LED照明电源单级PFC高频变压器设计----超实用

('livingstandards,poorfarmersinlessthancompleteeliminationof4600Yuan,8949,19008."Fivewatersrule":theCountyinvested2.169billionyuan,similarcountieslinethecity\'sfirstcompletethe42kmofsewagepipenetworkconstruction,completionraterankedfirstinthecity,wontheprovincialruralsewagetreatmentworkbetter;keypollutionsourcessuchaselectroplating,papermaking,chemicalindustrymanagementthroughverificationandacceptanceofthemunicipalgovernment,theCountyremovedBlackandodorousRiver,Riverwaste,beginningofriverecologicalrestorationeffects."Threemodifiedasplit"aspects:Countytotaldemolitionillegalareaup2.759millionsquaremeters,completedCityissuedannualtaskof153%,splitagainstarearankingcitysecond;completed"threemodified"area4.846millionsquaremeters,completedCityissuedannualtaskof403%,rankingcitythird,whichvillageintheatargetcompletedtotalcityrankingfirst;CountyGovernmentwasnamedcitylevel"threemodifiedasplit"workadvanced.Theseachievementsarehardwonandshouldbeappreciated.However,wearefullyaware,thenewperiod,andworkinthecountrysideandtheenvironmentfacinghigherstandardsandrequirements,provincialpartyCommitteeofferedtohighlevelbuildacomprehensivewell-offsocietygoalrequires"nofilth,dirtyenvironmentillegalbuildings,intoawell-off";municipalpartyCommitteealsoproposestobuildintothewell-offbenchmarkgoalsofthecity.Comparedwiththesuperiorclaim,"SouthGateofXXbeautiful"goal,myCounty"SanNong"andenvironmentthereareanumberofweaknessesandgaps,highlightedinthefollowingfiveaspects:first,agricultureremained"low"pattern."Low"isreflectedinthequalityandlow;short,valueaddedoftheindustrychainislow;123fusionyieldlowemployeeage,lowquality."Small"isreflectedinsmaller,specializedcooperativesthroughouttheCountytherewere3,396,butonthescaleoftoolittle."San"isreflectedinproduction,management,services,decentralized,centralized,standardized,brand,informationandorganizationallevelisnothigh.Second,thecountrysideisstillin"dirty"phase."Dirty"isdirtyofruralsanitationsituationhasnotchanged."Chaos"isavillageinruralhousingconstructionplanning,constructionofdisorder,nodrawings,noconstruction,novetting"fourno"phenomenon,heaplyingthere."Bad"istheweakruralbase,villagegovernanceispoor.Thirdly,farmerscontinuedtobe"persistent"look."Old"isaging,rurallaborforceaccountedfor70%overtheageof50."Big"isthatthereformmeasuresgroundresistance,suchasthetransactionsofpropertyrights,landreplacement;publicservicesupplygap,ruraleducation,healthcare,pensionsandotherservicescannotmeetthedemandstilldifficultforpovertyalleviation,withemphasisonpovertyalleviationand191."Hard"isa"peasants,peasants.Fourwatereffectsstilllacks五步搞定LED照明电源单级PFC高频变压器设计.由于LED照明电源要求：民用照明PF值必需大于0.7,商业照明必需大于0.9.对于10~70W的LED驱动电源，一般采用单级PFC来设计。即节省空间又节约成本。接下来我们来探讨一下单级PFC高频变压器设计。以一个60W的实例来进行讲解：输入条件：电压范围：176~265Vac50/60HzPF》0.95THD《25%效率ef〉0.87输出条件：输出电压：48V输出电流：1.28A第一步：选择ic和磁芯：Ic用士兰的SA7527,输出带准谐振，效率做到0.87应该没有问题。按功率来选择磁芯，根据以下公式：Po=100FsVePo:输出功率；100:常数；Fs:开关频率；Ve:磁芯体积。在这里，Po=VoIo=481.28=61.44;工作频率选择：50000Hz;则：Ve=Po/（10050000）=61.4/（10050000）=12280mmmPQ3230的Ve值为：11970.00mmm,这里由于是调频方式工作。完全可以满足需求。可以代入公式去看看实际需要的工作频率为：51295Hz.第二步：计算初级电感量。最小直流输入电压：VDmin=1761.414=249V.最大直流输入电压：VDmax=2651.414=375V.消火栓给水系统和自动喷淋给水系统由设在地下二层的消火栓给水泵和自动喷淋给水泵经消防水池到消防给水泵，再向大楼各层消火栓和喷淋管网供水。同时消火栓给水系统和自动喷淋给水系统管网均与屋顶设置的生活、消防共用水箱相连、并通过屋顶设置的消防稳压设备进行稳压。compelling."Althoughthe"fivewatertreatment"alot,workveryhard,butthefloodofscientificenough,beforethetreatmentandwaterqualityimprovementafterthetreatmenteffectisnotobvious,county-widefocusonriverstilllargelyinferiorfivewater,swimmingtheRivercouldnotbefound.Fiveis"threetosplit"taskstillliesahead.Noticeofstockthere,newconstructiondidnotreceivetimelytreatmenteveryyear(suchasancestralhallasunauthorisedrepeated),contrarytothecreatedworkisverydifferentfromtheprovincialandmunicipalstandards.Meanwhile,whenimplementationisnotinplace,generallyonlyfocusonillegalconstructiondemolished,failingthatsplitthatisclear,combineddemolition,insufficientattentiontoreconstructionofoldresidentialareas,urbanvillages,shantytownsandpromotepoor.Tosolvetheseproblems,wemustenhancethesenseofresponsibilityandurgency,insistonproblem-oriented,totakestrongmeasures,effortstomakeupthe"threeagriculture"and"fivewatertreatment","threetosplita"shortBoard,constructionofcomprehensivesafeguards,"SouthGateofXXbeautiful"goalofrealizing.II,andprecisionShipolicy,andmanpowerplayinggood"threeagricultural"workprotracted"threeagricultural"workisdoeconomicsocialdevelopmenttheworkofbased,countylevelsthesectortoaccordingto"basedagricultural,andandmanpowerrural,anddevelopmentfarmers"ofrequirements,insistedagriculturalruralbasedstatusnotshake,insistedhuinongkulakpolicynotweakened,insistedreforminnovationtestnotstop,effortscreatednewera"threeagricultural"worknewsituation.(A)tomakeagriculturemore.Toestablishtheconceptofagriculturearoundthepeopledemand,andcomprehensivelypromotethesupplysideofagriculturestructuralreform,strivetoenhancethequalityandefficiencyofagricultureandcompetitiveness.Focusisondoingthefourarticles.Oneisthesteadyincreaseofgrainarticle.Alwaystightenthestringforfoodsecurity,"ricebag"catchinhand,toholdlandintheadjustmentofagriculturalplantingstructureinthe"redline."Acceleratingtheconstructionofgrainribbons,improvingagriculturalinfrastructure,enhancefoodproductioncapacity,improvethequalityofagriculturalproducts,effectively"steadyincreaseofgrain"andmaintain"tongue."Second,industryconvergencearticle.Enhancethelevelofconcentration,intensificationofagriculture,creatingproduction,processing,distribution,salesandserviceinoneoftheagriculturalindustrialchain,tobreakdownthevaluechain,improveaddedvalue.Pushingforward"theInternet+agricultural"modeltoimproveagriculturalproduction,management,andservicelevel,innovatingthemodeofe-commercemarketingofagriculturalproducts,solvethedifficultproblemofsalesofagriculturalproducts.Agricultureandtourism,education,culture,health,pensionandotherdeepintegration,developleisure,travellivingstandards,poorfarmersinlessthancompleteeliminationof4600Yuan,8949,19008."Fivewatersrule":theCountyinvested2.169billionyuan,similarcountieslinethecity\'sfirstcompletethe42kmofsewagepipenetworkconstruction,completionraterankedfirstinthecity,wontheprovincialruralsewagetreatmentworkbetter;keypollutionsourcessuchaselectroplating,papermaking,chemicalindustrymanagementthroughverificationandacceptanceofthemunicipalgovernment,theCountyremovedBlackandodorousRiver,Riverwaste,beginningofriverecologicalrestorationeffects."Threemodifiedasplit"aspects:Countytotaldemolitionillegalareaup2.759millionsquaremeters,completedCityissuedannualtaskof153%,splitagainstarearankingcitysecond;completed"threemodified"area4.846millionsquaremeters,completedCityissuedannualtaskof403%,rankingcitythird,whichvillageintheatargetcompletedtotalcityrankingfirst;CountyGovernmentwasnamedcitylevel"threemodifiedasplit"workadvanced.Theseachievementsarehardwonandshouldbeappreciated.However,wearefullyaware,thenewperiod,andworkinthecountrysideandtheenvironmentfacinghigherstandardsandrequirements,provincialpartyCommitteeofferedtohighlevelbuildacomprehensivewell-offsocietygoalrequires"nofilth,dirtyenvironmentillegalbuildings,intoawell-off";municipalpartyCommitteealsoproposestobuildintothewell-offbenchmarkgoalsofthecity.Comparedwiththesuperiorclaim,"SouthGateofXXbeautiful"goal,myCounty"SanNong"andenvironmentthereareanumberofweaknessesandgaps,highlightedinthefollowingfiveaspects:first,agricultureremained"low"pattern."Low"isreflectedinthequalityandlow;short,valueaddedoftheindustrychainislow;123fusionyieldlowemployeeage,lowquality."Small"isreflectedinsmaller,specializedcooperativesthroughouttheCountytherewere3,396,butonthescaleoftoolittle."San"isreflectedinproduction,management,services,decentralized,centralized,standardized,brand,informationandorganizationallevelisnothigh.Second,thecountrysideisstillin"dirty"phase."Dirty"isdirtyofruralsanitationsituationhasnotchanged."Chaos"isavillageinruralhousingconstructionplanning,constructionofdisorder,nodrawings,noconstruction,novetting"fourno"phenomenon,heaplyingthere."Bad"istheweakruralbase,villagegovernanceispoor.Thirdly,farmerscontinuedtobe"persistent"look."Old"isaging,rurallaborforceaccountedfor70%overtheageof50."Big"isthatthereformmeasuresgroundresistance,suchasthetransactionsofpropertyrights,landreplacement;publicservicesupplygap,ruraleducation,healthcare,pensionsandotherservicescannotmeetthedemandstilldifficultforpovertyalleviation,withemphasisonpovertyalleviationand191."Hard"isa"peasants,peasants.Fourwatereffectsstilllacks最大输入功率：Pinmax=Po/ef=61.4/0.9=68.3W（设计变压器时稍微取得比总效率高一点）。最大占空比的选择：宽电压一般选择小于0.5,窄电压一般选择在0.3左右。考虑到MOS管的耐压，一般不要选择大于0.5,220V供电时选择0.3比较合适。在这里选择：Dmax=0.327.最大输入电流：Iinmax=Pin/Vinmin=68.3/176=0.39A最大输入峰值电流：Iinmaxp=Iin1.414=0.391.414=0.55AMOS管最大峰值电流：Imosmax=2Iinmaxp/Dmax=20.55/0.327=3.36A初级电感量：Lp=Dmax^2Vin_min/（2Iin_maxfs_min）10^3=0.3270.327176/（20.3950000）1000=482.55uH取500uH.第三步：计算初级匝数NP:查磁芯资料，PQ3230的AL值为：5140nH/N^2,在设计反激变压器时，要留一定的气息。选择0.6倍的AL值比较合适。在这里AL我们取：AL=2600nH/N^2则：NP=（500/0.26）^0.5=44第四步：次级匝数NS:VOR=VDminDmax=2490.327=81.4匝比n=VOR/Vo=81.4/48=1.696NS=NP/n=44/1.686=26第五步：计算辅助绕组NA查看IC的datasheet,知道VCC为11.5~30V.在这选16V.NA=NS/（VoVCC）=26/（48/16）=8.67取9.消火栓给水系统和自动喷淋给水系统由设在地下二层的消火栓给水泵和自动喷淋给水泵经消防水池到消防给水泵，再向大楼各层消火栓和喷淋管网供水。同时消火栓给水系统和自动喷淋给水系统管网均与屋顶设置的生活、消防共用水箱相连、并通过屋顶设置的消防稳压设备进行稳压。compelling."Althoughthe"fivewatertreatment"alot,workveryhard,butthefloodofscientificenough,beforethetreatmentandwaterqualityimprovementafterthetreatmenteffectisnotobvious,county-widefocusonriverstilllargelyinferiorfivewater,swimmingtheRivercouldnotbefound.Fiveis"threetosplit"taskstillliesahead.Noticeofstockthere,newconstructiondidnotreceivetimelytreatmenteveryyear(suchasancestralhallasunauthorisedrepeated),contrarytothecreatedworkisverydifferentfromtheprovincialandmunicipalstandards.Meanwhile,whenimplementationisnotinplace,generallyonlyfocusonillegalconstructiondemolished,failingthatsplitthatisclear,combineddemolition,insufficientattentiontoreconstructionofoldresidentialareas,urbanvillages,shantytownsandpromotepoor.Tosolvetheseproblems,wemustenhancethesenseofresponsibilityandurgency,insistonproblem-oriented,totakestrongmeasures,effortstomakeupthe"threeagriculture"and"fivewatertreatment","threetosplita"shortBoard,constructionofcomprehensivesafeguards,"SouthGateofXXbeautiful"goalofrealizing.II,andprecisionShipolicy,andmanpowerplayinggood"threeagricultural"workprotracted"threeagricultural"workisdoeconomicsocialdevelopmenttheworkofbased,countylevelsthesectortoaccordingto"basedagricultural,andandmanpowerrural,anddevelopmentfarmers"ofrequirements,insistedagriculturalruralbasedstatusnotshake,insistedhuinongkulakpolicynotweakened,insistedreforminnovationtestnotstop,effortscreatednewera"threeagricultural"worknewsituation.(A)tomakeagriculturemore.Toestablishtheconceptofagriculturearoundthepeopledemand,andcomprehensivelypromotethesupplysideofagriculturestructuralreform,strivetoenhancethequalityandefficiencyofagricultureandcompetitiveness.Focusisondoingthefourarticles.Oneisthesteadyincreaseofgrainarticle.Alwaystightenthestringforfoodsecurity,"ricebag"catchinhand,toholdlandintheadjustmentofagriculturalplantingstructureinthe"redline."Acceleratingtheconstructionofgrainribbons,improvingagriculturalinfrastructure,enhancefoodproductioncapacity,improvethequalityofagriculturalproducts,effectively"steadyincreaseofgrain"andmaintain"tongue."Second,industryconvergencearticle.Enhancethelevelofconcentration,intensificationofagriculture,creatingproduction,processing,distribution,salesandserviceinoneoftheagriculturalindustrialchain,tobreakdownthevaluechain,improveaddedvalue.Pushingforward"theInternet+agricultural"modeltoimproveagriculturalproduction,management,andservicelevel,innovatingthemodeofe-commercemarketingofagriculturalproducts,solvethedifficultproblemofsalesofagriculturalproducts.Agricultureandtourism,education,culture,health,pensionandotherdeepintegration,developleisure,travellivingstandards,poorfarmersinlessthancompleteeliminationof4600Yuan,8949,19008."Fivewatersrule":theCountyinvested2.169billionyuan,similarcountieslinethecity\'sfirstcompletethe42kmofsewagepipenetworkconstruction,completionraterankedfirstinthecity,wontheprovincialruralsewagetreatmentworkbetter;keypollutionsourcessuchaselectroplating,papermaking,chemicalindustrymanagementthroughverificationandacceptanceofthemunicipalgovernment,theCountyremovedBlackandodorousRiver,Riverwaste,beginningofriverecologicalrestorationeffects."Threemodifiedasplit"aspects:Countytotaldemolitionillegalareaup2.759millionsquaremeters,completedCityissuedannualtaskof153%,splitagainstarearankingcitysecond;completed"threemodified"area4.846millionsquaremeters,completedCityissuedannualtaskof403%,rankingcitythird,whichvillageintheatargetcompletedtotalcityrankingfirst;CountyGovernmentwasnamedcitylevel"threemodifiedasplit"workadvanced.Theseachievementsarehardwonandshouldbeappreciated.However,wearefullyaware,thenewperiod,andworkinthecountrysideandtheenvironmentfacinghigherstandardsandrequirements,provincialpartyCommitteeofferedtohighlevelbuildacomprehensivewell-offsocietygoalrequires"nofilth,dirtyenvironmentillegalbuildings,intoawell-off";municipalpartyCommitteealsoproposestobuildintothewell-offbenchmarkgoalsofthecity.Comparedwiththesuperiorclaim,"SouthGateofXXbeautiful"goal,myCounty"SanNong"andenvironmentthereareanumberofweaknessesandgaps,highlightedinthefollowingfiveaspects:first,agricultureremained"low"pattern."Low"isreflectedinthequalityandlow;short,valueaddedoftheindustrychainislow;123fusionyieldlowemployeeage,lowquality."Small"isreflectedinsmaller,specializedcooperativesthroughouttheCountytherewere3,396,butonthescaleoftoolittle."San"isreflectedinproduction,management,services,decentralized,centralized,standardized,brand,informationandorganizationallevelisnothigh.Second,thecountrysideisstillin"dirty"phase."Dirty"isdirtyofruralsanitationsituationhasnotchanged."Chaos"isavillageinruralhousingconstructionplanning,constructionofdisorder,nodrawings,noconstruction,novetting"fourno"phenomenon,heaplyingthere."Bad"istheweakruralbase,villagegovernanceispoor.Thirdly,farmerscontinuedtobe"persistent"look."Old"isaging,rurallaborforceaccountedfor70%overtheageof50."Big"isthatthereformmeasuresgroundresistance,suchasthetransactionsofpropertyrights,landreplacement;publicservicesupplygap,ruraleducation,healthcare,pensionsandotherservicescannotmeetthedemandstilldifficultforpovertyalleviation,withemphasisonpovertyalleviationand191."Hard"isa"peasants,peasants.Fourwatereffectsstilllacks绕法：总结通过样品的测试，实验结果为：整机效率0.88,PF值：176V时0.989;220V时0.984;265V时0.975.变压器温升25K.在整个变压器设计过程中。简化了一些东西。比如二极管的压降。对比一下，与一般反激式的变压器有点一致。只是由于整流桥后没有接大容量的电解电容。实际的直流最低电压没有1.414倍。随着LED在照明、背光等场合的应用，用户在面对体积、调光控制、成本、转换效率等方面有更多的考虑因素。近年来，采用原边反馈方式的LED驱动器发展迅速，与传统的副边反馈的光耦加TL431的结构相比，其最大的优势在于省去了这两个芯片以及与之配合工作的一组元器件，这样就节省了系统板上的空间，降低了成本并且提高了系统的可靠性。例如，美国MPS公司推出的MP4021/4020，在针对AC85V~265V全电压输入范围里，可以提供30W内的解决方案。其采用原边控制架构的LED驱动电路具有成本和性能优势，消火栓给水系统和自动喷淋给水系统由设在地下二层的消火栓给水泵和自动喷淋给水泵经消防水池到消防给水泵，再向大楼各层消火栓和喷淋管网供水。同时消火栓给水系统和自动喷淋给水系统管网均与屋顶设置的生活、消防共用水箱相连、并通过屋顶设置的消防稳压设备进行稳压。compelling."Althoughthe"fivewatertreatment"alot,workveryhard,butthefloodofscientificenough,beforethetreatmentandwaterqualityimprovementafterthetreatmenteffectisnotobvious,county-widefocusonriverstilllargelyinferiorfivewater,swimmingtheRivercouldnotbefound.Fiveis"threetosplit"taskstillliesahead.Noticeofstockthere,newconstructiondidnotreceivetimelytreatmenteveryyear(suchasancestralhallasunauthorisedrepeated),contrarytothecreatedworkisverydifferentfromtheprovincialandmunicipalstandards.Meanwhile,whenimplementationisnotinplace,generallyonlyfocusonillegalconstructiondemolished,failingthatsplitthatisclear,combineddemolition,insufficientattentiontoreconstructionofoldresidentialareas,urbanvillages,shantytownsandpromotepoor.Tosolvetheseproblems,wemustenhancethesenseofresponsibilityandurgency,insistonproblem-oriented,totakestrongmeasures,effortstomakeupthe"threeagriculture"and"fivewatertreatment","threetosplita"shortBoard,constructionofcomprehensivesafeguards,"SouthGateofXXbeautiful"goalofrealizing.II,andprecisionShipolicy,andmanpowerplayinggood"threeagricultural"workprotracted"threeagricultural"workisdoeconomicsocialdevelopmenttheworkofbased,countylevelsthesectortoaccordingto"basedagricultural,andandmanpowerrural,anddevelopmentfarmers"ofrequirements,insistedagriculturalruralbasedstatusnotshake,insistedhuinongkulakpolicynotweakened,insistedreforminnovationtestnotstop,effortscreatednewera"threeagricultural"worknewsituation.(A)tomakeagriculturemore.Toestablishtheconceptofagriculturearoundthepeopledemand,andcomprehensivelypromotethesupplysideofagriculturestructuralreform,strivetoenhancethequalityandefficiencyofagricultureandcompetitiveness.Focusisondoingthefourarticles.Oneisthesteadyincreaseofgrainarticle.Alwaystightenthestringforfoodsecurity,"ricebag"catchinhand,toholdlandintheadjustmentofagriculturalplantingstructureinthe"redline."Acceleratingtheconstructionofgrainribbons,improvingagriculturalinfrastructure,enhancefoodproductioncapacity,improvethequalityofagriculturalproducts,effectively"steadyincreaseofgrain"andmaintain"tongue."Second,industryconvergencearticle.Enhancethelevelofconcentration,intensificationofagriculture,creatingproduction,processing,distribution,salesandserviceinoneoftheagriculturalindustrialchain,tobreakdownthevaluechain,improveaddedvalue.Pushingforward"theInternet+agricultural"modeltoimproveagriculturalproduction,management,andservicelevel,innovatingthemodeofe-commercemarketingofagriculturalproducts,solvethedifficultproblemofsalesofagriculturalproducts.Agricultureandtourism,education,culture,health,pensionandotherdeepintegration,developleisure,travellivingstandards,poorfarmersinlessthancompleteeliminationof4600Yuan,8949,19008."Fivewatersrule":theCountyinvested2.169billionyuan,similarcountieslinethecity\'sfirstcompletethe42kmofsewagepipenetworkconstruction,completionraterankedfirstinthecity,wontheprovincialruralsewagetreatmentworkbetter;keypollutionsourcessuchaselectroplating,papermaking,chemicalindustrymanagementthroughverificationandacceptanceofthemunicipalgovernment,theCountyremovedBlackandodorousRiver,Riverwaste,beginningofriverecologicalrestorationeffects."Threemodifiedasplit"aspects:Countytotaldemolitionillegalareaup2.759millionsquaremeters,completedCityissuedannualtaskof153%,splitagainstarearankingcitysecond;completed"threemodified"area4.846millionsquaremeters,completedCityissuedannualtaskof403%,rankingcitythird,whichvillageintheatargetcompletedtotalcityrankingfirst;CountyGovernmentwasnamedcitylevel"threemodifiedasplit"workadvanced.Theseachievementsarehardwonandshouldbeappreciated.However,wearefullyaware,thenewperiod,andworkinthecountrysideandtheenvironmentfacinghigherstandardsandrequirements,provincialpartyCommitteeofferedtohighlevelbuildacomprehensivewell-offsocietygoalrequires"nofilth,dirtyenvironmentillegalbuildings,intoawell-off";municipalpartyCommitteealsoproposestobuildintothewell-offbenchmarkgoalsofthecity.Comparedwiththesuperiorclaim,"SouthGateofXXbeautiful"goal,myCounty"SanNong"andenvironmentthereareanumberofweaknessesandgaps,highlightedinthefollowingfiveaspects:first,agricultureremained"low"pattern."Low"isreflectedinthequalityandlow;short,valueaddedoftheindustrychainislow;123fusionyieldlowemployeeage,lowquality."Small"isreflectedinsmaller,specializedcooperativesthroughouttheCountytherewere3,396,butonthescaleoftoolittle."San"isreflectedinproduction,management,services,decentralized,centralized,standardized,brand,informationandorganizationallevelisnothigh.Second,thecountrysideisstillin"dirty"phase."Dirty"isdirtyofruralsanitationsituationhasnotchanged."Chaos"isavillageinruralhousingconstructionplanning,constructionofdisorder,nodrawings,noconstruction,novetting"fourno"phenomenon,heaplyingthere."Bad"istheweakruralbase,villagegovernanceispoor.Thirdly,farmerscontinuedtobe"persistent"look."Old"isaging,rurallaborforceaccountedfor70%overtheageof50."Big"isthatthereformmeasuresgroundresistance,suchasthetransactionsofpropertyrights,landreplacement;publicservicesupplygap,ruraleducation,healthcare,pensionsandotherservicescannotmeetthedemandstilldifficultforpovertyalleviation,withemphasisonpovertyalleviationand191."Hard"isa"peasants,peasants.Fourwatereffectsstilllacks可以节省光耦和其它反馈电路，使得产品体积大大减小，从而很好地兼顾了成本和性能。其应用特点可简单概括为：另外，MP4021/4020能实现精确的次级侧LED驱动电流控制，其内置的补偿线路保证了驱动器在全温、宽电压和量产条件下的输出电流精度。跟我学系列之一，CCM模式APFC电路设计传统的工频交流整流电路，因为整流桥后面有一个大的电解电容来稳定输出电压，所以使电网的电流波形变成了尖脉冲，滤波电容越大，输入电流的脉宽就越窄，峰值越高，有效值就越大。这种畸变的电流波形会导致一些问题，比如无功功率增加、电网谐波超标造成干扰等。功率因数校正电路的目的，就是使电源的输入电流波形按照输入电压的变化成比例的变化。使电源的工作特性就像一个电阻一样，而不在是容性的。目前在功率因数校正电路中，最常用的就是由BOOST变换器构成的主电路。而按照输入电流的连续与否，又分为DCM、CRM、CCM模式。DCM模式，因为控制简单，但输入电流不连续，峰值较高，所以常用在小功率场合。CCM模式则相反，输入电流连续，电流纹波小，适合于大功率场合应用。介于DCM和CCM之间的CRM称为电流临界连续模式，这种模式通常采用变频率的控制方式，采集升压电感的电流过零信号，当电流过零了，才开通MOS管。这种类型的控制方式，在小功率PFC电路中非常常见。消火栓给水系统和自动喷淋给水系统由设在地下二层的消火栓给水泵和自动喷淋给水泵经消防水池到消防给水泵，再向大楼各层消火栓和喷淋管网供水。同时消火栓给水系统和自动喷淋给水系统管网均与屋顶设置的生活、消防共用水箱相连、并通过屋顶设置的消防稳压设备进行稳压。compelling."Althoughthe"fivewatertreatment"alot,workveryhard,butthefloodofscientificenough,beforethetreatmentandwaterqualityimprovementafterthetreatmenteffectisnotobvious,county-widefocusonriverstilllargelyinferiorfivewater,swimmingtheRivercouldnotbefound.Fiveis"threetosplit"taskstillliesahead.Noticeofstockthere,newconstructiondidnotreceivetimelytreatmenteveryyear(suchasancestralhallasunauthorisedrepeated),contrarytothecreatedworkisverydifferentfromtheprovincialandmunicipalstandards.Meanwhile,whenimplementationisnotinplace,generallyonlyfocusonillegalconstructiondemolished,failingthatsplitthatisclear,combineddemolition,insufficientattentiontoreconstructionofoldresidentialareas,urbanvillages,shantytownsandpromotepoor.Tosolvetheseproblems,wemustenhancethesenseofresponsibilityandurgency,insistonproblem-oriented,totakestrongmeasures,effortstomakeupthe"threeagriculture"and"fivewatertreatment","threetosplita"shortBoard,constructionofcomprehensivesafeguards,"SouthGateofXXbeautiful"goalofrealizing.II,andprecisionShipolicy,andmanpowerplayinggood"threeagricultural"workprotracted"threeagricultural"workisdoeconomicsocialdevelopmenttheworkofbased,countylevelsthesectortoaccordingto"basedagricultural,andandmanpowerrural,anddevelopmentfarmers"ofrequirements,insistedagriculturalruralbasedstatusnotshake,insistedhuinongkulakpolicynotweakened,insistedreforminnovationtestnotstop,effortscreatednewera"threeagricultural"worknewsituation.(A)tomakeagriculturemore.Toestablishtheconceptofagriculturearoundthepeopledemand,andcomprehensivelypromotethesupplysideofagriculturestructuralreform,strivetoenhancethequalityandefficiencyofagricultureandcompetitiveness.Focusisondoingthefourarticles.Oneisthesteadyincreaseofgrainarticle.Alwaystightenthestringforfoodsecurity,"ricebag"catchinhand,toholdlandintheadjustmentofagriculturalplantingstructureinthe"redline."Acceleratingtheconstructionofgrainribbons,improvingagriculturalinfrastructure,enhancefoodproductioncapacity,improvethequalityofagriculturalproducts,effectively"steadyincreaseofgrain"andmaintain"tongue."Second,industryconvergencearticle.Enhancethelevelofconcentration,intensificationofagriculture,creatingproduction,processing,distribution,salesandserviceinoneoftheagriculturalindustrialchain,tobreakdownthevaluechain,improveaddedvalue.Pushingforward"theInternet+agricultural"modeltoimproveagriculturalproduction,management,andservicelevel,innovatingthemodeofe-commercemarketingofagriculturalproducts,solvethedifficultproblemofsalesofagriculturalproducts.Agricultureandtourism,education,culture,health,pensionandotherdeepintegration,developleisure,travellivingstandards,poorfarmersinlessthancompleteeliminationof4600Yuan,8949,19008."Fivewatersrule":theCountyinvested2.169billionyuan,similarcountieslinethecity\'sfirstcompletethe42kmofsewagepipenetworkconstruction,completionraterankedfirstinthecity,wontheprovincialruralsewagetreatmentworkbetter;keypollutionsourcessuchaselectroplating,papermaking,chemicalindustrymanagementthroughverificationandacceptanceofthemunicipalgovernment,theCountyremovedBlackandodorousRiver,Riverwaste,beginningofriverecologicalrestorationeffects."Threemodifiedasplit"aspects:Countytotaldemolitionillegalareaup2.759millionsquaremeters,completedCityissuedannualtaskof153%,splitagainstarearankingcitysecond;completed"threemodified"area4.846millionsquaremeters,completedCityissuedannualtaskof403%,rankingcitythird,whichvillageintheatargetcompletedtotalcityrankingfirst;CountyGovernmentwasnamedcitylevel"threemodifiedasplit"workadvanced.Theseachievementsarehardwonandshouldbeappreciated.However,wearefullyaware,thenewperiod,andworkinthecountrysideandtheenvironmentfacinghigherstandardsandrequirements,provincialpartyCommitteeofferedtohighlevelbuildacomprehensivewell-offsocietygoalrequires"nofilth,dirtyenvironmentillegalbuildings,intoawell-off";municipalpartyCommitteealsoproposestobuildintothewell-offbenchmarkgoalsofthecity.Comparedwiththesuperiorclaim,"SouthGateofXXbeautiful"goal,myCounty"SanNong"andenvironmentthereareanumberofweaknessesandgaps,highlightedinthefollowingfiveaspects:first,agricultureremained"low"pattern."Low"isreflectedinthequalityandlow;short,valueaddedoftheindustrychainislow;123fusionyieldlowemployeeage,lowquality."Small"isreflectedinsmaller,specializedcooperativesthroughouttheCountytherewere3,396,butonthescaleoftoolittle."San"isreflectedinproduction,management,services,decentralized,centralized,standardized,brand,informationandorganizationallevelisnothigh.Second,thecountrysideisstillin"dirty"phase."Dirty"isdirtyofruralsanitationsituationhasnotchanged."Chaos"isavillageinruralhousingconstructionplanning,constructionofdisorder,nodrawings,noconstruction,novetting"fourno"phenomenon,heaplyingthere."Bad"istheweakruralbase,villagegovernanceispoor.Thirdly,farmerscontinuedtobe"persistent"look."Old"isaging,rurallaborforceaccountedfor70%overtheageof50."Big"isthatthereformmeasuresgroundresistance,suchasthetransactionsofpropertyrights,landreplacement;publicservicesupplygap,ruraleducation,healthcare,pensionsandotherservicescannotmeetthedemandstilldifficultforpovertyalleviation,withemphasisonpovertyalleviationand191."Hard"isa"peasants,peasants.Fourwatereffectsstilllacks今天我们主要谈适合大功率场合的CCM模式的功率因数校正电路的设计。要设计一个功率因数校正电路，首先我们要给出我们的一些设计指标，我们按照一个输出500W左右的APFC电路来举例：已知参数：交流电源的频率fac——50Hz最低交流电压有效值Umin——85Vac最高交流电压有效值Umax——265Vac输出直流电压Udc——400VDC输出功率Pout——600W最差状况下满载效率η——92%开关频率fs——65KHz输出电压纹波峰峰值Voutp-p——10V那么我们可以进行如下计算：1，输出电流Iout=Pout/Udc=600/400=1.5A2，最大输入功率Pin=Pout/η=600/0.92=652W3，输入电流最大有效值Iinrmsmax=Pin/Umin=652/85=7.67A4，那么输入电流有效值峰值为Iinrmsmax1.414=10.85A5，高频纹波电流取输入电流峰值的20%，那么Ihf=0.2Iinrmsmax=0.210.85=2.17A6，那么输入电感电流最大峰值为：ILpk=Iinrmsmax+0.5Ihf=10.85+0.52.17=11.94A7，那么升压电感最小值为Lmin=(0.25Uout)/(Ihffs)=(0.25400)/(2.1765KHz)=709uH8，输出电容最小值为：Cmin=Iout/(3.142facVoutp-p)=1.5/(3.1425010)=477.7uF，实际电路中还要考虑holdup时间，所以电容容量可能需要重新按照holdup的时间要求来重新计算。实际的电路中，我用了1320uF，4只330uF的并联。有了电感量、有了输入电流，我们就可以设计升压电感了！消火栓给水系统和自动喷淋给水系统由设在地下二层的消火栓给水泵和自动喷淋给水泵经消防水池到消防给水泵，再向大楼各层消火栓和喷淋管网供水。同时消火栓给水系统和自动喷淋给水系统管网均与屋顶设置的生活、消防共用水箱相连、并通过屋顶设置的消防稳压设备进行稳压。compelling."Althoughthe"fivewatertreatment"alot,workveryhard,butthefloodofscientificenough,beforethetreatmentandwaterqualityimprovementafterthetreatmenteffectisnotobvious,county-widefocusonriverstilllargelyinferiorfivewater,swimmingtheRivercouldnotbefound.Fiveis"threetosplit"taskstillliesahead.Noticeofstockthere,newconstructiondidnotreceivetimelytreatmenteveryyear(suchasancestralhallasunauthorisedrepeated),contrarytothecreatedworkisverydifferentfromtheprovincialandmunicipalstandards.Meanwhile,whenimplementationisnotinplace,generallyonlyfocusonillegalconstructiondemolished,failingthatsplitthatisclear,combineddemolition,insufficientattentiontoreconstructionofoldresidentialareas,urbanvillages,shantytownsandpromotepoor.Tosolvetheseproblems,wemustenhancethesenseofresponsibilityandurgency,insistonproblem-oriented,totakestrongmeasures,effortstomakeupthe"threeagriculture"and"fivewatertreatment","threetosplita"shortBoard,constructionofcomprehensivesafeguards,"SouthGateofXXbeautiful"goalofrealizing.II,andprecisionShipolicy,andmanpowerplayinggood"threeagricultural"workprotracted"threeagricultural"workisdoeconomicsocialdevelopmenttheworkofbased,countylevelsthesectortoaccordingto"basedagricultural,andandmanpowerrural,anddevelopmentfarmers"ofrequirements,insistedagriculturalruralbasedstatusnotshake,insistedhuinongkulakpolicynotweakened,insistedreforminnovationtestnotstop,effortscreatednewera"threeagricultural"worknewsituation.(A)tomakeagriculturemore.Toestablishtheconceptofagriculturearoundthepeopledemand,andcomprehensivelypromotethesupplysideofagriculturestructuralreform,strivetoenhancethequalityandefficiencyofagricultureandcompetitiveness.Focusisondoingthefourarticles.Oneisthesteadyincreaseofgrainarticle.Alwaystightenthestringforfoodsecurity,"ricebag"catchinhand,toholdlandintheadjustmentofagriculturalplantingstructureinthe"redline."Acceleratingtheconstructionofgrainribbons,improvingagriculturalinfrastructure,enhancefoodproductioncapacity,improvethequalityofagriculturalproducts,effectively"steadyincreaseofgrain"andmaintain"tongue."Second,industryconvergencearticle.Enhancethelevelofconcentration,intensificationofagriculture,creatingproduction,processing,distribution,salesandserviceinoneoftheagriculturalindustrialchain,tobreakdownthevaluechain,improveaddedvalue.Pushingforward"theInternet+agricultural"modeltoimproveagriculturalproduction,management,andservicelevel,innovatingthemodeofe-commercemarketingofagriculturalproducts,solvethedifficultproblemofsalesofagriculturalproducts.Agricultureandtourism,education,culture,health,pensionandotherdeepintegration,developleisure,travellivingstandards,poorfarmersinlessthancompleteeliminationof4600Yuan,8949,19008."Fivewatersrule":theCountyinvested2.169billionyuan,similarcountieslinethecity\'sfirstcompletethe42kmofsewagepipenetworkconstruction,completionraterankedfirstinthecity,wontheprovincialruralsewagetreatmentworkbetter;keypollutionsourcessuchaselectroplating,papermaking,chemicalindustrymanagementthroughverificationandacceptanceofthemunicipalgovernment,theCountyremovedBlackandodorousRiver,Riverwaste,beginningofriverecologicalrestorationeffects."Threemodifiedasplit"aspects:Countytotaldemolitionillegalareaup2.759millionsquaremeters,completedCityissuedannualtaskof153%,splitagainstarearankingcitysecond;completed"threemodified"area4.846millionsquaremeters,completedCityissuedannualtaskof403%,rankingcitythird,whichvillageintheatargetcompletedtotalcityrankingfirst;CountyGovernmentwasnamedcitylevel"threemodifiedasplit"workadvanced.Theseachievementsarehardwonandshouldbeappreciated.However,wearefullyaware,thenewperiod,andworkinthecountrysideandtheenvironmentfacinghigherstandardsandrequirements,provincialpartyCommitteeofferedtohighlevelbuildacomprehensivewell-offsocietygoalrequires"nofilth,dirtyenvironmentillegalbuildings,intoawell-off";municipalpartyCommitteealsoproposestobuildintothewell-offbenchmarkgoalsofthecity.Comparedwiththesuperiorclaim,"SouthGateofXXbeautiful"goal,myCounty"SanNong"andenvironmentthereareanumberofweaknessesandgaps,highlightedinthefollowingfiveaspects:first,agricultureremained"low"pattern."Low"isreflectedinthequalityandlow;short,valueaddedoftheindustrychainislow;123fusionyieldlowemployeeage,lowquality."Small"isreflectedinsmaller,specializedcooperativesthroughouttheCountytherewere3,396,butonthescaleoftoolittle."San"isreflectedinproduction,management,services,decentralized,centralized,standardized,brand,informationandorganizationallevelisnothigh.Second,thecountrysideisstillin"dirty"phase."Dirty"isdirtyofruralsanitationsituationhasnotchanged."Chaos"isavillageinruralhousingconstructionplanning,constructionofdisorder,nodrawings,noconstruction,novetting"fourno"phenomenon,heaplyingthere."Bad"istheweakruralbase,villagegovernanceispoor.Thirdly,farmerscontinuedtobe"persistent"look."Old"isaging,rurallaborforceaccountedfor70%overtheageof50."Big"isthatthereformmeasuresgroundresistance,suchasthetransactionsofpropertyrights,landreplacement;publicservicesupplygap,ruraleducation,healthcare,pensionsandotherservicescannotmeetthedemandstilldifficultforpovertyalleviation,withemphasisonpovertyalleviationand191."Hard"isa"peasants,peasants.FourwatereffectsstilllacksPFC电路的升压电感的磁芯，我们可以有多种选择：磁粉芯、铁氧体磁芯、开了气隙的非晶/微晶合金磁芯。这几种磁芯是各有优缺点，听我一一道来。磁粉芯的优点是，μ值低，所以不用额外再开气隙了。气隙平均，漏磁小，电磁干扰比较低，不易饱和。缺点是，基本是环形的，绕线比较困难，不过目前市场上也出现了EE型的。另外，μ值随磁场强度的增加会下降。设计的时候需要反复迭代计算。铁氧体磁芯的优点是损耗小，规格多，价格便宜，开了气隙后，磁导率稳定。缺点是需要开气隙，另外饱和点比较低，耐直流偏磁能力比较差。非晶/微晶合金的优点是饱和点高，开气隙后，磁导率稳定。同样缺点是需要开气隙。另外，大都是环状的。在此说明一下，环形铁芯虽然绕线比较困难，没有E型什么带骨架的那种容易绕。但是环形铁芯绕出来的电感分布电容小，对将来处理电磁兼容带来了很多便利之处。E型的骨架绕线一般都是绕好几层，那么层间电容比较大，对EMC产生不利影响。另外，开气隙的铁芯，在气隙处，铜损会变大。因为气隙处的漏磁在铜线上产生涡流损耗。下面我们就选择一种环形磁粉芯来作为我们PFC电感的磁芯。我们上面已经计算出了几个参数：输入电流最大有效值Iinrmsmax=Pin/Umin=652/85=7.67A输入电感电流最大峰值为：ILpk=Iinrmsmax+0.5Ihf=10.85+0.52.17=11.94A升压电感最小值为Lmin=(0.25Uout)/(Ihffs)=(0.25400)/(2.1765KHz)=709uH下面继续计算：线圈选择电流密度为5A/平方毫米，那么可以计算出我们需要用的漆包线的线径为：2×SQRT(7.67/(5×3.14))=1.4毫米因为我们这是按照最极限的输入电压也就是说按照最大的输入电流时来计算的。所以电流密度取的裕量比较大。实际按照不同的成本要求，也可以把电流密度取大一些，比如此处取电流密度为8A/平方毫米的话，那么可以得到线径为：2×SQRT(7.67/(8×3.14))=1.1毫米这也是可以接受的。因为是CCM模式的工作方式，基波是低频的半正弦波，在此处我们就不考虑趋肤效应了。选用单根的漆包线就可以了。常用的几个公式：消火栓给水系统和自动喷淋给水系统由设在地下二层的消火栓给水泵和自动喷淋给水泵经消防水池到消防给水泵，再向大楼各层消火栓和喷淋管网供水。同时消火栓给水系统和自动喷淋给水系统管网均与屋顶设置的生活、消防共用水箱相连、并通过屋顶设置的消防稳压设备进行稳压。compelling."Althoughthe"fivewatertreatment"alot,workveryhard,butthefloodofscientificenough,beforethetreatmentandwaterqualityimprovementafterthetreatmenteffectisnotobvious,county-widefocusonriverstilllargelyinferiorfivewater,swimmingtheRivercouldnotbefound.Fiveis"threetosplit"taskstillliesahead.Noticeofstockthere,newconstructiondidnotreceivetimelytreatmenteveryyear(suchasancestralhallasunauthorisedrepeated),contrarytothecreatedworkisverydifferentfromtheprovincialandmunicipalstandards.Meanwhile,whenimplementationisnotinplace,generallyonlyfocusonillegalconstructiondemolished,failingthatsplitthatisclear,combineddemolition,insufficientattentiontoreconstructionofoldresidentialareas,urbanvillages,shantytownsandpromotepoor.Tosolvetheseproblems,wemustenhancethesenseofresponsibilityandurgency,insistonproblem-oriented,totakestrongmeasures,effortstomakeupthe"threeagriculture"and"fivewatertreatment","threetosplita"shortBoard,constructionofcomprehensivesafeguards,"SouthGateofXXbeautiful"goalofrealizing.II,andprecisionShipolicy,andmanpowerplayinggood"threeagricultural"workprotracted"threeagricultural"workisdoeconomicsocialdevelopmenttheworkofbased,countylevelsthesectortoaccordingto"basedagricultural,andandmanpowerrural,anddevelopmentfarmers"ofrequirements,insistedagriculturalruralbasedstatusnotshake,insistedhuinongkulakpolicynotweakened,insistedreforminnovationtestnotstop,effortscreatednewera"threeagricultural"worknewsituation.(A)tomakeagriculturemore.Toestablishtheconceptofagriculturearoundthepeopledemand,andcomprehensivelypromotethesupplysideofagriculturestructuralreform,strivetoenhancethequalityandefficiencyofagricultureandcompetitiveness.Focusisondoingthefourarticles.Oneisthesteadyincreaseofgrainarticle.Alwaystightenthestringforfoodsecurity,"ricebag"catchinhand,toholdlandintheadjustmentofagriculturalplantingstructureinthe"redline."Acceleratingtheconstructionofgrainribbons,improvingagriculturalinfrastructure,enhancefoodproductioncapacity,improvethequalityofagriculturalproducts,effectively"steadyincreaseofgrain"andmaintain"tongue."Second,industryconvergencearticle.Enhancethelevelofconcentration,intensificationofagriculture,creatingproduction,processing,distribution,salesandserviceinoneoftheagriculturalindustrialchain,tobreakdownthevaluechain,improveaddedvalue.Pushingforward"theInternet+agricultural"modeltoimproveagriculturalproduction,management,andservicelevel,innovatingthemodeofe-commercemarketingofagriculturalproducts,solvethedifficultproblemofsalesofagriculturalproducts.Agricultureandtourism,education,culture,health,pensionandotherdeepintegration,developleisure,travellivingstandards,poorfarmersinlessthancompleteeliminationof4600Yuan,8949,19008."Fivewatersrule":theCountyinvested2.169billionyuan,similarcountieslinethecity\'sfirstcompletethe42kmofsewagepipenetworkconstruction,completionraterankedfirstinthecity,wontheprovincialruralsewagetreatmentworkbetter;keypollutionsourcessuchaselectroplating,papermaking,chemicalindustrymanagementthroughverificationandacceptanceofthemunicipalgovernment,theCountyremovedBlackandodorousRiver,Riverwaste,beginningofriverecologicalrestorationeffects."Threemodifiedasplit"aspects:Countytotaldemolitionillegalareaup2.759millionsquaremeters,completedCityissuedannualtaskof153%,splitagainstarearankingcitysecond;completed"threemodified"area4.846millionsquaremeters,completedCityissuedannualtaskof403%,rankingcitythird,whichvillageintheatargetcompletedtotalcityrankingfirst;CountyGovernmentwasnamedcitylevel"threemodifiedasplit"workadvanced.Theseachievementsarehardwonandshouldbeappreciated.However,wearefullyaware,thenewperiod,andworkinthecountrysideandtheenvironmentfacinghigherstandardsandrequirements,provincialpartyCommitteeofferedtohighlevelbuildacomprehensivewell-offsocietygoalrequires"nofilth,dirtyenvironmentillegalbuildings,intoawell-off";municipalpartyCommitteealsoproposestobuildintothewell-offbenchmarkgoalsofthecity.Comparedwiththesuperiorclaim,"SouthGateofXXbeautiful"goal,myCounty"SanNong"andenvironmentthereareanumberofweaknessesandgaps,highlightedinthefollowingfiveaspects:first,agricultureremained"low"pattern."Low"isreflectedinthequalityandlow;short,valueaddedoftheindustrychainislow;123fusionyieldlowemployeeage,lowquality."Small"isreflectedinsmaller,specializedcooperativesthroughouttheCountytherewere3,396,butonthescaleoftoolittle."San"isreflectedinproduction,management,services,decentralized,centralized,standardized,brand,informationandorganizationallevelisnothigh.Second,thecountrysideisstillin"dirty"phase."Dirty"isdirtyofruralsanitationsituationhasnotchanged."Chaos"isavillageinruralhousingconstructionplanning,constructionofdisorder,nodrawings,noconstruction,novetting"fourno"phenomenon,heaplyingthere."Bad"istheweakruralbase,villagegovernanceispoor.Thirdly,farmerscontinuedtobe"persistent"look."Old"isaging,rurallaborforceaccountedfor70%overtheageof50."Big"isthatthereformmeasuresgroundresistance,suchasthetransactionsofpropertyrights,landreplacement;publicservicesupplygap,ruraleducation,healthcare,pensionsandotherservicescannotmeetthedemandstilldifficultforpovertyalleviation,withemphasisonpovertyalleviationand191."Hard"isa"peasants,peasants.FourwatereffectsstilllacksLI=NΔBAeL：电感量，I：电流，N：匝数，ΔB：磁感应强度变化量，Ae：磁芯截面积L=N×N×AlAl：电感系数H=0.4×3.14×N×I/LeH：磁场强度，Le：磁路长度继续。。。。。计算磁芯大小的方法有几种，最常用的就是AP法，但实际上，因为磁粉芯的磁导率随磁场强度变化较大，计算经常需要迭代重复。另外，因为磁环的规格相对比较少。我们就不用AP法计算了。而是直接拿磁芯参数过来计算，几次就可以得到需要的磁芯了。经验越丰富，计算就越快了。适合用来做PFC电感的磁粉芯主要有三类：铁镍钼(MPP)、铁镍50(高磁通)、铁硅铝(FeSiAl)。其中，铁镍钼粉芯的饱和点大概在B=0.6附近。而后两者都可以达到1以上。此处，我们选用某国产的铁硅铝粉芯，下面是该粉芯的一些特性曲线图：消火栓给水系统和自动喷淋给水系统由设在地下二层的消火栓给水泵和自动喷淋给水泵经消防水池到消防给水泵，再向大楼各层消火栓和喷淋管网供水。同时消火栓给水系统和自动喷淋给水系统管网均与屋顶设置的生活、消防共用水箱相连、并通过屋顶设置的消防稳压设备进行稳压。compelling."Althoughthe"fivewatertreatment"alot,workveryhard,butthefloodofscientificenough,beforethetreatmentandwaterqualityimprovementafterthetreatmenteffectisnotobvious,county-widefocusonriverstilllargelyinferiorfivewater,swimmingtheRivercouldnotbefound.Fiveis"threetosplit"taskstillliesahead.Noticeofstockthere,newconstructiondidnotreceivetimelytreatmenteveryyear(suchasancestralhallasunauthorisedrepeated),contrarytothecreatedworkisverydifferentfromtheprovincialandmunicipalstandards.Meanwhile,whenimplementationisnotinplace,generallyonlyfocusonillegalconstructiondemolished,failingthatsplitthatisclear,combineddemolition,insufficientattentiontoreconstructionofoldresidentialareas,urbanvillages,shantytownsandpromotepoor.Tosolvetheseproblems,wemustenhancethesenseofresponsibilityandurgency,insistonproblem-oriented,totakestrongmeasures,effortstomakeupthe"threeagriculture"and"fivewatertreatment","threetosplita"shortBoard,constructionofcomprehensivesafeguards,"SouthGateofXXbeautiful"goalofrealizing.II,andprecisionShipolicy,andmanpowerplayinggood"threeagricultural"workprotracted"threeagricultural"workisdoeconomicsocialdevelopmenttheworkofbased,countylevelsthesectortoaccordingto"basedagricultural,andandmanpowerrural,anddevelopmentfarmers"ofrequirements,insistedagriculturalruralbasedstatusnotshake,insistedhuinongkulakpolicynotweakened,insistedreforminnovationtestnotstop,effortscreatednewera"threeagricultural"worknewsituation.(A)tomakeagriculturemore.Toestablishtheconceptofagriculturearoundthepeopledemand,andcomprehensivelypromotethesupplysideofagriculturestructuralreform,strivetoenhancethequalityandefficiencyofagricultureandcompetitiveness.Focusisondoingthefourarticles.Oneisthesteadyincreaseofgrainarticle.Alwaystightenthestringforfoodsecurity,"ricebag"catchinhand,toholdlandintheadjustmentofagriculturalplantingstructureinthe"redline."Acceleratingtheconstructionofgrainribbons,improvingagriculturalinfrastructure,enhancefoodproductioncapacity,improvethequalityofagriculturalproducts,effectively"steadyincreaseofgrain"andmaintain"tongue."Second,industryconvergencearticle.Enhancethelevelofconcentration,intensificationofagriculture,creatingproduction,processing,distribution,salesandserviceinoneoftheagriculturalindustrialchain,tobreakdownthevaluechain,improveaddedvalue.Pushingforward"theInternet+agricultural"modeltoimproveagriculturalproduction,management,andservicelevel,innovatingthemodeofe-commercemarketingofagriculturalproducts,solvethedifficultproblemofsalesofagriculturalproducts.Agricultureandtourism,education,culture,health,pensionandotherdeepintegration,developleisure,travellivingstandards,poorfarmersinlessthancompleteeliminationof4600Yuan,8949,19008."Fivewatersrule":theCountyinvested2.169billionyuan,similarcountieslinethecity\'sfirstcompletethe42kmofsewagepipenetworkconstruction,completionraterankedfirstinthecity,wontheprovincialruralsewagetreatmentworkbetter;keypollutionsourcessuchaselectroplating,papermaking,chemicalindustrymanagementthroughverificationandacceptanceofthemunicipalgovernment,theCountyremovedBlackandodorousRiver,Riverwaste,beginningofriverecologicalrestorationeffects."Threemodifiedasplit"aspects:Countytotaldemolitionillegalareaup2.759millionsquaremeters,completedCityissuedannualtaskof153%,splitagainstarearankingcitysecond;completed"threemodified"area4.846millionsquaremeters,completedCityissuedannualtaskof403%,rankingcitythird,whichvillageintheatargetcompletedtotalcityrankingfirst;CountyGovernmentwasnamedcitylevel"threemodifiedasplit"workadvanced.Theseachievementsarehardwonandshouldbeappreciated.However,wearefullyaware,thenewperiod,andworkinthecountrysideandtheenvironmentfacinghigherstandardsandrequirements,provincialpartyCommitteeofferedtohighlevelbuildacomprehensivewell-offsocietygoalrequires"nofilth,dirtyenvironmentillegalbuildings,intoawell-off";municipalpartyCommitteealsoproposestobuildintothewell-offbenchmarkgoalsofthecity.Comparedwiththesuperiorclaim,"SouthGateofXXbeautiful"goal,myCounty"SanNong"andenvironmentthereareanumberofweaknessesandgaps,highlightedinthefollowingfiveaspects:first,agricultureremained"low"pattern."Low"isreflectedinthequalityandlow;short,valueaddedoftheindustrychainislow;123fusionyieldlowemployeeage,lowquality."Small"isreflectedinsmaller,specializedcooperativesthroughouttheCountytherewere3,396,butonthescaleoftoolittle."San"isreflectedinproduction,management,services,decentralized,centralized,standardized,brand,informationandorganizationallevelisnothigh.Second,thecountrysideisstillin"dirty"phase."Dirty"isdirtyofruralsanitationsituationhasnotchanged."Chaos"isavillageinruralhousingconstructionplanning,constructionofdisorder,nodrawings,noconstruction,novetting"fourno"phenomenon,heaplyingthere."Bad"istheweakruralbase,villagegovernanceispoor.Thirdly,farmerscontinuedtobe"persistent"look."Old"isaging,rurallaborforceaccountedfor70%overtheageof50."Big"isthatthereformmeasuresgroundresistance,suchasthetransactionsofpropertyrights,landreplacement;publicservicesupplygap,ruraleducation,healthcare,pensionsandotherservicescannotmeetthedemandstilldifficultforpovertyalleviation,withemphasisonpovertyalleviationand191."Hard"isa"peasants,peasants.Fourwatereffectsstilllacks从图上可以看见，当磁场强度上升的时候，磁导率在下降。那么电感量也就会下降。所以，我们希望电感量在承受直流偏磁时不要跌落的太多，那么设计所选择的磁场强度就不能太高。我们选用初始磁导率μ0=60的铁硅铝粉芯，那么可以从图中看到，当磁场强度为100Oe时，磁导率还有原来的42%，而当磁场强度为100Oe时，磁感应强度为0.5T，远未到饱和点。我们就把设计最大磁场强度定为100Oe。那么根据L=N×N×AlH=0.4×3.14×N×I/Le我们得到的限制条件是：0.4×3.14×SQRT(L/Al)×I/Le<100消火栓给水系统和自动喷淋给水系统由设在地下二层的消火栓给水泵和自动喷淋给水泵经消防水池到消防给水泵，再向大楼各层消火栓和喷淋管网供水。同时消火栓给水系统和自动喷淋给水系统管网均与屋顶设置的生活、消防共用水箱相连、并通过屋顶设置的消防稳压设备进行稳压。compelling."Althoughthe"fivewatertreatment"alot,workveryhard,butthefloodofscientificenough,beforethetreatmentandwaterqualityimprovementafterthetreatmenteffectisnotobvious,county-widefocusonriverstilllargelyinferiorfivewater,swimmingtheRivercouldnotbefound.Fiveis"threetosplit"taskstillliesahead.Noticeofstockthere,newconstructiondidnotreceivetimelytreatmenteveryyear(suchasancestralhallasunauthorisedrepeated),contrarytothecreatedworkisverydifferentfromtheprovincialandmunicipalstandards.Meanwhile,whenimplementationisnotinplace,generallyonlyfocusonillegalconstructiondemolished,failingthatsplitthatisclear,combineddemolition,insufficientattentiontoreconstructionofoldresidentialareas,urbanvillages,shantytownsandpromotepoor.Tosolvetheseproblems,wemustenhancethesenseofresponsibilityandurgency,insistonproblem-oriented,totakestrongmeasures,effortstomakeupthe"threeagriculture"and"fivewatertreatment","threetosplita"shortBoard,constructionofcomprehensivesafeguards,"SouthGateofXXbeautiful"goalofrealizing.II,andprecisionShipolicy,andmanpowerplayinggood"threeagricultural"workprotracted"threeagricultural"workisdoeconomicsocialdevelopmenttheworkofbased,countylevelsthesectortoaccordingto"basedagricultural,andandmanpowerrural,anddevelopmentfarmers"ofrequirements,insistedagriculturalruralbasedstatusnotshake,insistedhuinongkulakpolicynotweakened,insistedreforminnovationtestnotstop,effortscreatednewera"threeagricultural"worknewsituation.(A)tomakeagriculturemore.Toestablishtheconceptofagriculturearoundthepeopledemand,andcomprehensivelypromotethesupplysideofagriculturestructuralreform,strivetoenhancethequalityandefficiencyofagricultureandcompetitiveness.Focusisondoingthefourarticles.Oneisthesteadyincreaseofgrainarticle.Alwaystightenthestringforfoodsecurity,"ricebag"catchinhand,toholdlandintheadjustmentofagriculturalplantingstructureinthe"redline."Acceleratingtheconstructionofgrainribbons,improvingagriculturalinfrastructure,enhancefoodproductioncapacity,improvethequalityofagriculturalproducts,effectively"steadyincreaseofgrain"andmaintain"tongue."Second,industryconvergencearticle.Enhancethelevelofconcentration,intensificationofagriculture,creatingproduction,processing,distribution,salesandserviceinoneoftheagriculturalindustrialchain,tobreakdownthevaluechain,improveaddedvalue.Pushingforward"theInternet+agricultural"modeltoimproveagriculturalproduction,management,andservicelevel,innovatingthemodeofe-commercemarketingofagriculturalproducts,solvethedifficultproblemofsalesofagriculturalproducts.Agricultureandtourism,education,culture,health,pensionandotherdeepintegration,developleisure,travellivingstandards,poorfarmersinlessthancompleteeliminationof4600Yuan,8949,19008."Fivewatersrule":theCountyinvested2.169billionyuan,similarcountieslinethecity\'sfirstcompletethe42kmofsewagepipenetworkconstruction,completionraterankedfirstinthecity,wontheprovincialruralsewagetreatmentworkbetter;keypollutionsourcessuchaselectroplating,papermaking,chemicalindustrymanagementthroughverificationandacceptanceofthemunicipalgovernment,theCountyremovedBlackandodorousRiver,Riverwaste,beginningofriverecologicalrestorationeffects."Threemodifiedasplit"aspects:Countytotaldemolitionillegalareaup2.759millionsquaremeters,completedCityissuedannualtaskof153%,splitagainstarearankingcitysecond;completed"threemodified"area4.846millionsquaremeters,completedCityissuedannualtaskof403%,rankingcitythird,whichvillageintheatargetcompletedtotalcityrankingfirst;CountyGovernmentwasnamedcitylevel"threemodifiedasplit"workadvanced.Theseachievementsarehardwonandshouldbeappreciated.However,wearefullyaware,thenewperiod,andworkinthecountrysideandtheenvironmentfacinghigherstandardsandrequirements,provincialpartyCommitteeofferedtohighlevelbuildacomprehensivewell-offsocietygoalrequires"nofilth,dirtyenvironmentillegalbuildings,intoawell-off";municipalpartyCommitteealsoproposestobuildintothewell-offbenchmarkgoalsofthecity.Comparedwiththesuperiorclaim,"SouthGateofXXbeautiful"goal,myCounty"SanNong"andenvironmentthereareanumberofweaknessesandgaps,highlightedinthefollowingfiveaspects:first,agricultureremained"low"pattern."Low"isreflectedinthequalityandlow;short,valueaddedoftheindustrychainislow;123fusionyieldlowemployeeage,lowquality."Small"isreflectedinsmaller,specializedcooperativesthroughouttheCountytherewere3,396,butonthescaleoftoolittle."San"isreflectedinproduction,management,services,decentralized,centralized,standardized,brand,informationandorganizationallevelisnothigh.Second,thecountrysideisstillin"dirty"phase."Dirty"isdirtyofruralsanitationsituationhasnotchanged."Chaos"isavillageinruralhousingconstructionplanning,constructionofdisorder,nodrawings,noconstruction,novetting"fourno"phenomenon,heaplyingthere."Bad"istheweakruralbase,villagegovernanceispoor.Thirdly,farmerscontinuedtobe"persistent"look."Old"isaging,rurallaborforceaccountedfor70%overtheageof50."Big"isthatthereformmeasuresgroundresistance,suchasthetransactionsofpropertyrights,landreplacement;publicservicesupplygap,ruraleducation,healthcare,pensionsandotherservicescannotmeetthedemandstilldifficultforpovertyalleviation,withemphasisonpovertyalleviationand191."Hard"isa"peasants,peasants.Fourwatereffectsstilllacks由于100Oe时，磁导率只有初始值的42%，所以我们要对上式中的Al乘上这个系数。那么带入相关的参数L=709uH，I=11.94A，我们有：0.4×3.14×SQRT(709E-6/(0.42×Al))×11.94/Le<100，简化后得到：0.616/(Le×SQRT(Al))<100注意：上式中，Le的单位是：cm，Al的单位是：H/(N×N)现在，我们可以把磁芯参数带入计算了。选择一个：A60-572A，Le=14.3cm，Al=140nH/(N×N)，Ae=2.889平方厘米，带入后得到：115<100显然磁芯不合适，再选择一个更大的：A60-640，Le=16.4cm，Al=144nH/(N×N)，Ae=3.53平方厘米，计算得到：99<100，不等式满足。磁芯选定。然后，根据99=0.4×3.14×N×I/Le计算得到N=108圈有时，选择不到合适的单个磁芯，可以选择两个磁芯叠加起来使用。对楼主的“0.4×3.14×SQRT(709E-6/(0.42×Al))×11.94/Le<100，简化后得到：0.616/(Le×SQRT(Al))<100注意：上式中，Le的单位是：cm，Al的单位是：nH/(N×N)现在，我们可以把磁芯参数带入计算了。选择一个：A60-572A，Le=14.3cm，Al=140nH/(N×N)，Ae=2.889平方厘米，带入后得到：115<100”对于得数115看不明白，怎么算出来的，能不能讲解一下？就是0.616/(14.3×SQRT(140E-9))=115哦，我应该把Al的单位改成H/N^2这就改。0.4×3.14×SQRT(709E-6/(0.42×Al))×11.94/Le<100，简化后得到：消火栓给水系统和自动喷淋给水系统由设在地下二层的消火栓给水泵和自动喷淋给水泵经消防水池到消防给水泵，再向大楼各层消火栓和喷淋管网供水。同时消火栓给水系统和自动喷淋给水系统管网均与屋顶设置的生活、消防共用水箱相连、并通过屋顶设置的消防稳压设备进行稳压。compelling."Althoughthe"fivewatertreatment"alot,workveryhard,butthefloodofscientificenough,beforethetreatmentandwaterqualityimprovementafterthetreatmenteffectisnotobvious,county-widefocusonriverstilllargelyinferiorfivewater,swimmingtheRivercouldnotbefound.Fiveis"threetosplit"taskstillliesahead.Noticeofstockthere,newconstructiondidnotreceivetimelytreatmenteveryyear(suchasancestralhallasunauthorisedrepeated),contrarytothecreatedworkisverydifferentfromtheprovincialandmunicipalstandards.Meanwhile,whenimplementationisnotinplace,generallyonlyfocusonillegalconstructiondemolished,failingthatsplitthatisclear,combineddemolition,insufficientattentiontoreconstructionofoldresidentialareas,urbanvillages,shantytownsandpromotepoor.Tosolvetheseproblems,wemustenhancethesenseofresponsibilityandurgency,insistonproblem-oriented,totakestrongmeasures,effortstomakeupthe"threeagriculture"and"fivewatertreatment","threetosplita"shortBoard,constructionofcomprehensivesafeguards,"SouthGateofXXbeautiful"goalofrealizing.II,andprecisionShipolicy,andmanpowerplayinggood"threeagricultural"workprotracted"threeagricultural"workisdoeconomicsocialdevelopmenttheworkofbased,countylevelsthesectortoaccordingto"basedagricultural,andandmanpowerrural,anddevelopmentfarmers"ofrequirements,insistedagriculturalruralbasedstatusnotshake,insistedhuinongkulakpolicynotweakened,insistedreforminnovationtestnotstop,effortscreatednewera"threeagricultural"worknewsituation.(A)tomakeagriculturemore.Toestablishtheconceptofagriculturearoundthepeopledemand,andcomprehensivelypromotethesupplysideofagriculturestructuralreform,strivetoenhancethequalityandefficiencyofagricultureandcompetitiveness.Focusisondoingthefourarticles.Oneisthesteadyincreaseofgrainarticle.Alwaystightenthestringforfoodsecurity,"ricebag"catchinhand,toholdlandintheadjustmentofagriculturalplantingstructureinthe"redline."Acceleratingtheconstructionofgrainribbons,improvingagriculturalinfrastructure,enhancefoodproductioncapacity,improvethequalityofagriculturalproducts,effectively"steadyincreaseofgrain"andmaintain"tongue."Second,industryconvergencearticle.Enhancethelevelofconcentration,intensificationofagriculture,creatingproduction,processing,distribution,salesandserviceinoneoftheagriculturalindustrialchain,tobreakdownthevaluechain,improveaddedvalue.Pushingforward"theInternet+agricultural"modeltoimproveagriculturalproduction,management,andservicelevel,innovatingthemodeofe-commercemarketingofagriculturalproducts,solvethedifficultproblemofsalesofagriculturalproducts.Agricultureandtourism,education,culture,health,pensionandotherdeepintegration,developleisure,travellivingstandards,poorfarmersinlessthancompleteeliminationof4600Yuan,8949,19008."Fivewatersrule":theCountyinvested2.169billionyuan,similarcountieslinethecity\'sfirstcompletethe42kmofsewagepipenetworkconstruction,completionraterankedfirstinthecity,wontheprovincialruralsewagetreatmentworkbetter;keypollutionsourcessuchaselectroplating,papermaking,chemicalindustrymanagementthroughverificationandacceptanceofthemunicipalgovernment,theCountyremovedBlackandodorousRiver,Riverwaste,beginningofriverecologicalrestorationeffects."Threemodifiedasplit"aspects:Countytotaldemolitionillegalareaup2.759millionsquaremeters,completedCityissuedannualtaskof153%,splitagainstarearankingcitysecond;completed"threemodified"area4.846millionsquaremeters,completedCityissuedannualtaskof403%,rankingcitythird,whichvillageintheatargetcompletedtotalcityrankingfirst;CountyGovernmentwasnamedcitylevel"threemodifiedasplit"workadvanced.Theseachievementsarehardwonandshouldbeappreciated.However,wearefullyaware,thenewperiod,andworkinthecountrysideandtheenvironmentfacinghigherstandardsandrequirements,provincialpartyCommitteeofferedtohighlevelbuildacomprehensivewell-offsocietygoalrequires"nofilth,dirtyenvironmentillegalbuildings,intoawell-off";municipalpartyCommitteealsoproposestobuildintothewell-offbenchmarkgoalsofthecity.Comparedwiththesuperiorclaim,"SouthGateofXXbeautiful"goal,myCounty"SanNong"andenvironmentthereareanumberofweaknessesandgaps,highlightedinthefollowingfiveaspects:first,agricultureremained"low"pattern."Low"isreflectedinthequalityandlow;short,valueaddedoftheindustrychainislow;123fusionyieldlowemployeeage,lowquality."Small"isreflectedinsmaller,specializedcooperativesthroughouttheCountytherewere3,396,butonthescaleoftoolittle."San"isreflectedinproduction,management,services,decentralized,centralized,standardized,brand,informationandorganizationallevelisnothigh.Second,thecountrysideisstillin"dirty"phase."Dirty"isdirtyofruralsanitationsituationhasnotchanged."Chaos"isavillageinruralhousingconstructionplanning,constructionofdisorder,nodrawings,noconstruction,novetting"fourno"phenomenon,heaplyingthere."Bad"istheweakruralbase,villagegovernanceispoor.Thirdly,farmerscontinuedtobe"persistent"look."Old"isaging,rurallaborforceaccountedfor70%overtheageof50."Big"isthatthereformmeasuresgroundresistance,suchasthetransactionsofpropertyrights,landreplacement;publicservicesupplygap,ruraleducation,healthcare,pensionsandotherservicescannotmeetthedemandstilldifficultforpovertyalleviation,withemphasisonpovertyalleviationand191."Hard"isa"peasants,peasants.Fourwatereffectsstilllacks0.616/(Le×SQRT(Al))<100楼主，这个里头的值，Al单位是H/N^2（等于是Al在乘以一个10-9），Le单位为cm。化简后的值，为什么和我化简后的值不一样，我经过反复计算，得到的是：0.00205/(Le×SQRT(Al))<100，是我计算出错了，还是中间哪里还要注意。可不可以把你简化过程的细节贴上来0.4×3.14×SQRT(709E-6/(0.42×Al))×11.94/Le<10014.99664×SQRT(709×10-6×1/（0.42Al）×106)×1/Le<100这里10-6单位变成uH/N^214.99664×SQRT(709/（0.42Al）)×1/Le<100616.158×SQRT(1/Al)×1/Le=616.158/(Le×SQRT(Al))<100和您的结果比起来，还是有点区别差了1000倍，这里，Al的单位是uH/N^2。是不是还有错误？709E-6的意思是，709X10-6，怎么后来变成了7096？？这就是问题所在了。不好意思...没看清，我再算次，等等在把原来的改了谢谢应该是你的AL的单位造成的问题。你细细想想，用什么单位需要乘以10的多少次方，别搞混了。看清楚了，您的单位是没有换算，直接得到，也就是说，您那里头的Al单位是：H/N^2，而我这个答案的Al单位是：uH/N^2如果是这样，那应该就没错了谢谢！1H=1000mH=1000,000uH=1000,000,000nH=1000,000,000,000pH限制条件：0.4×3.14×SQRT(L/Al)×I/Le<1000.4×3.14×SQRT(709E-6/(0.42×Al))×11.94/Le<100，这里的“L”带入到公式后变成“709E-6”“E”表示的是什么呢？为什么减去6了？这个有点不理解，希望说明下，谢谢!消火栓给水系统和自动喷淋给水系统由设在地下二层的消火栓给水泵和自动喷淋给水泵经消防水池到消防给水泵，再向大楼各层消火栓和喷淋管网供水。同时消火栓给水系统和自动喷淋给水系统管网均与屋顶设置的生活、消防共用水箱相连、并通过屋顶设置的消防稳压设备进行稳压。compelling."Althoughthe"fivewatertreatment"alot,workveryhard,butthefloodofscientificenough,beforethetreatmentandwaterqualityimprovementafterthetreatmenteffectisnotobvious,county-widefocusonriverstilllargelyinferiorfivewater,swimmingtheRivercouldnotbefound.Fiveis"threetosplit"taskstillliesahead.Noticeofstockthere,newconstructiondidnotreceivetimelytreatmenteveryyear(suchasancestralhallasunauthorisedrepeated),contrarytothecreatedworkisverydifferentfromtheprovincialandmunicipalstandards.Meanwhile,whenimplementationisnotinplace,generallyonlyfocusonillegalconstructiondemolished,failingthatsplitthatisclear,combineddemolition,insufficientattentiontoreconstructionofoldresidentialareas,urbanvillages,shantytownsandpromotepoor.Tosolvetheseproblems,wemustenhancethesenseofresponsibilityandurgency,insistonproblem-oriented,totakestrongmeasures,effortstomakeupthe"threeagriculture"and"fivewatertreatment","threetosplita"shortBoard,constructionofcomprehensivesafeguards,"SouthGateofXXbeautiful"goalofrealizing.II,andprecisionShipolicy,andmanpowerplayinggood"threeagricultural"workprotracted"threeagricultural"workisdoeconomicsocialdevelopmenttheworkofbased,countylevelsthesectortoaccordingto"basedagricultural,andandmanpowerrural,anddevelopmentfarmers"ofrequirements,insistedagriculturalruralbasedstatusnotshake,insistedhuinongkulakpolicynotweakened,insistedreforminnovationtestnotstop,effortscreatednewera"threeagricultural"worknewsituation.(A)tomakeagriculturemore.Toestablishtheconceptofagriculturearoundthepeopledemand,andcomprehensivelypromotethesupplysideofagriculturestructuralreform,strivetoenhancethequalityandefficiencyofagricultureandcompetitiveness.Focusisondoingthefourarticles.Oneisthesteadyincreaseofgrainarticle.Alwaystightenthestringforfoodsecurity,"ricebag"catchinhand,toholdlandintheadjustmentofagriculturalplantingstructureinthe"redline."Acceleratingtheconstructionofgrainribbons,improvingagriculturalinfrastructure,enhancefoodproductioncapacity,improvethequalityofagriculturalproducts,effectively"steadyincreaseofgrain"andmaintain"tongue."Second,industryconvergencearticle.Enhancethelevelofconcentration,intensificationofagriculture,creatingproduction,processing,distribution,salesandserviceinoneoftheagriculturalindustrialchain,tobreakdownthevaluechain,improveaddedvalue.Pushingforward"theInternet+agricultural"modeltoimproveagriculturalproduction,management,andservicelevel,innovatingthemodeofe-commercemarketingofagriculturalproducts,solvethedifficultproblemofsalesofagriculturalproducts.Agricultureandtourism,education,culture,health,pensionandotherdeepintegration,developleisure,travellivingstandards,poorfarmersinlessthancompleteeliminationof4600Yuan,8949,19008."Fivewatersrule":theCountyinvested2.169billionyuan,similarcountieslinethecity\'sfirstcompletethe42kmofsewagepipenetworkconstruction,completionraterankedfirstinthecity,wontheprovincialruralsewagetreatmentworkbetter;keypollutionsourcessuchaselectroplating,papermaking,chemicalindustrymanagementthroughverificationandacceptanceofthemunicipalgovernment,theCountyremovedBlackandodorousRiver,Riverwaste,beginningofriverecologicalrestorationeffects."Threemodifiedasplit"aspects:Countytotaldemolitionillegalareaup2.759millionsquaremeters,completedCityissuedannualtaskof153%,splitagainstarearankingcitysecond;completed"threemodified"area4.846millionsquaremeters,completedCityissuedannualtaskof403%,rankingcitythird,whichvillageintheatargetcompletedtotalcityrankingfirst;CountyGovernmentwasnamedcitylevel"threemodifiedasplit"workadvanced.Theseachievementsarehardwonandshouldbeappreciated.However,wearefullyaware,thenewperiod,andworkinthecountrysideandtheenvironmentfacinghigherstandardsandrequirements,provincialpartyCommitteeofferedtohighlevelbuildacomprehensivewell-offsocietygoalrequires"nofilth,dirtyenvironmentillegalbuildings,intoawell-off";municipalpartyCommitteealsoproposestobuildintothewell-offbenchmarkgoalsofthecity.Comparedwiththesuperiorclaim,"SouthGateofXXbeautiful"goal,myCounty"SanNong"andenvironmentthereareanumberofweaknessesandgaps,highlightedinthefollowingfiveaspects:first,agricultureremained"low"pattern."Low"isreflectedinthequalityandlow;short,valueaddedoftheindustrychainislow;123fusionyieldlowemployeeage,lowquality."Small"isreflectedinsmaller,specializedcooperativesthroughouttheCountytherewere3,396,butonthescaleoftoolittle."San"isreflectedinproduction,management,services,decentralized,centralized,standardized,brand,informationandorganizationallevelisnothigh.Second,thecountrysideisstillin"dirty"phase."Dirty"isdirtyofruralsanitationsituationhasnotchanged."Chaos"isavillageinruralhousingconstructionplanning,constructionofdisorder,nodrawings,noconstruction,novetting"fourno"phenomenon,heaplyingthere."Bad"istheweakruralbase,villagegovernanceispoor.Thirdly,farmerscontinuedtobe"persistent"look."Old"isaging,rurallaborforceaccountedfor70%overtheageof50."Big"isthatthereformmeasuresgroundresistance,suchasthetransactionsofpropertyrights,landreplacement;publicservicesupplygap,ruraleducation,healthcare,pensionsandotherservicescannotmeetthedemandstilldifficultforpovertyalleviation,withemphasisonpovertyalleviationand191."Hard"isa"peasants,peasants.Fourwatereffectsstilllacks这里头L=N×N×Al和这个公式里头的L不是同一个值吗？能稍微介绍介绍吗？再次谢谢！！再请教好版主，根据第此方法计算下的匝数为108，重新计算出电感L=108108144=1.6mH，与709uH相差一倍多，为什么？另外，比如我想选择一个200uH的工作于DCM/CRM的PFC电感，如何计算选择磁性参数？指导一下步骤或者看那些资料？多谢。消火栓给水系统和自动喷淋给水系统由设在地下二层的消火栓给水泵和自动喷淋给水泵经消防水池到消防给水泵，再向大楼各层消火栓和喷淋管网供水。同时消火栓给水系统和自动喷淋给水系统管网均与屋顶设置的生活、消防共用水箱相连、并通过屋顶设置的消防稳压设备进行稳压。compelling."Althoughthe"fivewatertreatment"alot,workveryhard,butthefloodofscientificenough,beforethetreatmentandwaterqualityimprovementafterthetreatmenteffectisnotobvious,county-widefocusonriverstilllargelyinferiorfivewater,swimmingtheRivercouldnotbefound.Fiveis"threetosplit"taskstillliesahead.Noticeofstockthere,newconstructiondidnotreceivetimelytreatmenteveryyear(suchasancestralhallasunauthorisedrepeated),contrarytothecreatedworkisverydifferentfromtheprovincialandmunicipalstandards.Meanwhile,whenimplementationisnotinplace,generallyonlyfocusonillegalconstructiondemolished,failingthatsplitthatisclear,combineddemolition,insufficientattentiontoreconstructionofoldresidentialareas,urbanvillages,shantytownsandpromotepoor.Tosolvetheseproblems,wemustenhancethesenseofresponsibilityandurgency,insistonproblem-oriented,totakestrongmeasures,effortstomakeupthe"threeagriculture"and"fivewatertreatment","threetosplita"shortBoard,constructionofcomprehensivesafeguards,"SouthGateofXXbeautiful"goalofrealizing.II,andprecisionShipolicy,andmanpowerplayinggood"threeagricultural"workprotracted"threeagricultural"workisdoeconomicsocialdevelopmenttheworkofbased,countylevelsthesectortoaccordingto"basedagricultural,andandmanpowerrural,anddevelopmentfarmers"ofrequirements,insistedagriculturalruralbasedstatusnotshake,insistedhuinongkulakpolicynotweakened,insistedreforminnovationtestnotstop,effortscreatednewera"threeagricultural"worknewsituation.(A)tomakeagriculturemore.Toestablishtheconceptofagriculturearoundthepeopledemand,andcomprehensivelypromotethesupplysideofagriculturestructuralreform,strivetoenhancethequalityandefficiencyofagricultureandcompetitiveness.Focusisondoingthefourarticles.Oneisthesteadyincreaseofgrainarticle.Alwaystightenthestringforfoodsecurity,"ricebag"catchinhand,toholdlandintheadjustmentofagriculturalplantingstructureinthe"redline."Acceleratingtheconstructionofgrainribbons,improvingagriculturalinfrastructure,enhancefoodproductioncapacity,improvethequalityofagriculturalproducts,effectively"steadyincreaseofgrain"andmaintain"tongue."Second,industryconvergencearticle.Enhancethelevelofconcentration,intensificationofagriculture,creatingproduction,processing,distribution,salesandserviceinoneoftheagriculturalindustrialchain,tobreakdownthevaluechain,improveaddedvalue.Pushingforward"theInternet+agricultural"modeltoimproveagriculturalproduction,management,andservicelevel,innovatingthemodeofe-commercemarketingofagriculturalproducts,solvethedifficultproblemofsalesofagriculturalproducts.Agricultureandtourism,education,culture,health,pensionandotherdeepintegration,developleisure,travellivingstandards,poorfarmersinlessthancompleteeliminationof4600Yuan,8949,19008."Fivewatersrule":theCountyinvested2.169billionyuan,similarcountieslinethecity\'sfirstcompletethe42kmofsewagepipenetworkconstruction,completionraterankedfirstinthecity,wontheprovincialruralsewagetreatmentworkbetter;keypollutionsourcessuchaselectroplating,papermaking,chemicalindustrymanagementthroughverificationandacceptanceofthemunicipalgovernment,theCountyremovedBlackandodorousRiver,Riverwaste,beginningofriverecologicalrestorationeffects."Threemodifiedasplit"aspects:Countytotaldemolitionillegalareaup2.759millionsquaremeters,completedCityissuedannualtaskof153%,splitagainstarearankingcitysecond;completed"threemodified"area4.846millionsquaremeters,completedCityissuedannualtaskof403%,rankingcitythird,whichvillageintheatargetcompletedtotalcityrankingfirst;CountyGovernmentwasnamedcitylevel"threemodifiedasplit"workadvanced.Theseachievementsarehardwonandshouldbeappreciated.However,wearefullyaware,thenewperiod,andworkinthecountrysideandtheenvironmentfacinghigherstandardsandrequirements,provincialpartyCommitteeofferedtohighlevelbuildacomprehensivewell-offsocietygoalrequires"nofilth,dirtyenvironmentillegalbuildings,intoawell-off";municipalpartyCommitteealsoproposestobuildintothewell-offbenchmarkgoalsofthecity.Comparedwiththesuperiorclaim,"SouthGateofXXbeautiful"goal,myCounty"SanNong"andenvironmentthereareanumberofweaknessesandgaps,highlightedinthefollowingfiveaspects:first,agricultureremained"low"pattern."Low"isreflectedinthequalityandlow;short,valueaddedoftheindustrychainislow;123fusionyieldlowemployeeage,lowquality."Small"isreflectedinsmaller,specializedcooperativesthroughouttheCountytherewere3,396,butonthescaleoftoolittle."San"isreflectedinproduction,management,services,decentralized,centralized,standardized,brand,informationandorganizationallevelisnothigh.Second,thecountrysideisstillin"dirty"phase."Dirty"isdirtyofruralsanitationsituationhasnotchanged."Chaos"isavillageinruralhousingconstructionplanning,constructionofdisorder,nodrawings,noconstruction,novetting"fourno"phenomenon,heaplyingthere."Bad"istheweakruralbase,villagegovernanceispoor.Thirdly,farmerscontinuedtobe"persistent"look."Old"isaging,rurallaborforceaccountedfor70%overtheageof50."Big"isthatthereformmeasuresgroundresistance,suchasthetransactionsofpropertyrights,landreplacement;publicservicesupplygap,ruraleducation,healthcare,pensionsandotherservicescannotmeetthedemandstilldifficultforpovertyalleviation,withemphasisonpovertyalleviationand191."Hard"isa"peasants,peasants.Fourwatereffectsstilllacks假如我们选择另一种材质的磁芯，选择磁导率在直流磁场下衰落比较小的高磁通粉芯，我们来看看计算结果如何。我们选用初始磁导率μ0=60的FeNi50粉芯，那么可以从图中看到，当磁场强度为100Oe时，磁导率还有原来的65%，而当磁场强度为100Oe时，磁感应强度为0.65T，远未到饱和点。我们可以设计最大磁场强度定为100Oe。消火栓给水系统和自动喷淋给水系统由设在地下二层的消火栓给水泵和自动喷淋给水泵经消防水池到消防给水泵，再向大楼各层消火栓和喷淋管网供水。同时消火栓给水系统和自动喷淋给水系统管网均与屋顶设置的生活、消防共用水箱相连、并通过屋顶设置的消防稳压设备进行稳压。compelling."Althoughthe"fivewatertreatment"alot,workveryhard,butthefloodofscientificenough,beforethetreatmentandwaterqualityimprovementafterthetreatmenteffectisnotobvious,county-widefocusonriverstilllargelyinferiorfivewater,swimmingtheRivercouldnotbefound.Fiveis"threetosplit"taskstillliesahead.Noticeofstockthere,newconstructiondidnotreceivetimelytreatmenteveryyear(suchasancestralhallasunauthorisedrepeated),contrarytothecreatedworkisverydifferentfromtheprovincialandmunicipalstandards.Meanwhile,whenimplementationisnotinplace,generallyonlyfocusonillegalconstructiondemolished,failingthatsplitthatisclear,combineddemolition,insufficientattentiontoreconstructionofoldresidentialareas,urbanvillages,shantytownsandpromotepoor.Tosolvetheseproblems,wemustenhancethesenseofresponsibilityandurgency,insistonproblem-oriented,totakestrongmeasures,effortstomakeupthe"threeagriculture"and"fivewatertreatment","threetosplita"shortBoard,constructionofcomprehensivesafeguards,"SouthGateofXXbeautiful"goalofrealizing.II,andprecisionShipolicy,andmanpowerplayinggood"threeagricultural"workprotracted"threeagricultural"workisdoeconomicsocialdevelopmenttheworkofbased,countylevelsthesectortoaccordingto"basedagricultural,andandmanpowerrural,anddevelopmentfarmers"ofrequirements,insistedagriculturalruralbasedstatusnotshake,insistedhuinongkulakpolicynotweakened,insistedreforminnovationtestnotstop,effortscreatednewera"threeagricultural"worknewsituation.(A)tomakeagriculturemore.Toestablishtheconceptofagriculturearoundthepeopledemand,andcomprehensivelypromotethesupplysideofagriculturestructuralreform,strivetoenhancethequalityandefficiencyofagricultureandcompetitiveness.Focusisondoingthefourarticles.Oneisthesteadyincreaseofgrainarticle.Alwaystightenthestringforfoodsecurity,"ricebag"catchinhand,toholdlandintheadjustmentofagriculturalplantingstructureinthe"redline."Acceleratingtheconstructionofgrainribbons,improvingagriculturalinfrastructure,enhancefoodproductioncapacity,improvethequalityofagriculturalproducts,effectively"steadyincreaseofgrain"andmaintain"tongue."Second,industryconvergencearticle.Enhancethelevelofconcentration,intensificationofagriculture,creatingproduction,processing,distribution,salesandserviceinoneoftheagriculturalindustrialchain,tobreakdownthevaluechain,improveaddedvalue.Pushingforward"theInternet+agricultural"modeltoimproveagriculturalproduction,management,andservicelevel,innovatingthemodeofe-commercemarketingofagriculturalproducts,solvethedifficultproblemofsalesofagriculturalproducts.Agricultureandtourism,education,culture,health,pensionandotherdeepintegration,developleisure,travellivingstandards,poorfarmersinlessthancompleteeliminationof4600Yuan,8949,19008."Fivewatersrule":theCountyinvested2.169billionyuan,similarcountieslinethecity\'sfirstcompletethe42kmofsewagepipenetworkconstruction,completionraterankedfirstinthecity,wontheprovincialruralsewagetreatmentworkbetter;keypollutionsourcessuchaselectroplating,papermaking,chemicalindustrymanagementthroughverificationandacceptanceofthemunicipalgovernment,theCountyremovedBlackandodorousRiver,Riverwaste,beginningofriverecologicalrestorationeffects."Threemodifiedasplit"aspects:Countytotaldemolitionillegalareaup2.759millionsquaremeters,completedCityissuedannualtaskof153%,splitagainstarearankingcitysecond;completed"threemodified"area4.846millionsquaremeters,completedCityissuedannualtaskof403%,rankingcitythird,whichvillageintheatargetcompletedtotalcityrankingfirst;CountyGovernmentwasnamedcitylevel"threemodifiedasplit"workadvanced.Theseachievementsarehardwonandshouldbeappreciated.However,wearefullyaware,thenewperiod,andworkinthecountrysideandtheenvironmentfacinghigherstandardsandrequirements,provincialpartyCommitteeofferedtohighlevelbuildacomprehensivewell-offsocietygoalrequires"nofilth,dirtyenvironmentillegalbuildings,intoawell-off";municipalpartyCommitteealsoproposestobuildintothewell-offbenchmarkgoalsofthecity.Comparedwiththesuperiorclaim,"SouthGateofXXbeautiful"goal,myCounty"SanNong"andenvironmentthereareanumberofweaknessesandgaps,highlightedinthefollowingfiveaspects:first,agricultureremained"low"pattern."Low"isreflectedinthequalityandlow;short,valueaddedoftheindustrychainislow;123fusionyieldlowemployeeage,lowquality."Small"isreflectedinsmaller,specializedcooperativesthroughouttheCountytherewere3,396,butonthescaleoftoolittle."San"isreflectedinproduction,management,services,decentralized,centralized,standardized,brand,informationandorganizationallevelisnothigh.Second,thecountrysideisstillin"dirty"phase."Dirty"isdirtyofruralsanitationsituationhasnotchanged."Chaos"isavillageinruralhousingconstructionplanning,constructionofdisorder,nodrawings,noconstruction,novetting"fourno"phenomenon,heaplyingthere."Bad"istheweakruralbase,villagegovernanceispoor.Thirdly,farmerscontinuedtobe"persistent"look."Old"isaging,rurallaborforceaccountedfor70%overtheageof50."Big"isthatthereformmeasuresgroundresistance,suchasthetransactionsofpropertyrights,landreplacement;publicservicesupplygap,ruraleducation,healthcare,pensionsandotherservicescannotmeetthedemandstilldifficultforpovertyalleviation,withemphasisonpovertyalleviationand191."Hard"isa"peasants,peasants.Fourwatereffectsstilllacks那么根据L=N×N×AlH=0.4×3.14×N×I/Le我们得到的限制条件是：0.4×3.14×SQRT(L/Al)×I/Le<100由于100Oe时，磁导率只有初始值的65%，所以我们要对上式中的Al乘上这个系数。那么带入相关的参数L=709uH，I=11.94A，我们有：0.4×3.14×SQRT(709E-6/(0.65×Al))×11.94/Le<100，简化后得到：0.495/(Le×SQRT(Al))<100注意：上式中，Le的单位是：cm，Al的单位是：H/(N×N)现在，我们可以把磁芯参数带入计算了。选择一个：H60-572A，Le=14.3cm，Al=140nH/(N×N)，Ae=2.889平方厘米，带入后得到：92.5<100显然这个磁芯是可以的。然后，根据92.5=0.4×3.14×N×I/Le计算得到N=88圈假如用铁氧体磁芯来设计PFC升压电感呢？因为铁氧体的规格众多，所以，这时候用AP法来初步计算一下倒是很方便哦：AP=(L×I×I×100)/(B×Ko×Kj))^1.14=(709E-6×11.94×11.94×100/(0.25×0.75×5))^1.14=15cm^4上式中，B是工作磁感应强度最大值，Ko是窗口利用率，取0.75，Kj是电流密度，取的是5A/平方毫米，后面^1.14表示1.14次方。此公式见蔡宣三的《开关电源设计》一书。经过选择，我们可以选择某公司EE55B铁氧体磁芯：Ae=4.22cm^2，Aw=3.85cm^24.22×3.85=16.25>15所以可以选择此磁芯。然后，根据LI=NΔBAe，消火栓给水系统和自动喷淋给水系统由设在地下二层的消火栓给水泵和自动喷淋给水泵经消防水池到消防给水泵，再向大楼各层消火栓和喷淋管网供水。同时消火栓给水系统和自动喷淋给水系统管网均与屋顶设置的生活、消防共用水箱相连、并通过屋顶设置的消防稳压设备进行稳压。compelling."Althoughthe"fivewatertreatment"alot,workveryhard,butthefloodofscientificenough,beforethetreatmentandwaterqualityimprovementafterthetreatmenteffectisnotobvious,county-widefocusonriverstilllargelyinferiorfivewater,swimmingtheRivercouldnotbefound.Fiveis"threetosplit"taskstillliesahead.Noticeofstockthere,newconstructiondidnotreceivetimelytreatmenteveryyear(suchasancestralhallasunauthorisedrepeated),contrarytothecreatedworkisverydifferentfromtheprovincialandmunicipalstandards.Meanwhile,whenimplementationisnotinplace,generallyonlyfocusonillegalconstructiondemolished,failingthatsplitthatisclear,combineddemolition,insufficientattentiontoreconstructionofoldresidentialareas,urbanvillages,shantytownsandpromotepoor.Tosolvetheseproblems,wemustenhancethesenseofresponsibilityandurgency,insistonproblem-oriented,totakestrongmeasures,effortstomakeupthe"threeagriculture"and"fivewatertreatment","threetosplita"shortBoard,constructionofcomprehensivesafeguards,"SouthGateofXXbeautiful"goalofrealizing.II,andprecisionShipolicy,andmanpowerplayinggood"threeagricultural"workprotracted"threeagricultural"workisdoeconomicsocialdevelopmenttheworkofbased,countylevelsthesectortoaccordingto"basedagricultural,andandmanpowerrural,anddevelopmentfarmers"ofrequirements,insistedagriculturalruralbasedstatusnotshake,insistedhuinongkulakpolicynotweakened,insistedreforminnovationtestnotstop,effortscreatednewera"threeagricultural"worknewsituation.(A)tomakeagriculturemore.Toestablishtheconceptofagriculturearoundthepeopledemand,andcomprehensivelypromotethesupplysideofagriculturestructuralreform,strivetoenhancethequalityandefficiencyofagricultureandcompetitiveness.Focusisondoingthefourarticles.Oneisthesteadyincreaseofgrainarticle.Alwaystightenthestringforfoodsecurity,"ricebag"catchinhand,toholdlandintheadjustmentofagriculturalplantingstructureinthe"redline."Acceleratingtheconstructionofgrainribbons,improvingagriculturalinfrastructure,enhancefoodproductioncapacity,improvethequalityofagriculturalproducts,effectively"steadyincreaseofgrain"andmaintain"tongue."Second,industryconvergencearticle.Enhancethelevelofconcentration,intensificationofagriculture,creatingproduction,processing,distribution,salesandserviceinoneoftheagriculturalindustrialchain,tobreakdownthevaluechain,improveaddedvalue.Pushingforward"theInternet+agricultural"modeltoimproveagriculturalproduction,management,andservicelevel,innovatingthemodeofe-commercemarketingofagriculturalproducts,solvethedifficultproblemofsalesofagriculturalproducts.Agricultureandtourism,education,culture,health,pensionandotherdeepintegration,developleisure,travellivingstandards,poorfarmersinlessthancompleteeliminationof4600Yuan,8949,19008."Fivewatersrule":theCountyinvested2.169billionyuan,similarcountieslinethecity\'sfirstcompletethe42kmofsewagepipenetworkconstruction,completionraterankedfirstinthecity,wontheprovincialruralsewagetreatmentworkbetter;keypollutionsourcessuchaselectroplating,papermaking,chemicalindustrymanagementthroughverificationandacceptanceofthemunicipalgovernment,theCountyremovedBlackandodorousRiver,Riverwaste,beginningofriverecologicalrestorationeffects."Threemodifiedasplit"aspects:Countytotaldemolitionillegalareaup2.759millionsquaremeters,completedCityissuedannualtaskof153%,splitagainstarearankingcitysecond;completed"threemodified"area4.846millionsquaremeters,completedCityissuedannualtaskof403%,rankingcitythird,whichvillageintheatargetcompletedtotalcityrankingfirst;CountyGovernmentwasnamedcitylevel"threemodifiedasplit"workadvanced.Theseachievementsarehardwonandshouldbeappreciated.However,wearefullyaware,thenewperiod,andworkinthecountrysideandtheenvironmentfacinghigherstandardsandrequirements,provincialpartyCommitteeofferedtohighlevelbuildacomprehensivewell-offsocietygoalrequires"nofilth,dirtyenvironmentillegalbuildings,intoawell-off";municipalpartyCommitteealsoproposestobuildintothewell-offbenchmarkgoalsofthecity.Comparedwiththesuperiorclaim,"SouthGateofXXbeautiful"goal,myCounty"SanNong"andenvironmentthereareanumberofweaknessesandgaps,highlightedinthefollowingfiveaspects:first,agricultureremained"low"pattern."Low"isreflectedinthequalityandlow;short,valueaddedoftheindustrychainislow;123fusionyieldlowemployeeage,lowquality."Small"isreflectedinsmaller,specializedcooperativesthroughouttheCountytherewere3,396,butonthescaleoftoolittle."San"isreflectedinproduction,management,services,decentralized,centralized,standardized,brand,informationandorganizationallevelisnothigh.Second,thecountrysideisstillin"dirty"phase."Dirty"isdirtyofruralsanitationsituationhasnotchanged."Chaos"isavillageinruralhousingconstructionplanning,constructionofdisorder,nodrawings,noconstruction,novetting"fourno"phenomenon,heaplyingthere."Bad"istheweakruralbase,villagegovernanceispoor.Thirdly,farmerscontinuedtobe"persistent"look."Old"isaging,rurallaborforceaccountedfor70%overtheageof50."Big"isthatthereformmeasuresgroundresistance,suchasthetransactionsofpropertyrights,landreplacement;publicservicesupplygap,ruraleducation,healthcare,pensionsandotherservicescannotmeetthedemandstilldifficultforpovertyalleviation,withemphasisonpovertyalleviationand191."Hard"isa"peasants,peasants.Fourwatereffectsstilllacks709E-6×11.94=N×0.25×4.22E-4N=80，核算一下窗口面积，假如采用直径1.4mm的漆包线，那么80×1.4×1.4/100=1.57cm^2<