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1、畢業(yè)設(shè)計（論文）附錄A：英文參考文獻(xiàn)及其翻譯DirecttorquecontrolDirecttorquecontrol(DTC)isonemethodusedinvariablefrequencydrivestocontrolthetorque(andthusfinallythespeed)ofthree-phaseACelectricmotors.Thisinvolvescalculatinganestimateofthemotor'smagneticfluxandtorquebasedonthemeasuredvoltageandcurrentofthe
2、motor.MethodStatorfluxlinkageisestimatedbyintegratingthestatorvoltages.Torqueisestimatedasacrossproductofestimatedstatorfluxlinkagevectorandmeasuredmotorcurrentvector.Theestimatedfluxmagnitudeandtorquearethencomparedwiththeirreferencevalues.Ifeithertheestimatedfluxortorquedeviatesfr
3、omthereferencemorethanallowedtolerance,thetransistorsofthevariablefrequencydriveareturnedoffandoninsuchawaythatthefluxandtorquewillreturnintheirtolerancebandsasfastaspossible.Thusdirecttorquecontrolisoneformofthehysteresisorbang-bangcontrol.Thiscontrolmethodimpliesthefollowingproper
4、tiesofthecontrol:·Torqueandfluxcanbechangedveryfastbychangingthereferences·Highefficiency&lowlosses-switchinglossesareminimizedbecausethetransistorsareswitchedonlywhenitisneededtokeeptorqueandfluxwithintheirhysteresisbands·Thestepresponsehasnoovershoot·Nocoordinatetransformsareneede
5、d,allcalculationsaredoneinstationarycoordinatesystem·Noseparatemodulatorisneeded,thehysteresiscontroldefinestheswitchcontrolsignalsdirectly·TherearenoPIcurrentcontrollers.Thusnotuningofthecontrolisrequired·Theswitchingfrequencyofthetransistorsisnotconstant.However,bycontrollingthewi
6、dthofthetolerancebandstheaverageswitchingfrequencycanbekeptroughlyatitsreferencevalue.Thisalsokeepsthecurrentandtorqueripplesmall.Thusthetorqueandcurrentrippleareofthesamemagnitudethanwithvectorcontrolleddriveswiththesameswitchingfrequency.·Duetothehysteresiscontroltheswitchingproce
7、ssisrandombynature.Thustherearenopeaksinthecurrentspectrum.Thisfurthermeansthattheaudiblenoiseofthemachineislow·TheintermediateDCcircuit'svoltagevariationisautomaticallytakenintoaccountinthealgorithm(involtageintegration).Thusnoproblemsexistduetodcvoltageripple(aliasing)ordcvoltaget
8、ransients·Synchroni
