

1a. Waveform for fast edge@ reduced loop area

A B

A

B

Reduce loop area:less time and energy

needed to build H-field

single wire

11



current in a conductor is only possible when magnetic field exists


50

coax cable

single wire

2. Waveform for slow edge

A B

A

B


Simulation of Wire Inductance Demonstration

in LTSpice IV


12


All Currents Run in Loops

Kirchhoffs Current Law: basic for the design of component networks


I1 I2

I3

Ia Ib

Kirchhoff’s electrical current law

213 III

ba II

Every current musthave a return path!

As a Designer,

ask yourself:

Where does my

Return Current

Flow?


Common‐mode currents dominate the EMC arena

currents, generated by cables’ “desired currents” into CM or ground‐loop


Source Load

“Ground”

“Differential-mode” currentIdm

Icm

“Common-mode” current

CM: 99%of all EMIproblems!

Common-mode current is thatpart of the return current which

follows a different path thanthe designers intended route

CM-currentscan becreated

“elsewhere”

13


Demonstration of the Common Mode Current

using the three demonstration cables of slide 1


50

source (50)

scope

“ground” litz wire

Any Cable

50

amplitude depends on cable quality

Current clamp


“Common‐Resistance” Crosstalk

resistance in the common return path of two loops (SPICE model)


source current

· 1

Isource

Inoise

14


Resistive Crosstalk Waveform

linear operation: noise signal shape is identical to source waveform


SourceWaveform

NoiseWaveform


Kirchhoff Electrical Voltage Law

assumes all fields are inside the circuits components


Kirchhoff’s Voltage Law

Us

R1

R2

UR1

UR

2

021 RRS UUU

loop 1flux flux

Faraday’s Law:

?

15


Mutual induction: coupling of circuits (loops)

Field loop 1 induces voltage in loop 2 (“Crosstalk”‐ or: transformer)


I1

loop 1

loop 2

MModel:

flux 1

1

212

loop

loop

IM

1

11 I

L


Substitute source model for inductive crosstalk

Faraday’s Law expressed in the time and frequency domain


loop 1

loop 2

flux 1

1

212

loop

loopM

1

11

L

Faraday’s Law:Faraday’s Law:

Vnoise

22

looploop

noise jdt

dV

or

112112

looploop

noise Mjdt

dMV

1122 looploop M

Vnoise

I1

Note: capacitive modelyields current source

Voltagesource

16


Substitute source model for inductive probes

Faraday’s Law for a Loop Probe

Faraday’s Law:

Vloop

Vloop

Voltagesource

looploop

loop jdt

dV

or

looploop

loop AHjdt

AHdV

Loop Area, Aloop

External Magnetic Field H

HBDensityFlux r 0

looploop ABFlux

1, airr

m

H70 104

rtyPermeabiliMedium 0



Inductive probe for Magnetic Fields: the Model

derivation using a substitute voltage source

air gap inshielding

semi-rigid coax

chip resistor 50 (sometimes left out)

Area: A

Magnetic Field: H

instrument:50

Principle ofOperation:

MutualInduction

ABFluxCoupled HBDensityFlux


17


Alternative Shape: Current Clamps/Probes

current clamps use ferrite cores to guide magnetic field through coil

C-shaped Core

C-shaped Core

Both cores are clamped together aroundthe current conductor to be measured

Coil:90 turns of0.5 [mm] wire

Conductor/Current to be measuredmust be led through toroid

Coil:Fill toroid with

wire turns(Most sensitive)

MModel:

Principle ofOperation:MutualInduction

Current in Wire“to be measured”

IMFluxCoupled



Small Magnetic Sniffer Probe

5‐turn loop probe using ferrite to concentrate flux lines

Coil:5-6 turns of0.5 [mm] wire

Small C-shaped core

Conductor under test(or external field)

Usable for lower frequencies:• more sensitive than single loop probe• ferrite concentrates magnetic field lines

Note for Loop and Sniffer Probe

The probe output voltage is proportional to Bort

B

Hence, the MIL-STD-461 calls it a “B-dot” probe


18


Operation of the current probe

derivation using a substitute voltage source

R=50

Lprobe

Equivalent circuit diagram:

R=50

Measurement setup:

Vout

MjVind

probe

probeout

LR

j

LR

MjV

probeL

R

probeL

R MjVout

ML

RV

probeout



Operation of the current probe

graphical representation of results

probeC L

R

low frequencycut-off of probe

Calibrationlevel:

probeL

MR

Current probe: = M.Loop probe: = B.ANote

R = 50 Measure Lprobe

Calculate C


19


SPICE Simulation of an Inductive Probe

With LTSpice IV



Calibrating the Current Probe

use the following setup

coax cable

B

single wire

50 A 50

Current Probeunder test

Sine wave generator

Probe

Probe = VChannel A /50

VOutProbe = VChannel B

Make table for frequencies:

0.1, 0.2, 0.5, 1, 2, 5,10 kHz etc.


20


Simulate Current Probe in LTSpice

model the frequency dependent source using a transformer

The source I1 is the“current to be measured”,set as 1 Amp (no DC)

A transformer is usedto model the “frequencydependent source”Coupling Factor K1 = 1

http://www.linear.com/designtools/software/LTSpice IV (free on the Internet):



Examples of “home made” magnetic field probes

useful if professional equipment is unavailable

Current Clamp(separable)

magnetic field probe

Current Clamp(fixed)


21


Mutual induction in practice

two circuits with a common return (“ground”) conductor


source (50)

scope


single wire (source)

single wire (passive)

50

B

50

A



crosstalk created by mutual induction between two loops


source (50)

scope




Only a change in current produces crosstalk!

50

dt

dIVnoise ~

B

50

A

22



“common return” = common impedance, largely inductive


source (50)

scope




50

B

50

A



slower risetimes = less crosstalk


source (50)

scope




Note that a slower rise timeproduces less or no crosstalk at all!

50

dt

dIVnoise ~

B

50

A

23



thin line: two adjacent loops: high mutual inductance!


source (50)

scope




50

“Mutual inductance” also knownas “Common-Impedance”

B

50

A



solution 1: reduce loop area of source


source (50)

scope




50

B

50

A

24



solution 1a: also reduce area of victim loop


source (50)

scope




50

B

50

A


Ground Plane

Wide ground plane is preferredreturn path for current!


solution 2: wide return conductor (ground plane)


source (50)

scope



50

B

50

A

25


Ground Plane


proximity effect: return current concentrates under “red” wire


source (50)

scope



50

Icm “squeezes”under cable

(proximityeffect)

B

50

A

Separation of “loops” becomes much easier!

victimloop

sourceloop


Proximity effect

current concentrates under conductor, minimizing loop inductance


Current concentrates underconductor (proximity effect)

R=50R=50

Field distribution can bemeasured with smallsniffer probe

x

J(x)

26


Return Current Distribution Magnitude in Ground Plane

lowering the wire reduces volume “filled with flux”


H

D

J0 or 0 JD or D

200 1

1

HDJ

J DDSource:Johnson, H“High-SpeedDigital Design”1993


Wire /cable (!) distance is important

once a metal plane is used for separation


H

D

Current distribution of cm in cable guide ismeasure of flux density, , coupling into

cable: at source ~L, at victim ~M!

cm

sourcesourceL

cm

victim

victim

sourceM

proximity effect

closer cable“catches” more flux

Source:Johnson, H“High-SpeedDigital Design”1993

2

1

HD

LM source

2

1

1

HDL

Mk

source

COUPLING FACTOR: k

27


Wide metal also features: the Skin Effect

Lenz’Law and the basis for shielding effects


CurrentSource

0 d

Edd

y cu

rren

ts

curr

en

t de

nsi

ty

0 d

J0

e

J0d

d eJJ

0

Induced Eddy currents opposedirection of external current

(Lenz’ Law)

f

1 f = frequency [Hz] = conductivity [S/m] = permeability [H/m]


Any Voltage needs an Electric Field!

Two conductors in an interconnection each have an individual field pattern


-+

(Electric Force lines)

28


Combined Electric Field Pattern

concentric circles model the actual E‐field pattern of two conductors



Capacitive Probe for Electric Fields, the Model

derivation using a substitute current source

dielectricheight = d

relativedielectric

constant = r

C = capacitance to “ground”

E [V/m]

ExternalE-field

R=50

d

AC er

0

r

0

AertyPermittiviMedium 0

m

F120 1085.8 1, airr

ED 0


29


Not

e

Substitute source for capacitive probe

a current source, based on Gauss’ Theorem

electric field E

charge current I

plate used as Capacitive probe

surface charge Q

or

EAjI oe

t

QI

(time domain)

QjI (frequency domain)

EAQ oe (Gauss)

area: Ae

0

DE 0 (Dielectric Displacement)

DAort

DA

t

Qee

The MIL-STD-461 hence calls this device a “D-dot probe”



Equations for the measurement circuit

when loaded with a resistor

EAj oe

C RI

vo

d

AC er

0

dielectricheight = d

C = capacitance to “ground”

r

Ae

R=50

Equivalent Circuit Model:


30


Using a Capacitive Probe for Voltage Measurements

replace E by V (Voltage) divided by h (distance)

d r

Ae

h

R=50

V

assumption: d<<h

h

VAj oe

d

AC er

0

C RI

vo

VCQ Mutual Gauss rewritten:



Equations for the measurement circuit

when loaded with a resistor

1

RCj

Rvo

EAj oe

RCj

Edjv

ro 1

1

LF:

EARjv oeo

RC

1 HF:

ro

Edv

RC

1

C RI

vo

d

AC er

0


31


Operation of the capacitive probe

graphical representation of results

RC

1

low frequencycut-off of probe

“Calibration”level:

r

Ed

frequency

V0

dielectricheight = d r

Ae



SPICE Simulation of a Capacitive Probe

Using LTSpice IV

http://www.linear.com/designtools/software/LTSpice IV (free on the Internet):


32


Commercial Capacitive Clamp

Example of some electric field probes

useful if professional equipment is unavailable

Insulate!

Can sense E-fieldsand generate them!

Rod type probe



Combination of capacitive and inductive crosstalk

depending on load of source line, capacitive or inductive effects dominate


50 instrumentor termination



82

8

2

82

12

0

Terminationselect switch

H

E

Z0

3204

sizes in mm, line impedances 130

50

10

20

receiving line

source line

Aluminiumgroundplane

Construction details

Brassconductors

Electrical Diagram

active line

passive line

(Source)

(Load)

Source: J.J. Goedbloed “EMC”, Kluwer 1993

33


Flow of currents determines crosstalk behaviour

always look for the current paths, inductive and capacitive


MutualInduction

gene

rato

r

A B

Scope

Capacitive situation

C

cap

Crosstalk “in phase”

gene

rato

r

Inductive situation

ind

Crosstalk “in anti-phase”

react

A B

Scope

Open end Shorted end


Balancing capacitive and inductive crosstalk

terminating the source line with its characteristic impedance


MutualInduction

Z0 terminated situation

ind

Crosstalk far end “balanced”

react

terminatewith Z0

gene

rato

r C

cap

A B

Scope

12

0

34


Capacitive or Inductive Sniffer Probe shows Field

magnetic field (shorted source line) or electric field (open source line)


Use probe near source line

NoteTerminated Line:Both Field Types

“D-dot” (E-) probe

“B-dot”(H-) probe


Crosstalk between two circuits (loops)

interference between line 1 and 2; mutual induction, substitute source model

1

M12

1

2

1122 MjV


35


Addition of a cable screen

crosstalk not only between line 1 and 2 but also between line 1 and screen!

S

1

2

Line 2 and screen Stogether act asa transformer

M12

M1S



The effect of a cable screen

how does screening actually work for cables?

M12

1

1

2

S

MS2

M1S

2

C

11 SS MjV

1122 MjV

SS

SS LjR

V

SSC MjV 2 Remains to be proven:

VC = - V2

First step:

121 MM S

112 MjVS

S


36


Inside metal tube there is no field

if current is distributed evenly over 360° circumference of this tube

Evenly distributedcurrent density over360° circumference S

H

H

s S

SSL

S

SSM

2

if all flux is “outside”

hence,

SS LM 2

Source: Smythe W.R.“Static and Dynamic Electricity”p. 278. McGraw Hill, 1950

S2No fluxinside tube!

Presence of innerconductor: no change!



To find the remaining noise voltage after screening

fill out the equation for (V2 – VC)

2

S

MS2

2

C

1122 MjV

SS

SS LjR

V

SSC MjV 2

112 MjVS

S

SSC LjV

MS2 = LS

Remaining noise voltageon line 2 (fill out equations):

SSC LjMjVV 1122

and replace S:

SSSC LjR

IMjLjIMjVV

112

1122

)1(1122

S

SC

LR

j

jIMjVV

original crosstalk

without screening!

Improvement


37


Graphic representation of screening effect

in relation to the crosstalk in the unscreened situation

frequency

nois

e v

olta

ge o

n lin

e 2

with (ideal) screen

S

SSC L

R (screen cut-off frequency)

Message:Audio (lowfrequency)screeningis difficult!

Improvement



20 [dB] Attenuation Trace

-70

-60

-50

-40

-30

-20

-10

0

1.00E+06 2.01E+08 4.01E+08 6.01E+08 8.01E+08 1.00E+09 1.20E+09

linear frequency scale

Crosstalk at higher frequencies

transmission line effects when wire or cable length reaches \4


frequency

nois

e v

olta

ge o

n lin

e 2

Crosstalk does not increasewith frequency forever!

Wire

-leng

th =

/4

asymptote20 [dB] Attenuation Trace

-70

-60

-50

-40

-30

-20

-10

0

1.00E+06 1.00E+07 1.00E+08 1.00E+09

logarithmic frequency scale

38


The Common‐mode Coil

appearances: from factory installed to self made

Common-modecoils

Clip-onversion

open

closed

UTP cablewound onferrite ring

factoryinstalled



Loop-area responsible for Ls and Ms2


improve, essentially, the low frequency behaviour of a cable

ferrite tubeon cable

ferrite increases LS (RS unaffected)

cable (shielded)2

S

Vn

ois

e

frequency

S

SSC L

R

S

SSC L

R

''

LS increased


39



drawback: does not work at very high frequencies (fields travel around it)

Input and output“see” each other

(for high frequencies)

C



Incomplete screening

What if the screen does not completely cover the inner wire?


Ideal Screening

WorkableCompromise(Pig-Tail)

2

S

MS2

2

C

S

MS2 = LS

MS2 LS

e.g. MS2 = 0.95⋅LS

40


Incomplete screening

in relation to the crosstalk in the complete‐ and un‐screened situation

frequency

nois

e v

olta

ge o

n lin

e 2

with (ideal) screen

S

SSC L

R

Improvement


S

SHF L

R

95.01

1

Loss


Pig-Tail for EMCDemonstrations

Pig‐Tails

to some extent, pig‐tails are unavoidable


Commercially Available Pig-Tail

41


Lunch Break



Measures to Improve Low Frequency Performance

balancing measures e.g. using Unshielded Twisted Pairs (UTP)

Balanced Driver

1

2a

2b

M12

Two identicalsubstitute sourcesare introduced


Balanced Receivercommon mode noise

is cancelled!

42


Advanced Topic: STP and Triax cables

inside the screen: now we have two wires or a coax

outer braid shields high frequencies

differential driverreceiver pair

(receiver with high cm-rejection)

grounds connectedat only one position

termination resistor

screen floating!

outer braid shields high frequencies



cm

Advanced Topic: STP and Triax cables

the remaining low‐frequency noise is removed by balancing & cm‐rejection

Major threat: cm x RS noise(Very Low Frequencies e.g. lightning)

cm

1122 MjV LF inductive noise:

reduced by balancing& cm-rejection


x R noiseremoved by insulation

43


Properties of cables: Transfer Impedance ZTcable may produce or pick up common mode currents


external noise source

Inoise

Unoise

1. Coupling into external noise

cable length D

Idesired

return current flows where?

?

2. Generation of noise in other conductors(e.g. “ground”)

DI

UZ

noise

noiseT

[Ohm per meter]


Signal and Return Circuit have Mutual Induction

COAX example: screen and centre wire form a transformer


Cable

Loop 1 (Signal loop / induction)

Loop S (Return loop / induction)

1S

L1

LS

MS1

44


Mechanism of the transfer impedance

common‐mode current flows in return impedance


RS LS

L1

R0

Uin

Cable

Vin

MS1

cmSMjU 1

Scmin LjRU 1SSScmin MLjRU

Transfer Inductance (LT)

1

S

(Don White)

cm


Examples of Transfer Impedance

addition of the skin effect as important aspect of screening


103 104 105 106 107 108

frequency [Hz]

100

10

1

0.1

0.01

0.001

|ZT| (

m

/met

er)

3 braid + 2 mu metal(superscreen)

SolidCopperScreen

Single Braid(RG58)

Source:Green, M. “Optimized andSuperscreened Cables”(Raychem)

core

ret

urn

curr

ent cmTriax cable

ICORE (double braid)

OptimizedSingle Braid

Skin effectseparatescore return

from cm

45


In addition come the “Pig‐tails”

effect of geometry changes: fields outside interconnections; CM currents


whencompared…

“Coax is betterthan

twin wires”Coax

Twinwires

Pig-tail destroys cable symmetry

Fields aregenerated

ZT goes UP


Transfer‐Impedance

Every cable leaks to some extent… Here, twin‐wires driving a motor with a PWM signal


Plaatje motor demo zonder kabelgoot

50 Load

Unscreened wire

46


Transfer impedance of PWM driven DC motor

Switching moments visible as 2 Vpp transients



Transfer Impedance Crosstalk in practice

looks remarkably similar to inductive crosstalk between wires!


source (50)

scope

Cable 1 (source)

Cable 2 (passive)

50

B

50

A

(ZT cable 1)

(ZT cable 2)

I CM

(=

no

ise

)

47


EMC demo installation

► EM sources: variable speed drive, circuit breaker, RF transmitter

► EM victims (analog measurement/control, protection relay)

► Coupling paths

► Cable shielding



Complies with EMC Directive 2004/108/EC

Immunity to interference in acc. with EN 61000-6-2

Noise emission in acc. with EN 61000-6-4

EMC specification + installation requirement


48


Power electronics (variable speed drives/VSD, thyristor controllers, softstarters, UPS, HF lighting)

Switched devices (relays, circuit breakers, contactors, vacuum/GIS, pneumatic- and hydraulicvalves/solenoids)

Lightning and induction effects

HF transmitters (portable transmitters, mobile telephones, fixed transmitters for communication en navigation)

ESD (moving materials, machines with non-conductive elements, conveyor belt, oil tanks, etc.)

Frequently experienced EM sources



Continuous and transient sources

Continuous

► VSD

► Servo drive

► UPS

► Switched mode power supply(SMPS)

Transient

► Relay, circuit breaker/ contactor

► Valve (solenoid)

► ESD

► Lightning, short circuit


49


UPS = Uninterruptible Power Supply VSD = Variable Speed DriveFC = Frequency Converter

line inductor

input filter

output filter

rectifier inverter

Power electronics (UPS and VSD)



Low Frequency (LF)• harmonic currents• notches (from thyristors)

ILF

High Frequency (HF) transientcurrents and voltages from inverter(harmonics of inverterfrequency)

IHF

IHF

Rectifier direct (diodes) or

regulated (thyristors)

InverterIGBT’s/ fast transistors

for high efficiencyDC bus

Power distribution

system Load

Electrical motor/servo motor

M

VSD/servo drive

Variable Speed Drive


50


= PREFERRED CURRENT

RETURN PATH

CFD CDC

► Capacitance of motor winding(s) and motor cables causes capacitive current due to high dV/dt: I = (CM+CC).dV/dt

► Output filter required to mitigate dV/dt

► Motor cable shield provides preferred return current path

► Internal return path capacitors required in VSD (in DC bus and/or in power supply filter)

OPTIONAL

INPUT FILTER

CFO

CM

CC

CC

dV/dt

ICM

MOTOR

CM

MOTOR CABLE

VARIABLE SPEED DRIVE

TRANSFORMER

PLANT EARTH GRID

VSD EARTH BAR

Basic EMC concepts of VSD



Typical IGBT switching rate: 5kV/s (high efficiency)Example: finv = 4kHz T=250s

th = 50s 1/ th = 6.4kHztr = 100ns 1/ tr = 3.2MHz

U(t) log(U)

U(f)

Frequency spectrum of VSD emissions

TIME DOMAIN FREQUENCY DOMAIN

with

FOURIER


51


In the field

1. Coupling via process piping, vessels and instruments

2. Coupling via parallel cables

In the control room

3. Coupling via local control ports4. Coupling via LV power distribution system

Under construction

Coupling paths



1. Type of motor (isolation class, eddy current losses)

2. Motor cable length (cable capacitance, ICM, transient peak voltage at motor winding)

3. Shielding quality of motor cable (transfer impedance)

4. Low impedance terminations of cable shields (drive, motor, safety switch etc.), control cables

5. In- and output filters: reduction of dV/dt, noise voltage reduction on power supply

6. Segregation of power supplies

7. Segregation with other cables

Installation aspects of VSD/servo drive


52


frequency

150kHz 500kHz 5MHz 30MHz

66

79

130

c

ondu

cted v

olta

ge le

vel

(QP

, dBV

)

100

C1

C2

C3

C3

I>100A

I100A

IEC 61800-3 categories and emission limits: C1 Equivalent to generic emission level for residential environment (IEC 61000-6-3)

C2 Equivalent to generic emission level for industrial environment (IEC 61000-6-4)

C3 IPH ≤100A. No reference to generic standard. Severe industrial emission level (EM level 4)

C3 IPH>100A. Very severe industrial emission level (EM level 4+)

C4 No emission limit (IPH>400A and/or V>1000V)

C4

GENERIC PLANT EMISSION LEVEL (3)

• Emission level as per the product standard IEC 61800-3

• EMC plan required for category C4

Category C3/C4 EMI voltage in time domain

>50dB

Conducted emission via power supply



Overview of VSD per power range


53


The Three Dimensions of EMC

systems EMC requirements are set by the environment it is intended for

Ground BasedAirborneAt Sea

Industry

Domestic

Small

MediumLarge

[Tests to cover]



Standards address different EM Phenomena

tests are defined to check each relevant aspect


54


Front Door / Back Door EMI

Front Door: Intended Coupling Path; Back Door: Unintended Coupling Path

Receiver87 - 108 [MHz]

Mains Cord

100

[MH

z] in

-ban

din

terf

eren

ce

Front DoorCM

9 [MHz] out-of-bandinterference

Back Door

Back Door

I/O interface



Performance Criteria Determine Urgency of Measures

depending on criticality of failure, a criterion is selected (usually in test standard)

ASystem continues to work according to specificationDegradation not acceptableGenerally applies to all interference with a continuous nature

BTemporary degradation acceptable, auto recovery.Usually applies to sporadic interferenceto a non-critical function.

C Degradation acceptable. Recovery after manual RESET.e.g. at mains interruptions. Only for non-critical functions.


55


Measures to be taken by Designer at all interfaces

SystemInternalEnvironment

System Boundary is EM‐Environment Boundary

within the system boundary, compatibility levels can, in theory, be set as desired

System

External Environment

External Environment

system boundary.

syst

em b

ou

nd

ary.

syst

em b

ou

nd

ary.

system boundary.

example: Naval Military

example: Naval Military

example:Industrial

MIL

-ST

D-4

64C



Conducted and Radiated Emission / Susceptibility

type determines the approach to EMC measures

CE RE

CS RS


56


(Continuous) Immunity Aspects

“interference” from “others” through EM‐fields

Intentional Emitters



(Continuous) Immunity Aspects

from “elsewhere” through cabling (conducted interference)

FrequencyController

FrequencyControlled

Motor

Motor Cable

dttVtP )()(

Voltage Current

“MinimizeDissipationwith Fast V/Transitions”


57


In High Field Environments Equipment May Fail

booster transmitters and antennas are often installed for communication

Search party for the hidden source

Car remote controls were disturbed…



Non‐linear Effects

out of band interference

Voltage

Cur

rent

DC offset

frequency

ampl

itude

100 MHz

0 Hz

Prevent HF signals fromreaching semiconductors

Do not amplify HF signalsthat did get in


58


Non‐Linearity Disaster Pictures



ElectroStatic Discharge

charges built on persons or equipment cause electric sparks (and currents)

Sou

rce:

You

Tub

e


59


Electric charging by induction

direct contact not necessary!

Teflon

Wool

Printed Circuit Board

- - - - - - - - - - - - - - - - -+ + + + + + + + + + + + + + + +

1. Charging of an insulator

2. Insulated PCB on charged surface

- - - - - - - - - - - - - - - - - - - -

- - - - - - - - - - - - - - - - -Source:IEEE EMC Education ManualPage 13-15: “ESD”Tony NasutaWestinghouse Electric Corp.



Electric charging by induction

direct contact not necessary!

+ + + + + + + + + + + + + + + +

3.Touch or Ground PCB:

negative charge disappears (spark)(PCB possibly damaged)

4. Lift PCB: voltage increases! Sparks fly!

- - - - - - - - - - - - - - - - -

- - - - - - - - - - - - - - - - -

- - - - - - - - - - - - - - - - -

+ + + + + + + + + + + + + + + +

PCB

PCBPCB C

QV (CPCB decreases)


60


the ESD Threat

ESD pulse from IEC 61000‐4‐2 immunity standard

0 2 108

4 108

6 108

8 108

0

5

10

15

20Contact discharge current IEC 61000-4-2

time [sec]

Cur

rent

[A

]

I i( )

t i( )

The ESD contact discharge current waveform (IEC 61000-4-2)



Time to frequency domain conversion

two characteristic frequencies appear related to pulse duration and rise time

A

50%

90%

10%

h

r

Fknee

h 1

r 1

r2

1

F1 F2

ampl

itude

log (frequency)

f

1~

2

1~

f


61


ESD pulse can be decomposed into two trapezoids

this allows an estimate of the ESD current frequency spectrum

0 2 108

4 108

6 108

8 108

0

5

10

15

20Building blocks contact discharge pulse

time [s]

curr

ent [

A]

IS i( )

IF i( )

I i( )

t i( )

Short and long pulse added in the time domain

Fast pulse: r=0.7 ns; h=10 ns

Slow pulse: r=10 ns; h=60 ns

To convert the ESD pulseto frequencies, it can besplit into two trapezoids



Spectra of slow and fast pulse can be added

the resulting spectrum is used for shielding analyses

1 106

1 107

1 108

1 109

1 1010

1 1010

1 109

1 108

1 107

1 106

1 105

ESD current spectrum

frequency

curr

ent c

ontr

ibut

ion Iesd i( )

IesdS i( )

IesdF i( )

f i( )

Total current

Sum

Fast pulse

Slow pulse


62


Inductive load switching

Relays, Valves, and PWM motor control systems

V0

SW

L

C(parasitic)

R(parasitic)

Basic model

0

2

2

1 LEnergy

par

2

2

1VCEnergy

22

2

1

2

1VCL

L= 0.1 HC= 100 pF = 1 A

V = 32 kV (!)

Analysis:

Source: Jasper J. Goedbloed, “EMC”Prentice Hall/Kluwer 1992



High Voltage in Switch Arcs and Creates Spikes

reason for Electrical Fast Transients (EFT) tests on equipment

ampl

itude

time (s scale)

breakdown (ns scale)

from EN 61000-4-4

5/50 ns pulses


63


Lightning Electromagnetic Pulse (LEMP)

Sou

rce:

You

Tub

e



Time domain representation of Lightning First Stroke

Severe Lightning Strike, defined in terms of lightning current


0 2 104 4 10

40

1 105

2 105

time [s]

Cur

rent

[A

]

trtq eektLEMP 0)(

0 = 200 [kA]

k = 1.09

q = 11354

r = 647265

Note: the LEMPis a powerful

Low ImpedanceEffect

Rates of change @ 10 [m]

smVt

E//108.6 11

smA

t

H//102.2 9

remember: B = .H

64


Frequency Domain graph of Lightning First Stroke

it is clear that most of the lightning energy is in the low frequency area

1 100 1 104 1 10

6 1 108 1 10

100

5

10

15

20

frequency [Hz]

[A/H

z]



Calculate the Effect of an Indirect Lightning Stroke

using Faraday’s Law

Lig

htn

ing

Cu

rren

t

=

=

2·101

0A/s

=2.2· 109

[A/m/s] @ 10 [m]

H

R=distance to stroke

2

surface: A [m2]

Flux in Loop: ·

Induced Voltage:

·where

V

time domain:

frequency domain:

· ·

I, B or is multiplied by frequency!


65


Normalized Frequency Domain Graph of Lightning

shows frequencies of maximum impact (voltage induced in small loop)

1 100 1 104 1 10

6 1 108 1 10

10100

50

0

50

Frequency [Hz]

Indu

ced

volta

ge [d

BuV

/Hz]

multiply every amplitude in the graph by its frequency: “Normalization”



Distribution of Lightning over the World and the Year

NASA movie clip

Sou

rce:

You

Tub

e


66


High Altitude Nuclear Explosion Initiates E‐field Pulse

The Compton Effect converts Gamma Ray Energy into Electric Field

The Compton Effect



Extra‐Atmospheric Nuclear EMP Blast is Far‐Field

in the far field there is a fixed ratio of Electric and Magnetic Field (Impedance)

= 120· 377Ω 0

Impedance of Vacuum or Air

• This means that if you know one (E or H)

• You can calculate the other!

• EMP is usually specified in terms of E (!)

• If you need H, calculate it.


67


HEMP Impulse Illuminates Large Areas

Ground Coverage for High‐Altitude Bursts at 100, 300 and 500 km



The HEMP Phenomenon (movie clip)

Sou

rce

:Y

ouT

ube

Fut

ure

wea

pons

: E

MP

bom

b


68


Characteristics of the HEMP

time domain representation

0 2 108 4 10

8 6 108 8 10

8 1 107

0

2 104

4 104

6 104

time [s]

Am

plitu

de [

V/m

]

Time domain representation of RS105 pulse

trtq eekEtHEMP 0)(

E0 = 50000 [V/m]

k = 1.3

q = 4 x 107

r = 6 x 108

Note: the HEMPis a relatively

High ImpedanceEffect

(377 )



Characteristics of the HEMP

frequency domain representation

1 10 100 1 103 1 10

4 1 105 1 10

6 1 107 1 10

8 1 109

0

5 104

1 103

1.5 103

frequency [Hz]

Am

plitu

de [

V/m

/Hz]

HEMP in the frequency domain


69


Normalizing to find Frequency of Maximum Impact

effective induced voltage in a small loop as function of frequency

1 100 1 104 1 10

6 1 108 1 10

10100

50

0

50

Frequency [Hz]

Indu

ced

volta

ge [

dBuV

/Hz]

Induced voltage spectrum for HEMP



Estimation of the Effects

Sou

rce:

You

Tub

e


70


Power Quality: influence of power‐users

EMI related; Compatibility required

Power LinePower Supply -

Mains GeneratorPower User

Conducted Emissions

Conducted Susceptibility

Other users

Various Powerdisturbances

User Load Fluctuations

“Voltage Quality” or “Quality of Supply”

“Current Quality” or “Quality of Consumption”Reference: Bollen, Math H.J. “Understanding Power Quality Problems”, IEEE Press, 2000ISBN 0-7803-4713-7, IEEE Order Number PC5764



Non‐Sinusoidal Currents and Ohm’s Law

the root cause of most power‐quality related problems

Original Mains Voltage

User Mains Voltage

User Load Current

V = I x RLINE


71


Mains Voltage and Current as Users Like to See It

clean sine wave voltage and resistive load



History: Reactive Loads

result: phase shift, cosine()

re

im

true or real power

rea

ctiv

e p

ow

er


72


Today: Non‐Linear Loads

most prominent: diodes charging bulk capacitors

Mains Voltage

Mains Current

Legend



Modern Compact Fluorescent Lamp (CFL)

electronic circuit with diode bridge and bulk capacitor

Diode Bridge

Bulk Capacitor Current Waveformon a “Decent” Sine-Shaped

Voltage Waveform

Source: Wikipedia


73


Problem with Diode Rectifiers: Synchronicity

all conduct simultaneously on mains voltage! distortion adds up

Same Fluorescent Lampin Large Office Buildingwith distorted Voltage



Small Users <75 W Have No PF Requirements

e.g. all LED’s , CFL’s and many laptops are exempt

Wave-Shape in Large Office Building: Multiple Zero Crossings!

Effect….Heavily DistortedVoltage Waveform

Multiple Zero Crossings

This effect iscalled:HarmonicDistortion


74


Mapping of EMC on Power Quality (User Aspects)

users on the grid are sources and victims, the grid is the coupling path!

Source Victimcoupling pathcoupling path

Coupling path: always electrical interconnectionsEmission

Susceptibility(Immunity)

Grid

User 2User 1

SOURCE VICTIM



Problem 1: Synchronous Peaks Add Up

initial power budget new office building exceeded almost twofold

• Estimated required power: 3 MW• Initial installation: 4 MVA (4 x 1 MVA)• Installation upgraded to: 7.2 MVA (+ 2 x 1.6

MVA)• Question: are we or are we not saving cost and energy?


75


Problem 2: Switcher Frequencies Pollute Environment

low power fast switching requires short risetime IGBT’s and MOSFETs S

ourc

e:Y

ouT

ube



Problem 3: Power Islands: Overproduction

mains voltage too high at high illumination levels

>253 VAC@ 45 KVAgeneration


76


Mechanism of Overvoltage at Sunny Days: Ohm’s Law

farm’s powercable cannot handle 45 KVA in the opposite direction

400V/10kV

2.5 km

R R

∆ 2



What if all Neighbours Install Solar Panels?

like the little lamp‐currents, many small ones make one big one!


77


How to Solve these Conflicts?

supply and demand, storage, who is in control? the Smart Grid!

Traditional: One Way Traffic

Now: Everybody can Supply or Use



Coffee Break


78


The Current Boundary

a provision to split loops (and shut out noise sources)

“Ground 1” “Ground 2”

Icm (noise current)

loop closes through “ground”

“Ground 2”“Ground 1”Icm

loop closes through “ground”

Create one or more “inner-loops”Short

circuit(s)

reduce looparea

check

Unit 1

Unit 2

(Mains cord 1)(Mains cord 2)(I/O cable 1-2)

Situation in practicedetector:AM-radio



Install current boundaries at natural interfaces

edge of PCB, cabinet wall, basement of a building; one boundary per unit!

Right Wrong

Icm Icm

Drawbacks:

Current follows longpath over equipment

Loop area cannot easilybe minimized


79


Examples of current boundaries on equipment

wide conductors and low‐resistance transitions (be careful with paint) !

protect all units with a current boundary!(and check any conductor that passes it)

Short

Wid

e

check DC resistance witha milli- meter: < 1 m!

NoPaint!



Use Current Boundary to protect existing “pig‐tail”

pig‐tails can be acceptable as long as CM currents are kept away from it

Icm

H-fieldlines

Wide metal plate

(Current Boundary)

EMC glands


80


If many Cables are Guided through Shielding Wall..

other options exist



Roxtec / Brattberg Glands


81


Special Gland System: Many Cables Through Wall

all make good electrical contact in wall (< 10 m)

current boundary 3

Wal

l of

Eq

uip

men

t R

oo

m

Roxtec

Brattberg

MonitoringProbe

Analyserw. TrackingGenerator

Amplifier

InjectionProbe

Wa

ll o

f E

qu

ipm

ent

Ro

om

MIL-STD-1310H



Next: Separate Cableswith Current Boundaries

classify cables into categories

Model

ICM

Category

red = “source” =“Emission”

1. Noisy (E)

green =“sensitive” =“Immunity”

2. Sensitive (I)

blue =“indifferent” =

“Neutral”

3. Indifferent (N)

E

I N


82


Model the Real System in CM loops

Both sensitive (analog, various busses) and (polluted) power lines

M3~

Process control system

powerelectronics

relay’s circuitbreakers

pumps,fans, drives

pneumatic/hydraulic

valves

sensorsProduction process / machine

Controlequipment

Power supply 10 kV/400 V

Industrial Environment

I/Omodule

controlequipmentPLC/PC/Ccontrol buscontrol bus

CP

U b

us

machine structure

Source: C.J. Post “EMC of Large Systems” PATO 2007



1. herken kringN

Steps:

Separating Cables with Current Boundaries

use Neutral conductor to reduce loop area; then insert current boundary

1. recognize loop

E

I2. reduce looparea

N

3. add boundary


83



neutral conductor in practical cases: never a “wire”, always a structure part

cm

cross section:twin wires!

Emission Neutral

(CM-) Transfer impedance of combinationof two relatively thin conductors

is too high (radiates fields)(does not work for high frequencies)




wide metal reduces fields i.e. the transfer‐impedance of the cm‐current loop

cm

advantage:proximity & skin

effects

Emission

Neutral

Wide sheet metal (“cable guide”) is far superiorto the previous situation. The common-mode

transfer impedance is much lower. Skin effect helps.


84


Separating Cables (Alternative)

use structure metal parts to “guide” cables and insert current boundaries

N Steps:1. recognize loop

E

I

2. guide cables with metal strips or trays

3. connect current boundaries to strips




use (Ground‐) Plane to reduce loop area; then insert current boundaries

NSteps:1. recognize loop

E

I

2. cover loop with metal (ground-)plane

3. connect current boundaries to plane

Note: we are actuallyreducing CM-loop areashere, using wide metal “short-circuits”


85


“Plane” could be metal mesh


instead of a metal plane a metal mesh could be used

N

E

I


wavelength is key to mesh size:apertures should be very smallwith respect to ¼ wavelength ()


Transfer Impedance improvement

mechanism identical to the single wire case


source (50)

scope

Cable 1 (source)

Cable 2 (passive)

50

B

50

A ICM (=noise)

(proximity effect)Icm “squeezes”

under cable

86


Use available metal to “short‐out” CM‐currents

e.g. a ship’s deck and walls can be used as groundplane(s)

Important: keep cables near metal over their full length!(unless cables have sufficient shielding to go “unprotected”)

UNPROTECTED

PROTECTED

Good contact(< 1 m)

Goodcontact

?!



Cable distance is important

once a cable guide is used for protection

H

D

Current distribution of cm in cable guide ismeasure of flux density, , coupling into

cable: at source ~L, at victim ~M!

cm

sourcesourceL

cm

victim

victim

sourceM

proximity effect

closer cable“catches” more flux

Source:Johnson, H“High-SpeedDigital Design”1993

2

1

HD

LM source

2

1

1

HDL

Mk

source

COUPLING FACTOR: k


87


Two Types of Current Boundaries

Short Circuit for Common‐Mode “Sources”

Enclosure / EMC Cabinet / Shielded Room

Environment Region “0”


1. Connector Plate



Three Types of Current Boundaries

Short Circuit for Common‐Mode “Sources”

3. CompletelyShielded

EnclosureEnclosure / EMC Cabinet / Shielded Room


1. Connector Plate



88


Motor demonstration

After the addition of a metal cable tray



Motor demonstration

after the addition of a metal cable tray


89


Either filter or shield entire cable

when passing through shielding wall

EMC Gland

C L C

EMC Filter

O.K.

O.K.

Not O.K.

cm

E, H fields

E, H fieldsreradiate

1 V/m

10 mA(3 - 5 A = RE limit)



Shielding Experiment

Shielding a noisy interconnection using a metal tube (wave guide)

Wire carryingmodulated RF signal Battery

DC cable

Generator

Radio tuned to RFharmonic frequency

ModulationDetected

cm


90



Entering a conductor into tube couples out the noise again


DC cable

Generator


ModulationDetected




Insulating generator case: battery cable now reradiates noise (antenna)


DC cable

Generator


ModulationDetected

cm


91



Entering a screened conductor into tube also couples out the noise again


DC cable

Generator


ModulationDetected

grounding wire




Grounding the shield with the wire does not solve the interference problem!


DC cable

Generator


ModulationDetected


92



Cable shield must be grounded directly to the metal shield to stop the noise


DC cable

Generator


ModulationDetected



Bad “Grounding” habits

it is Inductance, not the milliOhms that count!


93



A filter in the inserted wire does not help if only grounded with a wire


DC cable

Generator


ModulationDetected




only when the wide metal filter plate touches, the shielding works


DC cable

Generator



94


Filter = “Frequency Dependent” Current Boundaries

EMI filter is usually employed as frequency dependent current boundary

L

N

PE

L‘

N’

LINE LOAD

CX CX

CY CYR

ble

ed

L

L



• Example of intended segregation of power supply

• Alternative in case of shared power supply: power supply filter

Conducted emission via power supply


95


Power supply

M1) Earthing of filter and drive

filter FC

Power supply

M

2) Inductive coupling between in- and output of filter

filterFC

Power supply

MOK

FCfilter

Installation of filter



50

50

50

50

Source: Goedbloed

Filter demo


96


Examples of bad installation practice of filters

Inductive coupling between input and output wiring makes the filter ineffective segregate input and output wiring



Installation of mains RFI and output filters

Source: Danfoss

Installation of shielded motor cable and cable termination details

Source: ABB

Vendor EMC installation requirements


97


Large number of switched applications (motors, valves etc.)

No EMC requirements for single component

Disturbing potential is determined by reactive properties of load, cable lengths, switching frequency and supply voltage

Emission standard for switching transients (clicks) not up to date (based on radio interference (CISPR), whereas immunity of digital circuits, field buses etc. is the main issue.

Installations with switched loads (transients)



Continuous emissions

Transient emission

EN-IEC 61000-6-4: generic emission standard for industrial environment

Emission as per EN-IEC 61000-6-4


98


LloadI

E =½LI2 [J] → ½CV2

V C

Typical specification of relay: Maximum Operating Frequency (No-Load Operation): 3000 Operations / HourMechanical Durability 10,000,000 OperationsElectrical Durability 1,000,000 Operations?Ageing of contacts due to repetitive sparking across contact material

before

Measurement of transients after 60.000

switching events

after

Ageing of switching contacts



DC AC

De-coupling network between solenoid and

connector

Solenoid of pneumatic valve

DC

AC

Contactor

De-coupling network in connector enclosure

De-coupling network

AC applications: Solid state relay (switching at zero-crossing, no stored energy)

Mitigation of switching disturbance


99


L

Mechanical relay

U

Switching transients due to dI/dt

Solid state relay

No switching transients due to dI/dt = 0

Mechanical switch versus solid state relay



Electromagnetic environments

Residential or industrial

But also: Medical/laboratory

Public space

Heavy industry

Shipping/offshore

Railways

etc.

Appropriate EMC specifications of equipment required to fit the EM level!


100


HV area

4

Production plant

3

Office

2

5

Interfaces between EM levels

Installation measures

IEC: 1. very sensitive2. sensitive, domestic / office3. disturbing/noisy, industrial4. very disturbing/noisy, heavy industry5. exception disturbance

1Laboratory

Electromagnetic zones in large installations



ZONE 3 INDUSTRIAL

ENVIRONMENT

ZONE 2PROTECTED

ENVIRONMENT

ZONE 1WELL PROTECTED ENVIRONMENT

(E.G. EQUIPMENT CABINET)

ELECTRICAL EQUIPMENT

AND INSTRUMENTS

BARRIER BUILDING CONSTRUCTION

(E.G. CONCRETE

REINFORCEMENT

BARRIER STEEL

EQUIPMENT

CABINET = EMC MEASURE AT

BARRIER (BONDING OF

ARMOURED CABLES, FILTERING OF NON-ARMOURED CABLES)

► Specify EM levels for equipment in various EM environments► Specify interfaces between EM zones► Similar to LPZ (Lightning Protection Zones) in EN-IEC-62305-3 and -4

EM zones


101


Control building of plant

cable entry framebonded to concrete

reinforcement

cable trenchwith PEC

concretereinforcement

grid

welded earthingand bonding grid

5 x 5 mAir termination network

bonded to column re-bar

bonding ofcable duct

reinforcement offoundation

wire-lashing details:

1. twisted soft steelwire

2. steel-reinforcingbars andearthing andbonding grid

1

2

1

2

foundation re-barbonded to

column re-bar

Building observed through spectacles

EMC spectacles

Required:

Different look at civil engineering



Cable entry of building


102


Current barrier at cable entry of Faraday Cage

Radio receiver

=c/f = 3.108 / f[m] =300 / f[MHz]

f=100MHz (=3m)Mesh size: 1x1mm

f=1MHz (=300m)Mesh size: 10x10cm

Demo cable entry



Planning of concrete reinforcement bonding


103


springclip

Cable entry inside (bonding of shield to cage)



Shielding clamps at panel entry

Gland plate

Cable entry in equipment panel


104


RJ45

15HD sub-D

PS

Metalic clamp

Bonding of current barrier rail to

equipment enclosure

Preferred: metalic enclosure with metalic

connectors (cable shield terminated in connector)

Additional current barrier in case of non-metalic connectors

Cable entry at equipment enclosure



EPCC: Engineering Procurement Construction Commissioning

Assign EMC focal point

EMC management of sub-contractor

Clarify typical EMC installation details in drawings for field installation

Project approach for LARGE installations


105


Separating Regions using Current Boundariesenclosures with current boundaries form individual “environments”

Region N

Region N+1

Top level (“outside”)Region 0



Regions/Environments can be Nested

example: generator in waveguide demonstration


106


Only Limited Shielding can be achieved per Enclosure

20 ‐40 [dB]; but it can be applied recursively!

In EMC terms,sometimes referred to as:Multipoint Grounding…



Regions are defined Electromagnetic Environments

(example) region 0: MIL‐STD‐464A, region 1: bridge, region 2: below deck

0

1

2

Aim: use commercial equipment in region 2 (susceptibility level 10 V/m)

Shielding between successive regions: 20 - 40 dB (factor 10 to 100)

Define where EM zones will be Define the EM levels per region Use adequate current boundaries between regions


107


Multipoint Grounding

hierarchy of current boundaries

PCB withground plane

current boundary 1

current boundary 2

Cabinet with Back-plane

Connector Plate

on Cabinet Wall



Multipoint Grounding

separating rooms in a ship is called Zoning (partitioning into EM‐Regions)

current boundary 2

current boundary 3

Cabinet Wall

Wall of Equipment Room

PCB 1 PCB 21

backplane 1

2

cabinet 1

3

room wall

4

cabinet 2

5

backplane 2

20 dB per boundary:= 100 dB!


108


Voltage Dependent Current Boundaries

varistors and tranzorbs are often used to absorb DM or CM spikes

Example from IEC 62305 part 4 (Annex C)

SPD1 SPD2 SPD3

500

volt

age

[V]

time [s]0

1

volt

age

[V]

time [s]0

1

volt

age

[V]

time [s]0

1

Source: Jasper J. Goedbloed, “EMC”Prentice Hall/Kluwer 1992note: 1 [m] cable 1 H



Try to stick to the “Low Frequency Approach”

use current boundaries to restrain sizes to way below half‐wavelength

Large ScaleLow Frequencies

Small ScaleHigh Frequencies


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Conclusions, summary of EMC measures

Take the EM level of the user’s environment, including EM zones, as basis of design for EMC specifications

Design and procure equipment with corresponding emission and immunity levels (verify and avoid any pitfalls in product standards)

Adhere to installation requirements mentioned in “user manuals”

Install de-coupling devices on inductive (switched) loads, use solid state relays for high switching frequencies

Apply generic installation rules in terms of earthing, bonding at EM zone interfaces and cable segregation, e.g.

IEC/TR 61000-5-2



EMC Basic Rules

Do not use high frequency signals (voltages and currents)

If you do use them:

Do not transport them over large distances

If you do:

Provide adequate current boundaries

Reduce Loop Areas

Use Connector plates

EMC Glands

Metal cable guides

Properly terminate transmission lines

Specify the EMC performance of your system


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“Systems Designers Heaven”

independent building blocks with “abstract” behaviour

System

Software

HardwareModules

Components

Object Oriented

realise complex from simpler behaviour

make assemblies independent

solve “undesired” as low as possible

EMC Principal Laws No high frequencies Do not transport them Use adequate boundaries



Two ways to achieve EMC: 1. The Crisis Approach

“Build the plane, push it off the cliff, let it crash and start all over again”

Sou

rce:

You

Tub

e


111


2. The “Systems Approach”

Consider EMC right from the start throughout the design

0

manyA

vaila

ble

Miti

gatio

n O

ptio

ns

Concept Design Manufacture Test Operational

Requirements

Measures

0

M$$

Cos

t of

Mod

ifica

tion

Check bonding

Repair/redesign

Bankruptcy

phase in the lifecycle



Four Key Elements

of EMC implementation in large organizations

1. Awareness

2. Network

3. Rules & Guidelines

4. Program support


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Network – Connect with other Experts

look for people interested in the subject, in‐house or outside

IEEE



Network

a way to implement EMC maturity

Aware Employees

Local Expert(s) Local Expert(s)

Common Expert Team(CET, Thales)

Division I Division II

UNIVERSITY. . IEEE – EMC chapters


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Build EMC assurance through the Knowledge Cycle

insert electro magnetic behavior up front

Problem definition:“desired behavior”

Research/Analyses

Behavioral Model

Validatedmodels

KnowledgeTransfer &Education

DevelopmentSupport

Validation/Verification

“Test”



EMC Rules and Guidelines

a lot of information on EMC engineering can be found on the internet


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Rules and Guidelines

a lot of good literature is available on the internet

http://genesis.ee.auth.gr/dimakis/egatastaseis/groupe%20schneider/cashier%20techn/ECT149.pdf

http://www.eschneider.pl/download/10%20Poradniki/EMC.pdf

Or try one of the EMC “Cahiers Technique” e.g. #149:

http://www.humerboard.at/ftkl/Design_Techniques_For_%20EMC.pdf

http://literature.rockwellautomation.com/idc/groups/literature/documents/rm/gmc-rm001_-en-p.pdf



EMC Rules and Guidelines

or: buy a book!

ISBN 978-0-470-18930-6


115


Product Development/Program Support

manage the implementation of “EMC” into your system


F. Leferink, S. Lerose, M. Sauvageot, W. van Etten “The Four Key Elements of EMC Implementation in Large Organizations” EMC Europe, 2002, Sorrento Italy. A. Roc’h, F. Leferink, “An Audit Tool for the Implementation of EMC in Large Companies”, EMC Europe, 2012, Roma Italy.



how to? Look e.g. at MIL‐HDBK‐237B

http://everyspec.com/MIL-HDBK/MIL-HDBK-0200-0299/MIL-HDBK-237B_21779/


116



perform engineering & qualification tests

http://www.thales-ecc.nl/onze-expertise/emc/


Click to edit Master title style


Further questions?

EMC Europe 2016 Wroclaw International Symposium and Exhibition on Electromagnetic Compatibility September 5-9, 2016, Wroclaw, Poland

117


Relation of MIL‐STD‐461F tests to Phenomena

survey of test identifiers

CE102 Conducted Emissions, Power Leads, 10 kHz to 10 MHz

RE101 Radiated Emissions, Magnetic Field, 30 Hz to 100 kHz

RE102 Radiated Emissions, Electric Field, 10 kHz to 18 GHz

RE103 Radiated Emissions, Antenna Spurious and Harmonic Outputs, 10 kHz – 40 GHz

CS101 Conducted Susceptibility, Power Leads, 30 Hz to 150 kHz

CS114 Conducted Susceptibility, Bulk Cable Injection, 10 kHz to 200 MHz

CS116 Conducted Susceptibility, Damped Sinusoidal Transients, 10 kHz to 100 MHz

RS101 Radiated Susceptibility, Magnetic Field 30 Hz to 100 kHz

RS103 Radiated Susceptibility, Electric Field, 2 MHz to 40 GHz

RS105 Radiated Susceptibility, Transient Electromagnetic Field (NEMP)


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