This project report summarizes the design and simulation of a current fed DC-DC converter. Key aspects include: - The converter uses an inductor as a constant current source and switches to direct current through transformer windings, enabling voltage conversion. - Proteus simulation used a 12V DC source, MOSFET switches, step-down transformer, diodes, inductors and capacitors. Microcontroller code provides switching. - Practical implementation used a 27V DC source, 2uH inductor, 75NF75 MOSFET switches, 13V/250V transformer, diodes and 2uF capacitor. It achieved a 1V output from 27V input.

1. Project Design and Progress
Report
Title: Current Fed Converter
Instructor: Engg Faheem Ali
Group Members:
Mehboob Ur Rehman 15PWELE4639
Muhammad Arsalan 15PWELE4640
Atta Ur Rehman 15PWELE4653

2. Introduction:
In electricalpower engineering powerconversionis converting
electricalenergyfrom one form to another form. A powerconverter is an
electricaldevice for converting electricalenergy. A dc-dc converteris an
electronic circuit that convert source ofdirect current from one voltage
level to another it is a type of electric power converter.Powerranges from
high level to low level voltage.
Theory:
In this converter we connectinductor with the DC source which
stores enoughenergy in its magnetic field and acts as a constant current
source. The switches are used to direct the current through the windings.

3.  When switch 1 is closed;
Current passes throughthe coilVp1.
In Vp1 Current goes towards the Dot(.),so in the Secondaryside ,the
current goes awayFromthe Dot. The Diode D1 becomes forward
biased and the diode D2 becomes reversedbiasedand output appears
across the Load.
 When Switch 2 is closed, current passes through the Winding Vp2
,going awayfrom the Dot. So in the Secondary,it will go towards the
Dot which results in Forwardbiased D2 and reversedbiased D1 and
output appears acrossthe load.

4.  With both switches closed, ILx divides evenly betweenthe two
primary windings, and both D1 and D2 are off. The voltage on each
primary winding is zero:
The output voltage is calculatedwith the farmula
Switching diagram:

6. Proteous Simulation:
We did simulation in Proteous.
For simulation we choose the following component;
1. 12 volt DC source
2. Switches;we use Enhancement type N channel Mosfet, which is a
three terminal device .the terminal are Gate ,source and Drain. We get
output from drain and source terminal and connectswitching voltage
betweenGate and Source.
3. Step down transformer;
In our Projectwe need double input and double transformer. We
connectedtwo simple transformers having which works as a double input
and out transformer.
4. Two diodes
5. Two micro Henry inductor
6. Two micro farad capacitor
7. Ten Kilo Ohm Load Resistor
Micro controller is used for providing switching Voltage to the Mosfet.

7. 8.

8. Micro Controller Coding:
ORG 00H
MOV TMOD,#01H
MOV TH0,#0FFH
MOV TL0,#08DH
BACK: SETB P1.1 //S1
SETB P1.2 //S2
ACALL DELAY
CLR P1.2
ACALL DELAY
ACALL DELAY
SETB P1.2
ACALL DELAY
CLR P1.1
ACALL DELAY
ACALL DELAY
SJMP BACK

9. DELAY:
SETB TR0
HERE:JNB TF0 ,HERE
CLR TR0
CLR TF0
MOV TL0,#08DH
MOV TH0,#0FFH
RET
END
Switching Waveform:
Out Put Waveform:

10. `Practical implementation:
For practicalimplementation we used the following components;
1. Transformer :we have used transformer having input 250
volt and output 13 volt.This is its maximum rating values. It
has turn ratio of 𝟏𝟑/𝟐𝟓𝟎 2nd ry to primry.it is a step down
transformer.
2. 27 volt dc source :we connectedthree 9 volts batteries in series
from which we get27 volt equilent.

11. 3. This 27 volt output is connectedto the 2u Henry inductor which
works as a constantcurrent source.
4. 75NF75Mosfet:the switches are ON and OFF through the
controllerwhich provides Gate to source pulse.
5. Transformerisolates the input and output side.
6. The diodes directs the current in one direction
7. The capacitoris used to keep constant at the output.the capacitor
is of 2 micro farad.
Procedure:
 We connectall the components on the bread board.
 The negative terminal of the battery is connectedto the source and
positive terminal is connectedto the inductor which acts as a
constantcurrent source.
 The inductor output is connectedwith common point of the
transformer primary side.
 The drain terminal of eachswitch is connectedwith the primary
winding of transformer.

12.  Two transformers are connectedat the output and input side
respectively.
Observations:
 First we make connections according to given circuit on the
breadboard transformers ratings are 230Vinput and 13V output but
it did not give the desiredvalue because we gives 9V dc voltage and
output is not too much to sense by a voltmeter it is order of 240mV
output acrossloadthen we increase the input voltage to 27V dc then
it gives 1V at output side theoretically it will be 2.37V but actually it
will give 1V because oflossesin wires(a single wire of 5 ohms) and
transformers and duty ratio(D) of 0.7.
VS=27V
VO =1V
NS/NP=0.0.52
D =0.7

13. Conclusion: - Through this project, we are
able to convert DC voltage to low value DC
voltage. Wires, transformer etc. that we have
used in our project actually loss power, so we
concluded that such project require special
type transformer.