Ti Digital Motor Control Solut

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  • TI Digital Motor Control SolutionsTI Digital Motor Control Solutions

    Texas Instruments Incorporated 2005No reproduction permitted without prior authorization from Texas Instruments. SPRB167A

    1H2004 Slide 1

  • Agenda Timeline Motor Control Fundamentals 25 min

    AC Induction and Permanent Magnet Motors

    Scalar and Vector Control

    Applications: Smarter controllers, high performance, lower cost 15 min

    Controller Selection 10 min

    Motor Control Collateral Overview 25 min

    Development Tools Overview: Faster HW+SW Development

    Modular Software Libraries: Development Accelerators

    Incremental Build Technology: Easy Deployment

    Completing the signal chain: TI Analog and Communications 25 min

    Get Started Today with TI! 5 min

    Question and Answers 10 min

    1H2004 Slide 2

  • Three Phase Machine Fundamentals

    Conceptual Practical

    Three phase machines have three windings, separated in phase by 120- a third of a rotation.

    1H2004 Slide 3

  • Three Phase Machine Fundamentals

    -1.50

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    1 24 47 70 93 116 139 162 185 208 231 254 277 300 323 346t

    ia ib icPhase currents

    The three phase winding produces three magnetic fields, which are spaced 120apart physically.

    When excited with three sine waves that are a 120 apart in phase, there are three pulsating magnetic fields.

    The resultant of the three magnetic fields is a rotating magnetic field.

    A`

    A

    Fa

    B

    C`

    C

    B`

    ia

    Fb

    Fc

    1H2004 Slide 4

  • A`

    A

    Fa

    B

    C`

    C

    B`

    ia

    Fb

    Fc

    Fs

    q (imaginary)

    d (real)

    $ sin( ). sin( ). sin( ).F F t e F t e F t es a i b o i c o io o o= + + + + 0 120 240120 240

    $ .F F es s j t= $F F jFs d q= +

    Three Phase Machine Fundamentals

    For instance, a 3 phase machine, with:60Hz Three Phase Supply; and 4 poles per phase will have a synchronous speed of 1800 r.p.m.

    Pf 120 r.p.m.)(in Speed =

    phaseper motor, for the poles of # P and

    frequency,supply AC f=

    =

    1H2004 Slide 5

  • Permanent Magnet Motor Operation

    1H2004 Slide 6

    Back EMF

    (v) t

    tStator Current

    (Is)

    The interaction between the rotating stator flux, and the rotor flux produces a torque which will cause the motor to rotate.

    The rotation of the rotor in this case will be at the same exactfrequency as the applied excitation to the rotor.

    A`

    B

    C`

    AB`

    C N

    S

    F

    F

    Stator field

    Rotor field

    This is an example of Synchronous operation.

  • Internal View: Induction Motor Rotor

    1H2004 Slide 7

  • ACI Operation FundamentalsA`

    A

    B

    C`

    C

    B`

    ia

    Ft

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    0.00

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    1.00

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    1 24 47 70 93 116 139 162 185 208 231 254 277 300 323 346

    ia ib icPhase currents

    Im

    Re

    120o Ia

    ~

    Ib~

    Ic~

    Current Phasors

    The induction machine has a rotor that is a closed circuit in the case of the squirrel-cage induction motor it is two rings joined by bars along the rotor axis.

    The rotor when placed in a moving magnetic field will have induced currents, which produce an induced magnetic field.The interaction of these two magnetic fields produces the rotational torque.

    1H2004 Slide 8

  • Agenda Timeline Motor Control Fundamentals 25 min

    AC Induction and Permanent Magnet Motors

    Scalar and Vector Control

    Applications: Smarter controllers, high performance, lower cost 15 min

    Controller Selection 10 min

    Motor Control Collateral Overview 25 min

    Development Tools Overview: Faster HW+SW Development

    Modular Software Libraries: Development Accelerators

    Incremental Build Technology: Easy Deployment

    Completing the signal chain: TI Analog and Communications 25 min

    Get Started Today with TI! 5 min

    Question and Answers 10 min

    1H2004 Slide 9

  • Scalar V/F control of 3-ph Induction Motor

    Vs(volt)

    f (Hz)fc frating

    Vrating

    0

    TORQUE

    MAXIMUMTORQUE

    NOMINALTORQUE

    SPEEDNOM SPEED

    VOLTAGE

    Vo

    LOW SPEED

    + Simple to implement: All you need is three sine waves feeding the ACI

    + No position information needed.

    Doesnt deliver good dynamic performance.1H2004 Slide 10

  • Limitations of the Scalar TechniqueACCELERATION DECELERATION

    TIME

    TORQUE

    Torque oscillationgenerates uncontrolled

    current overshoot:

    High peak current:In V/f the rotor flux and current are not controlled: Current reaches values based on circuit parameters.

    Poor response time:A solution to minimize these current overshoots is to decrease the performances of the speed regulator.Slow speed regulator poor mechanical behavior.

    1H2004 Slide 11

  • Stationary and Rotating Reference Frames

    Two phase orthogonal reference frame

    t

    t

    R/2

    a

    b

    R2/3

    2/3

    2/3c

    Three phase reference frame

    t

    DRQ

    rotort

    t

    IQ

    ID

    Rotating Orthogonal Reference Frame

    /2

    1H2004 Slide 12

  • Motor Flux Interaction

    TorqueT

    s and r constantTorque = sr sin()

    DR

    Q

    rotor

    S

    =load angle

    1H2004 Slide 13

  • Vector Control of 3-Ph Induction Motor

    FOC is a control strategy for 3-ph AC motors, where torque and flux are independently controlled.

    The approach is imitating the DC motors operation.

    Direct FOC: rotor flux angle is directly computed from flux estimation or measurement.

    Indirect FOC: rotor flux angle is indirectly computed from available speed and slip computation.

    1H2004 Slide 14

  • Maintain the load angleat 90

    Field Oriented Control - Vector Control

    A`

    B

    C`

    AB`

    C N

    S

    q=90F

    F

    + No torque ripple

    + Better dynamic response

    Need good knowledge of the rotor position

    Back EMF (v)

    Stator Current (Is)

    t = constant

    t

    t

    t

    1H2004 Slide 15

  • C28x Controllers

    1H2004 Slide 16

  • PMSM FOC with TMS320F2812 DSP

    PowerInverter

    Motor

    vas*

    vbs*Inv. Park

    rias

    ibs

    vqs*

    vds*

    PI

    ids*

    iqs*wr*

    wr

    Park

    PI

    PI

    Clarke

    SpaceVector Gen.

    PWM+

    Driver

    Ta

    Tb

    Tc

    PWM1PWM2

    ibs ADC+

    Driver

    PWM3PWM4PWM5PWM6

    ADCIN1

    ADCIN2

    ADCIN3

    ias

    ids

    iqs

    AngleSpeed Calculator

    r

    TMS320F2812 DSP controller

    QEP+ driver Phase

    Index

    Phase Encoder

    1H2004 Slide 17

  • ACI FOC System with TMS320F2812 DSP

    PowerInverter

    ACI

    vas*

    vbs*

    Inv. Park

    lr lrias

    ibs

    vqs*

    vds*

    PI

    ids*

    iqs*wr*

    wr

    Park

    PI

    PI

    Clarke

    SpaceVector

    Gen.

    PWMDriver

    TaTb

    Tc

    PWM1PWM2

    Vdc

    ibsIleg2_Bus

    Driver

    PWM3PWM4PWM5PWM6

    ADCIN1

    ADCIN2

    ADCIN3

    ias

    ids

    iqs

    Phase Voltage

    Cal.TaTbTc

    vasvbs

    Flux Est.

    Speed Est.

    iasibs

    iasibs

    lrlarlbr TMS320F2812 DSP

    controller

    1H2004 Slide 18

  • FOC TMS320F2812 DSP + Resolver

    PowerInverter

    Motor

    vas*

    vbs*Inv. Park

    rias

    ibs

    vqs*

    vds*

    PI

    ids*

    iqs*wr*

    wr

    Park

    PI

    PI

    Clarke

    SpaceVector Gen.

    PWM+

    Driver

    Ta

    Tb

    Tc

    PWM1PWM2

    ibs

    ADC+

    Driver

    PWM3PWM4PWM5PWM6

    ADCIN1

    ADCIN2

    ADCIN3

    ias

    ids

    iqs

    AngleSpeed Calculator

    r

    TMS320F2812 DSP controller

    ResolverPosition

    DetectionCosSin Resolver

    1H2004 Slide 19

  • Cost Effective High AccuracyPosition Measurement by Resolver

    12BitOPA4340ADS7861

    16BitOPA4350ADS8361

    1H2004 Slide 20

  • Sensored AC Induction Motor DTC Drive

    PowerInverter

    Motor

    Torque controller

    r*

    ADC

    State Selector

    TMS320F2812 DSP controller

    PWMGenSpeed Controller

    Input power stage

    Input power stage

    Flux and Torque calculator

    Communications modules

    SCI CAN

    Current and voltage vector calculator

    C

    A

    P

    T

    U

    R

    E

    I

    n

    p

    u

    t

    s

    1H2004 Slide 21

  • BLDC and PMSM Motor Types Both (typically) have permanent-magnet rotor and a

    wound stator BLDC (Brushless DC) motor is a permanent-magnet

    brushless motor with trapezoidal back EMF PMSM (Permanent-magnet synchronous motor) is a

    permanent-magnet brushless motor with sinusoidal back EMF

    300 900 1500 2100 2700 3300 300 90060000 1200 1800 2400 3000 3600 600

    Phase A

    Phase B

    Phase C

    ia

    ib

    ic

    e

    e

    e

    Ea

    Hall A

    Hall B

    Hall C

    Back EMF of BLDC Motor

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    ea eb ec

    Back EMF of PMSM

    A`

    B

    C