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Transcript of Three Phase Voltage Regulation using SCR & Micro-Controller (Project Report)
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
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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.
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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
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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
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A Project Report on Three Phase Voltage Regulation using SCR & Micro-Controller.
CHAPTER 4
Block Diagram
BLOCK DIAGRAM
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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
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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.
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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.
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A Project Report on Three Phase Voltage Regulation using SCR & Micro-Controller.
CHAPTER 6
Components Specification
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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.
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A Project Report on Three Phase Voltage Regulation using SCR & Micro-Controller.
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A Project Report on Three Phase Voltage Regulation using SCR & Micro-Controller.
SPECIFICATION OF L7915 (-15V REGULATOR)
• OUTPUT CURRENT UP TO 1.5A
• OUTPUT VOLTAGES OF -5; -6; -8; -12; -15; -18; -20; -24V
• THERMAL OVERLOAD PROTECTION
• SHORT CIRCUIT PROTECTION
• OUTPUT TRANSITION SOA PROTECTION
Department of Electronics science, University of Pune (Sep’06-Feb’07) Page 25 of 72
A Project Report on Three Phase Voltage Regulation using SCR & Micro-Controller.
The L7900 series of three-terminal negative regulators is available in TO-
220, TO-220FP, TO-3 and D2PAK packages and several fixed output voltages,
making it useful in a wide range of applications. These regulators can provide local
on-card regulation, eliminating the distribution problems associated with single
point regulation; furthermore, having the same voltage option as the L7800 positive
standard series, they are particularly suited for split power supplies. If adequate
heat sinking is provided, they can deliver over 1.5A output current. Although
designed primarily as fixed voltage regulators, these devices can be used with
external components to obtain adjustable voltages and currents.
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A Project Report on Three Phase Voltage Regulation using SCR & Micro-Controller.
SPECIFICATION OF 1N4007 DIODE
• Low forward voltage drop.
• High surge current capability.
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A Project Report on Three Phase Voltage Regulation using SCR & Micro-Controller.
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A Project Report on Three Phase Voltage Regulation using SCR & Micro-Controller.
• ZERO CROSSING DETECTOR
SPECIFICATION OF UA741(OP-AMP)
• LARGE INPUT VOLTAGE RANGE
• NO LATCH-UP
• HIGH GAIN
• SHORT-CIRCUIT PROTECTION
• NO FREQUENCY COMPENSATION
• SAME PIN CONFIGURATION AS THE UA709
The UA741 is a high performance monolithic operational amplifier
constructed on a single silicon chip. It is intended for a wide range of analog
applications.
-Summing amplifier
- Voltage follower
Department of Electronics science, University of Pune (Sep’06-Feb’07) Page 29 of 72
A Project Report on Three Phase Voltage Regulation using SCR & Micro-Controller.
- Integrator
- Active filter
- Function generator
The high gain and wide range of operating voltages provide superior
performances in integrator, summing amplifier and general feedback applications.
The internal compensation network (6dB/octave) insures stability in closed loop
circuits.
PIN CONNECTIONS
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A Project Report on Three Phase Voltage Regulation using SCR & Micro-Controller.
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A Project Report on Three Phase Voltage Regulation using SCR & Micro-Controller.
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A Project Report on Three Phase Voltage Regulation using SCR & Micro-Controller.
• MICROCONTROLLER
SPECIFICATION OF MICROCONTROLLER 89C51RD2
• The 89C51RB2/RC2/RD2 device contains a non-volatile 16kB/32kB/64kB
Flash
• Program memory that is both parallel programmable and serial In-System
and In-Application Programmable. In-System Programming (ISP) allows the
user to download new code while the microcontroller sits in the application.
In-Application Programming (IAP) means that the microcontroller fetches
new program code and reprograms itself while in the system. This allows for
remote programming over a modem link. A default serial loader (boot loader)
program in ROM allows serial In-System programming of the Flash memory
via the UART without the need for a loader in the Flash code. For In-
Application Programming, the user program erases and reprograms the
Flash memory by use of standard routines contained in ROM. This device
executes one machine cycle in 6 clock cycles, hence providing twice the
speed of a conventional 80C51. An OTPconfiguration bit lets the user select
conventional 12 clock timing if desired. This device is a Single-Chip 8-Bit
Microcontroller manufactured in advanced CMOS process and is a
derivative of the 80C51 microcontroller family. The instruction set is 100%
compatible with the 80C51 instruction set. The device also has four 8-bit I/O
ports, three 16-bit timer/event counters, a multi-source, four-priority-level,
nested interrupt structure, an enhanced UART and on-chip oscillator and
timing circuits. The added features of the P89C51RB2/RC2/RD2 make it a
powerful microcontroller for applications that require pulse width modulation,
high-speed I/O and up/down counting capabilities such as motor control.
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A Project Report on Three Phase Voltage Regulation using SCR & Micro-Controller.
FEATURES
• 80C51 Central Processing Unit.
• On-chip Flash Program Memory with In-System Programming (ISP) and In-
Application Programming (IAP) capability.
• Boot ROM contains low level Flash programming routines for downloading
via the UART.
• Can be programmed by the end-user application (IAP)
• 6 clocks per machine cycle operation (standard)
• 12 clocks per machine cycle operation (optional)
• Speed up to 20 MHz with 6 clock cycles per machine cycle(40 MHz
equivalent performance); up to 33 MHz with 12 clocks per machine cycle
• Fully static operation
• RAM expandable externally to 64 kB
• 4 level priority interrupt
• 8 interrupt sources
• Four 8-bit I/O ports
• Full-duplex enhanced UART
- Framing error detection
- Automatic address recognition
• Power control modes
- Clock can be stopped and resumed
- Idle mode
- Power down mode
• Programmable clock out
• Second DPTR register
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A Project Report on Three Phase Voltage Regulation using SCR & Micro-Controller.
• Asynchronous port reset
• Low EMI (inhibit ALE)
• Programmable Counter Array (PCA)
• PWM
• Capture/compare
BLOCK DIAGRAM
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A Project Report on Three Phase Voltage Regulation using SCR & Micro-Controller.
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A Project Report on Three Phase Voltage Regulation using SCR & Micro-Controller.
PIN DIAGRAM:-
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A Project Report on Three Phase Voltage Regulation using SCR & Micro-Controller.
PIN DESCRIPTION
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A Project Report on Three Phase Voltage Regulation using SCR & Micro-Controller.
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A Project Report on Three Phase Voltage Regulation using SCR & Micro-Controller.
OSCILLATOR CHARACTERISTICS
XTAL1 and XTAL2 are the input and output, respectively, of an inverting
amplifier. The pins can be configured for use as an on-chip oscillator. To drive the
device from an external clock source, XTAL1 should be driven while XTAL2 is left
unconnected. Minimum and maximum high and low times specified in the data
sheet must be observed.
This device is configured at the factory to operate using 6 clock periods per
machine cycle, referred to in this datasheet as “6 clock mode”. (This yields
performance equivalent to twice that of standard 80C51 family devices). It may be
optionally configured on commercially-available EPROM programming equipment
to operate at 12 clocks per machine cycle, referred to in this datasheet as “12 clock
mode”. Once 12 clock mode has been configured, it cannot be changed back to 6
clock mode.
RESET
A reset is accomplished by holding the RST pin high for at least two machine
cycles (12 oscillator periods in 6 clock mode, or 24 oscillator periods in 12 clock
mode), while the oscillator is running.
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A Project Report on Three Phase Voltage Regulation using SCR & Micro-Controller.
To ensure a good power-on reset, the RST pin must be high long enough to
allow the oscillator time to start up (normally a few milliseconds) plus two machine
cycles.
At power-on, the voltage on VCC and RST must come up at the same time for a
proper start-up. Ports 1, 2, and 3 will asynchronously be driven to their reset
condition when a voltage above VIH1 (min.) is applied to RESET. The value on the
EA pin is latched when RST is reasserted and has a further effect.
LOW POWER MODES
Stop Clock Mode
The static design enables the clock speed to be reduced down to 0 MHz
(stopped). When the oscillator is stopped, the RAM and Special Function Registers
retain their values. This mode allows step-by-step utilization and permits reduced
system power consumption by lowering the clock frequency down to any value. For
lowest power consumption the Power Down mode is suggested.
Idle Mode
In the idle mode (see Table 2), the CPU puts itself to sleep while all of the
on-chip peripherals stay active. The instruction to invoke the idle mode is the last
instruction executed in the normal operating mode before the idle mode is
activated. The CPU contents, the on-chip RAM, and all of the special function
registers remain intact during this mode. The idle mode can be terminated either by
any enabled interrupt (at which time the process is picked up at the interrupt
service routine and continued), or by a hardware reset which starts the processor in
the same manner as a power-on reset.
Power-Down Mode
To save even more power, a Power Down mode (see Table 2) can be
invoked by software. In this mode, the oscillator is stopped and the instruction that
invoked Power Down is the last instruction executed. The on-chip RAM and Special
Function Registers retain their values down to 2.0 V and care must be taken to
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A Project Report on Three Phase Voltage Regulation using SCR & Micro-Controller.
return VCC to the minimum specified operating voltages before the Power down
Mode is terminated.
Either a hardware reset or external interrupt can be used to exit from Power
Down. Reset redefines all the SFRs but does not change the on-chip RAM. An
external interrupt allows both the SFRs and the on-chip RAM to retain their values.
To properly terminate Power Down, the reset or external interrupt should not
be executed before VCC is restored to its normal operating level and must be held
active long enough for the oscillator to restart and stabilize (normally less than 10
ms). With an external interrupt, INT0 and INT1 must be enabled and configured as
level-sensitive. Holding the pin low restarts the oscillator but bringing the pin back
high completes the exit. Once the interrupt is serviced, the next instruction to be
executed after RETI will be the one following the instruction that put the device into
Power Down.
• SCR
SPECIFICATION OF MCR100
Introduction
PNPN devices designed for high volume, line-powered consumer applications such
as relay and lamp drivers, small motor controls, gate drivers for larger thyristors,
and sensing and detection circuits. Supplied in an inexpensive plastic TO-226AA
package which is readily adaptable for use in automatic insertion equipment.
Features
• Sensitive Gate Allows Triggering by Microcontrollers and Other Logic Circuits
• Blocking Voltage to 600 V
• ON State Current Rating of 0.8 Amperes RMS at 80°C
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A Project Report on Three Phase Voltage Regulation using SCR & Micro-Controller.
• High Surge Current Capability − 10 A
• Minimum and Maximum Values of IGT, VGT and IH Specified for Ease of
Design
• Immunity to dV/dt − 20 V/sec Minimum at 110°C
• Glass-Passivated Surface for Reliability and Uniformity
SYMBOL
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A Project Report on Three Phase Voltage Regulation using SCR & Micro-Controller.
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A Project Report on Three Phase Voltage Regulation using SCR & Micro-Controller.
Voltage Current Characteristic of SCR
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A Project Report on Three Phase Voltage Regulation using SCR & Micro-Controller.
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A Project Report on Three Phase Voltage Regulation using SCR & Micro-Controller.
• ANALOG TO DIGITAL CONVERTER
SPECIFICATION OF ADC 0808
General Description
The ADC0808 data acquisition component is a monolithic CMOS device with an
8-bit analog-to-digital converter, 8-channel multiplexer and microprocessor
compatible control logic.
The 8-bit A/D converter uses successive approximation as the conversion
technique. The converter features a high impedance chopper stabilized
comparator, a 256R voltage divider with analog switch tree and a successive
approximation register. The 8-channel multiplexer can directly access any of 8-
single-ended analog signals. The device eliminates the need for external zero and
full scale adjustments. Easy interfacing to microprocessors is provided by the
latched and decoded multiplexer address inputs and latched TTL TRI-STATEÉ
outputs. The design of the ADC0808 has been optimized by incorporating the most
desirable aspects of several A/D conversion techniques. The ADC0808 offers high
speed, high accuracy, minimal temperature dependence, excellent long-term
accuracy and repeatability, and consumes minimal power. These features make
this device ideally suited to applications from process and machine control to
consumer and automotive applications.
Features
• Easy interface to all microprocessors
• Operates ratio metrically or with 5 V dc or analog span adjusted voltage
reference.
• No zero or full-scale adjust required
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A Project Report on Three Phase Voltage Regulation using SCR & Micro-Controller.
• 8-channel multiplexer with address logic
• 0V to 5V input range with single 5V power supply
• Outputs meet TTL voltage level specifications
• Standard hermetic or molded 28-pin DIP package
• 28-pin molded chip carrier package
Key Specifications
• Resolution 8 Bits
• Total Unadjusted Error g(/2 LSB and g1 LSB
• Single Supply 5 VDC
• Low Power 15 mW
• Conversion Time 100 ms.
Absolute Maximum Ratings (Notes 1 & 2)
If Military/Aerospace specified devices are required, please contact the National
Semiconductor Sales Office/Distributors for availability and specifications.
• Supply Voltage (VCC) (Note 3) 6.5V
• Voltage at Any Pin b0.3V to (VCC+0.3V) Except Control Inputs
• Voltage at Control Inputs -0.3V to +15V
(START, OE, CLOCK, ALE, ADD A, ADD B, ADD C)
• Storage Temperature Range -65C to +150C
• Package Dissipation at TAe25C 875 mW
Lead Temp. (Soldering, 10 seconds)
• Dual-In-Line Package (plastic) 260C
• Dual-In-Line Package (ceramic) 300C
Molded Chip Carrier Package
• Vapor Phase (60 seconds) 215C
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A Project Report on Three Phase Voltage Regulation using SCR & Micro-Controller.
• Infrared (15 seconds) 220C
• ESD Susceptibility (Note 8) 400V
BLOCK DIAGRAM
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A Project Report on Three Phase Voltage Regulation using SCR & Micro-Controller.
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A Project Report on Three Phase Voltage Regulation using SCR & Micro-Controller.
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A Project Report on Three Phase Voltage Regulation using SCR & Micro-Controller.
CONNETION DIAGRAM:-
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A Project Report on Three Phase Voltage Regulation using SCR & Micro-Controller.
CHAPTER 7
Circuit Diagram
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A Project Report on Three Phase Voltage Regulation using SCR & Micro-Controller.
CIRCIUT DIAGRAM
R 7
1 k
D 8
DIO
DE
C 2
10uf
T 1
TRAN
SFO
RM
ER C
T
1 5
6
4 8
D 7
DIO
DE
2
-
+ U 8
UA7
41C
3
26
7 14 5
Q 1S C R
U 2 L M 7 8 0 5
1 3V I N V O U T
D 1 D I O D E
U 9
ADC
0808
7
1 0
1 1
1 21 6
2 2
2 32 42 5
2 62 72 8
12345
96
1 71 41 581 81 92 02 1
E O C
C L K
V C C
+ V R E F- V R E F
A L E
A D D CA D D BA D D A
I N 0I N 1I N 2I N 3I N 4I N 5I N 6I N 7
O ES T A R T
D B 0D B 1D B 2D B 3D B 4D B 5D B 6D B 7
V C C
V C C
Y 1
20 M
HZ
C 3
0.1u
f
R 21 k
1
D 4 D I O D E
+ 5 V
R 21 k
C 71 0 u f
U 6
M C 7 8 1 5 C1 3
V I N V O U T
R 6R 3
1 0 k
R 18 . 2 k
V C C
R 4
R4
+ R
5 +
R6
= 59
K
+ 1 5 v
R 5
C 6 3 0 p f
- 1 5 v
C 53 0 p f
D 6D I O D E
2 4 v D C
U 7L 7 9 1 5
2 3V I N V O U T
D 2D I O D E
D 3D I O D E C 4
0.1u
f
2 4 0 v a c
Q 2S C R
P 2 . 5C 51 0 u f
U 3
89C
51
9
1 81 9
2 93 0
3 1
12345678
2 12 22 32 42 52 62 72 8
1 01 11 21 31 41 51 61 7
3 93 83 73 63 53 43 33 2
R S T
X T A L 2X T A L 1
P S E NA L E / P R O G
E A / V P P
P 1 . 0P 1 . 1P 1 . 2P 1 . 3P 1 . 4P 1 . 5P 1 . 6P 1 . 7
P 2 . 0 / A 8P 2 . 1 / A 9
P 2 . 2 / A 1 0P 2 . 3 / A 1 1P 2 . 4 / A 1 2P 2 . 5 / A 1 3P 2 . 6 / A 1 4P 2 . 7 / A 1 5
P 3 . 0 / R X DP 3 . 1 / T X D
P 3 . 2 / I N T 0P 3 . 3 / I N T 1
P 3 . 4 / T 0P 3 . 5 / T 1
P 3 . 6 / W RP 3 . 7 / R D
P 0 . 0 / A D 0P 0 . 1 / A D 1P 0 . 2 / A D 2P 0 . 3 / A D 3P 0 . 4 / A D 4P 0 . 5 / A D 5P 0 . 6 / A D 6P 0 . 7 / A D 7
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CHAPTER 8
Functionality
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A Project Report on Three Phase Voltage Regulation using SCR & Micro-Controller.
FUNCTIONALITY
• Here, in our project we are controlling the single phase supply voltage 240V
ac by triggering the SCR from Microcontroller.
• Main purpose of our project is to get constant 240 V dc at load. To fulfill this
task we have to control the firing angle of SCR trigger pulse. And for control
purpose we have used Philips 89C52RD2 Microcontroller.
• Main parts of our circuits are SCR bridge circuit, Power supply, Zero
crossing detector, Potential divider.
• The input to the SCR bridge circuit is 240V ac. From this circuit we get
output which will initially be fluctuating so for controlling purpose we will take
a feedback signal from output.
• Now, we have to give this feedback signal to Analog to Digital converter but
here the feedback signal is of around 240V dc. When ADC 0808 can
operates up to +5 V dc. It will be damaged if we apply 240V dc to it. So for
that we must have to use some kind of step down circuitry. Here we have
used Potential divider circuitry. By the use of Potential divider we will step it
down to around +5V dc signal. Now it is safe to apply that signal to ADC
0808.
• Here input to the ADC 0808 is analog signal which will be converting to the
digital signal. And that digital signal will be fed to the Microcontroller.
• Microcontroller is the main decision making block of our project which is
used to control the firing angle of SCR. Digital signal which we get from the
ADC 0808 is then compared to the values which are stored in look table.
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A Project Report on Three Phase Voltage Regulation using SCR & Micro-Controller.
And according to that look table controller will take required value of firing
angle. As per firing angle controller will calculate the delay and according
that delay Controller will give triggering pulses to the gate of the SCR. So
that we get controlled output.
• But controller must have to give the triggering pulses at correct time means it
must have be synchronization with input signal. For that purpose we have
used zero crossing detector. So that when input analog signal will cross zero
voltage level, then only controller will give trigger pulse to the SCR.
CHAPTER 9
Software Flow-chart
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A Project Report on Three Phase Voltage Regulation using SCR & Micro-Controller.
Flow charts: Main Program:
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STAR
Set port P1 as input port
Read output of ADC
Delay calc. for firing pulse
Delay for firing pulse
Set port pin P2.0
Pulse width delay
Reset port pin P2.0
Is ZCD=
A
R
No
Yes
A Project Report on Three Phase Voltage Regulation using SCR & Micro-Controller.
Department of Electronics science, University of Pune (Sep’06-Feb’07) Page 61 of 72
A
Set port pin P2.1
Delay for firing pulse
Delay calc. for firing pulse
Read output from ADC
Is ZCD=
Reset port pin P2.1
Pulse width delay
R
Yes
No
A Project Report on Three Phase Voltage Regulation using SCR & Micro-Controller.
Read output of ADC:
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Start
Activate SOC
Monitor EOC
Activate output enable
ActivateALE
End
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A Project Report on Three Phase Voltage Regulation using SCR & Micro-Controller.
Pulse width Calculation:
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Start
Reset timer flag
Stop timer
Start timer
Load timer register
Set timer in mode zero
Is TF=1
End
Yes
No
A Project Report on Three Phase Voltage Regulation using SCR & Micro-Controller.
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A Project Report on Three Phase Voltage Regulation using SCR & Micro-Controller.
Delay calculation for firing pulse:
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Start
Get value for timer register from look-up
table
End
A Project Report on Three Phase Voltage Regulation using SCR & Micro-Controller.
Delay for firing:
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Start
End
Set timer in mode zero
Load timer with ADC Val.
Start timer
Stop timer
Reset timer flag
Is TF=1
No
Yes
A Project Report on Three Phase Voltage Regulation using SCR & Micro-Controller.
CHAPTER 10
Result & Discussion
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A Project Report on Three Phase Voltage Regulation using SCR & Micro-Controller.
RESULT AND DISCUSSION
Here by we have designed a device that is capable of detecting the
fluctuations in the input mains supply.
We designed hardware for voltage regulation by using SCR Bridge, which
senses fluctuations in the single phase voltage supply across the load and nullifies
it.
Hence our device is capable of regulating the single phase mains supply to a
constant dc supply across the load, irrespective of any changes in the supply,
hence providing protection to the load device from getting damaged due to sudden
variations in the mains.
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A Project Report on Three Phase Voltage Regulation using SCR & Micro-Controller.
CHAPTER 11
Bibliography
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A Project Report on Three Phase Voltage Regulation using SCR & Micro-Controller.
BIBLIOGRAPHY
REFERENCE BOOKS:-
• “The 8051 Microcontroller & Embedded System” by Mazidi.
• 8051 Micro controller by Kennith Ayala.
• “Power Electronics” by Katre.
• “Power Electronics” by Bhimra.
• “OP-AMP &Integrated circuits” by Ramakant gayakwad.
WEB SITES:-
• www.datasheets4u.com
• www.datasheetcatalog.com
• www.semiconductor.phillips.com
• www.alldatasheet.com
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