LLC电路基本原理分析及公式推导ST .doc

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1、SimplifiedAnalysisandDesignofSeries-resonantLLCHalf-bridgeConvertersMLDGROUPINDUSTRIAL&POWERCONVERSIONDIVISIONOff-lineSMPSBUApplicationLabl&PCDiv.•Off-lineSMPSAppl.LabPresentationOutline•LLCseries-resonantHalf-bridge:operationandsignificantwaveforms•Simplifiedmodel(FHAapproach)•300Wdesignexamplel&

2、PCDiv.•Off-lineSMPSAppl.LabSeries-resonantLLCHalf-BridgeTopologyandfeatureslKLlKLJJJa)>JaeOJPMCHw工3Q1Center-tappedoutputwithfullwaverectificationI(lowvoltageandhighcurrent)uPreferablyintegratedintoasinglemagneticstructure3reactiveelements,2resonantfrequenciesfr2=12K>/LsCr12冗々(Ls+Lp).CrSingle-ende

3、doutputwithbridgerectifiication(highvoltageandlowcurrent)■Multi-resonantLLCtankcircuit■Variablefrequencycontrol■Fixed50%dutycycleforQI&Q2■bead-timebetweenLGandHGtoallowMOSFETsZVS@turn-on■fsw«fr，sinusoidalwaveforms:lowturn-offlosses,lowEMI■Equalvoltage¤tstressforsecondaryrectifiers;ZC5,thenno

4、recoverylosses■Nooutputchoke;costsaving■Integratedmagnetics:bothL'scanberealizedwiththetransformer.■Highefficiency:>96%achievablel&PCDiv.•Off-lineSMPSAppl.LabLLCResonantHalf-bridgeWaveformsatresonance(fsw=frl)1.000.800.600.^00.200.00HV(SLV6Dead-timeGate-drivesignals_________.______-——————1i■i1iVfg

5、ndVeHBmid-pointVoltageResonantcapvoltageTransformercurrentsl&PCDiv.•Off-lineSMPSAppl.LabLLCResonantHalf-bridgeWaveformsatresonance(fsw=frl)l&PCDiv.•Off-lineSMPSAppl.LabLLCResonantHalf-bridgeWaveformsatresonance(fsw=frl)Time(us)DiodevoltagesDiodecurrentsl&PCDiv.•Off-lineSMPSAppl.LabLLCResonantHalf-

6、bridgeSwitchingdetailsatresonance(fsw=frl)l&PCDiv.•Off-lineSMPSAppl.LabLLCResonantHalf-bridgeSwitchingdetailsatresonance(fsw=frl)20.0C10.0CV(D1)<00.0C•10.0C•20.0C98U.UUy»2.00Time(us)3.002.502.001.501.000.500.00•0.50Gate-drivesignalsHBmid-pointVoltageResonantcapvoltageTransformercurrentsDiodevoltag

7、esDiodecurrentsKDD綱=0l&PCDiv.•Off-lineSMPSAppl.LabLLCResonantHalf-bridgeOperatingSequenceatresonance(Phase5/6)1•Q1OFFQ2ONQ1ONQ2OFFQ1OFFQ2ON祕LVG1/6woo3X001加—__j■>___0^00X)0………•1X)0•1-5QXOXJO伽00/)0•ta)x)otVout■QIis