Curtis Instruments 1232 - APPENDIX A: THEORY OF OPERATION; Motor Control Principles

#URTIS-ANUALOS
!00%.$)8!
4(%/29/&/0%2!4)/.
#URTISCONTROLLERSCONVERT$#BATTERYPOWERTOPHASE!#POWER
BYPRECISELYCONTROLLINGTHEINDUCTIONDRIVEFORHIGHBANDWIDTHHIGHEFlCIENCY
ANDLOWRIPPLETORQUEGENERATION4OREALIZETHISLEVELOFPRECISETORQUECONTROLOF
INDUCTIONMOTORDRIVESINELECTRICVEHICLES#URTISENGINEERSCAREFULLYEVALUATED
ANDINCORPORATEDTHELATESTTECHNOLOGYINMICROPROCESSORSPOWERELECTRONICS
ANDMOTORCONTROL
)NVENTEDBY.IKOLA4ESLAINTHEINDUCTIONMOTORBECAMEAWORKHORSE
THATCONTRIBUTEDTOTHEVASTINDUSTRIALGROWTHINTHETWENTIETHCENTURY5NTIL
RECENTLYRELEGATEDTONONDYNAMICAPPLICATIONSWHERETRANSIENTRESPONSEWASNTA
CRITICALCONCERNINDUCTIONMOTORSARENOWACOMMONMOTOROFCHOICEINHIGH
PERFORMANCECONTROLAPPLICATIONS4HISSHIFTWASFACILITATEDBYTHEENORMOUS
ADVANCEMENTSINMICROPROCESSORSANDPOWERSILICONDEVICESINTHELASTTHIRTY
YEARSCOUPLEDWITHINTENSERESEARCHANDDEVELOPMENT
4HEPHASEINDUCTIONMOTORHASTHREESETSOFDISTRIBUTEDWINDINGSINTHE
STATORWINDINGSLOTS4HESTANDARDINDUCTIONMOTORHASAROTORWITHALUMINUM
BARSSHORTCIRCUITEDBYCASTALUMINUMENDRINGS4HEREARENOBRUSHESCOM
MUTATORS
ORSLIPRINGS
ANDUNLIKE$#ANDSYNCHRONOUSMOTORSTHEREIS
NONEEDFORPERMANENTMAGNETSORASEPARATECURRENTSUPPLYFORTHEROTOR4HE
BRUSHLESSCONSTRUCTIONOFTHEINDUCTIONMOTORANDTHERUGGEDROTORPROVIDE
HIGHRELIABILITYFAULTTOLERANCELOWMAINTENANCEANDLOWCOST
4HREEPHASESINUSOIDALVOLTAGESELECTRICALLYDISPLACEDBYAREAPPLIED
TOTHEPHASEWINDINGSTOCREATETHESTATORMAGNETIClELD4HElELDROTATESAT
THESTATORVOLTAGEFREQUENCYDIVIDEDBYTHENUMBEROFPOLEPAIRS4HISROTATING
STATORlELDINDUCESCURRENTSINTHECONDUCTIVEROTORBARSBYTRANSFORMERACTION
WHICHINTURNCREATEASECONDROTORMAGNETIClELD4HEROTORlELDREACTSTO
THESTATORlELD TOGENERATE TORQUE4HE DIFFERENTIALSPEEDORSLIP FREQUENCY
BETWEEN THE STATOR lELD ANDROTOR SPEED IS CRITICAL TO THE TORQUEAND SPEED
CONTROLOFANINDUCTIONMOTOR
-OTOR#ONTROL!LGORITHMS
4WOMAINAPPROACHESARECOMMONLYUSEDFORINDUCTIONMOTORCONTROLSCALAR
CONTROLANDVECTORCONTROL
3CALARCONTROLEGVOLTS(ZMODULATESONLYTHEMAGNITUDEANDFREQUENCY
OFTHEAPPLIEDVOLTAGEORCURRENT!LTHOUGHSCALARCONTROLHASTHEADVANTAGE
OFBEINGSIMPLERTHANVECTORCONTROLITHASPOORDYNAMICRESPONSEANDLOWER
OPERATIONEFlCIENCY4HEVARIOUSMETHODSUSEDTOIMPROVEPERFORMANCEREQUIRE
EXTENSIVECHARACTERIZATIONOFTHEMOTORANDLOADS
6ECTORCONTROLEGINDIRECTROTORmUXORIENTATIONSTATORmUXORIENTATION
ETCMANIPULATESTHEMAGNITUDEFREQUENCYANDPHASEOFTHECONTROLVARIABLES
!00%.$)8!4(%/29/&/0%2!4)/.
!