Introductiony Thespeedcontrolmethodsofadcmotoraresimplerandlessexpensivey Digitalsignalprocessorshavepermittedtheincreasinglystringentperformancerequirementsandfast,efficient,andaccuratecontrolofservomotorandmotioncontrolsystems.y Theycontinuetobesuccessfulbecauseofavailablelowcostsupporttools.

y DSPprocessorwilltakethespeedofthemotorasthefeedbacksignaly Thedifferencebetweenthesetpointspeedandthepresentspeedfinallyitwillchangethedutycycleofthebasedrivesignal.y Itisgivenastheinputtothebuckconverter.

DSP

Applicationsy Audiosignalprocessingy Audiocompressiony Digital imageprocessingy Videocompressiony Speechprocessingy Speechrecognitiony Digital communicationsy RADAR,SONAR,Seismologyy Biomedicine.

IMPORTANCEOFDSPy Lowcost.y Highperformance.y Enhancedandintegratedpowerelectronicsperipherals.y Forexample:analogtodigital(A/D)convertersandpulsewidthmodulator(PWM).y Flexibilityofquickdesignmodifications.y Implementationofmorecontrolschemes.y Lesssusceptibletoaging,environmentalvariations&havebetternoiseimmunity

TMS320F2812

ProgrammingofTMS320F2812DigitalSignalProcessory TheTMS320F2812DSPhasmanyspecialfeaturesforthecontrolapplications.

IthasEventManagerthatisspeciallydesignedforthemotorcontrolandmotioncontrolApplications.

y ThegeneralpurposeTimer1inEVA(EventManagerA)isusedincontinuousup/downcountmodeforthesymmetricPWMgeneration.Timershaveassociatedcompareregisterswhichareusedtowritethecalculateddutyratiovalues.

y ThesevaluesthengetcomparedwiththetimercountervalueinordertogeneratethePWMoutput.

y TheF281xandC281xcanbeclockedbyanexternaloscillatororbyacrystalattachedtotheonchiposcillatorcircuit.APhaseLockedLoop(PLL)isprovidedsupportingupto10 inputclockscalingratios.Thephaselockloopcontrolregister(PLLCR);DIVbits(30)areusedtochangethePLLmultiplierofthedevice.WhentheCPUwritestotheDIVbits, thePLLlogicswitchestheCPUclock(CLKIN)toOSCCLK/2.

y OncethePLLisstableandhaslockedatthenewspecifiedfrequency,thePLLswitchesCLKINtothenewfrequency

ProgrammingofTMS320F2812DigitalSignalProcessory Thecodedevelopmentiscarriedoutthroughanapplicationsuite

calledCodeComposerStudioTM (CCS).TheCodeComposerStudio(CCS)providesanintegrateddevelopmentenvironment(IDE)toincorporatethesoftwaretoolwhichisfullycompatibleandenablestheengineerstosimplifythesourcecode.

y Ithasgraphicalcapabilitiesandsupportsrealtimedebugging.Fig(4)showsthecodecomposerwindow.

y The12bitADCmodulehas16channels,configurableastwoindependent8channelmodulestoserviceeventmanagersAandB.

y Thetwoindependent8channelmodulescanbecascadedtoforma16channelmodule.Althoughtherearemultipleinputchannelsandtwosequencers,thereisonlyoneconverterintheADCmodule.TheADCofDSPcouldbetriggeredbythesoftware,EVA/Bortheexternalpins.equaltothesamplingfrequencyoftheADC.

BlockdiagramoftheF2812ADCmodule

BuckConverterandDCMotor

y Basicallythebuckconverterisastepdownconverter.DCtoDCconvertersareinherentlynonlinearduetoswitchingoperation.y TheregulationisnormallyachievedbythePWM(markspaceratio)atfixedfrequency.y TheswitchingdeviceispowerMOSFET,whichhaslowlossesathighfrequencyandarevoltagecontrolled.y HerebuckconverterisusedtogivetheregulatedDCsupplytotheDCmotoraccordingtothedutycycleofinput.

Buckconverterorstepdown

PracticalDriveCircuitsy TodrivethepowerMOSFETofthechoppercircuitisneedsatleast

7Volt,andthePWMoutputfromDSPKitdoesnotexceed3.3Volt.Therefore,anelectricalcircuitmustbedesignedtoamplifyoutputsignalandisolatetheDSPKitfromMOSFETgate.

y Thiscircuitconsistsofthreestages,buffercircuit,Optocoupler circuitandmatchingcircuit.ThepracticalisolatedfiringcircuitisshowninFig.(3).Alsofor3.3VADC,thesensingandamplificationstagesusuallymustproduceattheADCinputasignalswingof03.3V.

y ThisistoachievemaximumsignalmagnitudeandsignaltonoiseratioattheADCinput.Itisagoodpracticetouseanopampdrivercircuitforsignalconditioningofinputanalog signalsandasabuffer.TheopampisolatestheADCactsasalowimpedancesourcetochargethesamplecapacitorandconfiguredasagainbuffer.

y Itprovideslow/stableoutputimpedanceandprotectstheADCinputs.

GATEDRIVERCIRCUIT

Codecomposerwindow.

ExperimentalResultsy Thehardwaresystemhasbeendevelopedandtestedunderlaboratoryconditions.The markspaceratiooutputfromTMS320F2812DSPwithdesiredswitchingfrequencyofthe5KHz.ThesystemisdesignedinsuchawayastogenerateaPWMsignalinwhichthedutycyclecanbevariedfromzerotoonehundredpercent.y TheDCmotorratingsthatareusedinthis.5hp,12volts.

Voltageacrossdspoutputterminals(3.3v)

VoltageacrossMotor(for25%Ton)

Voltageacrossoutput(for50%Ton)

Voltageacrossmotor(for90%Ton)

Conclusiony TheresultswereobtainedbyconnectingDCmotorasaloadwhichiscontrolledbyTMS320F2812DSP.y AlltheSimulationandexperimentalresultsdemonstratedthevalidityofthesystemandshowedthattheDSPisreliableinstrumenttocontrolthemotor.y Thesystemshowstheapplicabilitytodifferentsizesofthemotorsandcapableofcontrollingthespeedofthemotorswithveryhighprecision.

THANKYOU

DSP F2812 Based DC Motor Speed ControlIntroductionSlide Number 3 DSP ApplicationsIMPORTANCE OF DSP TMS320F2812Programming of TMS320F2812 Digital Signal ProcessorProgramming of TMS320F2812 Digital Signal ProcessorBlock diagram of the F2812 ADC moduleSlide Number 11Slide Number 12 Buck Converter and DC MotorBuck converter or step downPractical Drive CircuitsGATE DRIVER CIRCUITCode composer window.Experimental ResultsVoltage across dsp output terminals(3.3v)Voltage across Motor( for 25%Ton )Voltage across output(for 50% Ton)Voltage across motor (for 90% Ton)ConclusionTHANK YOU