Virtual Platform of Field Oriented Control of
Induction Motor to Assist in Education of
Undergraduate Students
G. H. Bazan
Electromechanics Department
Institute of Parana
Jacarezinho, Parana, Brazil
gustavo.bazan@ifpr.edu.br
W. C. A. Pereira
Department of Electrical Engineering
University of Sao Paulo – USP
Sao Carlos, Sao Paulo, Brazil
william.andrade@usp.br
M. F. Castoldi
Department of Electrical Engineering
Federal University of Technology Parana
Cornelio Procopio, Parana, Brazil
marcastoldi@utfpr.edu.br
A. Goedtel
Department of Electrical Engineering
Federal University of Technology Parana
Cornelio Procopio, Parana, Brazil
agoedtel@utfpr.edu.br
M. L. Aguiar
Department of Electrical Engineering
University of Sao Paulo – USP
Sao Carlos, Sao Paulo, Brazil
aguiar@sc.usp.br
Abstract—This paper proposes a virtual teaching platform
applied to undergraduate students concerning an induction motor
drive technique. Such a technique is called as Field Oriented
Control (FOC) and it is presented and analyzed, in a simple form,
by using the proposed platform. This virtual platform uses a
GUIDE tool from MATLAB jointly with the SIMULINK.
Simulation results of FOC strategy and also its simplicity usage
are shown in this work.
Keywords— Teaching, Education, Students, Induction motor,
FOC.
I. INTRODUCTION
The electrical motors are divided according to the type of
feeding and can be basically classified in two categories: Direct
Current (DC) or Alternating Current (AC). Therefore, the use of
DC motors has disadvantages regarding to their constructive
characteristics [1], [2].
speed control, being these methods basically classified in two
categories: scalar and vectorial [7]. The scalar control
manipulates only the magnitude of the electrical or magnetic
property while the vectorial controls both, the magnitude and the
angular position of these properties [1], [7].
An important vectorial control technique, focus of this study
is known as Field Oriented Control (FOC) presented in [8]. Due
to its mathematical complexity and the high cost of
microprocessors, this technique was effectively used only from
1980 on [9]. Since then, this technique has had a big impact on
the AC machines control increasing the TIM reliability in the
dynamic and steady-state.
This issue like the others related to the power electronics,
electric circuits, control systems, electric drives and signal
digital processing areas have been missing tools that can help the
electrical engineering students learning.
The three-phase induction machine (TIM) also known as
three-phase asynchronous motor is a AC motor widely used in
the industry because of its advantages when compared to other
machines such as DC and AC. The TIM is a machine that
requires little maintenance due to the fact of not having brushes
and commutator, also having the advantage of its low cost [3][5]. In this way, in the electrical engineering graduation course
the subjects related to three-phase electrical machines are among
the most important.
Thus, a lot of researchers are searching alternatives to solve
this problem. Reference [10] proposed an experimental bench
that is supporting the students of the Indian Institute of
Technology Bombay on the learning and research of the power
electronics and electric drives areas.
Therefore, in the graduation courses, the three-phase
induction machines are analyzed in a general way only in steadystate, not approaching in this way their drive dynamic
characteristics in the subjects. Thus, the learning process can be
damaged since the students don’t have contact with machine
control techniques which can be necessary when this student is
working in an industry.
In [12], a tool in the MATLAB/SIMULINK® software
allows their users to see the induction motor operation for
several types of conditions such as: no-load and locked rotor test.
The drive of such machines is an issue of great world
economic impact [6]. There are different methods for the TIM
978-1-7281-3666-0/19/$31.00 ©2019 IEEE
While [11] proposed a new teaching method for the students
of the electric drives course of the Kocaeli University, Turkey,
incorporating the active learning strategies in the classroom,
making it possible an improvement in these students’ teaching.
In [13], the concepts of the classical Indirect Field Oriented
Control (IFOC) theory are presented, and also, the valid design
guidelines for various motor types helping in the knowledge
comprehension of control technique.
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Observing the search for teaching tools that can help the
electrical engineering students, this present study has as the
objective to develop a virtual platform for TIM control and drive
using the technique of FOC with rotor field orientation for a TIM
squirrel-cage rotor.
The virtual platform was made with the help of the dynamic
system analysis tool of the MATLAB/SIMULINK® software
and has as the aim to create a graphical interface of easy access
and a comprehension for the users’ side. The principal objective
of the creation of this control virtual platform is to help the
technical comprehension of approached control and it can arouse
interest of these students in researches in the electrical machine
control field.
 
u 1dq , u 2 dq : stator and rotor voltage spatial vector, respectively;
 
i1dq , i 2 dq : stator and rotor current spatial vector, respectively;
 
ψ 1dq ,ψ 2 dq : stator and rotor flux spatial vector, respectively;
md : electromagnetic torque;
i1d , i1q : stator current direct and quadrature component,
respectively;
ψ
2 d , ψ 2 q : rotor flux direct and quadrature component,
respectively;
ψ : rotor flux total value;
2
II. FIELD ORIENTED CONTROL
The induction motor modelling using coordinated vector
transformation is fundamental to implement the FOC. This
control technique is based on the fixation of one of the three
magnetic fluxes (stator, rotor or air gap) in the system direct axis
of synchronous coordinated (dq coordinated). As it was
mentioned before, in this work it was used the IFOC technique
as a rotor flux guiding due to its wide applicability in the industry
when compared to other strategies of oriented control, and due
to its easy implementation.
It is important to highlight that for the vectorial control
technique development, it is necessary to know the
mathematical model of the induction motor. Since the IFOC
technique controls both the rotor (flux and speed) and stator
(voltage and current) properties, it is interesting to use a generic
framework for all these properties.
R 1 , R 2 : stator and rotor resistance, respectively;
L1 , L 2 , LH : stator, rotor and mutual inductance, respectively;
zp : poles;
ω
ω
mec
: rotor mechanical speed;
m2
: synchronous speed.
The operation mode is based on the simultaneous control of
two different grids being one of rotor flux and the other of speed.
The flux grid is responsible for the TIM drive according to the
desired magnetizing. The speed grid as suggested by the name
is responsible for the TIM drive according to the desired speed.
The Fig. 1 shows in a simplified way the proposed control
strategy.
Using the synchronous framework, it is possible to find a
representation for the induction motor of a similar way to the DC
motor with separately-excited, making the IFOC control strategy
comprehension easier applied to the TIM. But, at first, it is
necessary to know the motor modelling in the synchronous
reference which are described below according to [14]:




dψ 1dq
u 1dq = R1i1dq +
+ jω m 2ψ 1dq
dt




dψ 2 dq
u 2 dq = R 2i 2 dq +
+ j (ω m 2 − zpω mec )ψ 2 dq
dt



ψ 1 dq = L1i1 dq + LH i 2 dq

ψ
2 dq


= L 2i 2 dq + LH i1dq
ψ = ψ +ψ
2
md =
2d
2q
3 LH
zp (ψ 2 di1q −ψ 2 qi1d )
2 L2
Fig. 1. The proposed IFOC technique.
(1)
(2)
As it can be seen in the Fig. 1, from the motor measured
signals on (terminal current), it is possible to calculate stator
quadrature and direct current values and also magnetizing
current ( im 2 ). Imposing the guiding of ψ 2 in the d-axis, it
results that ψ 2 doesn’t have component in the q-axis and
(3)
ψ ∝i
(4)
In this way, the proposed vectorial control imposes the value
of the im 2 and consequently according to [9], the value of the
ψ 2 . In this way, taking into consideration [8], the motor torque
can be regulated in function of the i1q , as below:
(5)
2
m2
md = ψ 2i1q
(6)
that is, the induction motor behaves as a DC motor.
where,
1600
(7)
(8)
To perform the control, first the estimated rotor magnetizing
current is compared to the reference, and an error is obtained.
Such an error is processed by a Proportional Integral Controller
(PI) which determines the stator current reference value in the
direct axis. Simultaneously, the TIM speed is compared to the
reference speed and a second error is obtained. This error is also
processed by a PI controller which determines the stator current
reference value in the quadrature axis.
Both current components, direct and quadrature, are
compared to their present values and the obtained errors are
treated by P controllers. The results are stator voltage values in
direct axis ( u 1 d ) and quadrature axis ( u 1q ). These values are
generated in the synchronous coordinated system (dq) and need
to be transformed into the three-phase system (abc) in order the
TIM control can be performed.
the Fig. 5, which represents the window of the related
parameters definition to the speed loop PI. By turning on the
other buttons, similar windows are opened.
Fig. 3. Motor parameters panel.
After this transformation, a PWM (Pulse Width Modulation)
is used to generate the desired phase voltage to perform the
motor drive.
III. GRAPHIC INTERFACE
The graphic interface shown in the Fig. 2 was made in an
easy access program language to help different kinds of users,
from beginners to advanced ones in the approached technique
use.
Fig. 4. Controllers parameters panel.
Fig. 2. Virtual platform of the IFOC technique.
It’s possible to check in the Fig. 2 that platform was
basically divided in four sections. In each one of them, the user
has free access and can change the controllers and motor
parameters, simulation characteristics and still to access the
graphics. The other figures show the characteristics of the
created interface and it can be noticed that the interface is
intuitive and easily manageable.
The “Motor Parameters” panel is shown in the Fig. 3. Such
a panel allows the user to change the motor parameters to be
simulated.
The “Controllers Parameters” panel is shown in the Fig. 4.
This panel has four buttons that when turned on open its
respective windows. Two of these buttons are related to the
direct axis stator control, and the others are related to the
quadrature axis stator control.
In case the user needs to change the controllers constant
values, he can press one of the buttons shown in the Fig. 4. A
new window is opened with the changing options as shown in
Fig. 5. PI controller of motor mechanical speed.
The “Simulation Characteristics” panel is shown in the Fig.
6. Similarly to the other panels, the user is allowed to change
the voltage values of the inverter DC bus, switching frequency,
the simulation time, the machine magnetizing current
magnitude, the constant mechanical load applied in the motor
shaft and the speed reference. Each button opens its respective
window being the speed window shown in the Fig. 7. In this
window it can be defined the speed final and initial value
besides the time that the reference is changed. The mechanical
load and the rotor magnetizing current windows are similar to
the machine mechanical speed window with the same
configuration. After the definition of all the drive parameters,
the user has to press the “Simulate” button to start the collect of
the results. When the simulation is finished, the user can select
the desired graphics (three-phase currents, mechanical speed,
magnetizing current and electromagnetic torque).
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The electromagnetic torque behavior is shown in the Fig. 11.
It can be observed that its peak is high in the conditions in which
a sudden speed change is required, that is, in the start and the
rotation direction inversion. When the motor reaches the
reference speed the torque becomes small, only enough to
overcome the motor operating rotational losses. But, when the
load is inserted to its shaft, the motor develops a torque enough
to supply this load and the rotational losses.
Fig. 6. Simulation parameters.
The results obtained with this simulation validate the virtual
platform of the proposed IFOC technique. Besides being an easy
handling and dynamic platform, the results can be easily
observed and conclusions obtained in a very practical way by the
students. Besides that, the students can change any simulation
parameter observing the strategy behavior and the influence of
each changed parameter in the drive.
TABLE I.
MOTOR PARAMETERS
Motor Parameters
Fig. 7. Mechanical speed.
IV. SIMULATION RESULTS
To check the motor drive behavior using the proposed
technique, a simulation was made using the parameters
contained in the Tables I, II and III.
As it was foreseen, the speed regulation in the FOC drive is
very accurate, as it can be seen in the Fig. 8. At first the no-load
operate motor reaches the speed of initial reference in a short
time. Afterwards, at the time t=0.5s, the speed reference is
changed, including the rotation direction, also stabilizing in a
short time. At the time t=1.1s, a load is inserted in the rotor shaft
making the speed decrease for a short time and re-establish again
in the reference value soon after due to the speed PI
performance.
Observing the Fig. 9, it can be noticed the good regulation of
the magnetizing current control loop. As it was mentioned
before, for the making of the proposed control strategy it was
necessary to keep the constant rotor flux. It was only possible if
the magnetizing current is steady. Such a current reaches its
reference value in a short time, having a low change when the
motor rotation direction is changed. So the PI performance of
this control loop makes this current return to its reference value
very fast, validating the basic premise of the FOC strategy,
which is to have a good regulation of this property.
The Fig. 10 shows the three-phase current behavior. It is
possible to observe a high current value in the start, decreasing
to an operation value as the time goes by. At the time t=0.5s,
where there is a change in the motor rotation direction, there is
an over shut current since the torque required is very high due to
the speed degree that the machine is exposed. It is also possible
to observe that the current frequency is low when the machine
has reduced speed. Finally, it is observed an increase in the
current magnitude after the time t=1.1s, when a mechanical load
is inserted in the machine shaft.
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Poles (zp)
2
Stator Resistance (R1)
0.294 Ω
Rotor Resistance (R2)
0.156 Ω
Stator Inductance (L1)
0.0014 H
Rotor Inductance (L2)
0.0007 H
Mutual Inductance (LH)
0.041 H
Inertia (J)
0.40 kg.m2
Friction Factor (KD)
0.000018 N.m.s
Frequency (f)
60 Hz
TABLE II.
CONTROLLERS PARAMETERS
Controllers Parameters
PI Controller of Rotor Magnetizing Current
KP
10.00
KI
0.25
P Controller of Stator Direct-Axis Current
KP
1.00
PI Controller of Motor Mechanical Speed
KP
4.50
KI
0.03
P Controller of Stator Quadrature-Axis Current
KP
1.20
TABLE III.
SIMULATION PARAMETERS
600
Simulation Parameters
Mechanical Speed
123.50 rad/s
Final Value
-38.10 rad/s
Step Time
0.50 s
Rotor Magnetizing Current
18.00 A
Three-Phase Current (A)
400
Initial Value
Mechanical Load
Initial Value
0.00 N.m
Final Value
70.45 N.m
Step Time
1.10 s
Inverter DC Bus
230 V
Inverter Switching Frequency
6.00 kHz
Simulation Time
1.50
200
0
-200
-400
-600
0
0.5
1
1.5
Time (s)
Fig. 10. Simulation results of the three-phase current.
800
140
Measured Mechanical Speed
Reference Mechanical Speed
Electromechanical Torque (N.m)
120
100
Mechanical Speed (rad/s)
Measured Electromechanical Torque
Inserted Electromechanical Torque
600
80
60
40
20
400
200
0
-200
-400
-600
0
-800
-20
-1000
-40
0
0.5
1
0
0.5
1
1.5
Time (s)
1.5
Time (s)
Fig. 11. Simulation results of the electromechanical torque.
Fig. 8. Simulation results of the mechanical speed.
V. CONCLUSION
A TIM drive and control method was shown. The method
uses an indirect field oriented control model and a method
intuitive computational implementation is proposed. The drive
basic theory is the FOC control principle.
25
Measured Rotor Magnetizing Current
Reference Rotor Magnetizing Current
Rotor Magnetizing Current (A)
20
The system was validated by simulations based on a TIM
real model and the results showed a big robustness and accuracy
of the control method even with sudden changes in the load or
in the speed reference.
15
10
5
0
0
0.5
1
1.5
The proposed platform shows the FOC technique
fundamental concepts didactically. Thus, this study can be used
as a powerful tool in the electrical machines learning. Besides
that, the present study can be used to motivate the students to
research about machine drive methods since the interest in this
field can be aroused.
Time (s)
Fig. 9. Simulation results of the rotor magnetizing current.
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