升降壓斬波電路 Buckboost chopper circuit中英版

Item4DCChopperCircuit項(xiàng)目四直流斬波電路4.3Boost-BuckChopperCircuit4.3升降壓斬波電路TeachingResourcesDatabaseof

NationalVocationalEducationPowerSupplyTechnologyBilingualcourses.Powerelectronicstechnology電力電子技術(shù)

升降壓斬波電路

(Boost-BuckChoppercircuit)

電路結(jié)構(gòu)circuitstructure圖2升降壓斬波電路Fig.2Boost-BuckChopperCircuit4.3升降壓斬波電路Boost-BuckChopperCircuit基本工作原理Basicoperationprinciplea)otb)oti1i2tontoffILIL圖2升降壓斬波電路及其波形Boost-BuckChopperCircuitanditswaveformsa）電路圖circuitdiagram

b）波形waveformsV通時(shí)，電源E經(jīng)V向L供電使其貯能，此時(shí)電流為i1。同時(shí)，C維持輸出電壓恒定并向負(fù)載R供電。WhenVisturnedon,powersupplyEsuppliespowertoLthroughVtostoreenergy,andthecurrentatthistimeisI1.Atthesametime,CmaintainstheoutputvoltageconstantandsuppliespowertoloadR.V斷時(shí)，L的能量向負(fù)載釋放，電流為i2。負(fù)載電壓極性為上負(fù)下正，與電源電壓極性相反，該電路也稱作反極性斬波電路。WhenVisturnedoff,theenergyofLisreleasedtotheloadandthecurrentisI2.Thepolarityoftheloadvoltageisupnegativeanddownpositive,whichisoppositetothepolarityofthesupplyvoltage.Thiscircuitisalsocalledthereversepolaritychoppercircuit.4.3升降壓斬波電路Boost-BuckChopperCircuit數(shù)量關(guān)系Quantitative

Relations穩(wěn)態(tài)時(shí)，一個(gè)周期T內(nèi)電感L兩端電壓uL對(duì)時(shí)間的積分為零，即Insteadystate,theintegralofvoltageULatbothendsofinductanceLthatwithrespecttotimewithinaperiodTiszero,thatis:所以輸出電壓為：Sotheoutputvoltageisthat

:V處于通態(tài)uL=EV處于斷態(tài)uL=-uo4.3升降壓斬波電路Boost-BuckChopperCircuitWhenVisturnedonWhenVisturnedoff圖3-4b中給出了電源電流i1和負(fù)載電流i2的波形，設(shè)兩者的平均值分別為I1和I2，當(dāng)電流脈動(dòng)足夠小時(shí)，有：Fig.3-4bshowsthewaveformofthepowersupplycurrentI1andtheloadcurrentI2.LettheaveragevaluesofthetwobeI1andI2,respectively.Whenthecurrentpulsationissmallenough,thefollowingcanbeobtained:由上式得：Itcanbeobtainedfromtheaboveequation

結(jié)論Conclusion當(dāng)0<a<1/2時(shí)為降壓，當(dāng)1/2<a<1時(shí)為升壓，故稱作升降壓斬波電路。也有稱之為buck-boost變換器。When0<A<1/2,itisstep-down,andwhen1/2<A<1,itisstep-up,soitiscalledstep-downvoltagechoppercircuit.Itisalsocalledabuck-boostconverter.其輸出功率和輸入功率相等，可看作直流變壓器。Itsoutputpowerandinputpowerareequal,itcanberegardedasaDCtransformer.otb)oti1i2tontoffILIL圖3升降壓斬波電路波形Fig.3Boost-BuckChopperCircuitanditswaveforms4.3升降壓斬波電路Boost-BuckChopperCircuitTea