脉冲宽度调制（pwm）大学毕业论文外文文献翻译及原文

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1、毕业设计（论文）外文文献翻译文献、资料中文题目：脉冲宽度调制（PWM）文献、资料英文题目：文献、资料来源：文献、资料发表（出版）日期：院（部）：专业：班级：姓名：学号：指导教师：翻译日期：2017.02.14外文原文Pulse-widthmodulationPulse-widthmodulation(PWM)isamodulationtechniquethatconformsthewidthofthepulse，formallythepulseduration,basedonmodulatorsignalinformation.Althou

2、ghthismodulationtechniquecanbeusedtoencodeinformationfortransmission，itsmainuseistoallowthecontrolofthepowersuppliedtoelectricaldevices，especiallytoinertialloadssuchasmotors.Inaddition,PWMisoneofthetwoprincipalalgorithmsusedinphotovoltaicsolarbatterychargers,1'1Theaveragev

3、alueofvoltage(andcurrent)fedtotheloadiscontrolledbyturningtheswitchbetweensupplyandloadonandoffatafastpace.Thelongertheswitchisoncomparedtotheoffperiods，thehigherthepowersuppliedtotheloadis.ThePWMswitchingfrequencyhastobemuchfasterthanwhatwouldaffecttheload，whichistosaythe

4、devicethatusesthepower.Typicallyswitchingshavetobedoneseveraltimesaminuteinanelectricstove，120Hzinalampdimmer,fromfewkilohertz(kHz)totensofkHzforamotordriveandwellintothetensorhundredsofkHzinaudioamplifiersandcomputerpowersupplies.Thetermdutycycledescribestheproportionof’o

5、n’timetotheregularintervalor’period’oftime;alowdutycyclecorrespondstolowpower，becausethepowerisoffformostofthetime.Dutycycleisexpressedinpercent，100%beingfbllyon.ThemainadvantageofPWMisthatpowerlossintheswitchingdevicesisverylow.Whenaswitchisoffthereispracticallynocurrent，

6、andwhenitison，thereisalmostnovoltagedropacrosstheswitch.Powerloss,beingtheproductofvoltageandcurrent，isthusinbothcasesclosetozero.PWMalsoworkswellwithdigitalcontrols，which，becauseoftheiron/offnature,caneasilysettheneededdutycycle.PWMhasalsobeenusedincertaincommunicationsys

7、temswhereitsdutycyclehasbeenusedtoconveyinformationoveracommunicationschannel.HistoryInthepast,whenonlypartialpowerwasneeded(suchasforasewingmachinemotor)，arheostat(locatedinthesewingmachine’sfootpedal)connectedinserieswiththemotoradjustedtheamountofcurrentflowingthroughth

8、emotor，butalsowastedpowerasheatintheresistorelement.Itwasaninefficientscheme，buttolerable