33 rd power electronics specialists conference matching conducted emi to international standards...

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


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


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


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


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.


INDUSTRIAL INDUSTRIAL ENVIRONMENTENVIRONMENT


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


COMMUNICATIONCOMMUNICATION ENVIRONMENTENVIRONMENT


By Globalization´s By Globalization´s Highway...Highway...International Rules...International Rules...

ALCAALCA

MERCOSULMERCOSUL

EUROPEAN UNIONEUROPEAN UNION


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


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


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


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 CorrectorsPower Factor Correctors

Input Pre-RegulatorsInput Pre-Regulators

Power Factor Rectifiers Power Factor Rectifiers

Resistance EmulatorsResistance Emulators

PFPsPFPs


EMIEMI


High Frequency Switching Noise Degrades the Power Quality.High Frequency Switching Noise Degrades the Power Quality.

Input CurrentInput Current

Input VoltageInput Voltage


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)


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


EquipmentEquipment

ZZ LISNLISN

PhasePhase

NeutralNeutral

ii CDMCDM

CONDUCTED EMI in CONDUCTED EMI in DIFERENTIAL MODEDIFERENTIAL MODE


EquipmentEquipment

ZZ LISNLISN iiCCMCCM

CONDUCTED EMI IN CONDUCTED EMI IN COMMON MODECOMMON MODE

PhasePhase

NeutralNeutral

Ground - CommonGround - CommonParasitic CapacitorsParasitic Capacitors


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


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


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


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


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


In FM the Power Interference is DispersedIn FM the Power Interference is Dispersed


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


In PWM the Power Interference In PWM the Power Interference

is Concentratedis Concentrated


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.


Because the EMI is a function of the input current ripple.Because the EMI is a function of the input current ripple.


Correctives Actions:Correctives Actions:

Using Filter;Using Filter;

Applying Shielding;Applying Shielding;


More expensiveMore expensive


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


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


80 cm80 cm8080

cmcm

4040cmcm


LISNLISN



LISNLISN



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


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


EMI SIMULATION EMI SIMULATION RESULTRESULT

dBdB

µVµV

SWITCHING FREQUENCY (MHz)


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


GENERATED GENERATED ABACUSABACUS

BoostBoost Buck-BoostBuck-Boost ZetaZeta Sepic Sepic Cuk Cuk BuckBuck


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


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


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



Boost Converter in FMBoost Converter in FMBoost Converter in FMBoost Converter in FM

dB

µV


Experimental Result

EXPERIMENTAL EXPERIMENTAL RESULTS FM BOOST RESULTS FM BOOST


L C

RC

f 2

1

d

Converter sideLine side

EMI FILTEREMI FILTER


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


102 dB102 dB

150 kHz150 kHz

M’ = ____V output____ n V input

M’ = ____V output____ n V input


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


2

1

10 AAx

cf

f

21

24

1

cf

fCL

2C

LR fd

L C

RC

f 2

1

d


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


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


USING C2= 2USING C2= 2FF


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.



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.



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.



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.


33 rd power electronics specialists conference matching conducted emi to international standards...

Documents

definitions slide

introduction slide

process slide

emi input filter

emi pfcs

emi levels

conducted emi simulation

sul brazil slide