1. International Journal of Electronics and Communication Engineering & Technology (IJECET), ISSN
0976 – 6464(Print), ISSN 0976 – 6472(Online) Volume 4, Issue 2, March – April (2013), © IAEME
373
DESIGN AND DEVELOPMENT OF MATLAB-GUI BASED FUZZY
LOGIC CONTROLLERS FOR AC MOTOR SPEED CONTROL
Immanuel J.*
, Parvathi C. S., L. ShrimanthSudheer, and P. Bhaskar
Department of Instrumentation Technology, Gulbarga University P.G. Centre,
Yeragera-584133, Raichur, KARNATAKA, INDIA.
*
Email: immanuel.j009@gmail.com
ABSTRACT
In the present paper an attempt is made to design a graphical user interface (GUI) for
speed control of AC Motor. The AC motor speed is controlled by phase angle firing
technique. MATLAB based GUI is created and controllers such as PID, fuzzy logic controller
(FLC) and integrated fuzzy logic controller (IFLC) are designed and implemented. An AD-
DA board designed for the present application is interfaced to PC to acquire speed and send
control action to the actuator. MATLAB-GUI displays all the required parameters of AC
motor speed control system. Also, this paper discusses the performance comparison of PIDC,
FLC, and IFLC for step input of 7500RPM. It is found that IFLC performs better in terms of
less rise time, less settling time, and less steady state error.
Key words: AC Motor, FLC, IFLC, MATLAB-GUI, Speed,
1. INTRODUCTION
AC motors are used worldwide in many residential, commercial, industrial and utility
applications. AC motor speed is one of the important parameters monitored and controlled.
AC induction motor is most widely used type of electric motor in the modern world. The
conventional approaches are not convenient to solve the complexities in controlling the AC
motor speed. In the most of research work the fuzzy logic controller has been employed to
increase the efficiency of the motor/drive. Fuzzy logic control technology has been widely
and successfully utilized in numerous industrial applications and consumer products. Since
fuzzy logic with human like but systematic property can convert the linguistic control rules
based on expert knowledge into automatic control strategy. The main advantage of using
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2. International Journal of Electronics and Communication Engineering & Technology (IJECET), ISSN
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fuzzy logic control structure is that one does not have to redesign the existing control system
but also acquire the satisfactory response when disturbances and noise enter [1].
MATLAB is software where one can design fuzzy logic controllers very easily as it
contains fuzzy logic toolbox. MATLAB is an interactive program for numerical computations
and data visualizations. It integrates mathematical computing, visualization and powerful
language to provide flexibility environment for technical computing [2]. John G. Cleland, et
al reported a fuzzy logic energy optimizing controller developed to improve the efficiency of
motor/drive combinations running at various loads and speed conditions. The 2-20%
efficiency is obtained from laboratory demonstration. Also, they investigated to reduce
energy consumption when motors are operated at less than rated speed and load. In their
research, simulation results of a microprocessor based fuzzy logic motor controller are
described. Efficiency improvements by an FLMC controllers ASD over a constant V/Hz
ASD range from approximately 0.2% to 14% for the motors examined [3-4]. C. von Altrock,
et al represented fuzzy logic enhanced control of an AC induction motor with DSP. They
implemented the Texas Instruments DSP to control AC induction motor and control
performance has been improved while design effort has been significantly reduced. They
reported the fuzzy approach which delivered similar performance and higher robustness than
the traditional approach [5]. Z. Q. Zhu, et al described fuzzy logic control to a vector
controlled permanent magnet brushless AC motor drive and shows that fuzzy logic controller
performance better than the PI controller. Also, they proposed simple adaptive fuzzy logic
controller algorithm with self tuned threshold speed error. The results obtained are, the DSP
based FLC with linear distribution of fuzzy sets of the output variable presents excellent
speed tracking and disturbance performances [6].
Some of the searchers also implemented the field programmable gate array (FPGA) to
speed control of AC motor. Ying-Yu Tzou, et al presents the design and implementation of a
motor control IC for permanent magnet servo motors using the FPGA. The proposed control
structure has also been realized using FPGAs. The designed PMAC IC can be incorporated
with a general purpose microcontroller to provide simple, compact, low-cost and effective
solutions for high performance AC drives [7-8]. Some of the researchers proposed the design
and implementation of CPLD for AC motor drive. From the literature it is very rare to find
the work which has reported the design and development of a complete hardware and
software for the speed control of AC motor. Also, very less work has been reported to
implement MATLAB-GUI for speed control of AC motor. So this has motivated the authors
to design and develop MATLAB-GUI based fuzzy logic controllers for speed control of AC
motor.
2. HARDWARE DETAILS
The Fig.1 shows the block diagram of MATLAB-GUI based AC motor speed control
system using fuzzy logic controller. It includes the following elements:
• AC Motor
• Tacho-Generator
• Frequency to Voltage Convertor
• AD-DA Board
• Ramp Generator
• Comparator, and
• Opto-isolator and Triac

3. International Journal of Electronics and Communication Engineering & Technology (IJECET), ISSN
0976 – 6464(Print), ISSN 0976 – 6472(Online) Volume 4, Issue 2, March
2.1 AC MOTOR
A FHP AC single phase motor is used for the present study. The specifications of the
AC motor used in the present study
Table 1.
Description
Kilo Watts
Horse Power
Weight
Max Speed
Current
Voltage
2.2 TACHO-GENERATOR
It consists of slotted aluminum disc and optical encoder.
six slots, which produces six pulses for each rotation of disc. The disc is connected to the
shaft of the AC Motor. The disc is made to rotate between photo
isolator), a high pulse is produced at the output of optical encoder and whe
photo transistor a low pulse is produced. The frequency
of the AC motor. This frequency is directly proportional to the speed of AC motor.
this frequency is converted in to voltage by
International Journal of Electronics and Communication Engineering & Technology (IJECET), ISSN
6472(Online) Volume 4, Issue 2, March – April (2013), © IAEME
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A FHP AC single phase motor is used for the present study. The specifications of the
used in the present study are given in the Table 1.
Table 1. Specifications of AC Motor
Description Value
0.05KW
1/15 HP
1.60Kg
13000 rpm, at no load
4000 rpm, at full load
0.75A
230VAC, 50Hz
GENERATOR
It consists of slotted aluminum disc and optical encoder. The slotted disc is made with
pulses for each rotation of disc. The disc is connected to the
shaft of the AC Motor. The disc is made to rotate between photo- transistor and LED
, a high pulse is produced at the output of optical encoder and when light falls on
photo transistor a low pulse is produced. The frequency of these pulses depends on the speed
of the AC motor. This frequency is directly proportional to the speed of AC motor.
frequency is converted in to voltage by using F/V converter.
International Journal of Electronics and Communication Engineering & Technology (IJECET), ISSN
April (2013), © IAEME
A FHP AC single phase motor is used for the present study. The specifications of the
The slotted disc is made with
pulses for each rotation of disc. The disc is connected to the
transistor and LED (opto-
n light falls on
these pulses depends on the speed
of the AC motor. This frequency is directly proportional to the speed of AC motor. Further,

4. International Journal of Electronics and Communication Engineering & Technology (IJECET), ISSN
0976 – 6464(Print), ISSN 0976 – 6472(Online) Volume 4, Issue 2, March – April (2013), © IAEME
376
2.3 FREQUENCY TO VOLTAGE CONVERTER
The frequency of train of pulses from tacho-generator is converted in to voltage by
using LM2907 frequency to voltage converter. The output voltage obtained is V0=
Vcc*fin*C1*R1*K, where K is gain constant. Further the A/D converter is used to acquire
analog voltage.
2.4 AD-DA BOARD
In the present work, a AD-DA board is designed indigenously by the authors for the
data acquisition. This board contains Analog Devices make 12-bit analog to digital converter
and Burr-Brown make 12-bit digital to analog converter.
2.4.1 A/D Converter Specifications[9]
• Analog Devices AD1674
• Industry standard pin out
• 8 & 16-bit microprocessor interface
• Commercial, industrial and military temperature rang grades
2.4.2 D/A Converter Specifications[10]
• Burr-Brown make DAC 7541
• Low cost,12-bit four quadrant multiplying D/A converter
• Relative accuracy of ±1LSB = ±0.024% of FSR
2.5 RAMP GENERATOR
In the present study the AC motor is driven by AC power. The AC power should be
applied to the motor in both positive and negative half cycle of AC signal. From the
transformer the AC signal is drawn and converted in to ramp signal. This ramp signal acts as
one of the inputs to the comparator to generate PWM signal for the actuator. Here, the circuit
is constructed by using transistor and op-amp. Phase angle firing allows us to apply some
power every line-cycle, so the jerkiness associated with time proportioning is overcome. We
can adjust the amount of power applied to the load every half cycle.
2.6 COMPARATOR
A dedicated comparator, LM311, is used for the present applications. One input for
this comparator comes from ramp generator and other input from D/A converter output
voltage to generate PWM signal.
2.7 OPTO-ISOLATOR AND TRAIC
A triac is used as a final control element (actuator). Triac is most commonly used
device for power control in AC circuits. A triac can conduct in both directions and is
normally used in AC phase control. The AC voltage is applied to the motor through traic.
Here BTA06 is used as an actuator. As the high power devices are need to be isolated from
the rest of the circuit. The opto-diac is used to drive traic and to provide isolation from the
high power.

5. International Journal of Electronics and Communication Engineering & Technology (IJECET), ISSN
0976 – 6464(Print), ISSN 0976 – 6472(Online) Volume 4, Issue 2, March – April (2013), © IAEME
377
3. GRAPHICAL USER INTERFACE (GUI)
MATLAB provides GUIDE toolbox to design user defined graphical user interface.
The AC motor speed control GUI is selected by clicking on Control button. This GUI is a
main GUI which displays set point, current speed, and controller currently working with. The
Tune Controller GUI is selected by clicking on the respective button. This GUI allows user to
select a controller and tune the corresponding controller parameters.
Initially, the GUI initializes the DIOT card and prompts the user for entering set point.
After accepting set-point, clicking on Control button will initiate control process. Fig. 2
shows screen-shot of main AC motor speed control main GUI. In this GUI, provision is made
for the user to set the desired speed (in RPM) with current speed being displayed. It also
displays the current controller selected by the user in the tune controller GUI. In this GUI,
provision is made for the user to set the desired speed with present speed being displayed. It
also displays the present controller selected by the user in the tune controller GUI. Fig. 3
shows the GUI for tuning the PIDC and FLC controller parameters. The main GUI has
various components on it such as “Control”, “Tune Controllers”, “Plot” and edit boxes such
as Set-Point and text boxes such as Present Speed and controllers selected by the user. The
second GUI consists of PIDC and FLC parameters such as “Scaling Factor”, “OK” and
“Save” buttons. These GUIs are user friendly, when run, prompt user to enter set point and
other required parameter and prompt to run the process. The tuning and selection of different
controllers such as PID, FLC, and IFLC is done by or made possible by using check boxes.
The performance of the controller can be visualized on the axes components on the GUI. By
clicking on control button the control process starts and the values are stored on to a memory
after completion of predefined time. The response can be observed on the axes.
Fig. 2 Screen-shot of Main GUI for speed control of AC Motor

6. International Journal of Electronics and Communication Engineering & Technology (IJECET), ISSN
0976 – 6464(Print), ISSN 0976 – 6472(Online) Volume 4, Issue 2, March – April (2013), © IAEME
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4. SOFTWARE DETAILS
The software for the preset AC motor speed control application is written in MATLAB. The
graphical user interface is designed by using GUIDE toolbox in MATLAB for various controllers
such as PIDC, FLC, and IFLC.
4.1 FUZZY LOGIC CONTROLLER
Fuzzy logic controllers are easier to understand and develop because they involve human
operations strategy [11]. Generally, this controller accepts two inputs i.e., error and change-in error.
The error is obtained by subtracting the plant output from the desired value. The change-in error is
obtained by subtracting the previous error from current error. By forming rule base and choosing
membership functions the control action is produced. This control action is applied to the plant. The
fuzzy logic controller consists of three design stages; fuzzification, decision-making logic, and
defuzzification. The fuzzification stage converts real numbers into fuzzy values/linguistic terms. The
decision-making logic stage processes the input data and computes the control output. These outputs
which are fuzzy values are converted into real numbers by the defuzzification stage. This fuzzy logic
controller can be designed by using MATLAB software. The MATLAB provides the fuzzy tool kit to
design a FLC. Typing ‘fuzzy’ on command window the following GUI will be opened to create fuzzy
logic controller. Sugeno [12] type FLC is selected and 7-member triangular function is chosen to form
a controller. The membership functions for error, change-in-error, and control action, are shown in
Fig. 4, 5, and 6 respectively. The designed fuzzy inference system (fis) in MATLAB is saved as ‘fis’
file and is called by GUI. To evaluate the designed ‘fis’ the following command is used. fis= readfis
(‘ACspeedfis_1’); control_action=evalfis([en-en_1], fis).
Fig. 4. 7-member triangular function for error
Fig. 3 Screen-shot of PIDC and FLC tuning GUI

7. International Journal of Electronics and Communication Engineering & Technology (IJECET), ISSN
0976 – 6464(Print), ISSN 0976 – 6472(Online) Volume 4, Issue 2, March – April (2013), © IAEME
379
5. METHODOLOGY
The speed of the AC motor is sensed by tacho-generator. The tacho-generator
produces pulses. The frequency of these pulses is directly proportional to the speed of AC
motor. This frequency is converted in to voltage by using F/V converter and is acquired by
ADC on AD-DA board. This measured voltage is converted into actual speed of AC motor by
curve fitting method. The error is calculated by subtracting measured speed from set point
and is applied to the PID/FL/IFL controllers. The controller output is sent to the comparator
to decide power to be applied to the motor through DAC on AD-DA board. The comparator
compares DAC voltage with the ramp voltage generated by ramp generator. The phase angle
firing technique is used to apply power to the AC motor by comparing DAC voltage with the
ramp voltage in the present work. Depending on DAC voltage the power to be applied is
decided. The opto-diac is used to provide isolation between low power devices and AC line
and to drive TRAIC. The speed of AC motor is controlled at desired level. In the present
application the AC motor speed is controlled at step point of 7500RPM. The flowchart for the
complete algorithm is shown in Fig. 7.
Fig. 5. 7-member triangular function for change in error
Fig.6. 7-member triangular function for control action

8. International Journal of Electronics and Communication Engineering & Technology (IJECET), ISSN
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6. EXPERIMENTAL RESULTS
Fig. 8 shows the comparative study of PIDC, FLC and IFLC responses for step input
of 7500RPM. From the graph it is found that there is no much difference in the rise time of
FLC and IFLC. But there is a remarkable performance of IFLC during settling time. Table 2
shows the comparative values of performance of PIDC, FLC and IFLC for a step input of
7500RPM.
Table 2. Performance Comparison of PIDC, FLC and IFLC
Controller →
Parameters↓
PIDC FLC IFLC
Rise time (sec) 3.47 3.32 3.27
Settling time(sec) 7.20 6.92 5.24
Steady state error (RPM) 10.0 10.0 0.0
Start
Initialization of PCI DIOT card (Create an
object for DIOT card)
Invoke speed control GUI and prompt the user
to enter desired set point and select the
controller (Initially Turn-OFF the motor)
Acquire voltage corresponding to present speed
of motor through AD-DA broad
Compute actual speed in RPM to obtain
(error = set point – measured speed)
(change-in-error = present error –
previous error)
Display present AC motor speed on MATLAB
GUI
Solve selected controller algorithm
(PID/FLC/IFLC)
Apply control action to motor through TRIAC
Update controller variables
Plot the response on axes component on the
GUI
Is stipulated
time over ?
NO
YES
Store speed data to the file
(Turn-OFF Motor)
Stop
A
A
Fig. 7 Flowchart of AC motor speed control system

9. International Journal of Electronics and Communication Engineering & Technology (IJECET), ISSN
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7. CONCLUSIONS
The MATLAB-GUI designed for the study of AC motor speed control system
provides various facilities to run the control system and to tune controllers. The controller
such as PID, FLC and IFLC are implemented in MATLAB-GUI and speed of the AC motor
is controlled at 7500 RPM. It is found from the experimental results that integrated fuzzy
logic controller performs the best. The GUI designed for the present application provides
advantages over the conventional control approaches. This GUI is user friendly in nature and
need not require high technical knowledge about the particular task to work. AC motor GUI
allows user to tune controllers in much easier way than the conventional laborious tuning
methods. Also, GUI allows the user to analyze the response through plotting.
ACKNOWLEDGEMENT
The authors are thankful to University Grants Commission (UGC), New Delhi, India
for providing the financial assistance to carry out this project work successfully.
REFERENCES
[1] Ming-Yuan Shieh and Tzuu-Hseng S. Li, Integrated fuzzy logic controller design, in
Proc. of IEEE Conf. on Industrial Electronics, Control, & Instrumentation, 1993, vol. 1, pp.
279-284, 15-19th Nov. 1993.
[2] Rao V. Dukkipati, MATLAB for Control System Engineers, New Age International
Publishers, New Dehli, 2011.
0 3 5 7 9 11 13 15
0
1500
2500
3500
4500
5500
6500
7500
Time(sec)
Speed(RPM)
PIDC
IFLC
FLC
Fig. 8. Responses of PIDC, FLC and IFLC for step input of 7500RPM

10. International Journal of Electronics and Communication Engineering & Technology (IJECET), ISSN
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[3] John Cleland, Wayne Turner, Paul Wang, Todd Espy. P. Jeffry Chappell, Ronald J.
Spiegel and BimalBse, Fuzzy logic control of AC induction motors, IEEE, Inter. Conf. on
Fuzzy Systems, vol. 1, pp. 843-850, 8-12 March 1992.
[4] John G. Cleland, Vance E. McCormick and M. Wayne Turner, A Fuzzy logic based
energy optimizer for AC motors, Proc. IEEE, Inter. Conf on Fuzzy systems, vol. 4, pp. 1777-
1784, 20-24 March 1995.
[5] C. von Altrock and S. Beierke, Fuzzy logic enhancement control of an AC induction
motor with a DSP, proc. of 5th
IEEE Inter. Conf. on Fuzzy Systems, 1996, vol. 2, pp. 806-
810, 8-11 Sep. 1996.
[6] Z. Q. Zhu, J. KShn and D. Howe, Comparative study of alternative fuzzy logic control
strategies of permanent magnet brushless AC drive, Proc. of IEEE Inter. Conf. on Control
Applications, 18-20, Sep 2002.
[7] Ying-Yu Tzou and Jin-Yi Jyang, A programmable current vector control IC for AC
motor drives, Proc. of 25th
Annual Conf. IEEE, Industrial Electronics, Control &
Instrumentation (IECON,1999), vol.1, pp. 216-221, 29 Nov, 3 Dec. 1999.
[8] Ying-Yu Tzouand Tien Sung Kuo, Design and implementation of an FPGA based
motor control IC for permanent magnet AC servo motors, 23rd
Inter. Conf. on Industrial
Electronics, Control & Instrumentation (IECON’97), vol. 2, pp.943-947, 9-14 Nov 1997.
[9] www.analog.com/static/imported-files/data-sheet/AD1674.pdf
[10] www.burr-brown.com
[11] D. Driankov, H. Hellendroon & M. Reinfrank, An Introduction to Fuzzy Control,
Narosa Publishing House, New Delhi, 2001.
[12] http://www.mathworks.in/products/fuzzy-logic/ index.html.
[13] M. A. Majed and Prof. C.S. Khandelwal, “Efficient Dynamic System Implementation
of FPGA Based PID Control Algorithm for Temperature Control System”, International
Journal of Electrical Engineering & Technology (IJEET), Volume 3, Issue 2, 2012,
pp. 306 - 312, ISSN Print : 0976-6545, ISSN Online: 0976-6553.
[14] Vishal Rathore and Dr. Manisha Dubey, “Speed Control of Asynchronous Motor
using Space Vector Pwm Technique”, International Journal of Electrical Engineering &
Technology (IJEET), Volume 3, Issue 3, 2012, pp. 222 - 233, ISSN Print : 0976-6545, ISSN
Online: 0976-6553.
[15] M.Gowrisankar and Dr. A. Nirmalkumar, “Implementation & Simulation of Fuzzy
Logic Controllers for the Speed Control of Induction Motor and Performance Evaluation of
Certain Membership Functions”, International Journal of Electrical Engineering &
Technology (IJEET), Volume 2, Issue 1, 2011, pp. 25 - 35, ISSN Print : 0976-6545,
ISSN Online: 0976-6553.