JOURNAL OF INFORMATION, KNOWLEDGE AND RESEARCH IN
ELECTRICAL ENGINEERING
FIELD ORIENTED CONTROL OF INDUCTION
MOTOR USING MATLAB SIMULINK
1HIREN
1, 2
M. PATEL, 2PANKIT T. SHAH, 3HEMANGINI V. PATEL
M.TECH Electrical (Power System), Department of Electrical Engineering,
VJTI Matunga, Mumbai-400019, Maharashtra, India.
3
B.E. Electrical, Department of Electrical Engineering,
Faculty of Tech & Engg, The MSU, Baroda-390001, Gujarat, India
hiren_power@yahoo.com , pankit_power@yahoo.com, hema_power17@yahoo.in
ABSTRACT : Induction motor is main workhorse of the industry. Scalar control of induction motor has good
steady state response but poor dynamic response. But vector control method has good steady state as well as
dynamic response. Vector control method makes performance of induction motor very close to that of separately
excited DC motor which is best as far as controlling of speed and torque is concern. This paper discusses the
Field oriented control of induction motor. This drive designed in MATLAB SIMULINK. Stator current, rotor
speed, electromagnetic torque and stator flux are obtained which shows the performance of the drive. Drive
also tracks the reference speed and torque properly.
KEY WORDS: Induction Motor, Field Oriented Control, MATLAB SIMULINK.
1. INTRODUCTION
In initial years, DC motors were used in
applications where high performance in variable
speed and variable torque operations was required.
Separately excited DC motors were extremely used in
areas where fast response of speed and torque
required. It was main workhorse in industries. It has
inherent DE-COUPLING facility of independent
control of torque and flux in the motor.
DC machines had its disadvantage like
maintenance, sparking, difficulty in commutation at
high current and voltage, so it is limited to low power
and low speeds.
After the invention of induction motor and power
electronics, difficulties related to DC machines were
overcome but it did not have inherent DECOUPLING property between torque and flux which
was a major factor in controlling a speed and
improving dynamic response. Those were Scalar
control methods which have good steady state
response but poor dynamic response. They control
only magnitude of controlling vector but didn’t have
to deal with its phase [1].
So, some kind of controls required which
make independent control of flux and torque channel
in induction motor and makes the performance of
induction motor just like separately excited DC motor
which is best for speed and torque control
applications. These controlling methods were vector
control. They deals with controlling of magnitude,
phase and frequency of controlling vector which
makes de-coupling of flux and torque channel.
In this paper field oriented control (FOC)
method of induction motor discussed. This drive is
simulated in MATLAB SIMULINK and stator
current, rotor speed, electromagnetic torque and
stator flux obtained as output. Also good tracking of
reference speed and torque is obtained.
2. PRINCIPLE OF FIELD ORIENTED
CONTROL
In 1971, Blaschke proposed a scheme, which
represents the control of induction motor like a
separately excited dc motor, called “Field Oriented
Control or Vector Control”. In an AC machine, both the
phase angle and the modulus of the current must be
controlled. This is the reason for the terminology ‘Vector
Control’. In this scheme, the induction motor is analyzed
from a synchronously rotating reference frame where all
the fundamental AC variables appear to be DC equals.
The torque and flux components are identified and
controlled independently to achieve good dynamic
response. Vector control implies that an AC motor is
forced to behave dynamically as a D.C. motor by the use
of feed back control [1].
Field-oriented control (FOC) of induction machine
achieves decoupled torque and flux dynamics. This is
achieved by orthogonal projection of the stator current
into a torque-producing component and flux-producing
component. This technique is performed by two basic
methods. Direct and indirect vector control. With direct
field orientation, the instantaneous value of the flux is
required and obtained by direct measurement using flux
sensors or flux estimators, whereas indirect field
orientation is based on the inverse flux model dynamics
and there are three possible implementation based on the
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ELECTRICAL ENGINEERING
stator, rotor, or air gap flux orientation. The rotor flux
indirect vector control technique is the most widely used
due to its simplicity. FOC methods are attractive but
suffer from one major disadvantage. They are sensitive
to parameter variations such as rotor time constant and
incorrect flux measurement or estimation at low speeds
[3], [4]. Basic block diagram of FOC is shown in figure
1 [2].
Figure 1 Basic block diagram of FOC
3. MATLAB SIMULATION
ORIENTED CONTROL OF
MOTOR
OF FIELD
INDUCTION
shown in figure 2. The simulation time is 3 seconds
and sampling time is 2 micro seconds. For case study,
induction motor taken has parameters listed in table
1. Speed controller for FOC is shown in figure 3.
Here indirect field oriented control of induction
motor is simulated in MATLAB SIMULINK as
Table 1
Motor Output
Motor terminal voltage
Supply frequency
Stator Resistance
Stator Inductance
Rotor Resistance
Rotor Inductance
Mutual Inductance
Inertia
Friction Factor
Pole Pairs
200 HP
460 V
60 Hz
14.85e-3 Ω
0.3027e-3 Henry
9.295e-3 Ω
0.3027e-3 Henry
10.46e-3
3.1
0
2
Figure 2 FOC of induction motor in MATLAB SIMULINK
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Figure 3 Speed controller for FOC
Using park transformation and inverse park
transformation and signals from the machine we
have shown the control strategy of FOC of induction
motor in figure 4.
Figure 7
This block (figure 7) produces q-component of
stator current (Iq). This block uses the equation,
Iq= Te/(Kte * λ)
Where,
Iq = q- component of stator current
Te = torque
Kte = (2/3)* (P) (Lm/Lr)
P= pole pair
Lm =mutual inductance
Lr = rotor inductance
λ = flux
Block K represents (1/Kte).
Block 4
Figure 4 Field Oriented Controller
for Induction Motor
All blocks are represented as shown in figure
below.
Block 1
Figure 8
This block (figure 8) produces phasor angle theta
for stator current.
It produces Wm (mechanical speed) using Iq and λ as
shown in figure by A block.
Wr = Rotor frequency (rad/s) = Lm *Iq / (Tr * λ)
λ = Lm *Id / (1 +Tr .s)
Figure 5
Tr= Lr/Rr
Rr= rotor resistance
This block (figure 5) generates flux error signal as
shown in figure. Difference between reference and
actual flux is processed through PI controller and
limiter.
Block 2
Theta= Wr + Wm
This summation is shown in figure by B block.
Figure 6
This block (figure 6) produces d-component of
stator current (Id) from the flux.
Figure 9
This block (figure 9) generates flux from dcomponent of stator current.
Block 3
Inverse park transformation
Block 5
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ELECTRICAL ENGINEERING
Figure 14 Electromagnetic Torque
Figure 10
This block (figure 10) represents the inverse park
transformation which uses theta and d and q
components of stator current and produces ABC
stator current required to drive induction motor.
Figure 15 DC bus voltage
Park Transformation
Figure 11
This block (figure 11) represents park
transformation which converts ABC to DQ signal of
stator current.
4. SIMULATION RESULT
FOC is simulated in MATLAB which gives the
result as shown in figures below for stator current
(figure12), Rotor Speed (figure 13), Electromagnetic
Torque (figure 14), DC bus voltage (figure 15),
Stator Flux (figure 16), Rotor Flux (Figure 17), Rotor
Current (figure 18) and Rotor Angle (figure 19). As
shown in figure 13 and 14, rotor speed and
electromagnetic torque of simulated FOC drive
properly track reference values respectively.
Figure 16 Stator Flux
Figure 12 Stator current
Figure 17 Rotor Flux
Figure 13 Rotor Speed
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ELECTRICAL ENGINEERING
Figure 18 Rotor Current
Figure 19 Rotor Angle (rad)
5. CONCLUSION
From the simulation of FOC of induction motor in
MATLAB SIMULINK, we have found out different
result as shown above figures. Reference speed and
torque values are properly track by the drive. This
represents the proper design of the drive.
6. REFERENCES
[1]
Electromagnetic Motor Drives- Modeling,
Analysis and Design, R. Krishnan, Verginia Tech,
Blacksburg, VA, Prentice Hall, Upper Saddle River,
New Jersey 07458, pp 411-501
[2]
NEC Application Note, An Introduction to
Vector Control of AC Motors Using the V850,
Document No. U16483EE1V0AN00, Date published:
November 2002
[3]
Brett Hovingh, W.W.L Keerthipala, WeiYong Yan, Sensorless Speed Estimation of an
Induction Motor in a Field Orientated Control System
[4]
C. Nen, W. Schmitt, K. Karakaxis, S. N.
Manias, Adaptive Control System For A Field Oriented Induction Motor Drive, Department of
Electrical & Computer Engineering, Electric Power
Division 42, 28th October Str., 106 82 Athens,
GREECE
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