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1、几种pwm控制方法(SeveralPWMcontrolmethods)SeveralPWMcontrolmethod・TxtSeveralPWMcontrolmethodsIntroductionSamplingcontroltheoryhasanimportantconclusion:theimpulseequalanddifferentshapepulsewiththeinertiaofthelink,theeffectisbasicallythesame・PWMcontroltechnologyistotheconclusionasthetheoreticalbasisof
2、thesemiconductorswitchingdeviceturn-onandturnoffcontrol,theoutputendofaseriesofequalamplitudeandwidthequaltothepulse,usingthesepulsesinsteadofasinewaveorotherneededwaveform.Thepulsewidthmodulationaccordingtocertainrules,itcanchangethesizeoftheinvertercircuitoutputvoltagecanchangetheoutputfreq
3、uency.ThebasicprincipleofPWMcontrolisalreadyproposed,butrestrictedbythelevelofdevelopmentofpowerelectronicdevices,inthelastcenturybefore80shasnotbeenrealized.Intothelastcenturyuntil80s,withtheemergenceandrapiddevelopmentoffullcontrolledpowerelectronicdevices,PWMcontroltechnologyappliedtothere
4、a1.Withthedevelopmentofpowerelectronictechnology,microelectronicstechnologyandthedevelopmentofautomaticcontroltechnologyandavarietyofnewtheoreticalmethods,suchastheapplicationofmoderncontroltheory,nonlinearsystemcontroltheory,PWMcontroltechnologyhasachievedunprecedenteddevelopment・Sofar,there
5、havebeenavarietyofPWMcontroltechnology,accordingtothecharacteristicsofPWMcontroltechnology,sofar,therearemainly8kindsofmethods.1phasevoltagecontrolPWM1.1pulsewidthPWMlaw[1]VVVF(VariableVoltageVariableFrequency)deviceintheearlyistheuseofPAM(PulseAmplitudeModulation)controltechnologytoachieve,t
6、heinvertercanonlybepartoftheoutputfrequencyadjustablesquarewavevoltagecannotadjustthepressure・ThepulsewidthPWMlawistoovercometheshortcomingsofthedevelopmentofPAMmethodandPWMmethodisthemostsimpleone・ItisthepulseofeachpulsewidthequaltothecolumnasPWMwavebychangingthepulsetraincyclecanchangefrequ
7、ency,pulsewidthorthedutyratiocanbeadjustable,usingappropriatecontrolmethodcanmakethevoltageandfrequencycoordinationchanges・ComparedwiththePAMmethod,theadvantageofthismethodistosimplifythecircuitstructureandimprovethepowerfactoroftheinput,buta