matching conducted emi to international standards
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33 rd Power Electronics Specialists Conference
Matching Conducted EMI to International Standards
Matching Conducted EMI to International Standards
Presenter: Fernando Soares dos Reis
Pontifical Catholic University of the Rio Grande do SulPontifical Catholic University of the Rio Grande do Sul
BrazilBrazil
33 rd Power Electronics Specialists Conference
Table of Contents
INTRODUCTION INTRODUCTION
OBJECTIVES OBJECTIVES
TERMS AND DEFINITIONS - EMC, EMITERMS AND DEFINITIONS - EMC, EMI
PFCs PFCs
CONDUCTED EMICONDUCTED EMI
SIMULATIONSIMULATION
FILTER DESIGNFILTER DESIGN
CONCLUSIONSCONCLUSIONS
33 rd Power Electronics Specialists Conference
Some examples of problems caused by EMI: Some examples of problems caused by EMI:
Pistol Drill may Interfere on TV;Pistol Drill may Interfere on TV; Electronic Ballast's may change the TV Electronic Ballast's may change the TV channel;channel; Switching Inductive Load may generate Switching Inductive Load may generate noise in Radios;noise in Radios;
Necessity of accordance with Standards...Necessity of accordance with Standards...
INTRODUCTIONINTRODUCTION
33 rd Power Electronics Specialists Conference
To easily determine the EMI levels on To easily determine the EMI levels on basic PFC and to design the EMI input basic PFC and to design the EMI input filter in the design step facing the filter in the design step facing the following points:following points:
Main StandardsMain Standards Simulation of the Conducted EMISimulation of the Conducted EMI EMI Minimization TechniquesEMI Minimization Techniques
OBJECTIVESOBJECTIVES
33 rd Power Electronics Specialists Conference
TERMS AND TERMS AND DEFINITIONSDEFINITIONS
Electromagnetic Compatibility - EMC:Electromagnetic Compatibility - EMC:
• It´s the characteristic presented by an It´s the characteristic presented by an equipment, or system, working equipment, or system, working satisfactorily, in an electromagnetic satisfactorily, in an electromagnetic environment without causing or environment without causing or suffering unacceptable degradation in suffering unacceptable degradation in its individually designed function.its individually designed function.
33 rd Power Electronics Specialists Conference
INDUSTRIAL INDUSTRIAL ENVIRONMENTENVIRONMENT
33 rd Power Electronics Specialists Conference
Electromagnetic Interference – EMIElectromagnetic Interference – EMI
Any electromagnetic disturbance that Any electromagnetic disturbance that interrupts, obstructs, or otherwise degrades or interrupts, obstructs, or otherwise degrades or limits the effective performance of limits the effective performance of electronics/electrical equipment. It can be electronics/electrical equipment. It can be induced intentionally, as in some forms of induced intentionally, as in some forms of electronic warfare, or unintentionally, as a electronic warfare, or unintentionally, as a result of spurious emissions and responses, result of spurious emissions and responses, intermodulation products, and the like. Also intermodulation products, and the like. Also called radio frequency interference RFI.called radio frequency interference RFI.
TERMS AND TERMS AND DEFINITIONSDEFINITIONS
33 rd Power Electronics Specialists Conference
COMMUNICATIONCOMMUNICATION ENVIRONMENTENVIRONMENT
33 rd Power Electronics Specialists Conference
By Globalization´s By Globalization´s Highway...Highway...International Rules...International Rules...
ALCAALCA
MERCOSULMERCOSUL
EUROPEAN UNIONEUROPEAN UNION
33 rd Power Electronics Specialists Conference
IECIEC - International Electrotechnical Commission; - International Electrotechnical Commission; CISPRCISPR - International Special Committee on - International Special Committee on
Radio Interference;Radio Interference; CENELECCENELEC - Committee for Electrotechnical - Committee for Electrotechnical
StandardizationStandardization;; These organizations prepares and These organizations prepares and
publishes international standards for all electrical, publishes international standards for all electrical, electronic and related technologies;electronic and related technologies;
GLOBALIZATIONSGLOBALIZATIONS
33 rd Power Electronics Specialists Conference
CONSUMERS REQUIREMENTSCONSUMERS REQUIREMENTS
ELECTRONICS LOADSELECTRONICS LOADS
IN THE LAST YEARS THE ELECTRONIC LOADS GROW IN THE LAST YEARS THE ELECTRONIC LOADS GROW
UP OVER THE WORLDUP OVER THE WORLD
BRAZIL WAS NOT AN EXEPTION AT THIS PROCESSBRAZIL WAS NOT AN EXEPTION AT THIS PROCESS
IN THE LAST YEARS THE ELECTRONIC LOADS GROW IN THE LAST YEARS THE ELECTRONIC LOADS GROW
UP OVER THE WORLDUP OVER THE WORLD
BRAZIL WAS NOT AN EXEPTION AT THIS PROCESSBRAZIL WAS NOT AN EXEPTION AT THIS PROCESS
33 rd Power Electronics Specialists Conference
INPUT POWER LINEINPUT POWER LINE
CAPACITORS VOLTAGECAPACITORS VOLTAGECCCC
DIODES INPUT CURRENTDIODES INPUT CURRENT
POWER LINE CURRENTPOWER LINE CURRENT
CC DCDC
DC - DCDC - DC
CONVENTIONAL CONVENTIONAL INPUT RECTIFIERINPUT RECTIFIER
33 rd Power Electronics Specialists Conference
To solve those problems it was created the PFPsTo solve those problems it was created the PFPsTo solve those problems it was created the PFPsTo solve those problems it was created the PFPs
Power Factor Pre-RegulatorsPower Factor Pre-Regulators
Power Factor CorrectorsPower Factor Correctors
Input Pre-RegulatorsInput Pre-Regulators
Power Factor Rectifiers Power Factor Rectifiers
Resistance EmulatorsResistance Emulators
Power Factor Pre-RegulatorsPower Factor Pre-Regulators
Power Factor CorrectorsPower Factor Correctors
Input Pre-RegulatorsInput Pre-Regulators
Power Factor Rectifiers Power Factor Rectifiers
Resistance EmulatorsResistance Emulators
PFPsPFPs
33 rd Power Electronics Specialists Conference
EMIEMI
Power Factor Pre-RegulatorsPower Factor Pre-Regulators
High Frequency Switching Noise Degrades the Power Quality.High Frequency Switching Noise Degrades the Power Quality.
Input CurrentInput Current
Input VoltageInput Voltage
33 rd Power Electronics Specialists Conference
CISPR 11CISPR 11
LIMIT STANDARDSLIMIT STANDARDS
FCC 15FCC 15
8080
7070
6060
Limit ValueLimit Valueclass Aclass A
class Bclass B
7070
6060
dBdB
µVµV
100100
9090
MHzMHz0.010.01 0.10.1 11 1010 30301.61.60.450.45
5050
4040
3030
4848
Limit ValueLimit Value
Class AClass A. A device that is marketed for use in a commercial, . A device that is marketed for use in a commercial, industrial or business environment; industrial or business environment;
Class BClass B A device that is marketed for use in a residential A device that is marketed for use in a residential environment notwithstanding use in commercial, business and environment notwithstanding use in commercial, business and industrial environments;industrial environments;
0.15 0.5 30 MHz
100
90
80
70
60
50
40
300.9 10
73
6066
79
56
Limit Value Limit Value Quasi-peak (class A)Quasi-peak (class A)
dBµV
Quasi-peak (class B)Quasi-peak (class B)
33 rd Power Electronics Specialists Conference
It is the part of the electromagnetic interference It is the part of the electromagnetic interference
that flows by power cords.that flows by power cords.
This kind of interference can be propagated in:This kind of interference can be propagated in:
Differential Mode (DM) or inDifferential Mode (DM) or in Common Mode (CM)Common Mode (CM)
CONDUCTED EMICONDUCTED EMI
33 rd Power Electronics Specialists Conference
EquipmentEquipment
ZZ LISNLISN
PhasePhase
NeutralNeutral
ii CDMCDM
CONDUCTED EMI in CONDUCTED EMI in DIFERENTIAL MODEDIFERENTIAL MODE
33 rd Power Electronics Specialists Conference
EquipmentEquipment
ZZ LISNLISN iiCCMCCM
CONDUCTED EMI IN CONDUCTED EMI IN COMMON MODECOMMON MODE
PhasePhase
NeutralNeutral
Ground - CommonGround - CommonParasitic CapacitorsParasitic Capacitors
33 rd Power Electronics Specialists Conference
Conductive Surface Connected to GndConductive Surface Connected to Gnd
Equipment Under TestEquipment Under Test
LISNLISN
EMI ReceiverEMI Receiver
80 cm80 cm8080
cmcm
4040cmcm
Equipment Under Test (EUT) and Equipment Under Test (EUT) and Measurements Apparatus Measurements Apparatus
LABORATORY TESTSLABORATORY TESTS
Layout for conducted emissions testsLayout for conducted emissions tests
33 rd Power Electronics Specialists Conference
Difficulties for realization of the testsDifficulties for realization of the tests
Few test Facilities (in Brazil and South Few test Facilities (in Brazil and South America);America);
Test apparatus are very expensive;Test apparatus are very expensive; Technical Capacity;Technical Capacity;
Standards Interpretation;Standards Interpretation;
Conducted EMI testConducted EMI test
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If your equipment did not attend the If your equipment did not attend the standard limits...standard limits...
What can you do?What can you do?
AFTER LAB TESTS AFTER LAB TESTS
33 rd Power Electronics Specialists Conference
Preventives Actions: Preventives Actions:
Using Specific Control Methods;Using Specific Control Methods; Choosing the Best Topology;Choosing the Best Topology; Using Assembling Techniques;Using Assembling Techniques;
HOW TO MINIMIZE HOW TO MINIMIZE THE EMI?THE EMI?
LOW COSTLOW COST
33 rd Power Electronics Specialists Conference
10 1000 kHz
For example, you can use a Variable For example, you can use a Variable Switching Frequency to Reduce de EMISwitching Frequency to Reduce de EMI
For example, you can use a Variable For example, you can use a Variable Switching Frequency to Reduce de EMISwitching Frequency to Reduce de EMI
SWITCHING FREQUENCY (Hz)
INPUT CURRENT FMINPUT CURRENT FM
HOW TO MINIMIZE HOW TO MINIMIZE THE EMI?THE EMI?
In FM the Power Interference is DispersedIn FM the Power Interference is Dispersed
33 rd Power Electronics Specialists Conference
PWM Input Current PWM Input Current Harmonic SpectrumHarmonic SpectrumPWM Input Current PWM Input Current Harmonic SpectrumHarmonic Spectrum
10 1000 kHzSWITCHING FREQUENCY (Hz)
INPUT CURRENT PWMINPUT CURRENT PWM
HOW TO MINIMIZE HOW TO MINIMIZE THE EMI?THE EMI?
In PWM the Power Interference In PWM the Power Interference
is Concentratedis Concentrated
33 rd Power Electronics Specialists Conference
vvee
++
--
++
--
vvgg
++
--
CCdcdc VV
iigg
LL DD
iidd
RRiigg AVGAVG ( t)( t)
iigg ( t)( t)
tt
Choosing a Topology with an inductor in Choosing a Topology with an inductor in series with the bridge rectifier.series with the bridge rectifier.
HOW TO MINIMIZE HOW TO MINIMIZE THE EMI?THE EMI?
Because the EMI is a function of the input current ripple.Because the EMI is a function of the input current ripple.
33 rd Power Electronics Specialists Conference
Correctives Actions:Correctives Actions:
Using Filter;Using Filter;
Applying Shielding;Applying Shielding;
HOW TO MINIMIZE HOW TO MINIMIZE THE EMI?THE EMI?
More expensiveMore expensive
33 rd Power Electronics Specialists Conference
Making the Conducted EMI Generated Making the Conducted EMI Generated by Power Factor Pre-Regulators by Power Factor Pre-Regulators Compatible with the International Compatible with the International
Standards at the Design Time Standards at the Design Time
Making the Conducted EMI Generated Making the Conducted EMI Generated by Power Factor Pre-Regulators by Power Factor Pre-Regulators Compatible with the International Compatible with the International
Standards at the Design Time Standards at the Design Time
33 rd Power Electronics Specialists Conference
FIRST OF ALLFIRST OF ALL
SIMULATIONSIMULATION
Of the conducted EMI Of the conducted EMI measurements apparatus measurements apparatus according to CISPR 16according to CISPR 16
as proposed by ALBACHas proposed by ALBACH
Quantify EMIQuantify EMI
By SimulationBy Simulation
EMI ReceiverEMI Receiver
80 cm80 cm8080
cmcm
4040cmcm
Input CurrentInput Current
LISNLISN
EMI ReceiverEMI Receiver
Input CurrentInput Current
LISNLISN
EMI ReceiverEMI Receiver
33 rd Power Electronics Specialists Conference
EMI ReceptorEMI Receptor
80 cm80 cm8080
cmcm
4040cmcm
Frequency (MHz)
Impe
danc
e (
)
± 20 % Maximum Tolerance
kHz
10
10000
5,4
50
20
80
150
300
800
7,3
21
33
43
49
LISN Fre. Imp.
50µH
50
5
SIMULATION OF THE SIMULATION OF THE LISN CHARACTERISTICSLISN CHARACTERISTICS
CISPR 16
LISNLISN
33 rd Power Electronics Specialists Conference
U (t)U (t)DD RR2w2w
++
--
DD
U (t)U (t)
++
--
wwCCww
RR1w1w
Quase-Peak DetectorQuase-Peak Detector
FilterFilter
U (t)U (t)intint
RR
RR
1D1D
2D2D
++
--
DD
U (t)U (t)CDCD
++
--
CCDD
DemodulatorDemodulator
I I (t)(t)
ggintint
U (t)U (t)intint
LL
RR
RR
11
22
++
--
LISNLISN
SIMULATION OF THE SIMULATION OF THE COMPLETE MEASURING COMPLETE MEASURING SYSTEMSYSTEM
Model for the measuring systemModel for the measuring system
33 rd Power Electronics Specialists Conference
EMI SIMULATION EMI SIMULATION RESULTRESULT
dBdB
µVµV
SWITCHING FREQUENCY (MHz)
33 rd Power Electronics Specialists Conference
Using the proposed abacus we can determine Using the proposed abacus we can determine the amplitude of the EMI (first harmonic) in the amplitude of the EMI (first harmonic) in dB/dB/V in accordance with the CISPR 16 V in accordance with the CISPR 16 standard, without simulation, for the following standard, without simulation, for the following converters: converters:
M = 1,23
M = 1,62
M = 2,01
M = 2,39
M = 2,78
M = 3,16
dB
µV
SWITCHING FREQUENCY (MHz)
GENERATED GENERATED ABACUSABACUS
BoostBoost Buck-BoostBuck-Boost ZetaZeta Sepic Sepic Cuk Cuk BuckBuck
33 rd Power Electronics Specialists Conference
The EMI design curves (ABACUS) The EMI design curves (ABACUS) were built for an specific case were built for an specific case (Reference Converter).(Reference Converter).
How to correlate the results from How to correlate the results from the abacus with a real case?the abacus with a real case?
The EMI design curves (ABACUS) The EMI design curves (ABACUS) were built for an specific case were built for an specific case (Reference Converter).(Reference Converter).
How to correlate the results from How to correlate the results from the abacus with a real case?the abacus with a real case?
GENERATED GENERATED ABACUSABACUS
33 rd Power Electronics Specialists Conference
U (dB/U (dB/V) = 20 log P V + U (dB/V) = 20 log P V + U (dB/V)V)
refref
nomnom
g nomg nom
refref
P VP Vnomnomg refg ref
USING THE GAIN EQUATIONS!USING THE GAIN EQUATIONS!
GAIN EQUATIONSGAIN EQUATIONS
33 rd Power Electronics Specialists Conference
M = 1,23
M = 1,62
M = 2,01
M = 2,39
M = 2,78
M = 3,16
dB
µV
U (dB/U (dB/V) = 20 log P V + U (dB/V) = 20 log P V + U (dB/V)V)
refref
nomnom
g nomg nom
refref
P VP Vnomnomg refg ref
GAIN EQUATIONSGAIN EQUATIONS
SWITCHING FREQUENCY (MHz)
33 rd Power Electronics Specialists Conference
Boost Converter in FMBoost Converter in FMBoost Converter in FMBoost Converter in FM
dB
µV
SWITCHING FREQUENCY (MHz)
Experimental Result
EXPERIMENTAL EXPERIMENTAL RESULTS FM BOOST RESULTS FM BOOST
33 rd Power Electronics Specialists Conference
L C
RC
f 2
1
d
Converter sideLine side
EMI FILTEREMI FILTER
33 rd Power Electronics Specialists Conference
EMI design curve for the Boost converterEMI design curve for the Boost converter
M = 1,23
M = 1,62
M = 2,01
M = 2,39
M = 2,78
M = 3,16
dB
µV
SWITCHING FREQUENCY (MHz)
102 dB102 dB
150 kHz150 kHz
M’ = ____V output____ n V input
M’ = ____V output____ n V input
33 rd Power Electronics Specialists Conference
CISPR 11CISPR 11
0.15 0.5 30 MHz
100
90
80
70
60
50
40
300.9 10
73
60
6666
79
56
Limit Value Limit Value
Quasi-peak (class A)Quasi-peak (class A)
dBµV
Quasi-peak (class B)Quasi-peak (class B)M = 1,23
M = 1,62
M = 2,01
M = 2,39
M = 2,78
M = 3,16
dB
µV
102102
150 kHz150 kHz
Necessary AttenuationNecessary Attenuation
A1 = 102 - 66 = A1 = 102 - 66 = 36 dB36 dB
EMI FILTER DESIGNEMI FILTER DESIGN
33 rd Power Electronics Specialists Conference
2
1
10 AAx
cf
f
21
24
1
cf
fCL
2C
LR fd
L C
RC
f 2
1
d
Converter sideLine side
EMI FILTER EMI FILTER EQUATIONSEQUATIONS
ffcc is the cut-off frequency is the cut-off frequency
ffxx is the frequency in which the required is the frequency in which the required attenuation (Aattenuation (A11) is determined) is determined
AA22 is the filter characteristic attenuation is the filter characteristic attenuation
CC11+C+C22 value is 2.2 value is 2.2 FF
For a proper damping effect, CFor a proper damping effect, C22=10C=10C11
33 rd Power Electronics Specialists Conference
DESIGN EXAMPLE DESIGN EXAMPLE
At 150 kHz, At 150 kHz,
Attenuation is -36 dBAttenuation is -36 dB
40 dB40 dB
- 36 dB- 36 dB
- 80 dB- 80 dB
0 dB0 dB
1 kHz 10 kHz 150 kHz 1 MHz1 kHz 10 kHz 150 kHz 1 MHz
322 H 2 F
38 220 nF
Converter sideLine side
USING C2= 2USING C2= 2FF
33 rd Power Electronics Specialists Conference
The proposed method for determination and reduction of The proposed method for determination and reduction of
PFC conducted EMI DM presented here can be an useful tool to PFC conducted EMI DM presented here can be an useful tool to
help SMPS designers. This tool allows us to easily predict the help SMPS designers. This tool allows us to easily predict the
amplitude of the first harmonic in dB/amplitude of the first harmonic in dB/V in accordance with the V in accordance with the
CISPR 16 and to design the EMI filter. In this way we can CISPR 16 and to design the EMI filter. In this way we can
design the filters without needing to make a prototype or make design the filters without needing to make a prototype or make
complex simulations. This method could be a contribution to the complex simulations. This method could be a contribution to the
reduction of the product development time. reduction of the product development time.
The proposed method for determination and reduction of The proposed method for determination and reduction of
PFC conducted EMI DM presented here can be an useful tool to PFC conducted EMI DM presented here can be an useful tool to
help SMPS designers. This tool allows us to easily predict the help SMPS designers. This tool allows us to easily predict the
amplitude of the first harmonic in dB/amplitude of the first harmonic in dB/V in accordance with the V in accordance with the
CISPR 16 and to design the EMI filter. In this way we can CISPR 16 and to design the EMI filter. In this way we can
design the filters without needing to make a prototype or make design the filters without needing to make a prototype or make
complex simulations. This method could be a contribution to the complex simulations. This method could be a contribution to the
reduction of the product development time. reduction of the product development time.
CONCLUSIONSCONCLUSIONS
33 rd Power Electronics Specialists Conference
The analysis that we have developed in this The analysis that we have developed in this
paper is not a full description of the harmonics. But this paper is not a full description of the harmonics. But this
simplification does not represent a big problem, simplification does not represent a big problem,
because the design of the filter is generally made for because the design of the filter is generally made for
the first harmonic. In the majority of cases the filter that the first harmonic. In the majority of cases the filter that
eliminates the harmonics of low order (Feliminates the harmonics of low order (Fss) also ) also
eliminates the harmonics of high order.eliminates the harmonics of high order.
The analysis that we have developed in this The analysis that we have developed in this
paper is not a full description of the harmonics. But this paper is not a full description of the harmonics. But this
simplification does not represent a big problem, simplification does not represent a big problem,
because the design of the filter is generally made for because the design of the filter is generally made for
the first harmonic. In the majority of cases the filter that the first harmonic. In the majority of cases the filter that
eliminates the harmonics of low order (Feliminates the harmonics of low order (Fss) also ) also
eliminates the harmonics of high order.eliminates the harmonics of high order.
CONCLUSIONSCONCLUSIONS
33 rd Power Electronics Specialists Conference
From the analysis we can conclude that the FM From the analysis we can conclude that the FM
operation mode is an interesting solution in order to reduce the operation mode is an interesting solution in order to reduce the
conducted EMI with simple control circuits. Unfortunately this conducted EMI with simple control circuits. Unfortunately this
solution is not effective for switching frequencies in the solution is not effective for switching frequencies in the
proximity and higher than 150 kHz.proximity and higher than 150 kHz.
We must avoid design the converters in FM mode at FWe must avoid design the converters in FM mode at Fs s
minmin around 150 kHz. Minimal SF around 100 kHz are preferred. around 150 kHz. Minimal SF around 100 kHz are preferred.
From the analysis we can conclude that the FM From the analysis we can conclude that the FM
operation mode is an interesting solution in order to reduce the operation mode is an interesting solution in order to reduce the
conducted EMI with simple control circuits. Unfortunately this conducted EMI with simple control circuits. Unfortunately this
solution is not effective for switching frequencies in the solution is not effective for switching frequencies in the
proximity and higher than 150 kHz.proximity and higher than 150 kHz.
We must avoid design the converters in FM mode at FWe must avoid design the converters in FM mode at Fs s
minmin around 150 kHz. Minimal SF around 100 kHz are preferred. around 150 kHz. Minimal SF around 100 kHz are preferred.
CONCLUSIONSCONCLUSIONS
33 rd Power Electronics Specialists Conference
The curves presented here are similar to those The curves presented here are similar to those
presented by Albach [4], but in this paper we present presented by Albach [4], but in this paper we present
the curves as a function of normalised parameters M the curves as a function of normalised parameters M
and d. These curves associated with the gain and d. These curves associated with the gain
equations permit us to obtain the conducted EMI DM equations permit us to obtain the conducted EMI DM
(first harmonic) for a large range of converter (first harmonic) for a large range of converter
specifications.specifications.
The curves presented here are similar to those The curves presented here are similar to those
presented by Albach [4], but in this paper we present presented by Albach [4], but in this paper we present
the curves as a function of normalised parameters M the curves as a function of normalised parameters M
and d. These curves associated with the gain and d. These curves associated with the gain
equations permit us to obtain the conducted EMI DM equations permit us to obtain the conducted EMI DM
(first harmonic) for a large range of converter (first harmonic) for a large range of converter
specifications.specifications.
CONCLUSIONSCONCLUSIONS
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