Upfc

1. UPFC, UNIFIED POWER FACTOR CONTROL
Under the Guidance of
Submitted by
Project Title

2. ABSTARCT
• The time lag between the zero voltage pulse and zero current pul
se duly generated by suitable operational amplifier circuits are fe
d to two interrupt pins of the microcontroller where the program
takes over to calculate the time difference between the voltage a
nd current both for inductive load and capacitive load.
• The time difference is calculated to display the leading power fac
tor or the lagging power factor based on which appropriate num
ber of opto-isolators triggers the back to back SCRs to switch eith
er capacitor or inductor depending on the requirement.
• This is achieved by using a set of capacitors and inductor forming
as load whose current is sensed by a CT for further processing ag
ainst the voltage to display the power factor.
• The microcontroller used in the project is of 8051 family which is
of 8 bit.

3. PROJECT BLOCK DIAGRAM

4. MICROCONTROLLER (AT89S52/AT89C51)
SCR
OPTO-ISOLATOR
LCD
CURRENT TRANSFORMER
INDUCTIVE CHOKE
SHUNT CAPACITOR
PUSH BUTTONS
LED
1N4007 / 1N4148
RESISTOR
CAPACITOR
HARDWARE COMPONENTS

5. POWER SUPPLY
230 V AC
50 Hz
5V
DC
12V step down
transformer
Filter(470µf)
5v RegulatorBridge rectifier

6. MICROCONTROLLER
• It is a smaller computer
• Has on-chip RAM, ROM, I/O ports...
RAM ROM
I/O Po
rt
Timer
Serial
COM
Port
Microcontroller
CPU
A single chip

7. INTERNAL STRUCTURE OF A MICRO CONTROLLER-AT89S5
2/51
CPU
On-chip
RAM
On-chip
ROM for
program
code
4 I/O Ports
Timer 0
Serial
Port
OSC
Interrup
t Contro
l
External interrupts
Timer 1
Timer/Counter
Bus Con
trol
TxD RxDP0 P1 P2 P3
Address/Data
Counter
Inputs

8. Features of AT89S51/52
 Compatible with MCS®-51 Products
 8K Bytes of In-System Programmable (ISP) Flash Memory
 Endurance: 10,000 Write/Erase Cycles
 4.0V to 5.5V Operating Range
 Fully Static Operation: 0 Hz to 33 MHz
 256 x 8-bit Internal RAM
 32 Programmable I/O Lines
 Three 16-bit Timer/Counters
 Eight Interrupt Sources
 Full Duplex UART Serial Channel
 Interrupt Recovery from Power-down Mode
 Watchdog Timer
 Dual Data Pointer

9. Pin Description

10. SCR
• A Silicon Controlled Rectifier (or Semiconductor Cont
rolled Rectifier) is a four layer solid state device that c
ontrols current flow
• An SCR can be seen as a conventional rectifier contro
lled by a gate signal
• It is a 4-layered 3-terminal device
• When the gate to cathode voltage exceeds a certain t
hreshold, the device turns 'on' and conducts current

11. Contd..
• The operation of a SCR can be understood in terms o
f a pair of tightly coupled Bipolar Junction Transistors
• SCR has three states:
• Reverse blocking mode, forward blocking mode, and
forward conducting mode

12. Optocoupler
• Opto coupler is a 6 pin IC. It is a combination of 1 LED
and a traic. Pin 5 is not generally used and when light
falls on the triac then it switches ON the triac.

13. Contd..
• When logic zero is given as input to the LED then the li
ght doesn’t fall on triac so the triac is off means the cu
rrent does not flow through the triac.
• When logic 1 is given as input to the LED then light em
itted by LED falls on triac so it starts conducting i.e., n
ow there will be current flowing through the triac.

14. QUAD VOLTAGE COMPARATOR LM339
FEATURES
● Wide single supply voltage range 2.0VDC TO 36VDC or dual supplies ±1.0VD
C to ±18VDC
● Very low supply current drain (0.8㎃) independent
of supply voltage (1.0㎽/comparator at 5.0VDC)
● Low input biasing current 25㎁
● Low input offset current ±5㎁ and offset voltage
● Input common-mode voltage range includes ground
● Differential input voltage range equal to the power
supply voltage
● Low output 250㎷ at 4㎃ saturation voltage
● Output voltage compatible with TTL, DTL, ECL, MOS
and CMOS logic system
● Moisture Sensitivity Level 3

15. LIQUID CRYSTAL DISPLAY (LCD)
Most common LCDs connected to the microcontrollers are
16x2 and 20x2 displays.
This means 16 characters per line by 2 lines and 20 charact
ers per line by 2 lines, respectively.
The standard is referred to as HD44780U, which refers to t
he controller chip which receives data from an external sourc
e (and communicates directly with the LCD.

16. LCD BACKGROUND
If an 8-bit data bus is used the LCD will require 11 data lines
(3 control lines plus the 8 lines for the data bus)
The three control lines are referred to as EN, RS, and RW
EN=Enable (used to tell the LCD that you are sending it data)
RS=Register Select (When RS is low (0), data is treated as a command)
(When RS is High(1), data being sent is text data )
R/W=Read/Write (When RW is low (0), the data written to the LCD)
(When RW is low (0), the data reading to the LCD)

17. Soft ware Requirements
• Keil an ARM Company makes C compilers, macro assemblers, real-tim
e kernels, debuggers, simulators, integrated environments, evaluation b
oards, and emulators for ARM7/ARM9/Cortex-M3, XC16x/C16x/ST10,
251, and 8051 MCU families.
• Compilers are programs used to convert a High Level Language to obje
ct code. Desktop compilers produce an output object code for the under
lying microprocessor, but not for other microprocessors.

18. • i.e the programs written in one of the HLL like ‘C’ will compile the
code to run on the system for a particular processor like x86 (unde
rlying microprocessor in the computer).
• For example compilers for Dos platform is different from the Com
pilers for Unix platform So if one wants to define a compiler then
compiler is a program that translates source code into object code.