IRJET- Design of Micro Controller based Speed Control of DC Motor using Pi Controller

International Research Journal of Engineering and Technology (IRJET) e-ISSN: 2395-0056
Volume: 06 Issue: 04 | Apr 2019 www.irjet.net p-ISSN: 2395-0072
© 2019, IRJET | Impact Factor value: 7.211 | ISO 9001:2008 Certified Journal | Page 2098
DESIGN OF MICRO CONTROLLER BASED SPEED CONTROL OF DC
MOTOR USING PI CONTROLLER
C. Thiruvengatam1, K. Sanjeevikumar2, S. Karthick3
1P.G Scholar, Department of EEE, The Kavery Engineering College, Salem
2Assistant Professor, Department of EEE, The Kavery Engineering College, Salem
3Assistant Professor, Department of EEE, Muthayammal Engineering College, Namakkal
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Abstract - The objective of this paper is to speed control of
DC motor using SEPIC converter. This paperusingsingleended
primary inductor converter (SEPIC) with speed control of DC
motor. It is used to improve the efficiency at low input voltage
and reduce the switch-voltage stress. The absence of an input
in the SEPIC converter results in less conduction losses. Lower
switch voltage stress allows utilizing a MOSFET. The
discontinuous conduction mode (DCM) operation has
advantages such as zero-current turn-on in the power
switches and simple control circuitry. Speed control of the DC
motor is done using this SEPIC converter. Converter output is
given to the input of the DC motor speed control. Today every
industry becomes automated industry. To make the industry
automation the equipment and machineries should be
controlled automatically. In this project we control the PMDC
motor automatically through controller. Sowecancontrolthe
machineries which involving this motoraccurately. Bymaking
the industrial automation wecanincreasetheproductionrate.
The desired speed is entered to microcontroller through key
board. Then controller sends the corresponding digital signal
to MOSFET control unit. In many industrial applications like
Transformer, diesel engineetc., thereis neededtomaintain the
temperature to prevent the system from damage. Here the
PMDC (Permanent Magnet DC) motor is used to drive the
cooling fan in cooling system because they offer several
advantages like no field winding, small in size, increase in
efficiency .This study includes real time temperature control
using a PI controller. The terminal voltage of the motor is
controlled by using chopper, here MOSFET is used as a
switching device in which the on and off time depends on the
temperature variation. PI controller and PWM technique are
used to control the speed which is described. The temperature
variation and speed of the motor can be monitored in LCD
display. The power saving can be done by automation in the
speed control of the motor
Key Words: Single ended primary inductor converter
(SEPIC), Permanent Magnet DC motor, Metal oxide filed
effect transistor (MOSFET), switch-voltage stress, Pulse
width modulation (PWM).
1. INTRODUCTION
Direct Current motors are one of the motor types
rapidly gaining popularity. DC motors are used in industries
such as Appliances, Automotive, Aerospace, Consumer,
Medical, Industrial, Automation, Equipment and
Instrumentation. DC motors have many advantages over
brushed DC motors and induction motors. A few of theseare
Better speed versus torque characteristics, High dynamic
response, High efficiency, Long operating life, Noiseless
operation, Higher speed ranges. In addition to that the ratio
of torque delivered to the size of the motor is higher making
it useful in applications where space and weight are critical
factors.
1.1 Block Diagram
Fig-1: Block diagram of micro controller based speed
control of dc motor using pi controller
In above the fig-1 is the Block diagramofmicrocontroller
based speed control of dc motorusingpicontroller,Itconsist
of single ended primary inductor converter (SEPIC) with
speed control of DC motor, PI controller, speed sensor,
MOSFET driver circuit, PWM and LCD display.
1.2 Single-Ended Primary-Inductor Converter
Single-ended primary-inductor converter (SEPIC) is a
type of DC-DC converter allowing the electrical potential
(voltage) at its output to be greaterthan,lessthan,orequalto
that at its input; the output of the SEPIC is controlled by the
duty cycle of the control transistor. A SEPIC is essentially a
boost converter followed by a buck-boost converter,
therefore it is similar to a traditional buck boost converter,
but has advantagesofhavingnon-invertedoutput(theoutput
has the same voltage polarity as the input), using a series
capacitor to couple energy from the input to the output (and
thus can respond more gracefully to a short circuit output),

and being capable of true shutdown: when the switch is
turned off, its output drops to 0 V, following a fairly hefty
transient dump of charge. SEPICs areusefulinapplicationsin
which a battery voltage can be above and below that of the
regulator’s intended output. For example,asinglelithiumion
battery typically discharges from 4.2 volts to 3 volts; if other
components require 3.3 volts, then the SEPIC would be
effective.
Fig-2: Single-ended primary-inductor converter
In above Fig-2 is Single-ended primary-inductor
converter. The SEPIC exchanges energy between the
capacitors and inductors in ordertoconvertfromonevoltage
to another. The amount of energy exchanged is controlled by
switch S1, which is typically a transistor such as a MOSFET;
MOSFETs offer much higher input impedance and lower
voltage drop than bipolar junction transistors (BJTs), and do
not require biasing resistors as MOSFET switching is
controlled by differences in voltage rather than a current, as
with BJTs).
Continuous mode
A SEPIC is said to be in continuous-conduction mode in
fig-3 (“continuous mode”) if the currentthroughtheinductor
L1 never falls to zero. During a SEPIC’s steady-state
operation, the average voltage across capacitor C1 (VC₁) is
equal to the input voltage (Vᵢ). Because capacitor C1 blocks
direct current (DC), the averagecurrentacrossit(IC₁)iszero,
making inductor L2 the only source of load Current.
Therefore, the average current through inductor L2 (IL₂) is
the sameas the average loadcurrent and hence independent
of the input voltage. Looking at average voltages, the
following can be written: VIN = VL1 + VC1 + VL2 because the
average voltage of VC₁ is equal to VIN, VL₁ = −VL₂. For this
reason, the two inductors can be wound on the same core.
Since the voltages are the same in magnitude, their effects of
the mutual inductance will be zero, assuming the polarity of
the windings is correct. Also, since the voltages are the same
in magnitude, the ripple currents from the two inductorswill
be equal in magnitude.
The average currents can be summed as follows: ID1 =
IL1+ IL2 When switch S1 is turned on, current IL₁ increases
and the current IL₂ increases in the negative direction.
(Mathematically, it decreases due to arrow direction.) The
energy to increase the current IL₁ comes from the input
source. Since S1 isa shortwhileclosed,andtheinstantaneous
voltage VC₁ is approximately VIN, the voltage VL₂ is
approximately −VIN. Therefore, the capacitor C1suppliesthe
energy to increase the magnitude of the current in IL₂ and
thus increase the energy stored in L2. The easiest way to
visualize this is to consider the bias voltages of thecircuitina
D.C. state, then close S1.
Fig-3: Continuous mode Single-ended primary-inductor
converter
When switch S1 is turned off,the current IC₁ becomesthe
same as the current IL₁, since inductors do not allow
instantaneous changes in current. The current IL₂ will
continue in the negative direction, in fact it never reverses
direction. It can be seen from the diagram that a negative IL₂
will add to the current IL₁ to increasethecurrentdeliveredto
the load. Using Kirchhoff’s Current Law, it can be shown that
ID₁ = IC₁ - IL₂. It can then be concluded, that while S1 is off,
power is delivered to the load from both L2 and L1. C1,
however is being charged byL1 during this off cycle, and will
in turn recharge L2 during the on cycle.
Because the potential (voltage) across capacitor C1 may
reverse direction every cycle, a non-polarized capacitor
should be used. However, apolarizedtantalumorelectrolytic
capacitor may beusedinsomecases,[1]becausethepotential
(voltage) across capacitor C1 will not change unless the
switch isclosedlong enoughforahalfcycleofresonancewith
inductor L2, and by this timethe current in inductorL1could
be quite large. The capacitor CIN is required to reduce the
effects of the parasitic inductance and internal resistance of
the power supply. The boost/buck capabilities of the SEPIC
are possible because of capacitor C1 and inductor L2.
Inductor L1and switch S1createa standard boostconverter,
which generates a voltage (VS₁) that is higher than VIN,
whose magnitude is determined by the duty cycle of the
switch S1. Since the average voltage across C1 is VIN, the
output voltage (VO) is VS₁ - VIN. If VS₁islessthandoubleVIN,
then the output voltage will be less than the input voltage. If
VS₁ is greater than double VIN, then the output voltage will
be greater than the input voltage.
1.3 Simulation diagram and results:
Fig-4: Simulation diagram of micro controller based
speed control of dc motor using pi controller

Fig-5: Voltage output waveform
Fig-6: Speed output waveform
3. CONCLUSION
The progress in science & technology is a non-stop
process. New things and new technologyare being invented.
As the technology grows day by day, we can imagine about
the future in which thing we may occupy every place. The
proposed system based on Atmel microcontroller is found to
be more compact, user friendly and less complex, which can
readily be used in order to perform. Several tedious and
repetitive tasks. Though it isdesigned keeping in mind about
the need forindustry, itcanextendedforotherpurposessuch
ascommercial & researchapplications.Duetotheprobability
of high technology used this” SPEED CONTROL OF PMDC
MOTOR USING SEPIC CONVERTER” is fully software
controlled with less hardware circuit.Thefeature makesthis
system is the base for future systems.
REFERENCES
[1] MILL MAN J and HAWKIES C.C. “INTEGRATED
ELECTRONICS” MCGRAW HILL, 1972..
[2] ROY CHOUDHURY D, SHAIL JAIN, “ LINEAR
INTEGRATED CIRCUIT”, New Age International
Publishers, New Delhi,2000
[3] “THE 8051 MICROCONTROLLER AND EMBEDDED
SYSTEM” by Mohammad Ali Mazidi.
[4] K. Elissa, “Title of paper if known,” unpublished.
[5] S. Karthick, “Step Up DC-DC ConverterwithHighVoltage
GainUsingSwitched-InductorTechniques”International
Journal Of Innovative Research In Technology.
[6] S. Karthick, High Step-Up DC-DC Converter Based on
Voltage Multiplier Cell and Voltage-StackingTechniques
for Renewable Energy Applications International
Research Journal of Engineering and Technology.

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