The document discusses a project on a thyristor-controlled cycloconverter aimed at controlling the speed of induction motors, commonly used in domestic appliances. It highlights the advantages of these motors and the hardware requirements including a microcontroller, optoisolators, and SCRs. The project aims to generate different frequency outputs through controlled triggering of SCRs based on programming, and outlines the technical specifications and operation details of the components involved.

1. CYCLO CONVERTER FOR FUNDAMENTAL, F/2,
F/3 USING GATE CONTROLEED THYRISTORS
Under the Guidance of
Submitted by
Project Title

2. A.C. motors have the great advantages of being relatively
inexpensive and very reliable.
 Induction motors in particular are very robust and therefore
used in many domestic appliances such as washing machines,
vacuum cleaners, water pumps, and others.
The induction motor may be regarded as practically a constant-
speed machine, the difficulty of varying its speed economically
constitutes one of its main disadvantages.
 This drawback is overcome by using a thyristor controlled
cycloconverter that enables the speed to be lowered in steps by
Microcontroller triggering a SCR bank of 8nos in F/2 & F/3.
ABSTRACT

3. PROJECT BLOCK DIAGRAM

4. HARDWARE REQUIREMENTS
POWER SUPPLY BLOCK
 MICROCONTROLLER (AT89S52/AT89C51)
 OPTOISOLATOR (MOC3021)
 SINGLE PHASE INDUCTION MOTOR
PUSHBUTTON
SCR
LM358
LED
DIODE (IN4007)
RESISTORS
CAPACITORS

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

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

7. CPU
On-chip
RAM
On-chip
ROM for
program
code
4 I/O Ports
Timer 0
Serial
Port
OSC
Interrup
t
Control
External interrupts
Timer 1
Timer/Counter
Bus
Control
TxD RxDP0 P1 P2 P3
Address/Data
Counter
Inputs

8.  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

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

11. Contd..
• When logic zero is given as input to the LED then the
light doesn’t fall on diac so the diac is off means the
current does not flow through the diac.
• When logic 1 is given as input to the LED then light
emitted by LED falls on diac so it starts conducting i.e.,
now there will be current flowing through the diac.

12. Three Phase Induction Motor
• It consists of the fixed stator or frame, a three-phase winding
supplied from the three-phase mains and a turning rotor
• There is no electrical connection between the stator and the
rotor
• Stator and rotor are made of highly magnetizable core sheet
providing low eddy current and hysteresis losses

13.  The stator winding consists of three individual windings which
overlap one another and are offset by an electrical angle of
120°
 Synchronous Speed (Ns)= 60*f/p
 Ns= Synchronous Speed/ minute;
 F= frequency;
 P=Pole pair Number;
 Rotor in induction machines with squirrel-cage rotors consists
of a slotted cylindrical rotor core sheet package with aluminum
bars which are joined at the front by rings to form a closed cage

14. SCR
• A Silicon Controlled Rectifier (or Semiconductor
Controlled Rectifier) is a four layer solid state device
that controls current flow
• An SCR can be seen as a conventional rectifier
controlled by a gate signal
• It is a 4-layered 3-terminal device
• When the gate to cathode voltage exceeds a certain
threshold, the device turns 'on' and conducts current

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

16. LM358
The LM358 series consists of two independent, high
gain; internally frequency compensated operational
amplifiers which were designed specifically to operate
from a single power supply over a wide range of
voltages.
Operation from split power supplies is also possible
and the low power supply current drain is independent
of the magnitude of the power supply voltage.
Features
Available in 8-Bump micro SMD chip sized package.
Large dc voltage gain: 100 Db.
Wide power supply range:
Single supply: 3V to 32V
or dual supplies: ±1.5V to ±16V
Very low supply current drain (500 µA)-essentially independent of supply
voltage.

17. WORKING OF PROJECT
The project uses zero voltage reference ,8 Opto isolators(MOC3021) are used
for driving 8 SCR’s. Triggering pulses so generated by the MC as per the
program written provides input condition to the Opto isolator that drive the
respective SCR to get conducting for 20ms from 1st
bridge and next 20ms from
the 2nd
bridge to get the output, total time period of one AC cycle of 40ms which
is 25 Hz.
Thus F/2 is delivered to the load while switch 1 is closed. Similarly for F/3 the
conduction takes place for 30ms in the 1st
bridge and next 30ms from the next
bridge, such that a total time period of 1 cycle comes to 60ms which in turn in
F/3 while switch -2 is operated. Fundamental frequency of 50Hz is available by
triggering on pair from the 1st
bridge for 1st
10ms and for the next 10msfrom the
next bridge while both the switches are kept in “OFF” condition. Reverse
current flowing in the gates of the SCR’s are Opto – isolator output.

18.  Keil an ARM Company makes C compilers, macro assemblers,
real-time kernels, debuggers, simulators, integrated
environments, evaluation boards, 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 object code. Desktop compilers produce an
output object code for the underlying microprocessor, but
not for other microprocessors.

19.  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
(underlying microprocessor in the computer).
 For example compilers for Dos platform is different from the
Compilers for Unix platform So if one wants to define a compiler
then compiler is a program that translates source code into object
code.

20.  “The 8051 Microcontroller and Embedded systems”
by Muhammad Ali Mazidi and Janice Gillispie
Mazidi , Pearson Education.
 ATMEL 89S52 Data Sheets.
 www.atmel.com
 www.beyondlogic.org
 www.wikipedia.org
 www.howstuffworks.com
 www.alldatasheets.com

21. THANKYOU