電氣類外文翻譯

1、1、外文原文（復(fù)印件）外文原文（復(fù)印件）A:TheUtilityInterfacewithPowerElectronicSystemIntroductionWediscussedvariouspowerlinedisturbanceshowpowerelectronicconverterscanperfmaspowerconditionersuninterruptiblepowersuppliestopreventthesepoweli

2、nedisturbancesfromdisruptingtheoperationofcriticalloadssuchascomputersusedfcontrollingimptantprocessesmedicalequipmentthelike.Howeverallpowerelectronicconverters(includingthoseusedtoprotectcriticalloads)canaddtotheinhere

3、ntpowerlinedisturbancesbydisttingtheutilitywavefmduetoharmoniccurrentsinjectedintotheutilitygridbyproducingelectromagicinterferenceToillustratetheproblemsduetocurrentharmonicsihintheinputcurrentisofapowerelectronicloadco

4、nsiderthesimpleblockdiagramofFig.16A1.Duetothefinite(nonzero)internalimpedanceoftheutilitysourcewhichissimplyrepresentedbyLsinFig.l6A1thevoltagewavefmatthepointofcommoncouplingtotheotherloadswillbecomedisttedwhichmaycaus

5、ethemtomalfunction.Inadditiontothevoltagewavefmdisttionsomeotherproblemsduetotheharmoniccurrentsareasfollows:additionalheatingpossiblyovervoltages(duetoresonanceconditions)intheutilitysdistributiontransmissionequipmenter

6、rsinmeteringmalfunctionofutilityrelaysinterferencewithcommunicationcontrolsignalssoon.Inadditiontotheseproblemsphasecontrolledconverterscausenotchesintheutilityvoltagewavefmmanydrawpowerataverylowdisplacementpowerfactwhi

7、chresultsinaverypopowerfactofoperation.Thefegoingdiscussionshowsthattheproliferationofpowerelectronicsystemsloadshasthepotentialfsignificantnegativeimpactontheutilitiesthemselvesaswellasontheircustomers.Oneapproachtomini

8、mizethisimpactistofiltertheharmoniccurrentstheelectromagicinterference(EMI)producedbythepowerelectronicloads.Abetteralternativeinspiteofasmallincreaseintheinitialcostmaybetodesignthepowerelectronicequipmentsuchthatthehar

9、monicconsistoflargeharmonicmagnitudes.TherefefafiniteinternalperphasesourceimpedanceLsthevoltagedisttionatthepointofcommoncouplinginFig.16A1canbesubstantial.ThehighertheinternalsourceinductanceLsthegreaterwouldbethevolta

10、gedisttion.CurrentHarmonicsPowerFactAswediscussedinothersectionthepowerfactPFatwhichanequipmentoperatesistheproductofthecurrentratioIlIsthedisplacementpowerfactDPF:InEq.(16AI)thedisplacementpowerfactequalsthecosineofthea

11、ngleΦ1.ThecurrentratioIlIsinEq.(16Al)istheratioofthermsvalueofthefundamentalfrequencycurrentcomponenttothermsvalueofthetotalcurrent.Thepowerfactindicateshoweffectivelytheequipmentdrawspowerfromtheutilityatalowpowerfactof

12、operationfagivenvoltagepowerlevelthecurrentdrawnbytheequipmentwillbelargethusrequitingincreasedvoltampereratingsoftheutilityequipmentsuchastransfmerstransmissionlinesgenerats.Theimptanceofthehighpowerfacthasbeenrecognize

13、dbyresidentialofficeequipmentmanufacturersftheirownbenefittomaximizethepoweravailablefromawalloutlet.Fexamplefroma120V15Aelectricalcircuitinabuildingthemaximumpoweravailableis1.8kWprovidedthepowerfactisunity.Themaximumpo

14、werthatcanbedrawnwithoutexceedingthe15Alimitdecreaseswithdecreasingpowerfact.Thefegoingargumentsindicatetheresponsibilitydesirabilityonthepartoftheequipmentmanufacturersuserstodesignpowerelectronicequipmentwithahighpower

15、factofoperation.ThisrequiresthatthedisplacementpowerfactDPFshouldbehighinEq.(16AI).MeoverthecurrentharmonicsshouldbelowtoyieldahighcurrentratioI1IsinEq.(16A1).B:AThreephasePreconverterfInductionHeatingMOSFETBridgeInverte