磁芯资料讲解1.pdf

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1、PartIII.Magnetics12.BasicMagneticsTheory13.FilterInductorDesign14.TransformerDesignFundamentalsofPowerElectronics1Chapter12:BasicMagneticsTheoryChapter12.BasicMagneticsTheory12.1.Reviewofbasicmagnetics12.1.1.Basicrelations12.1.2.Magneticcircuits12.2.Transformermodeling12.2.1.Theidealtransformer12.2.

2、3.Leakageinductances12.2.2.Themagnetizinginductance12.3.Lossmechanismsinmagneticdevices12.3.1.Coreloss12.3.2.Low-frequencycopperloss12.4.Eddycurrentsinwindingconductors12.4.1.Theskineffect12.4.4.Powerlossinalayer12.4.2.Theproximityeffect12.4.5.Example:powerlossinatransformerwinding12.4.3.MMFdiagrams

3、12.4.6.PWMwaveformharmonicsFundamentalsofPowerElectronics2Chapter12:BasicMagneticsTheory12.1.Reviewofbasicmagnetics12.1.1.BasicrelationsFaraday'slawv(t)B(t),F(t)terminalcorecharacteristicscharacteristicsi(t)H(t),F(t)Ampere'slawFundamentalsofPowerElectronics3Chapter12:BasicMagneticsTheoryBasicquantit

4、iesMagneticquantitiesElectricalquantitieslengthllengthlmagneticfieldHelectricfieldExxxx1212+–+–MMFvoltageF=HlV=ElsurfaceSsurfaceSwithareaAwithareaAcctotalfluxF{totalcurrentI{fluxdensityBcurrentdensityJFundamentalsofPowerElectronics4Chapter12:BasicMagneticsTheoryMagneticfieldHandmagnetomotiveforceFMa

5、gnetomotiveforce(MMF)Fbetweenpointsxandxisrelatedto12themagneticfieldHaccordingtox2F=H×dlx1Example:uniformmagneticAnalogoustoelectricfieldoffieldofmagnitudeHstrengthE,whichinduceslengthlvoltage(EMF)V:lengthlmagneticfieldHelectricfieldExx12xx+–12+–MMFvoltageF=HlV=ElFundamentalsofPowerElectronics5Chap

6、ter12:BasicMagneticsTheoryFluxdensityBandtotalfluxFThetotalmagneticfluxFpassingthroughasurfaceofareaAiscrelatedtothefluxdensityBaccordingtoF=B×dAsurfaceSExample:uniformfluxdensityofAnalogoustoelectricalconductormagnitudeBcurrentdensityofmagnitudeJ,F=BAwhichleadstototalconductorccurrentI:surfaceSsurf

7、aceSwithareaAcwithareaActotalfluxF{totalcurrentI{fluxdensityBcurrentdensityJFundamentalsofPowerElectronics6Chapter12:BasicMagneticsTheoryFaraday’slawVoltagev(t)isinducedinaloopofwirebychangeinareaActh