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"Sharpening Skills.....
Serving Nation"
International Journal of Emerging Technology and Advanced Engineering
Website: www.ijetae.com (ISSN 2250-2459 (Online), Volume 4, Special Issue 1, February 2014)
International Conference on Advanced Developments in Engineering and Technology (ICADET-14), INDIA.
A Methodology to Develop A Simulink Model of Three Phase
Induction Motor
Manish Kumar Singh1, Madhur Chauhan2, Amit Kumar Singhal3, Nitin Saxena4
[email protected],[email protected],[email protected]
[email protected]
Abstract— Three phase induction motor is one of the most
widely used motors as industrial, commercial and residential
load. This motor has the simplest construction, reliable in
operation, low initial cost, easy operation, simple
maintenance, high efficiency and simple speed control. The
popularity of this motor has resulted into lot of research
including the transient behaviour of the motor. In this paper,
transient performance of three phase squirrel cage induction
motor is analyzed with dq0 axis based modeling in
synchronously rotating reference frame. The parameters are
being calculated by using the standard datasheet given by
the manufacturer of the motors. The parameters of the
motor are calculated first by using the MATLAB program
then proposed system is developed and simulated by using
MATLAB/SIMULINK. This paper gives the step by step
procedure for developing the simulation model of induction
motor in MATLAB Simulink using library Sim Power
System.
Index Terms— Three phase induction motor, MATLAB,
transient behaviour, equivalent circuit parameters
I. INTRODUCTION
In modern electrical technologies, application of the
induction motors in speed and position controlled drives
have been increased drastically. The main reason behind
this is that the large-scale development of the AC
induction motors over traditionally used DC motors. To
obtained high static and dynamic qualities of these AC
drives, control engineers need more information about the
control objective. Therefore, the importance of the
characteristics and parameter calculation of the induction
motor has gone up. Generally, an induction motor
dynamics is simulated in circuit simulators like PSpice, its
steady state model is used, but for electrical drive studies,
the transient behavior is also useful. One of the major
advantage of Simulink over circuit simulators is the in
modeling the transients of electrical motors. As the
equations are known, any control algorithm can be
developed in Simulink. A connection to the network and
starting of the induction motor is transient effect. Starting
the induction motor is followed by a current and torque
surges.
rediffmai.com3,
Any programming language or simulation program can
be used for induction motor simulated model. In this
paper, MATLAB Simulink model is used after calculating
the equivalent circuit parameters of the induction motor.
The calculation is done by developing an m file. Basic
concepts are used to complete the all necessary
calculations. In most of the paper parameters are being
calculated by performing the actual no load and blocked
rotor test. For the student working on the simulink model,
it is quite tough to do actual test for every motor for
calculating the circuit parameters used in defining the
simulink model box of induction motor. So, step by step
method is being discussed in this paper for calculating the
desired parameters without involving into the actual test
on the motor. Though, this method gives the approximate
results but it may be good for the starting the working on
the simulink model.
In this paper, MATLAB/Simulink is used to simulate
the dynamic performance of an induction motor model.
This simulated program makes it easy for the user to
follow and understand the development process since it
also gives full details about the Simulink structure of each
of the model equations.
Figure 1: Equivalent circuit of per phase induction motor
II. EVALUATION OF INPUT PARAMETERS
Normally a data sheet is given by the manufacture with
every motor. The details provided through this data sheet
with the motor are given in Appendix I. An equivalent
circuit for the induction motor referred to stator side is
given in Figure 1.
Lord Krishna College of Engineering (An ISO 9001:2008 Certified Institute) Ghaziabad, Uttar Pradesh, INDIA.
Page 93
"Sharpening Skills.....
Serving Nation"
International Journal of Emerging Technology and Advanced Engineering
Website: www.ijetae.com (ISSN 2250-2459 (Online), Volume 4, Special Issue 1, February 2014)
International Conference on Advanced Developments in Engineering and Technology (ICADET-14), INDIA.
The equivalent circuit model of the induction motor can
be drawn for per phase values. By using these data, the
parameters of the induction motor shown in Figure 1can
be calculated. The procedure for calculating the equivalent
circuit parameters are given from Equation 1 to 11. for
calculating the parameters, let the induction motor is run
on no-load at rated voltage and frequency and input power
at no load provides losses (stator copper losses, iron loss,
windage and friction loss and rotational loss) for the
induction motor.
Normally, the rating of the induction motor is the power
output of the induction motor. So its input power is
calculated for the given efficiency  of the motor as;
(1)
This input power is on stator side as shown in figure 1.
So input current is equal to the stator current which is
given by;
(2)
and
are the phase voltage and motor power
factor respectively. The per phase equivalent impedance,
resistance and reactance of the circuit can be
approximately determined as:
;
(3)
;
;
(4)
(10)
The stator resistance can be found out using the concept
of equivalent impendence of the circuit given in Figure 1.
For calculating
the voltage of rotor side terminal is
assumed to be zero i.e. these terminals are assumed to be
short circuited. This is done with the help of MATLAB
programming.
(11)
The value of two mechanical parameters friction
coefficient B and inertia constant H is given in Appendix
II along with the other parameters calculated using
Equation 1 to 11 in this section.
III. SIMULINK DESIGN OF INDUCTION MOTOR
The complete simulink model is developed on m file.
The complete model may be broadly classified into four
blocks namely input block, supply block, induction motor
block and output parameter block.
The input block allows selecting either the torque
applied to the shaft or the rotor speed as the Simulink
signal applied to the block's input. Mechanical input
torque is considered here. The mechanical torque is
applied in 1 second from no load to full load value. The
value of full load torque is calculated by the formula given
in equation 11.
(12)
(5)
A term of flux leakage coefficient is defined as;
is defined as the rotor speed given by the Equation 12.
(13)
(6)
The core resistance is assumed to be zero in the
equivalent circuit. For the supply frequency , the mutual
inductance of the motor is calculated as;
A signal is given through the ramp signal as shown if
Figure 2. The corresponding signal waveform is
represented by Figure 3.
(7)
The rotor resistance can be found for slip s by the
concept of ohmic loss at mechanical output;
(8)
The stator leakage inductances of the equivalent circuit
can be formulated as;
(9)
The rotor leakage inductance of the equivalent circuit is
assumed equal to stator leakage inductances in many
papers. So same is considered in this paper too.
Figure 2: Simulink block for input signal
Lord Krishna College of Engineering (An ISO 9001:2008 Certified Institute) Ghaziabad, Uttar Pradesh, INDIA.
Page 94
"Sharpening Skills.....
Serving Nation"
International Journal of Emerging Technology and Advanced Engineering
Website: www.ijetae.com (ISSN 2250-2459 (Online), Volume 4, Special Issue 1, February 2014)
International Conference on Advanced Developments in Engineering and Technology (ICADET-14), INDIA.
Table 2
Parameters of induction motor in simulink model
200
Nominal power, voltage (line-line), and frequency
[
Pn(VA),
Vn(Vrms),
fn(Hz) ]:
[ 1.67e+005
400
50]
Stator resistance and inductance
[ Rs(ohm)
Lls(H) ]:
[0.02922
0.00056889]
Rotor resistance and inductance
[ Rr'(ohm)
Llr'(H) ]:
[0.059175
0.00056889]
Mutual inductance Lm (H): 0.0360
Inertia,
friction factor,
pole pairs
[ J(kg.m^2)
F(N.m.s)
p()]:
[.5
.5
2]
180
160
Mechanical torque input
to induction motor
140
120
100
80
60
40
20
0
0
0.5
1
1.5
2
2.5
3
3.5
4
4.5
5
simulation time in sec
Figure 3: Mechanical torque input form no load to full load in 1 sec
The supply block consists a grounded star connected
three phase source of 400 V line to line voltages at 50 Hz
frequency. The reference phase angle is set to be zero.
The main block in this model is the third block
consisting the induction motor block. The block is
available in simulink power system library. The main
issue for using this is how to decide the configuration and
the parameters. On the basis of the Appendix I and II, the
configuration and parameters may be decided. The values
given to the model is depicted in Table 4 and 5. The initial
conditions are satisfied before running the simulink model
using powergui available in simulink library.
The last block is the output parameter block. The
Simulink output of the block is a vector containing 21
signals. These signals may be de-multiplexed by using the
Bus Selector block provided in the Simulink library. The
output parameters of interest in this model are rotor speed,
slip, electromagnetic torque and load torque with respect
to time.
IV. RESULT AND DISCUSSION
As the data sheet given in appendix I, the induction
motor is chosen. The parameters are calculated by
developing a m file in MATLAB 2010 using the
mathematical Equation 1 to11. The results are given in
Appendix I. by using these parameters a simulink model is
developed for the study of transients of induction motor.
The detail discussion about the various blocks of simulink
model is done in separate section of this paper. A linear
model of mechanical torque input is used for this paper.
To provide the smooth staring of induction motor the full
load is not applied in the staring of the motor. Time
duration of 2 second is used and load is increased
gradually from no load to full load which is designed with
the help of continuously increasing ramp function as
shown in Figure 3.
Table1
Configuration of induction motor in simulink model
S. No.
1
2
3
4
5
Description
Preset model
Mechanical Input
Rotor Type
Reference Frame
Mask units
Status
NO
Torque Tm
Squirrel Cage
Synchronous
SI
Figure 4: Mechanical load torque disturbance with time
Lord Krishna College of Engineering (An ISO 9001:2008 Certified Institute) Ghaziabad, Uttar Pradesh, INDIA.
Page 95
"Sharpening Skills.....
Serving Nation"
International Journal of Emerging Technology and Advanced Engineering
Website: www.ijetae.com (ISSN 2250-2459 (Online), Volume 4, Special Issue 1, February 2014)
International Conference on Advanced Developments in Engineering and Technology (ICADET-14), INDIA.
800
Electromechanical torque
600
400
200
0
-200
-400
-600
Figure 5: Rotor speed in induction motor with time
0
0.5
1
1.5
2
2.5
time
3
3.5
4
4.5
5
Figure 7: Electromechanical torque in induction motor with time
The results of simulink model are shown in Figures 4 to
7. The simulation time used is 5 sec. the mechanical load
is increasing from 0 to full load linearly upto 1 sec and
then it reaches to its steady state after transients as shown
in Figure 4. The rotor speed and slip variation is
represented in Figure 5 and 6 respectively. Both the
graphs show the transients at the staring and then achieve
its steady state value. Figure 6 shows a very interesting
behaviour due the gradual variation of load torque upto 1
sec so transients once reduces further comes at time of 1
sec.
V. CONCLUSIONS
In this paper, implementation of simulink model for
induction machine has been introduced. Unlike most other
induction machine model, parameters are fisrt calculated
using MATLAB programming.
Figure 6: Slip variation in induction motor with time
Lord Krishna College of Engineering (An ISO 9001:2008 Certified Institute) Ghaziabad, Uttar Pradesh, INDIA.
Page 96
"Sharpening Skills.....
Serving Nation"
International Journal of Emerging Technology and Advanced Engineering
Website: www.ijetae.com (ISSN 2250-2459 (Online), Volume 4, Special Issue 1, February 2014)
International Conference on Advanced Developments in Engineering and Technology (ICADET-14), INDIA.
These parameters are calculated with the help of
available manufacturer data sheet so the beginners may
calculate the data without involving into the real test
performance and may use these results for the
approximate calculation related with induction motor
system model. Individual parameter equations are solved
in each block, also configuration and parameters involved
for developing the simulink model is given in the paper for
the better understanding. Finally, the rotor speed, slip,
load torque and electromechanical torque responses of
induction motor operation is plotted with time. The author
believes that the Simulink will soon become an
indispensable tool for the teaching and research of
electrical machine drives.
REFERENCES
[1 ] Miloje M. Kostic,“ Equivalent circuit improvement method for
induction motor efficiency,” Electrical Engineering Vol. 25, No 1,
April 2012, pp. 31 – 42.
[2 ] Stanislav Rusnok, Pavel Sobota, Martin Slivka, Pavel Svoboda,
“Assessment
transients
during
starting of induction motor in matlab simulink and verification by
measurement,” Advanced Research in Scientific Areas 2012
December, 3/7/2012, international virtual conference, section-11.
electronics, electrical systems, electrical engineering,pp.
1672-1676.
[3 ] Mukesh Kumar Arya, Dr.Sulochana Wadhwani, “Transient
analysis of three phase squirrel cage induction machine using
matlab,” International Journal of Engineering Research and
Applications Vol. 1, Issue 3, pp.918-922.
[4 ] Sifat Shah, A. Rashid, MKL Bhatti, “Direct quadrate (d-q)
modeling of 3-phase induction motor using matlab / simulink,”
Canadian Journal on Electrical and Electronics Engineering Vol. 3,
No. 5, May 2012,pp. 237-243.
[5 ] K. S. Sandhu and Vivek Pahwa, “A novel approach to incorporate
the main flux saturation effect in a three-phase induction machine
during motoring and plugging,” international journal of computer
and electrical engineering, vol. 3, no. 3, june 2011,pp. 443-448.
[6 ] O. I. Okoro, “MATLAB simulation of induction machine with
saturable
leakage and magnetizing inductances,” The Pacific
Journal of Science and Technology, Volume 5. Number 1. April
2003 (Spring),pp. 5-15.
[7 ] D P Kothari,I J Nagrath,Electrical Machines 3rd Edition,Tata
McGraw Hill Education Private Limited,New Delhi,2009.
[8 ] P.S. Bimbra,Electrical Machinery,7th Edition, Khanna Publishers
Private Limited, New Delhi, 2012.
[9 ] Prabha Kundur,Power System Stability and Control,5 th Edition,
Tata McGraw Hill Education Private Limited, New Delhi,2008.
APPENDIX I
Rating of motor, Pout=150 kW
Line Voltage, VL=400 Volt
Power factor = 0.9 lagging
=0.9
s= 0.04
Supply frequency = 50 Hz
Pole pair=1
APPENDIX II
Tm=995 N.m
Lm=12.0 mH
R1=0.02922 Ω
LS=18.936 mH
Lr=18.936 mH
B=0.5 wb/m2
H=0.5 Amp-turn/m
R2=0.2630 Ω
Lord Krishna College of Engineering (An ISO 9001:2008 Certified Institute) Ghaziabad, Uttar Pradesh, INDIA.
Page 97