外文翻译外文文献英文文献现代变频器技术分析道

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1、ModernfrequencychangertechnicalanalysisChengXiHeilongjianglongmaymininggroupco.ltd.Thegeneralfrequencychangerbyitsmeritsandsoonintellectualizationdigitizationnetworkreceivespeoplesfavormoreandmorebutalongwiththegeneralfrequencychangerapplicationscopesexpansionexposessomequestions.Inviewoftheseque

2、stionsthisarticlecarriedonhasanalyzedandproposedthecountermeasure.Firstovertonequestionandcountermeasure.Thegeneralfrequencychangersmaincircuitformgenerallybytherectificationpartthecontravariantpartandthefilterpartiscomposed.Therectificationpartforthethree-phasebridge-typeuncontrolledrectifierthe

3、invertorspartistheIGBTthree-phasebridge-typeinvertorsandtheoutputisthePWMprofile.Becausethegeneralfrequencychangersrectificationpartusesthediodeuncontrolledbridge-typelevelingcircuitthemiddlefilterpartusesthebigelectriccapacitytotakethefilterthereforerectifiersinputcurrentinfactiscapacitorschargi

4、ngcurrentassumesahighermoreandprecipitouspulsewaveitsharmoniccomponentisbig.Fortheharmoniccancellationmayuse:1Increasesthefrequencychangerelectricpowersupplyinternalresistance.Usuallyinthesituationpowerequipmentsinternalresistancemayplaythecushionfrequencychangerconcurrentfilterelectriccapacitysr

5、eactivepowerrole.Thiskindofinternalresistanceistransformersshort-circuitimpedance.WhenpowersourcecapacityrelativefrequencychangercapacityhourthentheinternalresistancevaluerelativelyisbiggertheharmoniccontentissmallerWhenthepowersourcecapacityrelativefrequencychangercapacityisbiggerthentheinternal

6、resistancevaluerelativelyisbiggertheharmoniccontentisbigger.Thereforebestchoiceshort-circuitimpedancebigtransformer.2Installsthereactor.Installsthereactorisactuallyincreasesthefrequencychangerelectricpowersupplysinternalresistaneefromexterior.Installsthedirect-currentreactorinfrequencychangersexc

7、hangesideinstallmentexchangereactororinfrequencychangersdirect-currentsidealsoorinstallssuppressestheharmoniccurren匸3Transformerheterogeneitymovement.Thegeneralfrequencychangersrectificationpartissixpulsewaverectifiers