Industry speed-control final

Methods of Controlling DC motors and Servo Motors
Industrial Electronics
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DEPARMTENT OF ELECTRONIC ENGINEERING
FACULTY OF INFORMATION AND COMMUNICATION TEHCNOLOGY
BALOCHISTAN UNIVERSITY OF INFORMATION TECHNOLOGY ENGINEERING AND MANAGEMENT SCIENCES

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NAME DESIGNATION DEPARTMENT
ENGR .JUNAID ASSISTANT PROFESSOR DEPARMTENT OF ELECTRONIC ENGINEERING
NAME DESIGNATION ROLE DEPARTMENT
MUHAMMAD SAMAD KHAN UG-STUDENT 23846 DEPARMTENT OF ELECTRONIC ENGINEERING
HUMNA ZAHID UG-STUDENT 25308 DEPARMTENT OF ELECTRONIC ENGINEERING
TALALAHMED KAKAR UG-STUDENT 25149 DEPARMTENT OF ELECTRONIC ENGINEERING
MUHAMMAD WASIM UG-STUDENT 25367 DEPARMTENT OF ELECTRONIC ENGINEERING

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SEQUENCE OF PRESENTATION
SR. NO. SECTION TITLE
1. Motivation
2. Introduction
3. Methodology
a. Methods of controlling DC motors.
b. Methods of controlling servo motors.
4. Results.
5. References.

1. Motivation .
 Energy conservation and control power are two main important factors for
adjustable speed.
 Power saving can be achieved by controlling speed of pumps, fans,
motors, etc. power supply is very important to operate direct current (dc)
motor.
 In various applications, Accurate, precise and controlled angular
movements plays vital role
 Industrial demands are increasing day by day automation provide best
quality products, raise in yield and cost reduction automation is one of the
best application of controlling speed of motor.
 In vehicle industries, robots performing welding, coloring etc. must have
precise and accurate angular motions
 Power supply and speed have direct relation with each other if we don’t
know how to control the speed of motor it might create severe problems.
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2. Introduction
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Dc motors [1,4]
 converts direct current into mechanical energy.
 it consist of field winding, commutator, brushes, poles, stator, rotor
and yoke. construction of dc motor
Principle of dc motor.
 Dc motor work on the principle of electromagnetic induction.
 States that when a current carrying conductor is placed in a
magnetic field, it experiences a mechanical force.

3. Methodology .
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a. Methods for controlling speed of DC motor.
The speed of a DC motor can be controlled in four different ways.
 Flux control method.
 Armature control method.
 Voltage control method.
 Pulse width modulation.

I. Flux control method.[2]
 Speed is controlled via controlling the flux generated by field
winding
 Since flux generates due to flow of current so current through
winding is controlled to control the speed
 speed of the motor is inversely proportional to the flux means by
increasing flux speed decreases
 Current is controlled via introducing potentio meter in circuitry
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II. Armature control method[2]
 By using this method we can control the speed of
motor by controlling armature resistance.
 As we know that speed is directly proportional to
the armature current which can be proved by
equation 1.
𝑵 = 𝑲
𝑽 – 𝑰𝒂𝑹𝒂
ø
……….(1)
 If we add resistance in series with the armature just
like we adding resistance in flux control method
,Ia decreases and, hence, the speed also decreases.
Greater the resistance in series with the armature,
greater the decrease in speed.
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III. Voltage control method[2]
 As compared to flux and armature control method this method is best
because these 2 methods cannot provide speed control in desirable range.
 Flux control method affects commutator and armature current gives high
power loss.
 In voltage control method we control the voltage for controlling speed of
motor.
a. Multiple voltage control.
 In this method shunt field is connected to a fixed voltage and armature is
supplied with different voltages. Voltage across armature is changed with
the help of a suitable switchgear.
 The speed is approximately proportional to the voltage across the armature.
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b. Ward-Leonard method.
 We use this system where sensitive speed control of motors
are required.
 M2 is the motor whose speed control is required
 M1 may be any AC motor or dc motor with constant speed.
 G is a generator directly coupled to M1.
 In this method the output of the generator is the input of
motor whose speed is to be controlled.
 The output voltage of the generator G can be varied from zero
to its maximum value by means of its field regulator
 The armature voltage of the motor M2 is varied
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IV. Pulse width modulation PWM[3]
 The technique that is used to control the power deliver across
electrical devices.
 In PWM power can be controlled across load by changing duty
cycle of the signal.
 Duty cycle is define as the proportion of on and off time during
one cycle.
 Off time (Toff) and ON time (Ton) are shown in figure 5.
Formulae for calculating duty cycle is
𝐷𝑢𝑡𝑦 𝐶𝑦𝑐𝑙𝑒 =
𝑇𝑜𝑛
𝐶𝑦𝑐𝑙𝑒
𝑥 %
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4. Results and discussion.
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Schematic of PWM, Simulation and their Results.

b. Servo Motor[5]
Introduction.
Servo motor is combination of 4 parts
 DC motor
 Feedback system (usually a potentiometer to sense the position of
motor shaft)
 Gear configuration ( controls movement of the shaft of DC motor)
 Control circuit (usually a Comparator)
• Servo motor used to attain the maximum precision and accuracy of
angular motion or to perform repetitive operations
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Working[5]
 The entire process operates on Pulse Width Modulation
(PWM), technique used to control devices via variation
of duty cycle
 Feedback (actual output) from potentiometer is
compared with desired output via comparator which
yields pulses with different duty cycle, percentage ratio
of on time by total pulse time, applied to DC motor.
 Gear system controls the movement of Shaft maintains
its position on desired output
 Block diagram of servo motor is given in following
figure7.
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Controlling Speed of Servo motor by using PWM[6]
 Angular position of servo motor can be controlled by
using pulse width modulation.
 Interconnections in servo motor driver are shown in
block diagram.
 For controlling angular position of motor 1st we have
to generate PWM signal, which can be generated by
the PWM module of microcontroller or with timers.
 Now, we also need to tell the microcontroller how
much it has to rotate. For this purpose, we can use a
simple potentiometer
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Conclusion.
We have various method for controlling speed of motor like
flux control method, armature control, voltage control and pulse
width modulation .amongst all these method, the best is PWM
because it consumes less power ,easy to implement, easy to
program and we get accurate results.
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References
1. [1]DC Motor or Direct Current Motor | Electrical4u", Electrical4u.com, 2016. [Online]. Available:
http://www.electrical4u.com/dc-motor-or-direct-current-motor/. [Accessed: 29- Nov- 2016].
2. [2]T. Agarwal, "Speed Control Methods of DC Motor - Electrical Projects", Buy Electronics &
Electrical Projects in India, 2016. [Online]. Available: https://www.edgefx.in/speed-control-
methods-of-dc-motor/. [Accessed: 29- Nov- 2016].
3. [3]"What are the Best Ways to Control the Speed of DC Motor?", ElProCus - Electronic Projects
for Engineering Students, 2016. [Online]. Available: https://www.elprocus.com/what-are-the-best-
ways-to-control-the-speed-of-dc-motor/. [Accessed: 29- Nov- 2016].
4. [4]"Construction of DC Motor | Yoke Poles Armature Field Winding Commutator Brushes of DC
Motor | Electrical4u", Electrical4u.com, 2016. [Online]. Available:
http://www.electrical4u.com/construction-of-dc-motor-yoke-poles-armature-field-winding-
commutator-brushes-of-dc-motor/. [Accessed: 29- Nov- 2016].
5. [5]"Servomechanism | Theory and Working Principle of Servo Motor |
Electrical4u", Electrical4u.com, 2016. [Online]. Available: http://www.electrical4u.com/servo-
motor-servo-mechanism-theory-and-working-principle/. [Accessed: 29- Nov- 2016].
6. [6]"Servo Motor Controller or Servo Motor Driver | Electrical4u", Electrical4u.com, 2016.
[Online]. Available: http://www.electrical4u.com/servo-motor-controller-or-servo-motor-driver/.
[Accessed: 29- Nov- 2016].
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