A comparative analysis of speed control of separately excited dc motors by conventional 2

International Journal of Electrical Engineering and Technology (IJEET), ISSN 0976 –
6545(Print), ISSN 0976 – 6553(Online) Volume 4, Issue 2, March – April (2013), © IAEME
229
A COMPARATIVE ANALYSIS OF SPEED CONTROL OF
SEPARATELY EXCITED DC MOTORS BY CONVENTIONAL AND
VARIOUS AI TECHNIQUE BASED CONTROLLERS
Debirupa Hore*
(M.Tech Power and Energy systems, B.E Electrical Engineering)
*Assistant Professor Electrical Engineering Department
KJ Educational Institutes” KJCOEMR Pune Maharashtra India
ABSTRACT
This paper presents a comparison of speed control of a separately excited DC motor
using different types of controllers. Conventional controllers are generally used to control the
speed of the separately excited DC motors in various industrial applications. It is found to be
simple and high effective if the load disturbances are small. But during high load or large
variation of load the AI technique based controllers such as proves to be fast and reliable. To
control the speed of the motor a step down chopper is also used. The control scheme of the
motor was tested with convention PI controller following the Fuzzy controller and then
ANFIS Based speed controller. All the responses were analyzed in MATLAB/SIMULINK
environment. The simulation results show that the Artificial Intelligence based speed
controllers gives good performance and high robustness in large load disturbances.
I.INTRODUCTION
Development of high performance motor drives is very essential for industrial
applications. A high performance motor drive system must have good dynamic speed
command tracking and load regulating response. Depending on the application, some of them
have fixed speed and some have variable speed. The variable speed drives, have various
limitations such as poor efficiencies, lower speeds etc. With the advent of power electronics
today we have variable drive systems which are not only smaller in size but also very
efficient, highly reliable and meeting all the stringent demands of the various industries of
modern era. DC motors provide excellent control of speed for acceleration and deceleration.
The power supply of a DC motor connects directly to the field of the motor which allows for
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230
precise voltage control, and is necessary for speed and torque control applications. DC
drives, because of their simplicity, ease of application, reliability and favorable cost
have long been a backbone of industrial applications. DC drives are less complex as
compared to AC drives system. DC drives are normally less expensive for low horsepower
ratings. DC motors have a long tradition of being used as adjustable speed machines and a
wide range of options have evolved for this purpose. Cooling blowers and inlet air flanges
provide cooling air for a wide speed range at constant torque. DC regenerative drives are
available for applications requiring continuous regeneration for overhauling loads. AC drives
with this capability would be more complex and expensive. Properly applied brush and
maintenance of commutator is minimal. DC motors can provide high starting torques which
is required for traction drives. They are also used for mobile equipment such as golf carts,
quarry and mining applications. DC motors are conveniently portable and well fit to
special applications, like industrial equipments and machineries that are not easily run
from remote power sources.
With the advent of thyristors and thyristor power converters the variable voltage to
the dc motor is obtained from static power converters. Phase controlled rectifiers provide
variable dc voltage from constant voltage, constant frequency mains. The static apparatus is
very efficient, compact and has a very good dynamic behavior. It is very easy to provide a
four quadrant drive with slight modifications in the converter. A dc chopper can be used to
obtain a variable voltage from a constant dc voltage. The average value of the output voltage
can be varied by varying the time ratio of the chopper.
II.CHOPPERS
A DC chopper is a static power electronic device that converts fixed dc input voltage
to a variable dc output voltage. A Chopper may be considered as dc equivalent of an AC
transformer since they behave in an identical manner. As chopper involves one stage
conversion, these are more efficient. Choppers are now being used all over the world for
rapid transit systems. These are also used in trolley cars, battery-operated vehicles, traction-
motor control, and control of induction motors, marine hoists, forklift trucks and mine
haulers. The future electric automobiles are likely to use choppers for their speed control and
braking. Besides, the saving in power, the DC chopper offers greater efficiency, faster
response, lower maintenance, small size, smooth control, regeneration facility and for many
applications, lower cost, than motor-generator sets or gas tubes approaches.
A. PRINCIPLE OF STEP-DOWN CHOPPER (BUCK-CONVERTER) OR CLASS A
CHOPPER
A chopper is a high speed ON or OFF semiconductor switch which is consists of
power semiconductor devices, input dc power supply, elements (R, L, C, etc.) and output
load. The average output voltage across the load is controlled by varying on-period and off-
period (or duty cycle) of the switch In fig.1 when chopper CH1 is ON, V0 = Vୱ and current i0
flows in the arrow direction shown. When CH1 IS OFF, V0 = 0 but i0 in the load continues
flowing in the same direction through freewheeling diode FD. Hence average values of both
load voltage and current, i.e. V୭ and I0 are always positive as shown by the hatched area in the
first quadrant of V୭-I୭ plane in fig.1 (b). The power flow in type-A chopper is always from
source to load. This chopper is also called step-down chopper as average output voltage V0 is
always less than the input dc voltage.

231
Fig. 1(a) Class A Chopper Circuit
Fig. 1(b): Voltage and Current Directions
The variations in on and off periods of the switch provides an output voltage with an
adjustable average value.
Fig 1(c): Voltage Waveforms
Average voltage, V୭ = (T୭୬ / (T୭୬ +T୭୤୤))* Vୱ
= (T୭୬ /T)* Vୱ
=αVୱ (1)
T୭୬ = on-time
T୭୤୤ = off-time
T = T୭୬ + T୭୤୤= chopping period
Thus the voltage can be controlled by varying duty cycle.
V୭ = f*T୭୬ *Vୱ (2)
f = 1/T = chopping frequency
III. MODELLING OF SEPARATELY EXCITED DC MOTOR
A separately excited dc motor is very versatile as a variable speed motor. Its speed can be
varied by varying the applied voltage to the armature or field current. The speed control using the
variation of armature voltage can be used for constant torque application in the speed range from
zero to rated speed (base speed). Speeds above base speed are obtained by means of field
weakening, the armature voltage being kept at the rated value. The speed control in this case is at
constant power. In both cases the speed control is smooth and step-less

International Journal of Electrical Engineering and Technology (IJEET), ISSN 0976
6545(Print), ISSN 0976 – 6553(Online) Volume 4, Issue 2, March
Fig 2
Fig 2(b): Complete
A. OPERATION OF SEPARATELY EXCITED DC MOTOR
When a separately excited
current of ia flows in the circuit, the motor develops a back EMF and a torque to ba
torque at a particular speed. The field current if is independent of the armature current
winding is supplied separately. Any change in the armature current has no effect on the field
current. In general ia is much less than
B. FIELD AND ARMATURE EQUATIONS
Instantaneous field current:
dif
Vf = Rf if + Lf
dt
Where, Rf and Lf are the field resis
Instantaneous armature current:
dia
Va = Raia+La + Eg
dt
Where, Ra and La are the armatu
The motor back emf, which is also known as speed voltage, is expressed as:
Eg = Kvωif
Kv is the motor voltage constant (
lectrical Engineering and Technology (IJEET), ISSN 0976
6553(Online) Volume 4, Issue 2, March – April (2013), © IAEME
232
Fig 2(a): Separately Excited DC motor
Complete layout for DC motor speed control
OPERATION OF SEPARATELY EXCITED DC MOTOR
excited dc motor is excited by a field current of if and an
flows in the circuit, the motor develops a back EMF and a torque to ba
torque at a particular speed. The field current if is independent of the armature current
is much less than if.
FIELD AND ARMATURE EQUATIONS
(3)
, Rf and Lf are the field resistor and inductor, respectively.
(4)
are the armature resistor and inductance respectively.
The motor back emf, which is also known as speed voltage, is expressed as:
(5)
constant (in V/A-rad/sec and ω is the motor speed (in rad/sec).
lectrical Engineering and Technology (IJEET), ISSN 0976 –
April (2013), © IAEME
and an armature
flows in the circuit, the motor develops a back EMF and a torque to balance the load
torque at a particular speed. The field current if is independent of the armature current ia.. Each
in rad/sec).

C. BASIC TORQUE EQUATION
The torque developed by the motor is:
Td = Kt if ia
where, (Kt=Kv) is the torque constant.(in V/A
For normal operation, the developed torque must be equa
inertia, i.e.
dω
Td = J + Bω + TL
dt
Where, B: viscous friction constant, (
: load torque (N.m)
J: inertia of the motor (kg.m
D. STEADY-STATE TORQUE AND SPEED
The motor speed can be easily derived:
ω = (Va - IaRa)/KvIf
If Ra is a small value (which is usual), or when the m
ω = Va /KvIf
That is if the field current is kept constant, the motor speed depends only on the supply voltage.
The developed torque is:
Td = Kt If Ia = Bω + TL
The required power is:
Pd= Tdω
E. TORQUE AND SPEED CONTROL
An important fact can be deduced for steady
current, or flux (If) the torque demand can be satisfied by varying the armature current
motor speed can be controlled by controlling
F. VARIABLE SPEED OPERATION
Fig. 3(a): Torque Vs Speed Characteristic
233
BASIC TORQUE EQUATION
The torque developed by the motor is:
a (6)
) is the torque constant.(in V/A-rad/s)
For normal operation, the developed torque must be equal to the load torque plus the friction and
(7)
, (N.m/rad/s)
J: inertia of the motor (kg.m2)
STATE TORQUE AND SPEED
The motor speed can be easily derived:
(8)
If Ra is a small value (which is usual), or when the motor is lightly loaded, i.e. Ia is small,
(9)
(10)
(11)
TORQUE AND SPEED CONTROL
deduced for steady-state operation of DC motor. For a fixed field
the torque demand can be satisfied by varying the armature current
controlling Va (voltage control) or controlling Vf (field control).
VARIABLE SPEED OPERATION
Torque Vs Speed Characteristic for Different Armature Voltages
l to the load torque plus the friction and
otor is lightly loaded, i.e. Ia is small,
For a fixed field
the torque demand can be satisfied by varying the armature current Ia. The
(field control).
Different Armature Voltages

234
Family of steady state torque speed curves for a range of armature voltage can be drawn as above. The
speed of DC motor can simply be set by applying the correct voltage. The speed variation from no
load to full load (rated) can be quite small. It depends on the armature resistance.
G. BASE SPEED AND FIELD-WEAKENING
Fig. 3(b): Torque Vs Speed and Power Vs Speed Characteristic of Separately Excited DC Motor
The motor speed can be varied by-
(a) Controlling the armature voltage Vୟ, known as voltage control;
(b) Controlling the field current I୤, known as field control; and
(c) Torque demand, which corresponds to an armature current Iୟ, for a fixed field current I୤.
The speed corresponds to the rated armature voltage, rated field current and rated armature current
which is known as the rated (or base) speed. In practice, for a speed less than the base speed, the
armature current and field currents are maintained constant to meet the torque demand, and the
armature voltage Vୟ is varied to control the speed. For speed higher than the base speed, the armature
voltage is maintained at the rated value and the field current is varied to control the speed. However,
the power developed by the motor (power = torque * speed) remains constant.
Base speed (Wୠୟୱୣ)
-The speed which correspond to the rated Vୟ , rated Iୟ and rated I୤ .
Constant torque region (W< Wୠୟୱୣ)
-Ia and If are maintained constant to met torque demand. Vୟ is varied to control the speed as power
increases with speed.
Constant power region (W> Wୠୟୱୣ)
-Vୟ is maintained at the rated value and If is reduced to increase speed. However the power
developed by the motor (= torque x speed) remains constant. This phenomenon is known as Field
weakening.
Fig 3(c): Typical Operating Regions of Separately Excited DC Machines

IV. DESIGN OF CONTROLLER
Three types of controllers were used
involves the design of three types of controller
1. Conventional PI Controller
2. Fuzzy Controller
3. ANFIS Controller
A. DESIGN OF PI CONTROLLER
1. DESIGN CURRENT CONTROLLER
Fig4: Block diagram for d
KtKp(1+Tis)*( Ra
Ia Tis(1+sTa)
=
Iaref KtKp(1+Tis)*(Ra)
Tis(1+sTa)
Here, (Current Controller Para
such that it cancels the largest time constant in t
of the system in 7.2.and, the response
Ti=Ta
Now, putting the value in equation
Ia KtKp/RasTa
=
Iaref K1KtKp/RaTa
s(1+T1s)
KtKp
Let Ko =
RaTa
235
CONTROLLER
Three types of controllers were used and the result was analyzed. Design of Controller
involves the design of three types of controller
Conventional PI Controller
DESIGN OF PI CONTROLLER
CURRENT CONTROLLER
Block diagram for design of Current Controller
)
(12)
K1
1+T1s
(Current Controller Parameter) can be varied as when required. should be chosen
largest time constant in the transfer function in order to reduce order
of the system in 7.2.and, the response will be much faster. Assuming
Now, putting the value in equation (12) we have
(13)
Design of Controller
should be chosen
he transfer function in order to reduce order

236
So,
୍౗
୍౗౨౛౜
= I୅=
୏౥/ୱ
ଵା୏౥
ేభ
౩(భశ ౐భ౩)
I୅=
(ଵା ୘భୱ)୏౥
ୱ²୘భ ା ୱା୏౥୏భ
(14)
Therefore, the characteristic equation of the above equation is given as
s²Tଵ + s + K୭Kଵ =0
s² +
ୱ
୘భ
+
୏౥୏భ
୘భ
=0
s² + 2€ ω + ω ²=0; ω =ට
୏౥୏భ
୘భ
€=1/(2Tଵ )=
ଵ
ଶඥ୏౥୏భ୘భ
For a second order system value of €=0.707 to have a proper response.
0.707=
ଵ
ଶඥ୏౥୏భ୘భ
K୭Kଵ =1/2Tଵ
୏౪୏౦୏భ୘భ
ୖ౗୘౗
=
ଵ
ଶ
(15)
K୮ =
ୖ౗୘౗
ଶ୏భ୘భ ୏౪
(16)
From Eq.14 we have
I୅=
ଵ
ଶ୏భ୘భ
‫כ‬
(ଵା ୘భୱ)
ୱ²୘భ ା ୱା୏౥୏భ)
=
(ଵା ୘భୱ)/୏భ
ୱ²୘²భ ା ୱ୘భ ାଵ
(17)
The zero in the above equation may result in an overshoot. Therefore, we will use a time lag
filter to cancel its effect. The current loop time constant is much higher than filter time
constant. For a small delay we can write
(1 + Tଵs)I୅ =
భశ ౐భ౩
ేభ
ୱమ୘²భ ା ୱ୘భ ାଵ
(18)
I୅=
భ
ేభ
ୱమ୘²భ ା ୱ୘భ ାଵ
(19)
Neglecting s² term we have
I୅=
భ
ేభ
ଵାଶ ୱ୘భ
(20)
This equation is used as a response for the speed controller.

237
2. DESIGN OF SPEED CONTROLLER
Fig5: Block diagram for design of Speed Controller
ω(s)/ሼω(s)(ref) = (Kn/K2)(Ra/KmTmTn)(1 + TnS/(1 + 2T2S)S²)/ሼ1 + (KnRa/K2KmTmTn)(1 +
TnS/(1 + 2T2S)S²)(K1/(1 + T1S))ሽ (21)
Here, we have the option to Tn such that it cancels the largest time constant of the transfer function
So, Tn=2T2
Hence, equation 21 will be written as:
ω(s)/ω(s)(ref. ) = (KnRa/K2KmTmTn)(1 + T1S)/ሼK2KmTnS2(1 + T1S) + KnRaK1ሽ (22)
Ideally, ω(s) =1/S (S²+αs+β)
The damping constant is zero in above transfer function because of absence of S term, which results in
oscillatory and unstable system. To optimize this we must get transfer function whose gain is close to
unity
Then using Modulus og Hugging method and deducing the above equation we finally get
߱(‫/)݂()ݏ‬ሼ߱(‫)݂݁ݎ()ݏ‬ = 1/(‫1ܭ‬ + 4ߜ‫1ܭ‬ + 8‫1ܭߜ2ݏ‬ + 8‫)1ܭߜ3ݏ‬ (23)
3. DESIGN OF FUZZY CONTROLLER
The fuzzy controller used in this scheme is a Speed Controller. The Conventional Speed PI
Controller is replaced by a Fuzzy Logic Based speed Controller for providing more reliable controller
outputs for the Speed control of The Induction Motor. The main objective of the fuzzy controller is that
the actual speed response of the induction motor must track the reference speed response The design of
a Fuzzy logic system includes the design of a rule base, the design of the member-ship functions
determination of the Linguistic values. Here, the inputs of fuzzy controllers are the error in speed and
the rate of change of this error at any time interval. The output of the fuzzy controller is the Active
Power. Here, five fuzzy sets (NB, N, Z, P, and PB) are adopted for each input and output variables.
The Character NB, N Z, P, PB represents Negative big, Negative, Zero, Positive, Positive Big. The
membership functions of the two input variables and the one output variable has normalized universe
of discourse over the interval [- 1, 1].For the implementation of FLC, firstly, the universe of discourse
of input and output variables of FLC are determined. In practice, each universe is restricted to an
interval that is related to the maximal and minimal possible values of the respective variables. That is
to the operating range of the variable. The universe of discourse of the input and output variables of the
Mamdani type (PI like) FLC can be determined as-
The universe of the error is defined by the maximal and minimal values of the variables. It {emin,
emax] is the interval where:
݁௠௔௫ = ܹ௠௔௫ െ ܻ௠௜௡
݁௠௜௡ = ܹ௠௜௡ െ ܻ௠௔௫

238
Analogously the change in error and the change of the output have operating ranges between
[∆݁௠௜௡,∆݁௠௔௫] and [∆‫ݑ‬௠௜௡,∆‫ݑ‬௠௔௫].
Where,
` ∆݁௠௔௫ = ݁௠௔௫ െ ݁௠௜௡
∆݁௠௜௡ = ݁௠௜௡ െ ݁௠௔௫
∆‫ݑ‬௠௔௫ = ‫ݑ‬௠௔௫ െ ‫ݑ‬௠௜௡
∆‫ݑ‬௠௜௡ = ‫ݑ‬௠௜௡ െ ‫ݑ‬௠௔௫
The operating ranges are defined with respect to the external values of the relevant variables. They
can be further adjusted by taking into account the dynamics of the controlled systems and the
sampling intervals.
For simplification and unification of the design of the FLC and its computer implementation,
however it is more convenient to operate with normalizes universe of discourse of the input and
output variables of the FLC. The normalized universes are well defined domains; the fuzzy values
of input and output variables are fuzzy subsets of these domains. In general, the normalized
universes can be identical to the real operating ranges of the variables, but in most applications
they coincide with the closed interval [-1 1].Otherwise ,scaling of both input and output variables
are done in order to bring the values within prescribed limit.
The Rule Table is formulated based on which the Fuzzy Controller is designed.
Table:1 Rule base for speed controller
4. DESIGN OF ANFIS CONTROLLER
Steps Involved in the making of the ANFIS Controller
Step1: Get the Error and Change in Error values from the previous model and save it in workspace
and finally define these values in a matrix in the M-file of Matlab.
Step2: Run the matrix file.
Step3: Open the ANFIS editor.
Step4: Load data from workspace in the ANFIS editor.
Step5:Generate FIS using Grid Partition. Here, the number of Member Functions and type of
Member Functions are taken.
Step6: Train the data using training FIS. Here the Error tolerance and epochs are also given.
Step7: The data is trained using Train FIS.
Step8: Step2 to 7 are performed using Checking Data.
Step9: The file is saved in both workspace and matlab-file by exporting it.
Step10: The Simulink model for ANFIS is opened and the controller is named after the name of
the file saved in Step9.
The ANFIS Speed Controller is obtained using the above steps.

239
V. SIMULATION RESULTS AND DISCUSSIONS
The graph responses of the Fuzzy and ANFIS controllers has been compared with the.
conventional PI controller. With the implementation of AI techniques (Fuzzy ANFIS), the
response shows that there is much flexibly with the variation of load found as compared to
conventional model. In all the responses it has been found that the actual speed of the DC
motor is as par with the reference speed of the motor. With Conventional PI speed controller
the actual speed of the motor is tracking the reference speed of the motor up to the rated
speed and even beyond it. But with Fuzzy ANFIS Controller the actual speed of the motor
is tracking the reference speed of the motor upto the rated speed and when the motor is
overloaded the responses falls and error goes on increasing concluding that the motors fails to
start or the motor stops. Thus the AI technique based controllers provides much better and
precise control of the DC motor.
FIG 6:-Block Representation of Motor Model with Fuzzy PI Controller
Fig 7:-Block Representation of Motor Model with ANFIS PI Controller

240
Appendix
Table:2
I. Performance of DC motor using PI speed Controller
It is observed from the responses that the actual speed of the DC motor tracks the reference
speed of the motor up to the rated speed of the motor (55rpm). Beyond the rated speed the PI
controller has limitations in controlling the speed of the dc motor.
Fig 8: Speed Responses of a Separately Excited dc Motor with Step Source as Input Using PI
Controller
Fig 9: Speed Responses of a Separately Excited dc Motor with Ramp Source as Input Using
PI Controller
0 0.5 1 1.5 2 2.5 3 3.5 4 4.5 5
-20
0
20
40
60
Reference Speed
Time in Sec
Speedinrpm
0 0.5 1 1.5 2 2.5 3 3.5 4 4.5 5
-20
0
20
40
60
Actual Speed
Time in Sec
Speedinrpm
0 0.5 1 1.5 2 2.5 3 3.5 4 4.5 5
-20
0
20
40
60
Error Speed
Time in Sec
Speedinrpm
0 0.5 1 1.5 2 2.5 3 3.5 4 4.5 5
0
20
40
60
Reference Speed
Time in Sec
Speedinrpm
0 0.5 1 1.5 2 2.5 3 3.5 4 4.5 5
0
20
40
60
ActualSpeed
Time in Sec
Speedinrpm
0 0.5 1 1.5 2 2.5 3 3.5 4 4.5 5
-0.5
0
0.5
1
Error Speed
Time in Sec
Speedinrpm

241
II.Performance of DC motor using Fuzzy speed Controller
A. With motor running up to rated speed
Fig 9: Speed Responses of a Separately Excited dc Motor with Step Source as Input with
Rated Load Using Fuzzy Controller
Fig10: Speed Responses of a Separately Excited dc Motor with Ramp Source as Input with
Rated Load Using Fuzzy Controller
0 0.5 1 1.5 2 2.5 3 3.5 4 4.5 5
0
20
40
60
ReferenceSpeed
TimeinSec
Speedinrpm
0 0.5 1 1.5 2 2.5 3 3.5 4 4.5 5
0
20
40
60
ActualSpeed
TimeinSec
Speedinrpm
0 0.5 1 1.5 2 2.5 3 3.5 4 4.5 5
0
20
40
60
ErrorSpeed
TimeinSec
Speedinrpm
0 0.5 1 1.5 2 2.5 3 3.5 4 4.5 5
0
20
40
60
ReferenceSpeed
TimeinSec
Speedinrpm
0 0.5 1 1.5 2 2.5 3 3.5 4 4.5 5
0
20
40
60
ActualSpeed
TimeinSec
Speedinrpm
0 0.5 1 1.5 2 2.5 3 3.5 4 4.5 5
-0.5
0
0.5
1
ErrorSpeed
TimeinSec
Speedinrpm

242
B. With motor running at overloaded condition
Over Loading Condition Using Fuzzy Controller
Fig 12: Speed Responses of a Separately Excited dc Motor with Ramp Source as Input with
Over Loading Condition
III. Performance of DC motor using ANFIS based speed Controller
A. With motor running up to rated speed
Rated Load Using ANFIS Controller
0 0.5 1 1.5 2 2.5 3 3.5 4 4.5 5
0
20
40
60
Reference Speed
Time in Sec
Speedinrpm
0 0.5 1 1.5 2 2.5 3 3.5 4 4.5 5
-400
-200
0
Actual Speed
Time in Sec
Speedinrpm
0 0.5 1 1.5 2 2.5 3 3.5 4 4.5 5
0
100
200
300
400
500
Error Speed
Time in Sec
Speedinrpm
0 0.5 1 1.5 2 2.5 3 3.5 4 4.5 5
0
50
100
Reference Speed
Time in Sec
Speedinrpm
0 0.5 1 1.5 2 2.5 3 3.5 4 4.5 5
-400
-200
0
Actual Speed
Time in Sec
Speedinrpm
0 0.5 1 1.5 2 2.5 3 3.5 4 4.5 5
0
100
200
300
Error Speed
Time in Sec
Speedinrpm
0 0.5 1 1.5 2 2.5 3 3.5 4 4.5 5
0
20
40
60
Time in Sec
Speedinrpm
0 0.5 1 1.5 2 2.5 3 3.5 4 4.5 5
0
20
40
60
Time in Sec
Speedinrpm
0 0.5 1 1.5 2 2.5 3 3.5 4 4.5 5
0
20
40
60
Time in Sec
Speedinrpm
Actual Speed
Error Speed
Reference Speed

243
Rated Load Using ANFIS Controller
B. With motor running at overloaded condition
Over Loading Condition Using ANFIS Controller
Over Loading Condition Using ANFIS Controller .
0 0.5 1 1.5 2 2.5 3 3.5 4 4.5 5
0
20
40
60
Reference Speed
Time in Sec
Speedinrpm
0 0.5 1 1.5 2 2.5 3 3.5 4 4.5 5
0
20
40
60
ActualSpeed
Time in Sec
Speedinrpm
0 0.5 1 1.5 2 2.5 3 3.5 4 4.5 5
0
20
40
60
Error Speed
Time in Sec
Speedinrpm
0 0.5 1 1.5 2 2.5 3 3.5 4 4.5 5
0
20
40
60
Reference Speed
Time in Sec
Speedinrpm
0 0.5 1 1.5 2 2.5 3 3.5 4 4.5 5
-60
-40
-20
0
Actual Speed
Time in Sec
Speedinrpm
0 0.5 1 1.5 2 2.5 3 3.5 4 4.5 5
0
50
100
ErrorSpeed
Time in Sec
Speedinrpm
0 0.5 1 1.5 2 2.5 3 3.5 4 4.5 5
0
20
40
60
Reference Speed
Time in Sec
Speedinrpm
0 0.5 1 1.5 2 2.5 3 3.5 4 4.5 5
-200
-100
0
ActualSpeed
Time in Sec
Speedinrpm
0 0.5 1 1.5 2 2.5 3 3.5 4 4.5
0
100
200
ErrorSpeed
Time in Sec
Speedinrpm

244
VI.CONCLUSION
In this paper the speed of a dc motor has been done using three different types of
Controllers viz Speed PI controller, Fuzzy logic based controller and ANFIS based controller.
The responses of the motor with three different types of controllers are simulated and studied
and compared with step and ramp responses. With varying load responses it is observed that
the AI technique based controllers’ gives a flexible and precise control of speed both on
normal loaded and overloaded condition as compared to the conventional PI controller.
REFERENCES
[1].Waleed I. Hameed1 and Khearia A. Mohamad2” Speed control of separately excited dc
motor using fuzzy neural model reference controller” International Journal of Instrumentation
and Control Systems (IJICS) Vol.2, No.4, October 2012 PP 27-39.
[2] Dr.P.S Bimbhra “Power Electronics”,Khanna Publishers.
[3]Ronald R Yager, Dimitar P Filev, “Essentials of Fuzzy Modeling and Control “Wiley
Interscience Publications.
[4]Jun Yan, Michael Ryan, James Power “Using Fuzzy
Logic towards Intelligent systems”
[5]Singari.v.s.r Pavankumar, Sande.krishnaveni, Y.B.Venugopal, Y.S.Kishore Babu, “A
Neuro- Fuzzy Based Speed Control of Separately Excited DC Motor”, IEEE Transactions on
Computational Intelligence and Communication Networks, pp. 93-98, 2010.
[6] Basma A. Omar, Amira Y. Haikal, Fayz F. Areed, “An Adaptive Neuro-Fuzzy Speed
Controller for a Separately excited DC Motor”, International Journal of Computer
Applications, pp. 29-37, Vol. 39 No.9, February 2012.
[7] Vandana Jha, Dr. Pankaj Rai and Dibya Bharti, “Modelling and Analysis of Dc-Dc
Converter Using Simulink for Dc Motor Control”, International Journal of Electrical
Engineering Technology (IJEET), Volume 3, Issue 2, 2012, pp. 58 - 68, ISSN Print : 0976-
6545, ISSN Online: 0976-6553.
[8] 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.
BIBLIOGRAPHY
Debirupa Hore was born in Guwahati Assam India on April 19th
1983.She
received her B.E Degree in Electrical Engineering from Assam Engineering
College Guwahati in 2006 and M.Tech in Energy and Power Systems in 2010
from NIT Silchar. She worked in GIMT Guwahati for 5 years as Assistant
Professor. Currently she is working as an Assistant Professor in Electrical
Engineering Department in KJ Educational Institutes, KJCOEMR, Pune
(Maharashtra).Her research areas of interest includes Power Systems, AI
Techniques, Power Electronics and Drives etc.

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