电力电子技术英文版 chapter07

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1、PPoowwererEEllececttrronionicscsChapter7PWMTechniquesThemostwidelyusedcontroltechniqueinpowerelectronicsDC/DCAC/ACElectronicsPulseWidthModulation(PWM)(Choppingcontrol)PowerDC/ACAC/DC2OuOuttlliinene7.1Basicprinciples7.2SomemajorPWMtechniquesinDC/ACinverters7.3PWMtechniqueswithfeedbackcont

2、rolElectronics7.4PWMrectifiersPower37.1Basic7.1BasicpprriinncciippleslesofofPPWMWMSimilarresponsetodifferentshapeofimpulseinputElectronicsPowerTheequal-areatheorem:Responsestendtobeidenticalwheninputsignalshavesameareaandtimedurationsofinputimpulsesbecomeverysmall.4BasicprinciplesofPWMAp

3、plicationoftheequal-areatheoremThisissinusoidalPWM(SPWM)ElectronicsTheequal-areatheoremcanbeappliedtorealizeanyshapeofwaveformsPower5AlistofPWMtechniquesTriangular-wavesampling–Naturalsampling–UniformsamplingCalculationElectronics–Calculationbasedonequal-areacriterion–Selectiveharmonicse

4、liminationHystereticcontrolSpaceVectorModulation(SVM,orSVPWM)PowerRandomPWM67.27.2SSomomeemmajajoorrPPWWMMttecechnhniiququesesNaturalsamplingUniformsamplingSelectiveharmonicseliminationElectronicsSomepracticalissues–Synchronousmodulationandasynchronousmodulation–HarmonicsinthePWMinverter

5、outputvoltages–WaystoimproveDCinputvoltageutilizationandreducePowerswitchingfrequency–ConnectionofmultiplePWMinvertersSpaceVectorPWM7Triangular-wavenaturalsamplingUni-polarPWMinsingle-phaseVSIVV13VDVD13+RLUdVuV2o4VDVDElectronics24ControlursignalMudulationCarrierCarrierucPowerUni-polarsam

6、plingisusedtorealizeuni-polarPWM.8Triangular-wavenaturalsamplingBi-polarPWMinsingle-phaseVSIVV13VDVD13+RLUdVuV2o4ElectronicsVDVD24ControlursignalMudulationCarrierCarrierucPowerBi-polarsamplingisusedtorealizebi-polarPWM.9Triangular-wavenaturalsamplingIn3-phaseVSIElectronicsPowerThree-phas

7、ebridgeinvertercanonlyrealizebi-bolarPWMthereforeshouldbecontrolledbybipolarsampling.10Triangular-waveuniformsamplingEasiertorealizebycomputer-controlElectronicsModulationfactorPower11SelectiveharmonicseliminationPWM(SHEPWM)ElectronicsPower12Frequencyrelationshipbetweentr