应用于直流微网系统的移相控制dc-dc变换器

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1、万方数据浙江大学硕士学位论文Abs仃actAbstractTheenergycrisisandenvironmentalproblemshaveaffectedthehumanbeing’Slivinganddevelopment．Itisimminenttosearchfortheenergiesthatarerenewableandclean．Nowadays，themicrogridisproposedtoutilizethenewenergies，suchaswindpower，sorl

2、arenergyandfuelcells．ComparedwiththeAC-microgrid，DC—microgridisprovidedwithmoreadvantages．Forexample，stagesofconversionwillbereducedintheDC—microgrid，andthefrequencyandphasesynchronizationwillneverbetakenintoaccount．Therefore，theDC—microgridhasawided

3、evelopmentalforeground．1．Aphaseshiftcontrollednon-isolatedbidirectionalDC—DCconverterisdesignedinthispaper，toconnecttheDCbusandtheenergystoragecomponentsintheDC-microgrid．Thetopologyisobtainedbyintergratingtheresonantcapacitorcircuitandtheconventiona

4、lbidirectionalBuck-Boostconverter．Theserieshalfbridgestructureinthehighvoltagesideachievesthegoalofreducingthevoltagestressofthepowerswithestohalfofthehighvoltage．Byregulatingthedutycycle，thehighvoltageandthelowvoltageoftheconvertercanbematched，andth

5、evoltageauto-balancefunctionatthehighvoltagesideisrealizedatthesametime．Phaseshiftcontrolschemeisadoptedtodeterminetheenergyflow．Inaddition，allofthepowerswitchesachievezero-voltage—switching(zvs)，todepresstheswitchinglosses．Theeffectivenessofthetopol

6、ogyisverifiedbythesimulationandexperiments．2．FortheapplicationofconnectingtheDCbuswiththeDCroads，amodularmultilevelDC-DCconverterisdesignedtosustainthehighstep-downandhighpower，byintegratingthefull-bridgeconvertersandthethree-levelflying-capacitorcir

7、cuit．Thehighswitchvoltagestressintheprimarysideiseffectivelyreducedbythefull-bridgemodulesinseries．Therefore，thelow-voltageratedpowerdevicescanbeemployedtoobtainthebenefitsoflowconductionlosses．Moreimportantly，thevoltageauto·balanceabilityamongthecas

8、cadedmodulesisachievedbytheinherentflyingcapacitor．Inaddition，ZVSperformanceforalltheactiveswitchescanbeprovided，whichcanreducetheswitchinglosses．Finally，theperformanceofthepresentedconverterisverifiedbythesimulationandexperiments．III万方数据浙江大学硕士学位论文Ab