A Project Report on Three Phase Voltage Regulation using SCR & Micro-Controller. ACKNOWLEDGEMENT Our Quest for practical knowledge led us in to the esteemed Organization Automatic Electric Co. (Lonavla), which is a hall of fame. If words are considered as symbols of approved and tokens of acknowledges, then let Words play the heralding role of expressing our gratitude. We profusely thank our director Sri. Mr. Pramod Kale and our university Coordinator Dr. D. Shaligram for their encouragement and support through out the project. We extend our heartiest thanks to our respected Project coordinator, Mrs. Preeti Salunkhe, who is always a constant source of inspiration for us and for her motivations in making this project completion. We are very thankful to our beloved guide Ms. Jyutika Nalawade, for her valuable and patient guidance throughout our endeavor. We remember With Regards and respect the assistance and encouragement given by her. We are very much indebted to our beloved parents who have given this opportunity to join in this course and are great source of encouragement for us. Above all, the GRACE OF GOD of all creations led us to complete our project successfully. Department of Electronics science, University of Pune (Sep’06-Feb’07) Page 1 of 72
72
Embed
Three Phase Voltage Regulation using SCR & Micro-Controller (Project Report)
This document is posted to help you gain knowledge. Please leave a comment to let me know what you think about it! Share it to your friends and learn new things together.
Transcript
A Project Report on Three Phase Voltage Regulation using SCR & Micro-Controller.
ACKNOWLEDGEMENT
Our Quest for practical knowledge led us in to the esteemed Organization
Automatic Electric Co. (Lonavla), which is a hall of fame. If words are considered
as symbols of approved and tokens of acknowledges, then let Words play the
heralding role of expressing our gratitude. We profusely thank our director Sri. Mr.
Pramod Kale and our university Coordinator Dr. D. Shaligram for their
encouragement and support through out the project.
We extend our heartiest thanks to our respected Project coordinator,
Mrs. Preeti Salunkhe, who is always a constant source of inspiration for us and for
her motivations in making this project completion.
We are very thankful to our beloved guide Ms. Jyutika Nalawade, for her
valuable and patient guidance throughout our endeavor. We remember With Regards
and respect the assistance and encouragement given by her. We are very much
indebted to our beloved parents who have given this opportunity to join in this
course and are great source of encouragement for us. Above all, the GRACE OF
GOD of all creations led us to complete our project successfully.
Department of Electronics science, University of Pune (Sep’06-Feb’07) Page 1 of 72
A Project Report on Three Phase Voltage Regulation using SCR & Micro-Controller.
EXECUTIVE SUMMERY
In our day to day life we use a lot many devices to satisfy our needs or to
make our life comfortable and luxurious. Every device needs a power supply, to
work on. And for the optimum functioning of the device it is necessary that the
supply should be reliable. That is, it should provide a constant voltage.
But this is not possible always. There are many reasons due to which there
is a fluctuation in the supply voltage. This change in the supply voltage may cause
the device to damage or make it work in an undesired way, which no one would
desire.
Hence the best alternative is to regulate the supply voltage. This is what we
have tried to achieve here. Our project is supply voltage regulation, using controller
and SCR.
In our project we provide the load with a constant voltage of 240 V ac., in
spite of any variation in the input voltage. The voltage regulation is achieved by
controlling the firing angle of the SCR so precisely that the load receives a constant
supply. The voltage across the load is stepped down and provided to ADC. ADC will
produce a digital signal corresponding to the input analog signal. This digital signal
from ADC is then processed by the controller and generates a firing pulse for SCR,
hence controlling the load current.
Department of Electronics science, University of Pune (Sep’06-Feb’07) Page 2 of 72
A Project Report on Three Phase Voltage Regulation using SCR & Micro-Controller.
INDEX
1. INTRODUCTION .………………………………………………. 4
2. AIM & OBJECTIVES ....………………………………………... 7
3. PROJECT PLANNING .…………………………………………. 9
4. BLOCK DIAGRAM ...………..………………………………… 12
5. BLOCK DIAGRAM DESCRIPTION .……….………………… 14
6. COMPONENT SEPECIFICATIONS .…………………………. 18
7. CIRCUIT DIAGRAM .…………………………………………. 47
8. FUNCTIONALITY .……………………………………………. 49
9. SOFTWARE FLOW CHART .…………………………………. 51
Department of Electronics science, University of Pune (Sep’06-Feb’07) Page 3 of 72
A Project Report on Three Phase Voltage Regulation using SCR & Micro-Controller.
10. RESULTS & CONCLUSION .…………………………………. 58
11. BIBLIOGRAPHY .……………………………………………... 60
CHAPTER 1
IntroductionDepartment of Electronics science, University of Pune (Sep’06-Feb’07) Page 4 of 72
A Project Report on Three Phase Voltage Regulation using SCR & Micro-Controller.
INTRODUCTION
In our day to day life we use a lot many devices to satisfy our needs or to
make our life comfortable and luxurious. Every device needs a power supply, to
work on. And for the optimum functioning of the device it is necessary that the
supply should be reliable. That is, it should provide a constant voltage.
But this is not possible always. There are many reasons due to which there
is a fluctuation in the supply voltage. This change in the supply voltage may cause
the device to damage or make it work in an undesired way, which no one will
desire.
Hence the best alternative is to regulate the supply voltage. This is what we
have tried to achieve here. Our project is supply voltage regulation, using controller
and SCR.
Department of Electronics science, University of Pune (Sep’06-Feb’07) Page 5 of 72
A Project Report on Three Phase Voltage Regulation using SCR & Micro-Controller.
Silicon Controlled Rectifiers also called Thyristors controller, employing novel
technology, which is designed to provide a price effective solution for applications
that require power, current or voltage regulation with some power factor correction
and a smother process control. Traditional phase-angle control causes lots of
harmonic current distortion on the main power supply. This in turn creates voltage
distortion which affects power quality. There is no simple accessory available for
reducing this problem.
However, when simple voltage or current regulation is required often phase-
angle control is the most cost effective solution.
Thyristors and triacs are switched on by using a gate. They automatically
switch off again when the conducted current reaches zero.
Therefore, these devices can be used in power regulators and by switching
at a predetermined position on the AC sine wave (the phase-angle) the effective
voltage can be reduced or increased. This can be used to regulate voltage or
power to a load.
Department of Electronics science, University of Pune (Sep’06-Feb’07) Page 6 of 72
A Project Report on Three Phase Voltage Regulation using SCR & Micro-Controller.
In our project we provide the load with a constant voltage of 240 V ac., in
spite of any variation in the input voltage. The voltage regulation is achieved by
controlling the firing angle of the SCR so precisely that the load receives a constant
supply. The voltage across the load is stepped down and provided to ADC. ADC will
produce a digital signal corresponding to the input analog signal. This digital signal
from ADC is then processed by the controller and generates a firing pulse for SCR,
hence controlling the load current.
Department of Electronics science, University of Pune (Sep’06-Feb’07) Page 7 of 72
A Project Report on Three Phase Voltage Regulation using SCR & Micro-Controller.
CHAPTER 2
Aim & Objective
AIM & OBJECTIVE
AIM:-
To develop a system for controlling fluctuation in the three phase Voltage
supply using SCR and Controller.
Department of Electronics science, University of Pune (Sep’06-Feb’07) Page 8 of 72
A Project Report on Three Phase Voltage Regulation using SCR & Micro-Controller.
OBJECTIVE:-
To upgrade the existing three phase analog regulatory system, to a three
phase, microcontroller based SCR drive system. So that if any fluctuation comes in
three phase voltage supply, controller will Sense that fluctuation and accordingly
give triggering pulses to the SCR to get controlled regulated output at the load.
Department of Electronics science, University of Pune (Sep’06-Feb’07) Page 9 of 72
A Project Report on Three Phase Voltage Regulation using SCR & Micro-Controller.
CHAPTER 3
Project planning
PROJECT PLANNING
Exactly what was planned in the project?
• To design hardware for voltage regulation by using SCR bridge
• To sense fluctuation in the single phase voltage supply.
Department of Electronics science, University of Pune (Sep’06-Feb’07) Page 10 of 72
A Project Report on Three Phase Voltage Regulation using SCR & Micro-Controller.
• To sense zero crossing of the input sine wave.
• To get correct firing angle of SCR for getting correct control voltage.
• To calculate the correct delay time for giving trigger pulse to SCR.
• To trigger SCR depending upon calculated data and get the regulated
output.
• To implement the same for three phase voltage supply.
What is achieved?
• We designed hardware for voltage regulation by using SCR bridge
• We sensed fluctuation in the single phase voltage supply.
• We sensed zero crossing of the input sine wave.
• We got correct firing angle of SCR for getting correct control voltage.
• We calculated the correct delay time for giving trigger pulse to SCR.
TIME SCHEDULING
S.no Schedule days
Department of Electronics science, University of Pune (Sep’06-Feb’07) Page 11 of 72
A Project Report on Three Phase Voltage Regulation using SCR & Micro-Controller.
1 Understanding project details 22 Finalizing project modules 33 Data collection 74 Selection of Microcontroller and its peripherals 45 Component search 116 Circuit Design 57 Hardware assembly 78 Hardware testing and debugging 79 Software coding (for calculating correct delay for different
angle)
2
10 Preparing look up table for different ADC values 1
11 Software coding(for voltage fluctuation) 3
12 Testing code on hardware 8
13 Project report & presentation 3
Department of Electronics science, University of Pune (Sep’06-Feb’07) Page 12 of 72
A Project Report on Three Phase Voltage Regulation using SCR & Micro-Controller.
CHAPTER 4
Block Diagram
BLOCK DIAGRAM
Department of Electronics science, University of Pune (Sep’06-Feb’07) Page 13 of 72
A Project Report on Three Phase Voltage Regulation using SCR & Micro-Controller.
Department of Electronics science, University of Pune (Sep’06-Feb’07) Page 14 of 72
POWER SUPPLY
SCR BRIDGE CKT
230V AC
ADC
MICRO--CONTROLLER
O/P
ZEROCROSSINGDETECTOR
CLOCK & RESET CKT
POTENTIAL DIVIDER
24V AC
A Project Report on Three Phase Voltage Regulation using SCR & Micro-Controller.
CHAPTER 5
Block Diagram Description
Department of Electronics science, University of Pune (Sep’06-Feb’07) Page 15 of 72
A Project Report on Three Phase Voltage Regulation using SCR & Micro-Controller.
BLOCK DIAGRAM DESCRIPTION
• POWER SUPPLY
This is the first block of our system. We have used a step-down centre tap
transformer, with the voltage rating of 240V ac as primary voltage and 24-0-24V ac
as the secondary voltage. The current rating of the transformer is 500mA.
The stepped-down ac signal is supplied to the rectifier & regulator. It consists
of a simple rectifier diode bridge network along with some filtering circuit, for
smoothing out the input signal. This filtered and rectified signal is then regulated
using a positive voltage regulator, to the desired value (say 5 V dc & 15 V dc) and
also negative voltage regulator to the desired value (say -15 V dc).For these
purpose; we are using three regulator chips.
LM7805 (+5V DC)
MC7815C (+15V DC)
L7915 (-15V DC)
The basic input requirement of the two regulators 7815 & 7915 is 23v dc. i.e.
it needs at lest this voltage to provide a constant +/-15V. This is why we have
selected the center-tap transformer of 24V dc. But the input voltage requirement of
7805 is just about 13v dc; hence we have reduced the voltage of the transformer to
13V through a resistor in series.
The input of the regulator is provided with a filter capacitor of 10uF, 50v. and
the output with 0.01uf, forming a pie filter for better signal to noise ratio.
Department of Electronics science, University of Pune (Sep’06-Feb’07) Page 16 of 72
A Project Report on Three Phase Voltage Regulation using SCR & Micro-Controller.
• ZERO CROSSING DETECTOR
This circuit is containing of OP-AMP UA 741.This is mainly used to detect
the zero crossing of the input sine wave so that we can get Synchronization.
The output of ZCD is given to the PORT pin 2.5 of the Microcontroller. Here
ZCD is used so that we can give trigger angle to the SCR at Correct time.
The op-amp in the ZCD is just a sine to square wave generator. It converts
in the input 24V ac signal to the square wave of 5 V and of the same frequency as
that of the sine wave. Op-amp UA 741 is provided with a dual supply, obtained from
the positive and negative regulators (+15V & -15V dc).
The output pin of the ZCD is provided with a rectifying diode which restricts
the negative signal from reaching the controller pin to avoid any damage to it.
• SCR BRIDGE NETWORK
This block consists of a pair of SCR & diodes. Input to the SCR Bridge circuit
is fluctuated Single phase voltage supply, which is given to anode of both the SCRs
and cathode of both the diodes. Cathode of both the SCRs and Anode of both the
diodes are provided to the load. We have assumed a resistive load of 10K ohm.
From this load resistor one voltage signal will go to the Potential divider for
feedback purpose. This will act as the input signal to the ADC.
The gate of the SCR is connected to the PORT2.0 and PORT2.1. A specific
triggering pulse is provided to the gate of the SCR of sufficient time delay so as to
keep the load voltage constant.
• POTENTIAL DIVIDER
To get controlled output we need to give feedback signal from the SCR
bridge circuit to ADC. But here feed back signal is nearer of 240V. So, we required
to step it down to the +5V.
Department of Electronics science, University of Pune (Sep’06-Feb’07) Page 17 of 72
A Project Report on Three Phase Voltage Regulation using SCR & Micro-Controller.
Because of this, here we have used potential divider network. From this
potential divider network we will get voltage signal around +5V. To obtain the
voltage of 5V ac from 240V ac we have used the network ratio of 59:1. The upper
59K resistor is fix while the lower 1K is a pot of 10k. Then after this voltage signal is
given to ADC0808.
• ANALOG TO DIGITAL CONVERTER (ADC 0808)
Here we get input from potential divider network which is around +5V. Then
this analog value is converted to digital data and is given to Microcontroller. ADC
0808 has four channels but we need only one, hence we have selected channel 0
for input. The 8 bit digital output of ADC is provided to the port 1 of controller.
• MICROCONTROLLER 89C51RD2
This block is the only decision making block, which decides whether any
fluctuation in the supply line has occurred or not. It continuously compares the
signal with the reference described in the software. If there is no change then SCR
will be fired by it at phase angle 0 deg. But if it finds some fluctuation, then it will
generate the pulse at a measured time delay to provide the firing angle of the SCR
(through gate) such that the fluctuations will be nullified, and the supply to the load
remains unaffected, in-spite the fluctuations.
Department of Electronics science, University of Pune (Sep’06-Feb’07) Page 18 of 72
A Project Report on Three Phase Voltage Regulation using SCR & Micro-Controller.
CHAPTER 6
Components Specification
Department of Electronics science, University of Pune (Sep’06-Feb’07) Page 19 of 72
A Project Report on Three Phase Voltage Regulation using SCR & Micro-Controller.
COMPONENT SPECIFICATION
• POWER SUPPLY
SPECIFICATION OF IC LM7805:-
_ 3-Terminal Regulators
_ Output Current up to 1.5 A
_ Internal Thermal-Overload Protection
_ High Power-Dissipation Capability
_ Internal Short-Circuit Current Limiting
_ Output Transistor Safe-Area Compensation
Description information
This series of fixed-voltage integrated-circuit voltage regulators is designed
for a wide range of applications. These applications include on-card regulation for
elimination of noise and distribution problems associated with single-point
regulation. Each of these regulators can deliver up to 1.5 A of output current. The
Department of Electronics science, University of Pune (Sep’06-Feb’07) Page 20 of 72
A Project Report on Three Phase Voltage Regulation using SCR & Micro-Controller.
internal current-limiting and thermal-shutdown features of these regulators
essentially make them immune to overload. In addition to use as fixed-voltage
regulators, these devices can be used with external components to obtain
adjustable output voltages and currents.
Absolute maximum ratings over virtual junction temperature range (unless
otherwise noted)
Input voltage, VI: A7824C 40 V)
All others 35 V
Operating virtual junction temperature, TJ 150C
Lead temperature 1,6 mm (1/16 inch) from case for 10 seconds 260C
Storage temperature range, Tst -65C to 150C
The LM7805 series of three terminal regulators are available with several
fixed output voltages. The voltages available allow regulators to be used in logic
systems, instrumentations, Hi-Fi and other solid state electronics equipment without
any external feedback components.
These ICs are designed as fixed voltage regulator and with adequate heat
sinking can deliver output currents in excess of 1A.The input capacitor Ci=0.33µF is
used, if regulator is located far from the power supply filter capacitor. It filters out
the effect of stray inductance of wire, ceramic or tantalum capacitor may be used.
To improve the transient response of regulator capacitor of 0.1µF is connected at
output. It utilizes common ground fir input and output and has dropout voltage (Vin
– Vo) of 2 V.
Device type with input voltages
Output voltage(V)
Output current
QuiescentCurrent(mA)
Line regulation(mV)
Load regulation(mV)
Ripple rejection(dB)
78XXC(35)
51215
1A 8 256075
50120150
807270
78LXXAC 5 100Ma 3 to 5 10 5 62
Department of Electronics science, University of Pune (Sep’06-Feb’07) Page 21 of 72
A Project Report on Three Phase Voltage Regulation using SCR & Micro-Controller.
(35) 1215
3 to53.1 to 5
2025
1012
5451
78LXXC(35)
51215
100mA 3 to 63 to 6.53.1 to 6.5
102025
51012
605249
78MXX (35)
51215
0.5A 4 to 104 to 104 to 10
50120150
100240300
787169
SPECIFICATION OF MC7815 (+15V REGULATOR)
Department of Electronics science, University of Pune (Sep’06-Feb’07) Page 22 of 72
A Project Report on Three Phase Voltage Regulation using SCR & Micro-Controller.
These voltage regulators are monolithic integrated circuits designed as
fixed–voltage regulators for a wide variety of applications including local, on–card
regulation. These regulators employ internal current limiting, thermal shutdown, and
safe–area compensation. With adequate heat sinking they can deliver output
currents in excess of 1.0 A. Although designed primarily as a fixed voltage
regulator, these devices can be used with external components to obtain adjustable
voltages and currents.
• Output Current in Excess of 1.0 A
• No External Components Required
• Internal Thermal Overload Protection
• Internal Short Circuit Current Limiting
• Output Transistor Safe–Area Compensation
• Output Voltage Offered in 2% and 4% Tolerance
• Available in Surface Mount D2PAK and Standard 3–Lead Transistor Packages
• Previous Commercial Temperature Range has been extended to a Junction
Temperature Range of –40°C to +125°C.
Department of Electronics science, University of Pune (Sep’06-Feb’07) Page 23 of 72
A Project Report on Three Phase Voltage Regulation using SCR & Micro-Controller.
Department of Electronics science, University of Pune (Sep’06-Feb’07) Page 24 of 72
A Project Report on Three Phase Voltage Regulation using SCR & Micro-Controller.