Curtis Instruments 1232 - Motor Control Techniques and Power Section

#URTIS-ANUAL/3 
TO PROVIDE BETTER CONTROL4HE MATHEMATICAL MODEL OF AN INDUCTION MOTOR
ISCOMPLEX5SINGASERIESOFREFERENCEFRAMETRANSFORMATIONSVECTORCONTROL
SIMPLIlESTHEMODELTOENABLEPRECISECONTROLOFTORQUEANDmUXSIMILARTOA
3EP%XMOTORCONTROLLER
&IGURE! SHOWS A TYPICAL DIAGRAM OFINDIRECT ROTOR mUX ORIENTATION
4HE INSTANTANEOUS PHASE CURRENTSARE TRANSFORMED TO THE ROTOR mUX REFER
ENCE
FRAMEUSING
ROTORSPEEDANDSLIPFREQUENCYWHICHMEANSTHATTHEMO
TORCURRENTS
ARENOWOBSERVEDFROMTHEVIEWPOINTOFROTATINGWITHTHEROTOR
mUX!SARESULTOFTHISTRANSFORMATIONTHECURRENTSNOWINWHATISCALLEDTHE
DQ
REFER
ENCEFRAMELOSETHEIRSINUSOIDALNATUREANDLOOKLIKE$#SIGNALS)NTHE
DQREFERENCEFRAMEQAXISCURRENTCONTROLSTORQUEANDDAXISCURRENTCONTROLS
mUX)FPROPERLYORIENTEDTHETORQUEANDmUXREMAININDEPENDENTOFEACHOTHER
ANDTHEMOTORCANACHIEVEHIGHEFlCIENCYANDDYNAMICRESPONSE
&IG! $IAGRAMOF
)NDIRECT&IELD/RIENTATION
)&/TECHNIQUE
4HECONTROLLERUSESANADVANCEDPULSEWIDTHMODULATIONTECHNIQUETO
MAXIMIZE THE UTILIZATION OF BATTERY VOLTAGE MINIMIZE HARMONIC LOSSES AND
INCREASESYSTEMEFlCIENCY4HISMETHODACHIEVESGREATERLINEARUTILIZATION
OFBATTERYVOLTAGETHEREBYEFFECTIVELYGETTINGMOREUSABLEMOTORPOWERTHAN
STANDARD07-ATTHESAMEBATTERYVOLTAGE
0OWER3ECTION
4HEPOWERSECTIONEFlCIENTLYGENERATESHIGHCURRENTPHASE!#SIGNALSFROM
THE$#BATTERYVOLTAGETODRIVETHE!#MOTORASREQUESTEDBYTHEMOTORCON
TR
OL
ALGORITHMS
4HE
POWERSECTION ISIMPLEMENTED ASTHREEHIGH FREQUENCY-/3&%4
HALFBRIDGEPOWERSTAGESCONTROLLEDBYTHREEPULSEWIDTHMODULATORSASSHOWN
IN&IGURE!%ACHHALFBRIDGEPOWERSTAGEISAPARALLELARRAYOFHIGHSIDEAND
LOWSIDEPOWER-/3&%4SMOUNTEDTO)NSULATED-ETAL3UBSTRATE)-3CIRCUIT
BOARD4HISTECHNOLOGYPROVIDESAVERYLOWTHERMALRESISTANCETOTHEHEATSINK
ANDENABLESHIGHPOWERCAPABILITYINACOMPACTAREA
!00%.$)8!4(%/29/&/0%2!4)/.
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