电磁兼容及其保护前言教学文案.ppt
电磁兼容及其保护前言Withthewidespreaduseofhigh-speeddigital-operatedelectronic devices,especially the exponential growth inwirelesscommunicationssuchasBluetooth,GSMMobile,WLAN,UWB,andsoon,withoutpropercontrol,thesedevices will be interrupted by the ElectromagneticInterference(EMI).About this courseIfEMIarenotdiscovereduntilproducttestingoccurs.The resolution of interference problems of productdevelopment often involves additional componentswhichaddtosystemscostandcomplexity.ItistobefacetheElectromagneticCompatibility(EMC).2The understanding of the behavior of electronicdevices and systems requires that of Maxwellsequationsandsignalanalysistechniques.However,suchapplicationisoftencumbersome.Toavoidthiscomplexity,anapproximateanalysistechnique is electric circuit theory at lowfrequency.For example,Kirchoffs Voltage Law(fromFaradaysLaw)andKirchoffsCurrentLaw(fromAmperesLaw).3EMC involves the operation of these and other familiardevices in a regime where the special cases andsimplificationsthatareassociatedwithnormalbehaviorbreak down,and requires one to return to a morefundamentalsetofrulestodescribethebehaviorofthesedevices.Non-idealbehaviorimpliesthatdevicesarefunctioninginanabnormalway,whentheyarereallybehavinginaperfectlynaturalway.Itisonlythroughtheapplicationoffundamentalprinciplesthatthebehaviorofdevicesunderalloperatingconditionsispredictable.About this course4For instance,it is impossible to know where certainelectronic devices such as notebook computers will beoperated.Notebooks are commonly used in the home,inautomobiles,atconstructionsites,onboardairplanes,andeven aboard manned spacecraft in Earth orbit.Each ofthese environments presents unique hazards and alsorequiresavarietyofemissionlimits.Thesamenotebookcomputermustbedesignedtofunctioninthepresenceofahairdryer,andalsocannotinterferewith the instrument landing system of a commercialairliner.5characteristic of this coursenBased on theory of electromagnetic fieldnA new,cross subjectnParticularity of unitsnConcepts and terms coming from radio technologynPracticability nRely on measurement intensively6Why we need to learn EMC?(1)Jul.29,1967-Fire broke out on the deck of USS Forrestal CV 59 in GulfofTonkinduringVietnamWarandcause 134dead,161injured.OnMay4th,1982ThedestroyerHMSSheffieldwashitbyanmissile.Manysoldierswerekilled.DisasterscausedbylightningDisasterscausedbyESD(ElectrostaticDischarge)tweezers7nThedebuggingofelectronicdeviceismoredifficult.nTheobligedactualizationofEMCstandardsThecompetitionshortenedtheperiodofdevelopmentWhy we need to learn EMC?(2)8EMC is necessarycircuitproductEMCSI9Why debuggingSignal distortionCant achieve expect functionSelf-distortion reflection lossCrosstalkEarthSource noiseInterference（radiation、conduct）Electromagnetic CompatibilitySignal Integrity10ElectromagneticInterference220ACDigitalPulseCircuitsDigitalVideoDeviceSwitchmodepower11Interference SourceRadio communicationLightningNEMPPulse circuitESDOn and off of inductive loadsFrequency conversion timing12There are four basic coupling mechanisms:conductive,capacitive,magnetic(inductive),and radiative.Anycouplingpathcanbebrokendownintooneormoreofthesecouplingmechanismsworkingtogether.For example the lower path in the diagram involvesinductive,conductive,capacitivemodes.13Sothewaysofcouplingelectromagneticenergyfromasourcetoareceptorare:1.Conducted(electriccurrent)2.Inductivelycoupled(magneticfield)3.Capacitivelycoupled(electricfield)4.Radiated(electromagneticfield)Some Types of EMC Problem ExcessiveRFEmissionsSusceptibility(Immunity)ESD(ElectrostaticDischarge)Coupling paths,often utilize a complex combination of thesemethods,makingthepathdifficulttoidentifyevenwhenthesourceandreceptorareknown.Theremaybemultiplecouplingpathsandstepstakentoattenuateonepathmayenhanceanother.14Ways to solvenConductorradiationThe conductors(tracks,component leads)on thecircuit that are not grounded will be acting asantennae,radiatingRFenergy.Bykeepingtheseconductorsshortandrunningthemclosetogroundedareas,theybecomelessefficientandwillemitlessnSuppressioncomponentsSuppression components for broadband sources:capacitors,varistorsnGroundingnForemissionsproblem:shielding15Other waysnPowerSupplyBusDesignnSignalTrackDesignnPrintedCircuitBoard（PCB）andComponentLayoutnCircuitDesignTechniques16EMC Education nIntroduction to Electromagnetic Interference(EMI)anditsEffectsnEM Waves Radiation Mechanisms and practicalantennasnThe EMC Directive,implementing regulations andEMCStandardsnMeasurementEnvironmentsandtesting,includingtheOpenFieldTestSiteandAnechoicChamber.17EMC Education nMeasurement and Measurement Systems(receiversandspectrumanalyzers)nOverviewofEMCDesignPrinciplesnConductedInterference-SuppressionTechniquesCrosstalkPowerSupplies-EMCConsiderationsEMConaPCBnShieldingdemonstratedusingComputationalElectromagnetics/EMCpredictionsoftware18Research advancesnParasiticInductance,CapacitanceandResistanceinCircuitsnTimeDomainCircuitAnalysisnHigh-Speed,TimeDomainMeasurementsnCrosstalkinCablesandPrintedCircuitBoardsnPropertiesofHigh-SpeedLogicFamiliesnDifferentialSignaling19Research advancesnPowerDissipationinDevicesandCircuitsnTimeDomainTransmissionLineAnalysisnHigh-FrequencyMeasurementsnProperGroundingStrategiesnPrintedCircuitBoardDecouplingnPrintedCircuitBoardLayoutnNewHardwareandSoftwareTechnologies20Computer Softwaren AnSys Inc.nFEKO(EM Software&Systems-S.A.(Pty)Ltd.The name is derived from the German,which can be translated as Field Calculations for Bodies with Arbitrary Surface.)n Apsim（Applied Simulation Tech）nCompact(Computerized Optimization of Microwave Passive and Active CircuiTs)n CST(Computer Simulation Technology)nXFDTD（REMCOM）21EMC Test EquipmentnAntennanSignalGeneratornLISN(anabbreviationforLineImpedanceStabilizationNetwork)nNetworkAnalyzerEMC Equipment ProducernRohde&SchwarznAgilentTechnologiesnTeseqnNationalInstruments22EMC Testing-How to do It nRadiatedemissiontestingontheopenfieldtestsite,(eg.EN55011,EN55022)nConductedemissiontestingusingtheabsorbingclamp(EN55014)nConductedemissiontestingusingaLISN(eg.EN55011,EN55022)nConducted immunity-electrical fast transient/burst,(EN61000-4-4)nConductedRFimmunity,(EN61000-4-6)nRadiated immunity testing in an anechoic chamber,(EN61000-4-3)nElectrostaticdischargetesting,(EN61000-4-2)23nInternationalElectrotechnicalCommission(IEC),hasseveralcommitteesworkingfulltimeonEMCissues.Theseare:nTechnicalCommittee77(TC77),workingonelectromagneticcompatibilitybetweenequipmentincludingnetworks.nComitInternationalSpcialdesPerturbationsRadiolectriques(CISPR),orInternationalSpecialCommitteeonRadioInterference.nTheAdvisoryCommitteeonElectromagneticCompatibility(ACEC)co-ordinatestheIECsworkonEMCbetweenthesecommittees.nInternationalOrganizationforStandardization(ISO)promotesworldwideproprietary,industrialandcommercialstandards.Organizations and standards of EMC24nEurope:nComitEuropendeNormalisation(CEN)orEuropeanCommitteeforStandardization).nEuropeanTelecommunicationsStandardsInstitute(ETSI).nUnitedStates:TheFederalCommunicationsCommission(FCC).nBritain:TheBritishStandardsInstitution(BSI).Organizations and standards of EMC25EMC related publicationsnIEEEtransactiononEMC,AntennaandPropagationIEEEPressnCableShieldingforElectromagneticCompatibilityAnatolyTsaliovich,VanNostrandReinhold,1995.nCapacitance,InductanceandCrosstalkAnalysisCharlesS.Walker,ArtechHouse,1990.nElectromagneticCompatibility:PrinciplesandApplicationsD.A.Weston,MarcelDekker,1991.nElectromagneticCompatibilityJ.J.Goedbloed,PrenticeHall,1992.nSomeChineseBooksonEMC.2628On July 29,1967,the U.S.aircraftcarrierForrestalwasdeployedoffthecoast of North Vietnam.The carrierdeckcontainednumerousattackaircraft that were fueled and loadedwith1000-pound(lb)bombs,aswellasair-to-airandair-to-groundmissiles.Oneoftheaircraftmissileswasinadvertentlydeployed,strikinganotheraircraftandcausingan explosion of its fuel tanks and thesubsequentdeathof134servicepeople.Theproblem was thought to be caused by thegeneration of radiofrequency(RF)voltagesacrossthecontactsofashieldedconnectorbytheshipshigh-powersearchradar.29In1982theUnitedKingdomlostadestroyer,theHMSSheffield,toanExocetmissileduringanengagementwithArgentinianforcesinthebattleoftheFalklandIslands.ThedestroyersradiosystemforcommunicatingwiththeUnitedKingdomwouldnot operate properly while the ships antimissile detection system was beingoperatedduetointerferencebetweenthetwosystems.Totemporarilypreventinterference during a period of communication with the United Kingdom,theantimissilesystemwasturnedoff.Unfortunately,thiscoincidedwiththeenemylaunchoftheExocetmissile.30The Hindenburg disaster has been attributed to spark discharge 313233Anechoic chamberClose-up of a pyramidal RAMAntennaVReceiving Vradiation Biconical antennaOmnidirectional biconical antennaLISN(an abbreviation for Line Impedance Stabilization Network)a standard LISN with top cover removedLISN block diagram.This is standard diagram of a typical LISN.Part values for a particular standard(MIL-STD 461E):C1=8F,R1=5,C2=250nF,R2=1knetwork analyzer(an instrument used to analyze thepropertiesofelectricalnetworks,especiallythosepropertiesassociatedwiththereflectionandtransmissionofelectricalsignalsknownasscatteringparameters(S-parameters)ZVA40 vector network analyzer from Rohde&Schwarz.Agilent Technologies,orAgilent,isanAmericancompanythatdesignsandmanufactureselectronicandbio-analyticalmeasurementinstrumentsandequipmentformeasurementandevaluation.Agilentsmajorproductlinesinclude:ElectronicTestandmeasurementproductssuchasoscilloscopes,logicanalyzers,signalgenerators,spectrumanalyzers,vectornetworkanalyzers,atomicforcemicroscopes(AFM),automatedopticalinspection,automatedX-ray,in-circuittest,andelectronicdesignautomation(EDA)softwareAgilent Technologies headquarters lobby in Santa Clara,California39An analog RF signal generatorA vector signal generatorBACK40ANSYS,Inc.isanengineeringsimulationsoftware(computer-aided engineering,or CAE)developer headquartered south ofPittsburghintheSouthpointebusinessparkinCecilTownship,Pennsylvania,United States.It was founded in Canonsburg,Pennsylvania,U.S.in 1970.It has many products includingANSYS Multiphysics,Fluent,Workbench,HFSS,SIWave,SpaceClaim.FEKO is a computational electromagnetics software productdeveloped by Altair Engineering.It is a general purpose 3Delectromagnetic(EM)simulator.FEKOoriginatedin1991attheUniversityofStuttgart,Germany.ThesoftwareisbasedontheMethod of Moments(MoM)integralformulationof Maxwellsequationsandvarioushybridmethodssuchas:(FEM)/MoM,MoM/PO(PhysicalOptics),MoM/GO(GeometricalOptics),MoM/UTD(UniformTheoryofDiffraction).41Rohde&Schwarz GmbH&Co KGisaninternationalelectronicsgroup specialized in the fields of electronic test equipment,broadcasting,radiomonitoringandradiolocation,andradiocommunication.The company provides products for the wirelesscommunications,broadcasting and electronics industry,aerospaceanddefense,homelandsecurityandcriticalinfrastructures.Thegrouphasbeendeveloping,producingandmarketingelectronicproductsforthecapitalgoodssectorsince1933.InadditiontotheMunich headquarters,there are regional headquarters in the US(Columbia,Maryland)andinAsia(Singapore).OutsideGermany,Rohde&SchwarzhasdevelopmentcentersintheUS,Singapore,Korea,China,Denmark,FranceandGreatBritain.The company has also production facilities in Singapore andMalaysia.Back42Teseq AG,formerly Schaffner Test Systems is a supplier ofElectromagneticcompatibility(EMC)testsolutions.TheydevelopandmanufactureinstrumentsforEMCemissionsandimmunitytestingbothforradiatedandconductedemissionsandimmunity.TeseqoperatesISO17025accreditedcalibrationlaboratorieswithEMCspecialization.Teseq was twice nominated for Best in Test by Test&Measurement World Magazine and has been awarded A2LAcertification.They delivered over 10,000 electrostatic discharge(ESD)simulators.TeseqequipmentmaybefoundinmostEMCtestlaboratories.Teseq,formerlySchaffnerTestSystemswasthefirstcompanytorecognizethethreatofEMCemissionsandinterferenceandbeginofferingEMCinstruments.Back43National Instruments Corporation,or NI,is an Americancompany with international operation.Headquartered in Austin,Texas,it is a producer of automated test equipment and virtualinstrumentation software.Common applications include dataacquisition,instrumentcontrolandmachinevision.Intheearly1970s,JamesTruchard,JeffKodosky,andBillNowlin,wereusingearlycomputertechnologytocollectandanalyzedata.Frustrated with the inefficient data collection methods they wereusing,thethreedecidedtocreateaproductthatwouldenabletheirtasktobedonemoreeasily.In1976,workinginthegarageatTruchardshome,thethreefoundedanewcompany.Theyattemptedtoincorporateunderseveralnames,including Longhorn Instruments and Texas Digital,but all wererejected.Finally,they settled on the current name of NationalInstruments.44LabVIEW,agraphicaldevelopmentenvironmentLabWindows/CVI,anANSICprogrammingenvironmentMeasurementStudio,asetofcomponentsforMicrosoftVisualStudioNITestStand,fortestexecutionsequencingNIVeriStandforreal-timetestNIDIAdemfordatamanagementNIMultisimforcircuitdesignNIUltiboardforPCBdesignNIVisionBuilderforAutomatedInspectionNILabVIEWSignalExpressfordataloggingNISwitchExecutiveforswitchmanagementNIRequirementsGatewayforrequirementstrackingNationalInstrumentsengineeringsoftwareincludes:NICompactRIO,programmableFPGA-basedindustrialcontrollerNICompactDAQ,dataacquisitionsystemsforUSBandEthernetPXIPlatform,amodularinstrumentationstandardwithmorethan1,500productsNationalInstrumentshardwareplatformsinclude:Back4546此课件下载可自行编辑修改，仅供参考！此课件下载可自行编辑修改，仅供参考！感谢您的支持，我们努力做得更好！谢谢感谢您的支持，我们努力做得更好！谢谢
