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Real-Time Simulation &
Vector Control ofInduction Motor/PMSM
for Hybrid Vehicles
Vikrant MoreAkshay Mhalgi
Akshat Khanna
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Induction Motor Speed Control
Scalar Control : The magnitudes of control variables arecontrolled, while the coupling effect is disregarded.
For example, the voltage of a machine can be controlled tocontrol the flux, frequency and slip can be controlled to
control torque. The various scalar methods employed are:
Stator Voltage Control.
Current control.
Volts/hertz control.
Rotor voltage control.
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Scalar control methods provide satisfactory steady stateperformance but poor dynamic response.
Vector Control : Both magnitude and phase of controlvariables are controlled. The aim of vector control is toget the response from a induction motor similar to thatof a separately excited DC motor.
The machine control is considered in a synchronouslyrotating reference frame.
Sinusoidal quantities appear as dc quantities in steadystate.
With vector control, ids is analogous to field current & iqsto armature current of a dc machine and areorthogonal.
Induction Motor Speed Control
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dqs
equivalent
circuit
diagram
(steady
state)
Steady state Phasor diagrams
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d-q Model
Vector control drives are based on the dynamicd-q model of the machine.
In dynamic model, coupling coefficients
between stator & rotor phases vary with rotorposition. Such an analysis is complex.
Using Parks transformation, we refer statorvariables to a synchronously rotating referenceframe fixed in the rotor thereby eliminatingvarying magnetic reluctances .
For vector control drives, we transform threephase stationary reference frame into two phasestationary frame and then transform these into arotating reference frame.
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Transformation from stationary reference frame to rotating reference frame
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Dynamic equivalent circuits of the
machine in synchronously rotating frame
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Vector Control Principle
Vector control implementationprinciple with machine deqe model
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Indirect Vector Control
In indirect vector controlmethod, the unit vector signalsare fed in feed forwardmanner.
The synchronously rotating axis
de-qe is rotating ahead of thedr-qraxis by positive slip anglecorresponding to slipfrequency.
we=wr+wsl. This gives us the
value of
e upon integration
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Required Motor
Characteristics
0
5
10
15
20
25
30
0 500 1000 1500 2000 2500 3000 3500 4000 4500
MotorPower(kW)
Motor Speed (rpm)
Electric Motor Characteristics
MotorCharacteristics
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Rotor winding of synchronous motors is replaced bypermanent magnets.
Advantages- Elimination of rotor Cu loss, higher powerdensity, low rotor inertia and robust construction.
Essentially two types based on construction-
Sinusoidal Surface Mounted PMSM
Sinusoidal Interior Mounted PMSM
Permanent Magnet Synchronous
Motors
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For application in hybrid vehicles, we need operation ofthe motor above base speed.
Both types of motor provide operation above basespeed, but the interior mounted PMSM provides a betteroperation above base speed and so it is preferred.
Cross section of a interior mounted PMSM is as shown--
Permanent Magnet Synchronous
Motors
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Operation in Field
Weakening Mode PMSM used is to be operated above its base speed.
In vector control of a PMSM, to get operation abovebase speed, we operate the motor in flux weakening
mode.
IPM PMSM provides a greater range of operation infiled weakening mode.
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