Speed Control of Induction Motor by V/F Method

Pallavi shrikant Alagur.Int. Journal of Engineering Research and Application www.ijera.com
ISSN: 2248-9622, Vol. 6, Issue 9, (Part -3) September 2016, pp.76-79
www.ijera.com 76|P a g e
Speed Control of Induction Motor by V/F Method
Pallavi shrikant Alagur1
, J.A.Shaikh2
Department of Electronics, Shivaji university, Kolhapur, India
Department of Electronics, Shivaji university, Kolhapur, India
ABSTRACT
This paper presents the design & implementation of voltage & frequency ratio constant & controller based on
sinusoidal pulse width modulation technique for a single phase induction motor using fuzzy logic. The work
involves implementation of an closed loop control scheme for an induction motor. The technique is used
extensively in the industry as it provides the accuracy required at minimal cost. V/f controlled motors fall under
the category of variable voltage variable frequency drives. The ratio of voltage & frequency must be constant.
Keywords: Fuzzy controller, induction motor, real time system.
I. INTRODUCTION
Nowadays electric power plays a major role
in the increasing needs of the basic human life.
Induction motor is used in many application like
industry, company, irrigation because of its low
maintenance & efficiency.
Many methods are used for the speed control
of the induction motor. The speed control of
induction motor is the main issue achieves maximum
torque & efficiency. Scalar control presents a simple
structure characterized by low steady-state error.
Therefore, the constant voltage–frequency (V/f) scalar
control system is there due to its wide application in
industrial fields Proportional–integral (PI) control
methodology is commonly applied in constant V/f
control strategy for induction motors. However, in
addition to the fact that a mathematical model is
desirable for a systematic controller design with
conventional methods, conversely, fuzzy-based
control methodology has the ability to cope with
system nonlinearity, and its control performance is
less affected by system parameter variations.
Moreover, fuzzy techniques utilize a linguistic rule
base that is designed by taking advantage of system
qualitative aspects and expert knowledge. Generally,
an embedded system may be implemented in
microcontroller and digital signal processor (DSP), or
in field programmable gate array (FPGA). An
integrated circuit dedicated to a particular application
can also be used.
Another fully embedded fuzzy system was
applied in order to adjust the PI parameters of a direct
torque control of the induction motor. In hardware
solution for an embedded neural network with a
proportional-integral-derivative (PID) controller is
also presented.
The speed control can be performed using
open loop algorithms or closed loop algorithms. The
most commonly used open loop algorithm is voltage/
frequency control methods. Closed loop algorithms
include sensor & sensor less feedback using scalar or
vector control. The main advantage of v/f control is
its simplicity & for this reason it has been
traditionally implemented using low cost
microcontrollers.
II. RELEVANCE
Speed control of induction motor this is
because now a day‟s many manufacturing industries
requires motor for their works process so, speed
control of motor is necessary. To achieve that an
efficient method is necessary this gives benefits like,
energy savings as well as cost effective etc.
Due to flux saturation problems with
induction motors with voltage applied to the motor
must alter with the frequency. The v/f induction
motor drives with inverters are widely used in no. of
industrial application leading not only to energy
saving but also to improvement in productivity &
quality. There are many different way to speed
control of induction motor by v/f method.
Microcontroller based, DSP based speed control of
induction motor, FPGA based, Fuzzy logic based
speed control of induction motor using v/f method,
neural network based, Adaptive control based
methods are also used. Proposed work is intended to
achieve good performance by above several methods
to speed control of induction motor. In connection to
the study topic the following literature has been
studied
III. LITERATURE REVIEW
There is many several methods for the speed
control of induction motor by v/f method. Method
suggested by Roufin Mahmood & Habibur Rehman
based on square wave & sine triangle inverter. These
two techniques are used for the controlling the
inverter below & above base speed for high speed
control of induction machine. Square wave inverter is
that only the frequency of the output voltage can be
RESEARCH ARTICLE OPEN ACCESS

controlled & not the magnitude. Square wave inverter
at low frequency is that if volt per hertz speed control
is used, it becomes difficult to control the voltage
level for maintaining a constant flux operation below
the base speed. Therefore, this paper designs a speed
controller with a hybrid approach in which a Sine
Triangle Pulse Width Modulated (SPWM) inverter is
used below the base speed and a square wave inverter
is employed above the base speed.[1] Mineo Tsuji,
Shinichi Hamasaki present a new simplified v/f
control system of induction motor for precise speed
operation which is based on the vector control theory.
A linear model is derived for analyzing the system
stability, including the influences of motor operating
states in motoring and regenerating operations, and
parameter variation of low pass filter. Stator
resistance identification is proposed by using d axis
current. [2] Method suggested by Y. Sangsefidi, and
A. Shoulaie method needs neither mechanical sensor
nor current transducers, so it can be compared with
"Variable Voltage Variable Frequency (v/f)" method.
High-speed operation of induction motor controlled
by this method & it is compared with that of v/f
method that leads to the fact that in addition to
control of motor dynamic behavior, in this method
uses DC-link voltage in a more efficient way. In the
stator flux modulus control, the amplitude of
electromagnetic torque ripple and average switching
frequency are computable and analytical formulas for
calculation of them are derived. [3] The suggested
methods are the compact embedded fuzzy system for
three phase induction motor scalar speed control. The
control strategy consists in keeping constant the
voltage-frequency ratio of the induction motor supply
source. A fuzzy control system is built on a digital
signal processor which uses speed error & speed error
variation to change both the fundamental voltage
amplitude & frequency of a sinusoidal pulse width
modulation inverter.[4] Krishna Chandran Vinay and
S. Moorthi presents the design and implementation of
a Variable-Voltage Variable-Frequency (VVVF)
Controller based on Sinusoidal Pulse Width
Modulation (SPWM) Technique for a 3 Phase
Induction Motor using a Field Programmable Gate
Array (FPGA). The ratio of Voltage to frequency
must be held constant. For Variable Voltage Variable
Frequency (VVVF) drives, there is a need to control
the fundamental voltage of the inverter if its
frequency (and therefore the frequency of the
induction motor), need to be varied. To vary the
fundamental component of the inverter, the
Modulation Index of the carrier signal has to be
changed. The speed at rated supply frequency is
normally used as the base speed. At frequencies
below the base speed, the supply magnitude needs to
be reduced so as to maintain a constant Volt/Hertz.
The FPGA controller is used to generate SPWM
pulses based on the frequency input, that are used to
control the inverter. The VVVF output of the inverter
can be used as supply to a three phase induction
motor and thereby speed of the motor can be
controlled.[5] Method suggested by M. Harsha
Vardhan Reddy V.Jegathesan Space Vector Pulse
Width Modulation (SVPWM) has become the
successful techniques to construct three phase sine
wave Voltage Source Inverter (VSI) parallel to
control three-phase induction motor using v/f control.
VSI fed induction motor produces a pulsating torque
due to the application of non sinusoidal voltages. In
this method 3 phase voltage source inverter produces
eight switching states comprising two zero states &
six active states. the torque ripples of induction motor
is reduced by hybrid PWM technique. The different
space vector based sequences used to generate the
switching pulse for hybrid PWM.The implementation
of SVPWM technique with other sequence carried
out by taking one zero vector instead of two zero
vectors as in convectional SVPWM. The applied
voltage vector equals the reference voltage vector
only in an average sense over the given sub cycle,
and not in an instantaneous fashion. The difference
between the reference vector and the instantaneous
applied voltage vector is the instantaneous error
voltage vector. The time integral of the error voltage
vector, referred to as „stator flux ripple vector‟, is a
measure of the ripple in the line current of the
converter. In the open loop system the frequency is
taken as input to V/f control for all voltage
conversion and pulse generation. The sub systems of
open loop control are coding for pulse generation,
inverter modeling and induction motor modeling.[6]
Vijay Babu Koreboina, A. B. Raju,presents
VSI fed 3-phase induction motor drive system with
constant „v/f‟ control method is modeled, simulated
and is implemented using PC and an add-on card, The
actual speed of the induction motor is sensed and is
compared with the reference speed. The error so
obtained is processed in a Proportional Integral (PI)
controller and its output sets the inverter frequency as
well as the modulation index. In order to simulate the
drive system using Scilab/Scicos, it is required to
model the various components of the system in terms
of their mathematical equations.[7]
Guohai Liu, Xiao Xiao, Yan Jiang, Yue
Shen presents 2 methods are combined for speed
control of the induction motor in v/f mode. These two
methods are neural network inverse system &internal
model control. AC variable frequency speed control
system working on the condition of constant
proportion of voltage to frequency (v/f), a modified
internal model control combined with the method of
neural network generalized inverse system On the
basis of reversibility analysis of original system, the
generalized inverse model approximated by the
dynamical BP neural network was cascaded with the
original system. Then the robust stability can be

improved by introducing modified internal model
control to generalized pseudo-linear system.[8]
Prof. J. G. Chaudhari Dr. M.V. Aware
present a (intelligent power module) IPM module
which is the three diode bridge rectifier with
capacitors is provided which gives the rectified DC
voltage to IGBT based IPM. The DSP PWM testing
unit is used to verify programs based on Micro-2407
trainer. In this program for fixed PWM, which can be
executed in the Micro-2407 DSP trainer and its
output waveforms with load can be observed using
this testing Unit. The DSP is programmed to generate
the pulse width modulated signal of 5 KHz with 20%
of duty cycle, with micro-2407 trainer. The
generation of PWM can be verified by using an
oscilloscope.[9]
Xiang-Dong Sun, Kang-Hoon Koh, presents
a Fuzzy-logic-based V/f control of the induction
motor is proposed for the speed sensorless power-
leveling system. The flywheel power leveling system
using fuzzy logic speed picking-up & fuzzy logic PI
regulator is used.[10] K. Sandeep kumar, K. Pritam
satsangi presents deals with variable speed drives of
induction motor for constant torque using V/F ratio
method. The above system is designed with closed
loop where the actual speed of motor is compared
with the reference speed. The difference in the speed
is adjusted by changing firing angles of switching
devices and there by obtaining variable speeds. As
the motor is running, the microcontroller 89C54 reads
the speed value, voltage and frequency set by the
user, at the same time, the speed sensor circuit
obtains actual speed through speed sensor and
accordingly variation required in voltage and
frequency are made through respective switches.[11]
Method suggested by Md. Nurul Islam and
M. Bashir Uddin the control strategy can be
implemented by scalar control and vector control.in
closed loop speed control the speed loop error signal
controls the PWM inverter frequency & voltage of a
VSI fed induction machine. A fuzzy controller is used
which can directly map the change of speed to the
change of frequency & change of modulation index.
One algorithm is used for determine the switching
points of 3 phase inverter. Numerical solution of
differential equation to estimate flux in scalar control
with flux loop. [12]
IV. SCOPE
There are several methods to control the
speed of induction motor but still v/f method is a
challenging task in order to obtain better accuracy so,
keeping in view a robust system so here main
objective is to fuzzy logic based speed control of
induction motor by v/f method
So the proposed work is to develop & implement:
1. To control the speed of induction motor by v/f
method.
2. To improve the efficiency of entire system.
3. Performance improvement included accuracy,
robustness & with energy saving system.
REFERENCES
[1]. Roufin Mahmood, etl.“High Speed Control
of Induction Machines” IEEE GCC
Conference and exhibition, November 17-
20, Doha, Qatar 2013
[2]. Mineo Tsuji, etl. “A New Simplified V/f
Control of Induction Motor for Precise
Speed Operation” 2012
[3]. Y. Sangsefidi, etl.“A Simple and Low-Cost
Method for Three-phase Induction Motor
Control in High-Speed Applications” 2012
[4]. Marcelo Suetake, etl., “Embedded DSP-
Based Compact Fuzzy System and Its
Application for Induction-Motor V/f Speed
Control” IEEE TRANSACTION ON
INDUSTRIAL ELECTRONICS, VOL. 58,
NO. 3, MARCH 2011
[5]. Krishna Chandran Vinay, etl. “FPGA Based
Implementation of Variable-Voltage
Variable-Frequency Controller for a Three
Phase Induction Motor” journal of National
Institute of Technology, 2011
[6]. M. Harsha Vardhan Reddy, etl, “Open loop
V/f Control of Induction Motor based on
hybrid PWM With reduced torque ripple”,
PROCEEDINGS OF ICETECT 2011
[7]. Vijay Babu Koreboina, etl. “Modeling,
Simulation and PC Based Implementation of
a Closed Loop Speed Control of VSI Fed
Induction Motor Drive” journal IEEE,2011
[8]. Guohai Liu, etl, “Modified Internal Model
Control of Induction Motor Variable
Frequency Speed Control System in v/f
mode Based on Neural Network Generalized
Inverse” Chinese Control and Decision
Conference 2010
[9]. Mr.C.S. Kamble, etl, “ DIGITAL SIGNAL
PROCESSOR BASED V/f CONTROLLED
INDUCTION MOTOR DRIVE” Third
International Conference on Emerging
Trends in Engineering and Technology DOI
10.1109/ICETET.2010
[10]. Xiang-Dong Sun, etl.“Fuzzy-Logic-Based
V/f Control of an Induction Motor for a DC
Grid Power-Leveling System Using
Flywheel Energy Storage Equipment”, IEEE
TRANSACTIONS ON INDUSTRIAL
ELECTRONICS, VOL. 56, NO. 8,
AUGUST 2009
[11]. K. Sandeep kumar, etl, “ MICRO-
CONTROLLER BASED CLOSED LOOP
CONTROL OF INDUCTION MOTOR
USING V/F METHOD”, IET-UK
International Conference on Information and

Communication Technology in Electrical
Sciences (ICTES 2007).
[12]. Md. Nurul Islam, etl, “ Fuzzy Logic
Enhanced Speed Control System of a VSI-
Fed Three Phase Induction Motor “, 2nd
International Conference on Electrical and
Electronics Engineering (ICEEE) and XI
Conference on Electrical Engineering (CIE
2005)

Speed Control of Induction Motor by V/F Method

More Related Content

What's hot

Viewers also liked

Similar to Speed Control of Induction Motor by V/F Method

Recently uploaded

Speed Control of Induction Motor by V/F Method