torque prod duct ion with ac drives and motors-understanding the technology
TRANSCRIPT
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After 25 years of AC DriveAfter 25 years of AC Driveacceptance, drive manufacturersacceptance, drive manufacturers
offer the industry many types of offer the industry many types of control methods.control methods.
Well review some motor & driveWell review some motor & drivebasics and then discuss thebasics and then discuss thetechnologies offered in AC Drivestechnologies offered in AC Drivesalong with the selection process.along with the selection process.
Presentation AbstractPresentation Abstract
Presentation AbstractPresentation Abstract
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REVIE WING MOTO R REVIE WING MOTO R FU N DAMEN TALSFU N DAMEN TALS
AC & DC Motor Basics AC & DC Motor Basics
AC & DC Motor Basics AC & DC Motor Basics
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Motor nameplate HP is achieved at Base RPM:Motor nameplate HP is achieved at Base RPM:
HP = Torque * Speed / 5252HP = Torque * Speed / 5252Torque
RP MBase Speed
100%Constant TorqueConstant TorqueR angeR ange Constant Horsepower Constant Horsepower R angeR ange
Motor BasicsMotor Basics
Motor BasicsMotor Basics
N ameplate H P is onlyN ameplate H P is only
achieved at baseachieved at basespeed, N OT B E FO RE!speed, N OT B E FO RE!
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3 phase stator winding circuit w/ connections T1, T2 & T 33 phase stator winding circuit w/ connections T1, T2 & T 3
Motor BasicsMotor Basics -- AC Motor Construction AC Motor Construction
Motor BasicsMotor Basics -- AC Motor Construction AC Motor Construction
Motor FrameMotor FrameAssemblyAssembly
R otor & ShaftR otor & ShaftAssemblyAssembly
Stator WindingStator WindingAssemblyAssembly
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R otating Magnetic Field of a 2 P ole AC Induction Motor R otating Magnetic Field of a 2 P ole AC Induction Motor
Motor RP M is equal to:
120 * Frequency
# Motor P oles
2 P ole Motor 2 P ole Motor
N ote that FrequencyN ote that Frequency
is the only variable tois the only variable toaffect motor speedaffect motor speed
Motor BasicsMotor Basics -- AC Motor Operation AC Motor Operation
Motor BasicsMotor Basics -- AC Motor Operation AC Motor Operation
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ArmatureArmatureAssemblyAssembly
Distinct Armature & Field Circuits are mechanically separatedDistinct Armature & Field Circuits are mechanically separated
N OT E : The Armature & FieldN OT E : The Armature & FieldCircuits are mechanicallyCircuits are mechanically
fixed at 90fixed at 90 at all timesat all times
Field P olesField P oles
AssembliesAssemblies
Commutator &Commutator &Brush AssemblyBrush Assembly
Motor BasicsMotor Basics -- DC Motor ConstructionDC Motor ConstructionMotor BasicsMotor Basics -- DC Motor ConstructionDC Motor Construction
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R otating Magnetic Field of a 2 P ole AC Induction Motor R otating Magnetic Field of a 2 P ole AC Induction Motor
Motor RP M is equal to:
Both Armature TerminalBoth Armature TerminalVoltage & Field StrengthVoltage & Field Strengthaffect DC Motor speedaffect DC Motor speed
Simple ModelSimple Model
Voltage - ( Voltage Drop )
Field FluxArmSS N NV
V
To create motor torqueTo create motor torqueat the shaft, we increaseat the shaft, we increase
Armature Current Armature Current
Motor BasicMotor Basic -- DC Motor OperationDC Motor OperationMotor BasicMotor Basic -- DC Motor OperationDC Motor Operation
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K ey P oints of UnderstandingK ey P oints of Understanding
Mechanical differences must be overcome mathematicallyMechanical differences must be overcome mathematically
AC Induction Motors have one circuit to connectAC Induction Motors have one circuit to connect
Connection to T1, T2 & T3
for the stator Connection to T1, T2 & T3
for the stator DC Motors have 2 separate circuits to connectDC Motors have 2 separate circuits to connect
Connection to F1 & F2 for the FieldConnection to F1 & F2 for the Field
Connection to A1 & A2 for the ArmatureConnection to A1 & A2 for the Armature
To make AC Motors perform like DC MotorsTo make AC Motors perform like DC MotorsTreat the AC motor like a 2 circuit machineTreat the AC motor like a 2 circuit machine
Motor BasicsMotor Basics -- AC & DC Summary AC & DC SummaryMotor BasicsMotor Basics -- AC & DC Summary AC & DC Summary
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P WM AC D RIVE P WM AC D RIVE FU N DAMEN TALSFU N DAMEN TALS
AC Drive Basics AC Drive Basics AC Drive Basics AC Drive Basics
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Diode rectifier converts AC line voltage to fixed voltage DC.DC voltage is filtered to reduce current ripple from rectification.Inverter changes fixed voltage DC to adjustable PWM AC voltage.
Diode rectifier converts AC line voltage to fixed voltage DC.DC voltage is filtered to reduce current ripple from rectification.Inverter changes fixed voltage DC to adjustable PWM AC voltage.
Motor Motor AC LineAC Line
IG BTIG BTInverter Inverter
DiodeDiodeR ectifier R ectifier
DC BusDC BusFilter Filter
Drive BasicsDrive Basics -- PWM AC Drive ConstructionPWM AC Drive ConstructionDrive BasicsDrive Basics -- PWM AC Drive ConstructionPWM AC Drive Construction
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P WM waveform is a series of repetitiveP WM waveform is a series of repetitive Voltage pulsesVoltage pulses
1
3
+ DC Bus+ DC Bus
-- DC BusDC Bus
VVLLLL @ Drive@ Drive500 Volts / Div.500 Volts / Div.
P hase CurrentP hase Current10 Amps / Div.10 Amps / Div.
M2.00 Qs Ch1 1.18 V
AC Drive Basics AC Drive Basics -- PWM AC WaveformsPWM AC Waveforms AC Drive Basics AC Drive Basics -- PWM AC WaveformsPWM AC Waveforms
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Motor speed is controlled by ramping Voltage & FrequencyMotor speed is controlled by ramping Voltage & Frequency
OutputOutputFrequencyFrequencyBase FrequencyBase Frequency
6060
OutputOutput
VoltageVoltage
Hz3 0
460460
23 0
115
15 90
R atio @ 460 VAC= 7.67 V /Hz
0
Operation at Base SpeedOperation at Base Speed
AC Drive Basics AC Drive Basics -- V/Hz OperationV/Hz Operation AC Drive Basics AC Drive Basics -- V/Hz OperationV/Hz Operation
At 100% of the motors base speed, the V/Hz ratio is At 100% of the motors base speed, the V/Hz ratio isdetermined: HP = 100% of motor nameplatedetermined: HP = 100% of motor nameplate
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At 50% of base speed, Voltage & Frequency decrease by 1/2At 50% of base speed, Voltage & Frequency decrease by 1/2
OutputOutputFrequencyFrequencyBase FrequencyBase Frequency
60
OutputOutput
VoltageVoltage
Hz3 03 0
460
23 023 0
115
15 90
R atio @ 460 VAC= 7.67 V /Hz
0
AC Drive Basics AC Drive Basics -- V/Hz OperationV/Hz Operation AC Drive Basics AC Drive Basics -- V/Hz OperationV/Hz Operation
At 50% of the motors base speed, the V/Hz ratio is At 50% of the motors base speed, the V/Hz ratio ismaintained: HP = 50% of motor nameplatemaintained: HP = 50% of motor nameplate
Operation at 50% Base SpeedOperation at 50% Base Speed
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At 25% of the motors base speed, the V/Hz ratio is At 25% of the motors base speed, the V/Hz ratio ismaintained: HP = 25% of motor nameplatemaintained: HP = 25% of motor nameplate
OutputOutputFrequencyFrequencyBase FrequencyBase Frequency
60
OutputOutput
VoltageVoltage
Hz3 0
460
23 0
115115
1515 90
R atio @ 460 VAC= 7.67 V /Hz
0
At 25% base speed, Voltage & Frequency decreases by 3 /4sAt 25% base speed, Voltage & Frequency decreases by 3 /4s
AC Drive Basics AC Drive Basics -- V/Hz OperationV/Hz Operation AC Drive Basics AC Drive Basics -- V/Hz OperationV/Hz Operation
Operation at 25% Base SpeedOperation at 25% Base Speed
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To increase starting torque, V/Hz Drives use Voltage BoostTo increase starting torque, V/Hz Drives use Voltage Boostto over to over- -flux the motor to increase starting torqueflux the motor to increase starting torque
Offsetting the voltage ratio increases motor starting torqueOffsetting the voltage ratio increases motor starting torque
OutputOutputFrequencyFrequencyBase FrequencyBase Frequency
60
OutputOutput
VoltageVoltage
Hz3 0
460
248
13 8
15 90
R atio @ 460 VAC= 7.67 V /Hz +
% BOOST
0VoltageVoltageBoostBoost
AC Drive Basics AC Drive Basics -- V/Hz OperationV/Hz Operation AC Drive Basics AC Drive Basics -- V/Hz OperationV/Hz Operation
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Voltage Boost over prolonged operatingVoltage Boost over prolonged operatingperiods may result in overheating of theperiods may result in overheating of themotors insulation system and result inmotors insulation system and result indamage or premature failure.damage or premature failure.
Unable to perform like DC, the industry looks to Vector ControlUnable to perform like DC, the industry looks to Vector Control
CAUTION: Motor Insulation Life isdecreased by 50% for every 10 C abovethe insulations temperature capacity
CAUTION: Motor Insulation Life isdecreased by 50% for every 10 C abovethe insulations temperature capacity
AC Drive Basics AC Drive Basics -- V/Hz OperationV/Hz Operation AC Drive Basics AC Drive Basics -- V/Hz OperationV/Hz Operation
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If we can deIf we can de- -couple and Regulatecouple and Regulate Current, theCurrent, thecomponent that creates torque at the motor component that creates torque at the motor , we, wecan regulate motor torque, not just motor speed!can regulate motor torque, not just motor speed!
Current R egulation allows Torque ControlCurrent R egulation allows Torque Control
This is the premise for
Vector Control
This is the premise for
Vector Control
AC Drive Basics AC Drive Basics -- Vector OperationVector Operation AC Drive Basics AC Drive Basics -- Vector OperationVector Operation
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AC VE CTO R DRIVE AC VE CTO R DRIVE FU N DAMEN TALSFU N DAMEN TALS
AC Drive Basics AC Drive Basics AC Drive Basics AC Drive Basics
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Magnetizing Current is the current required to excite theMagnetizing Current is the current required to excite themotor laminations and copper winding w/o doing work.motor laminations and copper winding w/o doing work.
Magnetizing Current is: NO LOAD AMP draw lessMagnetizing Current is: NO LOAD AMP draw lessfriction and windagefriction and windage
Establishes the motors FluxEstablishes the motors Flux
(FLA(FLA -- Mag. Amps) = 100% Torque CurrentMag. Amps) = 100% Torque CurrentWrong data will reduce motor torque productionWrong data will reduce motor torque production
Magnetizing Current will range from 3 5% to 50% of FLA valueMagnetizing Current will range from 3 5% to 50% of FLA value
AC Drive Basics AC Drive Basics -- Motor ModelingMotor Modeling AC Drive Basics AC Drive Basics -- Motor ModelingMotor Modeling
AC Drive P arameters: Magnetizing CurrentAC Drive P arameters: Magnetizing Current
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Torque is produced, as well as regulated even at 0 RPMTorque is produced, as well as regulated even at 0 RPM
Magnetizing Current is the equivalent of Field CurrentMagnetizing Current is the equivalent of Field Current
Magnetizing Current = Motor No Load AmpsMagnetizing Current = Motor No Load Amps
a fixed value from 0 RPM to Motor Base RPMa fixed value from 0 RPM to Motor Base RPM
AC Drive Basics AC Drive Basics -- Vector OperationVector Operation AC Drive Basics AC Drive Basics -- Vector OperationVector Operation
TorqueCurrent
Magnetizing Current
100%
90 r
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The motor FLA valueThe motor FLA value maymay set the scaling for:set the scaling for:
Motor OverloadMotor OverloadDrive OverloadDrive Overload
Torque Current AvailableTorque Current Available
(FLA * %OL)(FLA * %OL) -- Mag. Amps = Max. Available Torque CurrentMag. Amps = Max. Available Torque Current
Wrong data affects available torque current and mayWrong data affects available torque current and mayallow damage to the motor.allow damage to the motor. Since every Vector algorithm is unique, check w/ manufacturer Since every Vector algorithm is unique, check w/ manufacturer
AC Drive Basics AC Drive Basics -- Motor ModelingMotor Modeling AC Drive Basics AC Drive Basics -- Motor ModelingMotor Modeling
AC Drive P arameters: Full Load AmpsAC Drive P arameters: Full Load Amps
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Voltage & Base Hz valuesVoltage & Base Hz values will will::
Establish the motor V/Hz ratio for the drive outputEstablish the motor V/Hz ratio for the drive outputWrong data will cause motor heating and possiblyWrong data will cause motor heating and possiblyreduce motor torque as well as shorten insulation life.reduce motor torque as well as shorten insulation life.
N eeded to assure proper motor operation w/o over N eeded to assure proper motor operation w/o over- -heatingheating
AC Drive Basics AC Drive Basics -- Motor ModelingMotor Modeling AC Drive Basics AC Drive Basics -- Motor ModelingMotor Modeling
AC Drive P arameters: Voltage & Base HzAC Drive P arameters: Voltage & Base Hz
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Base Hz & RPM valuesBase Hz & RPM values willwill set the scaling for:set the scaling for:
Calculation of motor slipCalculation of motor slipIdentifies expected motor RPM at FrequencyIdentifies expected motor RPM at Frequency
Allows for speed error detection & correction Allows for speed error detection & correction
Establishing the point of field weakeningEstablishing the point of field weakening
Wrong data here can cause excessive current drawWrong data here can cause excessive current draw
AC Drives regulate speed based upon motor slipAC Drives regulate speed based upon motor slip
AC Drive Basics AC Drive Basics -- Motor ModelingMotor Modeling AC Drive Basics AC Drive Basics -- Motor ModelingMotor Modeling
AC Drive P arameters: Base HZ & RP MAC Drive P arameters: Base HZ & RP M
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The Horsepower valueThe Horsepower value maymay be used to:be used to:
Estimate the expected motor impedanceEstimate the expected motor impedanceEstimate the expected motor inductanceEstimate the expected motor inductance
Calculate the torque loop gainsCalculate the torque loop gains
Wrong data here can cause poor speed and torqueWrong data here can cause poor speed and torqueregulationregulation
Horsepower information gets us in the BallparkHorsepower information gets us in the Ballpark
AC Drive Basics AC Drive Basics -- Motor ModelingMotor Modeling AC Drive Basics AC Drive Basics -- Motor ModelingMotor Modeling
AC Drive P arameters: HorsepowerAC Drive P arameters: Horsepower
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Flux Vector Drives act very much like DC DrivesFlux Vector Drives act very much like DC Drives
Field Weakening Field Weakening occurs whenever we exceed Motor Base RP Moccurs whenever we exceed Motor Base RP M
Magnetizing Current is decreased above Motor Base RPMMagnetizing Current is decreased above Motor Base RPM
AC Drive Basics AC Drive Basics -- Vector OperationVector Operation AC Drive Basics AC Drive Basics -- Vector OperationVector Operation
TorqueCurrent
Magnetizing Current
100%
90r
TorqueCurrent
Magnetizing Current
100%
90r
90r
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Torque at the motor shaft based upon loadTorque at the motor shaft based upon load
Torque Current increases or decreases dependent upon loadTorque Current increases or decreases dependent upon load
Torque Current = Motor Load at the ShaftTorque Current = Motor Load at the Shaft
a variable value during speed regulated operationsa variable value during speed regulated operations
AC Drive Basics AC Drive Basics -- Vector OperationVector Operation AC Drive Basics AC Drive Basics -- Vector OperationVector Operation
TorqueCurrent
Magnetizing Current
100%
90 r
TorqueCurrent
Magnetizing Current
10%
90 r
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Torque at the motor shaft based upon Torque ReferenceTorque at the motor shaft based upon Torque Reference
Torque Current can be commanded as a reference valueTorque Current can be commanded as a reference value
Torque Current = Reference settingTorque Current = Reference setting
a fixed value during torque regulated operationsa fixed value during torque regulated operations
AC Drive Basics AC Drive Basics -- Vector OperationVector Operation AC Drive Basics AC Drive Basics -- Vector OperationVector Operation
TorqueCurrent
Magnetizing Current
100%
90 r
TorqueCurrent
Magnetizing Current
10%
90 r
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Torque production suffers if 90Torque production suffers if 90 is not maintainedis not maintained
Motor torque is optimized O N LY when 90Motor torque is optimized O N LY when 90 rr is maintainedis maintained
Improper tuning, incorrect motor parameters, problemsImproper tuning, incorrect motor parameters, problemswith motor speed feedback or undersized drivewith motor speed feedback or undersized driveapplications will result in poor load (torque) regulation.applications will result in poor load (torque) regulation.
AC Drive Basics AC Drive Basics -- Vector OperationVector Operation AC Drive Basics AC Drive Basics -- Vector OperationVector Operation
TorqueCurrent
Magnetizing Current
100%
90 r
OptimizedOptimizedTorqueTorqueProductionProduction
TorqueCurrent
Magnetizing Current
? r
Poor TorquePoor TorqueProduction &Production &RegulationRegulation
ie: Impact Loadie: Impact Load
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Load Type: Forward Speed & Reverse TorqueLoad Type: Forward Speed & Reverse Torque
Time to find motor rpm & position is limited by inertia & speedTime to find motor rpm & position is limited by inertia & speed
How a load becomes appliedHow a load becomes appliedto the drive system can beto the drive system can becritical to system success.critical to system success.
A load where there is Forward A load where there is Forward
Velocity & Reverse Torque isVelocity & Reverse Torque isthe most difficult load tothe most difficult load tohandle.handle.
AC Drive Basics AC Drive Basics -- Vector OperationVector Operation AC Drive Basics AC Drive Basics -- Vector OperationVector Operation
? r
If the Nip Rolls are engaged duringIf the Nip Rolls are engaged duringweb travel, a condition withweb travel, a condition withforward velocity and reverseforward velocity and reversetorque can occur.torque can occur.
Use either V/Hz or a closed loopUse either V/Hz or a closed loopsystem if inertia or speed is high.system if inertia or speed is high.
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Motor Current is = Vector Sum of Torque & MagnetizingMotor Current is = Vector Sum of Torque & Magnetizing
This is where the termThis is where the term VECTOR DRIVE VECTOR DRIVE is derived is derived
Motor Current is whats measured with a clampMotor Current is whats measured with a clamp- -on meter on meter
AC Drive Basics AC Drive Basics -- Vector OperationVector Operation AC Drive Basics AC Drive Basics -- Vector OperationVector Operation
100%
Magnetizing Current
TorqueCurrent
Magnetizing Current
100%
Motor Current
90 r
TorqueCurrent
Motor Current
90 r
A+
B = CA+
B = C
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Flux Vector Drives regulate current & torque using rotor Flux Vector Drives regulate current & torque using rotor speed & position to optimize torque at the motor shaftspeed & position to optimize torque at the motor shaftalong w/ current feedback from the motor.along w/ current feedback from the motor.
E ncoders provide rotor speed & position informationE ncoders provide rotor speed & position information
L1L2L3
Current
Feedback
Motor
EMicro P
AC Drive Basics AC Drive Basics -- Flux Vector OperationFlux Vector Operation AC Drive Basics AC Drive Basics -- Flux Vector OperationFlux Vector Operation
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As motor temperature reaches nominal operating values, As motor temperature reaches nominal operating values,torque linearity and accuracy improves in FVC operationtorque linearity and accuracy improves in FVC operation
Torqueaccuracy of 5%
or better !
AC Drive Basics AC Drive Basics -- Rotor Temperature & TorqueRotor Temperature & Torque AC Drive Basics AC Drive Basics -- Rotor Temperature & TorqueRotor Temperature & Torque
% Torque
Inch - Lbs
-800
-600
-400
-200
0
200
400
600
-200 -150 -100 -50 0 50 100 150 200 30 deg
80 deg
Ideal Value
HOTMotor
COLDMotor
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Field Oriented Control uses the same basic technology asField Oriented Control uses the same basic technology asFlux Vector Control, but adds Voltage Feedback toFlux Vector Control, but adds Voltage Feedback tooptimize / adapt to changes in motor temperature.optimize / adapt to changes in motor temperature.
The drive continuously adapts to motor temperature changeThe drive continuously adapts to motor temperature change
L1L2L3
Voltage
Feedback
Motor
EMicro P
AC Drive Basics AC Drive Basics -- Field Oriented ControlField Oriented Control AC Drive Basics AC Drive Basics -- Field Oriented ControlField Oriented Control
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K ey P oints of UnderstandingK ey P oints of Understanding
Motor information, measured or programmed is key to successMotor information, measured or programmed is key to success
Errors in Encoder Feedback affect the MicroErrors in Encoder Feedback affect the Micro- -Processor Processor
Speed instability will occur Speed instability will occur
Encoder Feedback Signals must be NOISE FREEEncoder Feedback Signals must be NOISE FREE
Select an appropriate encoder for Vector Motor useSelect an appropriate encoder for Vector Motor use
Proper grounding is very importantProper grounding is very important
Motor Data programmed in the drive must be accurateMotor Data programmed in the drive must be accurate
AC Drive Basics AC Drive Basics -- SummarySummary AC Drive Basics AC Drive Basics -- SummarySummary
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Those with aThose with a V/Hz CoreV/Hz Core
All Sensorless Vector Drives areAll Sensorless Vector Drives are N OTN OT the same !the same !
There are actually 2 types of drives advertised asThere are actually 2 types of drives advertised asSensorless Vector;Sensorless Vector;
Those with aThose with a V ector CoreV ector Core
AC Drive Basics AC Drive Basics -- Sensorless Vector OperationSensorless Vector Operation AC Drive Basics AC Drive Basics -- Sensorless Vector OperationSensorless Vector Operation
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S VC withS VC with V/Hz Core Technology V/Hz Core Technology
V /Hz Core S VC Drives can operate multiple motorsV /Hz Core S VC Drives can operate multiple motors
Use sophisticated Current Limiting algorithms toUse sophisticated Current Limiting algorithms toimprove constant torque & starting torque operationimprove constant torque & starting torque operation
Typically needs less motor information for setup addingTypically needs less motor information for setup addingsome simplicitysome simplicity
Can operate multiple motors from one driveCan operate multiple motors from one drive
ONLY regulates V/Hz output, clamps CURRENTONLY regulates V/Hz output, clamps CURRENTCan only operate as a Speed Regulator, NOT TORQUECan only operate as a Speed Regulator, NOT TORQUE
AC Drive Basics AC Drive Basics -- Sensorless Vector OperationSensorless Vector Operation AC Drive Basics AC Drive Basics -- Sensorless Vector OperationSensorless Vector Operation
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S VC withS VC with V ector Core Technology V ector Core Technology
Vector Core S VC Drives can operate only one motor at a timeVector Core S VC Drives can operate only one motor at a time
De-couples Torque & Magnetizing Currents to maintain90 r alignment
Typically needs more motor information for setup addingsome complexity
Can operate only one motor per drive due to theinformation required to regulate current
Regulates SPEED and Regulates TORQUE
AC Drive Basics AC Drive Basics -- Sensorless Vector OperationSensorless Vector Operation AC Drive Basics AC Drive Basics -- Sensorless Vector OperationSensorless Vector Operation
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S VC Drives w/ a Vector CoreS VC Drives w/ a Vector Core estimatesestimates rotor speed &rotor speed &positionposition
A Speed E stimator calculates rotor speed & positionA Speed E stimator calculates rotor speed & position
L1L2L3
Motor
CurrentSensors
Micro P
( F VC + Speed E stimator )
AC Drive Basics AC Drive Basics -- Sensorless Vector OperationSensorless Vector Operation AC Drive Basics AC Drive Basics -- Sensorless Vector OperationSensorless Vector Operation
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POSITIONPOSITION SPEEDSPEED TORQUETORQUE MOTORMOTOR
Position ReferencePosition Referenceis optional in mostis optional in mostVector Controls,Vector Controls,internal in someinternal in some
Speed Reference isSpeed Reference istypical of how wetypical of how wecontrol motor control motor operationoperation
Torque Reference can madeTorque Reference can madedirectly, bypassing the speeddirectly, bypassing the speedloop as a reference for loop as a reference for applications such as Winders &applications such as Winders &Test StandsTest Stands
There are 3 Basic Control Loops in High P erformanceThere are 3 Basic Control Loops in High P erformanceDrives:Drives:
Bandwidth ratio between loops ranges from 3 :1 to 10:1Bandwidth ratio between loops ranges from 3 :1 to 10:1
1,000 rad/sec100 rad/sec10 rad/sec
AC Drive Basics AC Drive Basics -- Control LoopsControl Loops AC Drive Basics AC Drive Basics -- Control LoopsControl Loops
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SpeedR eference
FluxFluxCommandCommand
TorqueCommand G ate
Signals
AC Line
CurrentFeedback
R otor Speed& P osition
++
--
TorqueTorqueLoopLoop
SpeedSpeedLoopLoop
FieldFieldController Controller
P WMP WMInverter Inverter
SpeedSpeedFeedbackFeedback
ACMotor
E
Typical R egulator Control Diagram for F VCTypical R egulator Control Diagram for F VC
AC Drive Basics AC Drive Basics -- Regulator DiagramRegulator Diagram AC Drive Basics AC Drive Basics -- Regulator DiagramRegulator Diagram
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INVER TERINVER TERDUTYDUTYMOTO R SMOTO R S
AC Motor Basics AC Motor Basics -- Inverter DutyInverter Duty AC Motor Basics AC Motor Basics -- Inverter DutyInverter Duty
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Some motor frames are sized soSome motor frames are sized sothat just the surface area is suitablethat just the surface area is suitableto dissipate motor heat w/o the needto dissipate motor heat w/o the need
of a fan or blower of a fan or blower
Blowers may be added toBlowers may be added tomotors to allow operation atmotors to allow operation atlow speed including 0 RPMlow speed including 0 RPMwith 100% Torque continuouswith 100% Torque continuous
AC Motor Basics AC Motor Basics -- Inverter DutyInverter Duty AC Motor Basics AC Motor Basics -- Inverter DutyInverter Duty
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Types of AC Motors
Definite purpose laminated frameDefinite purpose laminated framedesigns provide higher power designs provide higher power densities & improved torque todensities & improved torque toinertia performance.inertia performance.
Definite purpose laminated frameDefinite purpose laminated framedesigns provide higher power designs provide higher power densities & improved torque todensities & improved torque toinertia performance.inertia performance.
TT--Frame Construction Motors allowFrame Construction Motors allowcommonality in footprint & shaftcommonality in footprint & shaftheight.height.
TT--Frame Construction Motors allowFrame Construction Motors allowcommonality in footprint & shaftcommonality in footprint & shaftheight.height.
AC Motor Basics AC Motor Basics -- Inverter DutyInverter Duty AC Motor Basics AC Motor Basics -- Inverter DutyInverter Duty
Match Motor typeto meet your
needs!
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R otor Designs Vary by motor type:
Definite purpose single squirrelDefinite purpose single squirrelcage rotor design for Variablecage rotor design for VariableFrequency Drive useFrequency Drive use
Standard Industrial AC Motor doubleStandard Industrial AC Motor doublesquirrel cage R otor Design for squirrel cage R otor Design for improved across the line startingimproved across the line startingtorque.torque.
AC Motor Basics AC Motor Basics -- Inverter DutyInverter Duty AC Motor Basics AC Motor Basics -- Inverter DutyInverter Duty
Rotor designaffects torqueproduction!
Rotor designaffects torqueproduction!
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E quivalent Circuit Diagram of an AC Induction Motor E quivalent Circuit Diagram of an AC Induction Motor
Resistan ce
Stator
Indu ctan ce
Stator
Indu ctan ce
Rotor
Resistan ce
Rotor
Indu ctan ce Magnetizing
ACIn put
Vo ltage
-
+
Current Working
AC Motor Basics AC Motor Basics -- Equivalent Circuit DiagramEquivalent Circuit Diagram AC Motor Basics AC Motor Basics -- Equivalent Circuit DiagramEquivalent Circuit Diagram
Rotor heating
affects torqueproduction!
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P eak Torque capacity is dependent upon the motor BDT %P eak Torque capacity is dependent upon the motor BDT %
AC Motor Basics AC Motor Basics -- Drive Operating RegionDrive Operating Region AC Motor Basics AC Motor Basics -- Drive Operating RegionDrive Operating Region
NE MA Design B Motor NE MA Design B Motor
Full Load Torque
Breakdown Torque R ule of Thumb:R ule of Thumb:
Approximately 80% of BDT Approximately 80% of BDT(ft(ft--lbs) is usable for PEAKlbs) is usable for PEAKTorque needs when currentTorque needs when currentis available.is available.
Therefore, currentTherefore, currentheadroom from the driveheadroom from the drivecan improve recovery fromcan improve recovery fromsudden load changes.sudden load changes.
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Breakdown Torque identifies P eak Torque capabilitiesBreakdown Torque identifies P eak Torque capabilities
AC Motor Basics AC Motor Basics -- Drive Operating RegionDrive Operating Region AC Motor Basics AC Motor Basics -- Drive Operating RegionDrive Operating Region
NE MA Design B Motors vary in Breakdown Torque capacityNE MA Design B Motors vary in Breakdown Torque capacity
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Inverter Duty Motors operate at 1/10th Base RP MInverter Duty Motors operate at 1/10th Base RP M
Speed / Torque Curve of an AC Drive & Inverter Duty Motor Speed / Torque Curve of an AC Drive & Inverter Duty Motor
%TORQ
UE
0
10
20
3 0
40
50
60
70
80
90
100
0 6 12 18 24 3 0 3 6 42 48 54 60 66 72 78 84 90
TorqueTorque
TorqueTorque
HZ
Acceptable Regionfor Continuous Operation
AC Motor Basics AC Motor Basics -- Operating RangeOperating Range AC Motor Basics AC Motor Basics -- Operating RangeOperating Range
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CHp Operation above Base RP M is typically limited to 150%CHp Operation above Base RP M is typically limited to 150%
Speed / Torque Curve of an AC Drive & Inverter Duty Motor Speed / Torque Curve of an AC Drive & Inverter Duty Motor
%TORQ
UE
0
10
20
3 0
40
50
60
70
80
90
100
0 6 12 18 24 3 0 3 6 42 48 54 60 66 72 78 84 90
TorqueTorque
TorqueTorque
HZ
Torque abovebase RPM =
100%% Above Base RPM
AC Motor Basics AC Motor Basics -- Operating RangeOperating Range AC Motor Basics AC Motor Basics -- Operating RangeOperating Range
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Vector Duty Motors operate at 0 RP M w/ 100% Torque Cont.Vector Duty Motors operate at 0 RP M w/ 100% Torque Cont.
Speed / Torque Curve of a Vector Drive & Vector Duty Motor Speed / Torque Curve of a Vector Drive & Vector Duty Motor
%TORQ
UE
0
10
20
3 0
40
50
60
70
80
90
100
0 6 12 18 24 3 0 3 6 42 48 54 60 66 72 78 84 90
TorqueTorque
TorqueTorque
HZ
Acceptable Regionfor Continuous Operation
AC Motor Basics AC Motor Basics -- Operating RangeOperating Range AC Motor Basics AC Motor Basics -- Operating RangeOperating Range
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Some Vector Duty Motors can provide CHp ( 2 * Base RP M )Some Vector Duty Motors can provide CHp ( 2 * Base RP M )
Speed / Torque Curve of a Vector Drive & Vector Duty Motor Speed / Torque Curve of a Vector Drive & Vector Duty Motor
HZ
%TORQ
UE
0 6 12 18 24 3 0 3 6 42 48 54 60 66 72 78 84 90
TorqueTorque
TorqueTorque
010
20
3 0
40
50
60
70
80
90
100
96 102 108 114 120
Vector Duty Motors may haveCHP Ranges of
2 * Base Speed or moredepending on their design
AC Motor Basics AC Motor Basics -- Operating RangeOperating Range AC Motor Basics AC Motor Basics -- Operating RangeOperating Range
Special motor & driveSpecial motor & drivedesigns can allowdesigns can allow
operation up to 8 *operation up to 8 *Base RPMBase RPM
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COM P ARINGCOM P ARINGAC D RIVE AC D RIVE PER FO R MAN CEPER FO R MAN CE
AC Drive Performance AC Drive Performance AC Drive Performance AC Drive Performance
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Control SelectionControl SelectionControl SelectionControl Selection
Starting in torotating loads
/ z S C F C
etter Good est
FVC operation is best since the position and velocity of theFVC operation is best since the position and velocity of therotor is known and restarting is immediate.rotor is known and restarting is immediate.
V /Hz being a soft speed regulator is very forgiving for V /Hz being a soft speed regulator is very forgiving for restarting into loads with high inertia.restarting into loads with high inertia.
S VC may be more difficult to implement due to limitations byS VC may be more difficult to implement due to limitations bymanufacturer. P rocessor & algorithm dependent.manufacturer. P rocessor & algorithm dependent.
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V /Hz operation inheriently controls multiple motors.V /Hz operation inheriently controls multiple motors.S VC or F VC operation with multiple motors is only possibleS VC or F VC operation with multiple motors is only possiblewhen motor shafts are mechanically locked together andwhen motor shafts are mechanically locked together andassumptions are made about total motor current values.assumptions are made about total motor current values.
Control SelectionControl SelectionControl SelectionControl Selection
ulti- otor peration fro
one drive/ z S C F C
estot
eco endedot
eco ended
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V /Hz is typically good for up to 10:1 Constant Torque.V /Hz is typically good for up to 10:1 Constant Torque.
S VC is typically good for up to 40:1 Constant Torque.S VC is typically good for up to 40:1 Constant Torque.
FVC is typically good for up to 1,000:1 which includesFVC is typically good for up to 1,000:1 which includescontinuous operation at Zero Speed.continuous operation at Zero Speed.
Control SelectionControl SelectionControl SelectionControl Selection
ConstantTorque Range V/Hz SVC FVC
ood Better Best
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V /Hz has no quantifiable response time or bandwidth.V /Hz has no quantifiable response time or bandwidth.
Typical S VC specifications may state 100 R adians/second.Typical S VC specifications may state 100 R adians/second.
Typical F VC specifications may state 1,000 R adian/second.Typical F VC specifications may state 1,000 R adian/second.
Control SelectionControl SelectionControl SelectionControl Selection
yna icesponse / z S C F C
Good etter esto
tuningdjustable
Gains for tuningdjustable
Gains for tuning
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Both AC & DC Drives have specific areas of merit to consider Both AC & DC Drives have specific areas of merit to consider
Feature Flux ector - benefits rive - li itations
o er Factor 92% to 96% at all speedsloads
88% to 33% dependent onspeed load
Torque roduction 1,000 radian/sec 300 radian/secperation at tall losed Loop Flux ector at
tall continuousoperation at tall li ited by
brushes co utator
otor ost otor cost is lessexpensive due to si plicity
otor cost is higher due tolabor co plexity parts
igh peedpplications
Lo er rotor ass allo shigh speed operation
echanically li ited in speeddue to construction
rive electionrive electionrive electionrive election
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Both AC & DC Drives have specific areas of merit to consider Both AC & DC Drives have specific areas of merit to consider
Feature Flux Vector - limitations DC Drive - benefits
Line Regeneration 60% to 100% premium over drive cost to do
5% to 25% premium over drivecost to do
Motor Lead Length Limitation of lead length canaffect operation & reliability
No concerns of lead lengthother than voltage drop
Drive Only Cost More expensive due tocontroller complexity
Less expensive due tocontroller simplicity
Shock Load Applications
Less inertia at motor requiresmore tuning and setup time
Armature inertia helps todampen shock loads
Drive SelectionDrive SelectionDrive SelectionDrive Selection
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PerformanceFeatures
DC Drivew/ Encoder
DC Drivew/ Tach
DC Drivew/o Fdbk
FluxVector
SensorlessVector
OperatingSpeed Range
0 RPM toBase RPM
90 RPM toBase RPM
90 RPM toBase RPM
0 RPM toBase RPM
45 RPM toBase RPM
CT SpeedRegulationw/o loadchange
1,000 : 10.01%
70 : 11.0%
20 : 13.0%
1,000 : 10.01%
40 : 10.5%
CT SpeedRegulationw/ 100% loadchange
100 : 10.05%
30 : 13.0%
10 : 15.0%
100 : 10.05%
20 : 11.0%
Digital DC Drives & AC Vector Drives performance similarlyDigital DC Drives & AC Vector Drives performance similarly
Drive SelectionDrive Selection -- Speed RangeSpeed RangeDrive SelectionDrive Selection -- Speed RangeSpeed Range
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Any Q uestions?
Thank You!Thank You!Thank You!Thank You!