imposedpowerbydedecms

FujiElectricJournalVol.
75No.
8,20021PowerElectronicsTechnologyTrendsandProspectsHidetoshiUmida1.
IntroductionPowerelectronicdeviceshaveachievedhigherperformancebyusingnewtechnologiessuchaspowertransistors,IGBTs(InsulatedGateBipolarTransistors),andmicroprocessors.
Inrecentyears,inresponsetothetrendofIT(InformationTechnology),FA(FactoryAutomation),andHA(HomeAutomation),facilitiesmanagementisbecomingintegratedinfactories,transportationsystems,powersystems,offices,andstores,whicharethetraditionalapplicationareaofpowerelectronicdevices.
Athome,thenumberofelectricalappliancesthatincludemarks"IH"(InductionHeating)and"Inverter"areincreasing.
Thebasicfunctionsofpowerelectronicsincludetheuseofelectronicstocontrolandtransformelectricenergyintermsofvoltage,current,frequency,andwaveform.
Thebasicfunctionsalsoincludetheuseofelectroniccontrolforconversiontootherformsofenergysuchaselectromagneticenergy,actuators,andhigh-frequencyinductionheating(Figure1).
Wecanthereforeexpectpowerelectronicstoplayanincreasinglyimportantroleintheaccuratemanagementandcontrolofelectricenergyathighspeedintheageofinformation.
ThispaperreportsonthetrendsinpowerelectronicsandthecurrentstateofresearchanddevelopmentatFujiElectric.
Fig.
1.
EssentialtechnologiesandpowerelectronicsproductsInverterfornewenergyapplicationPowersystemcompensatorServoUPSHigh-frequencyapplicationEngineeringPowerdeviceTopologyElectroniccircuitElectromagneticsCoolingStructureNumericalanalysisControlITVarioustypesofpowerunitsMotorInverter2.
CurrentStateandIssuesofPowerElectronicsPowerelectronicdevicesnormallyfeaturelowlossesbecausetheswitchingoperationsthattheyperformarecontrolledbytheon/offstateofsemiconductors.
However,becausetheycanalsocauseelectromagneticinterferenceduetoswitching,itisnecessarytomaximizetheadvantagesofthedeviceswhileeliminatingorminimizingtheirdisadvantages.
Sincethecontroltechnologyisflexibleandwideinapplicationsfromhigh-speedcontrolinthegenerationofpowerwithahighpeakdemandtooperationsthatsaveenergy,appropriateoperationscanbeadjustedtotherequiredconditions.
Itisthereforeusefultohaveaclearideaofthetrendoftechnologyfortheimprovementofperformance,functionsandofthenecessarybenchmarkswhilemaintainingharmonywithoursurroundings,includingtheenvironment,asseenfromvariouspointsofview.
(1)ReductionofresourceconsumptionandstresstotheenvironmentRoughlyspeaking,thesizeofcurrentpowerelectronicsequipmentisaboutone-tenththatof20yearsagoandtheirweightaboutone-fifth.
Ineffortstoreducetheamountofenergyconsumedandtoreducecarbondioxidelevels,attemptstosaveenergybyreducinglossrelatedtoelementsandcircuitsandtouseregenerativeenergyrecoveryhavebeenmade.
Tocontinuallymaximizetheeffectsoftheseefforts,newtechnologiesareneededtooptimizesystemoperationbeyondthepartialoptimizationtechniques,suchasthelow-losscircuitsystemsandnewpowerdevices,andthesizeandweightreductionprovidedbysuchtechniques.
(2)LimitingnoiseandharmonicsdistortionCircuitsthatsuppressnoiseandharmonicsdistortioncausedbytheswitchingofpowerdevicesandstructuresthatblocktheradiationofnoiseareimportantasmeansofpreventingfailuresanderrorsinotherelectronicequipment.
Inrecentyears,steadyprogresshasbeenmadeinthestandardizationofEMC(ElectromagneticCompatibility).
IntheIECstandardoftheInternationalElectrotechnicalCommission,adirectivewasissuedtolimittheterminalvoltagenoise(conductivenoise)in150kHz-30MHztonomorethanthepresetvalue.
InJapan,"TheGuidelinesforHigh-VoltageUsers"andthe"GuidelinesforProtectiveMeasuresagainstHarmonicsinHouseholdAppliancesandGeneral-PurposeProducts"alongwiththeIECdirectivewereestablishedin1994toimposeself-regulation.
Fordomesticinformationprocessingdevices,self-regulationwasimposedbytheVCCI(VoluntaryControlCouncilforInformationProcessingEquipmentandElectronicOfficeMachines)toeliminateradiointerferencecausedbyelectromagneticradiation.
Thedevelopmentofequipmentthatconformtotheaboverequirementsandthatareelectromagneticallyclean,requiresadvancedcircuitsandstructuretechnologiesthatsuppresspowersupplyharmonicsandterminalvoltagenoise.
FujiElectricJournalVol.
75No.
8,20022(3)SeekingnewvaluesAsinformationcontinuestogaingreaterimportance,wecanexpectmorecontributionsfromthecreationofnewcutting-edgetechnologies,inwhichthecontrolofelectricenergy,motionandITarecloselyintegrated,byimprovingthelevelofdeviceperformance.
Eventoday,practicalequipmentwithsurprisinglevelsofperformance,suchasfastresponseIGBTtypeSVCs(StaticVarCompensator)thatcontrolsreactivepowerofseveraltensofMVA,high-speedpowersupplieswhichprovidelow-voltageandlargecurrentstohigh-speedCPUs,andservosthatcontrolprecisionmechanicalequipmentontheorderofnm,arebeingintroducedoneaftertheother.
3.
AppliedPowerElectronicTechnologiesThekeyelementsrequiredinpowerelectronicequipmentarethepowerdevices.
AsshowninFigure2,controllablepowerdevicesstartedwiththethyristor.
Theyhavesinceprogressedtothebipolartransistor,GateTurn-Offthyristor(GTO)andlatelytotheIGBT.
Becauseitisrelativelyeasytomakeahigh-voltage,large-capacityIGBT,theIGBTisexpectedtoreplacethethyristorandGTO.
ItisalsoimportanttodevelopIGBTswhichhavesuperiorcharacteristicstootherpowerdevices.
Thefollowingdescribesappliedtechnologiesforpowerdevices.
Fig.
2.
PowerdevicetimelineDevicecapacityMVA2000199019801970YearThyristorGTOIGBTMOSFETBipolartransistor3.
1AppliedTechnologiesforNewPowerDevicesFujiElectriciscurrentlyworkingtodeveloptwonewdevices,theFS-IGBT(FieldStopIGBT)andreverse-blockingIGBT.
Astheworkondevicedevelopmentcontinues,appliedtechnologiesarebeingdeveloped,too.
(1)FS-IGBTTheFS-IGBTisafasterdevicecomparedwithconventionalonesaswellasithasasubstantialreducedforwardvoltagedrop(seeFigure5inthepaper"AppliedTechnologyforLarge-Capacity6-in-1IGBTModules"inthisspecialissue).
Aslim-linepackagewithafootprintone-halfthatofconventionaldeviceshasbeenimplementedbyoptimallylayingoutIGBTchipsthatcantakehighercurrentdensitiesandinput/outputterminals.
Whenweevaluatedaprototypeinverterstackthatincludesahigh-performancecoolingfan,theresultweobtainedshowedareductioninlossofabout20%.
Thisresultleadstoasubstantialminiaturizationofinvertersandpowersupplyequipment.
(2)Reverse-blockingIGBTThereverse-blockingIGBTisanentirelynewdevicewithreversewithstandvoltage.
ConventionalIGBTshavenoreversewithstandvoltageandarelimitedtoopeningandclosingintheforwarddirectiononly.
TheconventionalIGBTisthereforenotsuitableforcircuitstowhichreversevoltageisapplied,eventhoughsimpleones,suchasathyristorrectifier.
Thenewlydevelopedreverse-blockingIGBT,withitsproprietarywithstandvoltagestructure,succeedsinhavingreversewithstandvoltagewithoutincreasingtheforwardvoltagedrop.
Whentworeverse-blockingIGBTsareconnectedinanantiparallelconnection,abidirectionalswitchthatisalmostideallyfastandlowinlosscanberealized(seeFigure4inthepaper"AppliedTechnologyforReverse-BlockingIGBTs"inthisspecialissue).
Anewpowerdeviceisasourcefornewapplications.
Withtheadventofthereverse-blockingIGBT,wecanexpectnewdevelopmentsincircuitsystems,includingAC-ACdirectconversion.
3.
2SensingTechnologywithinthePackageInalarge-capacitypowerdeviceinwhichmultiplechipsaremounted,ensuringreliabilityisamajorproblem.
MultipleIGBTchipsmountedinapackagearedesignedsothattheloadamongthemisbalanced.
Thebalancingisaccomplishedbyreducingdifferencesinoperatingconditionsresultingfromthestructureandlayouttoaminimum.
However,whenweattemptedtochecktheloadbalancingundermorestringentconditions,itwasnoteasytomeasurethecurrentofeachchipwithinanarrowpackagewithhighelectromagneticfields,andasmall,high-speedsensorwiththerequiredprecisionwasdifficulttoobtain.
Wethereforedevelopedamicrosensorthatcouldbeincorporatedintopressureweldingelements(seeFigure3)andsucceededinobservingminutedifferencesinchipcurrentwithoutaffectingtheelements.
Thisprocedurealsoverifiedthattheloadisbalancednormallyinallareas.
Wethinkitispossibletousethismeasuringtechnologytoimprovetheperformanceandreliabilityoflarge-capacitypowerdevices.
Fig.
3.
PrincipleandappearanceofthecurrentsensorSmallcoilcross-section(a)PrincipleoftheRogowskiicoil(b)AppearanceisipRovtvtdtIntegrator()()FujiElectricJournalVol.
75No.
8,200234.
TechnologicalTrendsandChallengesFigure4summarizestherelationshipsamongthepowersupply,drivefieldsandtheessentialtechnologyforcircuits,control,andinformation.
Becauselownoise,highpowerfactor,lowharmonics,andhighefficiencyarethemeasuresofdevicesinthepowersupplyfield,theemphasisisoncircuittechnology.
Inparticular,ifthecapacityissmall,implementationwiththeminimumnumberofpartsbecomesimportant.
Inthedrivefield,ontheotherhand,theemphasisisonoperationandcontrol––forexample,energy-savingoperation,reductionoflaborbytuning,andbetterperformancethroughstateestimationandidentification.
Theseries-parallelconnectiontechnologyoftheIGBTposesachallengeinboththedrivefieldandinpowersupplyfieldforincreasingcapacity.
Thefollowingexplainshowtheseessentialtechnologiesandapplicationsarebeingaddressed.
Fig.
4.
RelationshipsamongessentialtechnologiesandthepowersupplyanddrivefieldsSoftswitchingMultilevelconverterEnergy-savingoperationComputerizationHigh-performanceconverterHigh-speedcontrolEstimation/identificationTuningAdvancecontrolControltechnologyCircuittechnologyElementseries-parallelconnectionLownoise,lowlossHighpowerfactor,lowharmonicsMaintenance,serviceSystemcontrol,plantcontrol,maintenance,serviceHighperformanceLowlossLesslaborHighresponseHighresponseLargecapacityLargecapacityLowsurge,highvoltagePowersupplyfieldDrivefield4.
1ChallengesinthePowerSupplyField4.
1.
1Noise,harmonics,andlossreductionSoftswitchingisatechnologythatattacksthegivenproblemsbyusingtheresonanceofcircuits.
Thistechnologyisparticularlysuitableforasmallpowersupplywithhighswitchingfrequencies.
Oneoftheproblemsenteringpublicawarenessrecentlyisthereductionofpowerconsumptioninthestandbystate.
Asasolutiontothisproblem,atopclasstechnologyforlowpowerconsumptioninthestandbystatethatusesintermittentoperationbyburstoscillationhasbeendeveloped.
Ahighlevelofintegrationiseffectiveforimplementingasmall-capacitycircuitwithgoodreproducibilitywhilesatisfyingthecomplexrequirementsdescribedabove.
FujiElectrichasalreadybroughttomarketICsforpowersupplyswitching.
Figure5showstheIC.
ApowersupplywitharatingoftheseveralhundredsWtoseveralkWisinmanycasesusedforserverandcommunicationsequipment.
Suchapowersupplyshouldthereforefeaturehighlevelsofprecisionandefficiency,ahighpowerfactor,andlowharmonicssothatthesystemwilloperateefficientlyandstably.
FujiElectrichasproposedthesystemshowninFigure1ofthepaper"AC-ACConversionCircuitTechnology"inthisspecialissueasasuperiorconversioncircuitinprinciplethatcancaptureallofthesefeaturesinasinglesystem(Figure6showsthecircuitconfigurationandthedevice).
Fig.
5.
ICforswitchingpowersupplyFig.
6.
Three-phaseAC-DCpowersupplyforworldwideuse3200VACor400VAC800VDC(a)Circuitconfiguration(b)Deviceappearance11kW/400VDCSR++TPNWorldwidePFCDC-DCconverterFujiElectricJournalVol.
75No.
8,200244.
1.
2NewapplicationsSomedevicesusedinrecentproductionfacilitiesandinformationprocessingrequireaverystablepowersupplyenvironment.
Ifaninstantaneousvoltagedropoccurs,thedamages,suchasvariousproblemsandreductioninyield,areserious.
Also,aproblemwiththeconventionalUPS(UninterruptiblePowerSupply)istherapiddeteriorationofbatteriescausedbyrepeatedcharginganddischargingofthebatteriesifinstantaneousvoltagedropsarefrequent.
FujiElectrichasmadecommerciallyavailableequipmentthattakesspecialmeasuresforinstantaneousvoltagedrops.
Figure7(b)showstheprincipleofoperation.
BecausealargecapacitorisusedasanenergystoringelementinsteadofthebatteriesusedinaUPSinFigure7(a),thedevicehasexcellentreliabilityanddoesnotrequiremaintenanceforalongtime.
Wethinkthatthedevicewillcontributemuchtoimprovethequalityofsuppliedpower.
Fig.
7.
ComparisonofbasicconfigurationsofUPSandequipmentprovidingproprietarymeasuresforinstantaneousvoltagedropsConverterACDCInverterACDCConverterACDCInverterACDC(a)UPSWhenbiasedWhenbiasedPowersystemBatteryLargecapacitorThenumberofcharginganddischargingtimesislimited.
(b)EquipmentprovidingproprietarymeasuresforinstantaneousvoltagedropsPowersystemThereisnolimitonthenumberofcharginganddischargingtimes.
+LoadLoad4.
2DriveSystemChallengesPresentedherearethetechnologiesfortheinverterandservo,themainapplicationsinthemotordrivefield.
4.
2.
1InvertercontroltechnologyInverterssuitableforinductionmachinesorpermanentmagnetsynchronousmachineshavebeendeveloped.
Withregardtoinductionmachines,vectorcontrol,speedsensorlessvectorcontrol,V/fcontrol,andanenhancedtypeofV/fcontrol(thatis,torquevectorcontrol)arealreadybeingusedinawiderangeofmotors,fromspecializedmotorsandgeneral-purposemotorstohigh-voltagemotors.
FujiElectrichasanoperationalversionofvectorcontrolandV/fcontrolforpermanentmagnetsynchronousmachinedrives.
AV/fcontrolthatcanbeeasilyhandledisappropriateforenergy-savingdrivesbecausehigh-efficiencycontrolisimplemented.
TheV/fcontrolachievesacontrolperformancethatiscomparabletothespeedsensorlessvectorcontrol(seeFigure6inthepaper"SensorlessControlTechnologyofPermanentMagnetSynchronousMotors"inthisspecialissue).
4.
2.
2NewservofunctionsWorkonservosystemsusedforhigh-speedandhigh-precisionapplicationsisfocusedontwoareas.
Oneareaistheperformanceimprovementoftheservoamplifier.
High-speedpositioninganddampingcontrolareessentialinobtainingthebestperformancefrommachinesinwhichaservoisinstalled.
Theotherareaisasupporttoolusedfortuningwhentheworkingmachinesareincorporated.
Themachineanalysisfunctionincorporatedinthetoolcananalyzethecomplexmachineoscillationmodesthataretobeusedtotunethesystem.
Figure8showsanexampleofcombiningtheservosystemandthesupporttool.
Hithertoalongtimewasneededfortuningiftherewerecomplexmachinevibrations.
Whenthesupporttoolisused,tuningofthevibrationsuppressioncontrolarebothquickandaccurate.
Iftheidentificationaccuracyofthemachinetransferfunctionisimprovedinthefuture,automatictuningoftheservomaybeexpected.
Fig.
8.
FALDIC-βandsupportsystemFujiElectricJournalVol.
75No.
8,200254.
3HighPowerTechnologyInalarge-capacityconverterusedforflickercompensation,reactivepowercompensation,ordrivingofalargemotorinapowersystem,therequiredequipmentcapacitymustbeimplementedusingseries-parallelconnectionsofpowerdevices.
Intheconventionalseriestechnology,afunctionthatbalancesthevoltageamongthethyristor,GTO,andIGBTisimplementedusingaresistororsnubbercircuit.
Whenthismethodisused,lossduetotheresistorislargeandthebalancecanbemaintainedatalowcarrierfrequencyandswitchingspeed.
Theserestrictionspreventminiaturizationoftheconvertersandhinderperformance.
FujiElectrichasdevelopedanewseriestechnologythatcouldovercometheseproblems.
Theconfigurationisasimpleoneinwhichbalancecoresareinsertedforthegatedrive.
SincethebalanceismaintainedautomaticallybytheamplificationoftheIGBT,thetechnologyhaspotentialforhigherperformanceathighcarrierfrequencies.
Figure9showsabasicconfigurationwhenamultiseriescircuitisappliedtotheinverter.
Fig.
9.
BasicconfigurationofmultiseriescircuitsDCvoltageGatedrivecircuit(upperarm)GatebalancecoreGatedrivecircuit(lowerarm)+5.
ConclusionInthispaper,wepresentedanoverviewofthecurrentresearchanddevelopmentinpowerelectronics.
Inthefuture,wealsointendtoconsolidateandimproveourtechnicalexpertiseinresponsetovarioustypesofneedsandtoquicklydevelopnewtechnologiesthatwillplayapartinsolvingenvironmentalandenergyproblems.
References(1)Gekinozu,M.
High-EfficiencySelf-OscillatingCurrentResonantConverter.
ElectronicTechnology.
vol.
43,no.
5,2001,pp.
22-25.
(2)Miwa,K.
,Kuroki,K.
SimulationAnalysisResultsandExperimentResultsofRectifierCircuitsforWorldwideUse.
SemiconductorPowerConversionSPC-00-78IndustrialElectronicsApplicationIEA-00-54JointSymposium.
2000,pp.
23-28.
(3)Igarashi,M.
etal.
SimplePowerFactorImprovedNewSectionResonantConverter.
SemiconductorPowerConversionSocietySPC-00-19.
2000,pp.
37-42.
(4)Itoh,J.
etal.
HigherPerformanceofV/fControlofPermanentMagnetSynchronousMotors.
JournalDoftheInstituteofElectricalEngineersofJapan.
vol.
122,no.
3,2002,pp.
253-259.