Under the Guidance of Sham Datto Lecturer Dept. of ETE, RUET Submitted by Md. Nazmus Sakib Roll:124018

Project Title ELECTRONICS & TELECOMMUNICATION ENGINEERING

WHY WE USE IT?????????????High Intensity Discharge lamps (HID) used for urban street light

are based on principle of gas discharge, thus the intensity is not

controllable by any voltage reduction method as the discharge path

is broken. White Light Emitting Diode (LED) can replace the HID lamps

where intensity control is possible by pulse width modulation. The

intensity control helps in saving energy during late nights while

traffic density on the streets is low. A programmable microcontroller is engaged to provide different

intensities at the different times of late night for energy saving for

solar based system, using a charge controller for battery charging,

overload and deep discharge protection

OBJECTIVE

PROJECT BLOCK DIAGRAM

HARDWARE REQUIREMENTS

POWER SUPPLY BLOCKARDUINO UNOSOLAR PANNEL

LEDPWMMOSFETPHOTOVOLTAIC CELLS/SOLAR CELLSLM3241N4007/1N4148 RESISTOR CAPACITOR

230 V AC 50 Hz

5V DC

12V step down transformer

Filter(470µf)

5v RegulatorBridge rectifier

MOSFET(IRF 510)

The metal–oxide–semiconductor field-effect

transistor (MOSFET, MOS-FET, or MOS

FET) is a device used for amplifying or

switching electronic signalsThe basic principle of the device a voltage on

the oxide-insulated gate electrode can induce a

conducting channel between the two other

contacts called source and drainIt is by far the most common transistor in

both digital and analog circuits, though the

bipolar junction transistor was at one time

much more common.

OPAMP LM324FeaturesInternally frequency compensated for unity gainLarge DC voltage gain 100 dBWideband with 1Mhz (Temperature compensated)Wide power supply range:

Single supply 3V to 32Vor dual supplies ±1.5V to ±16V

Very low supply current drain (700 μA) essentially

independent of supply voltageLow input biasing current 45 nA (temperature

compensated)Low input offset voltage 2mV and offset current:5

nALarge output voltage swing 0V to V+ − 1.5V

BC547 (NPN –Transistor)

The BC547 transistor is an NPN Epitaxial

Silicon Transistor.It is used in general-purpose switching and

amplification BC847/BC547 series 45 V, 100

mA NPN general-purpose transistors.

The ratio of two currents (Ic/Ib) is called the DC Current Gain of

the device and is given the symbol of hfe or nowadays Beta, (β).

The current gain from the emitter to the collector

terminal, Ic/Ie, is called Alpha, (α), and is a function of the

transistor itself

1N4148The 1N4148 is a standard small signal silicon

diode used in signal processing. The 1N4148 is generally available in a DO-35

glass package and is very useful at high frequencies

with a reverse recovery time of no more than 4ns. This permits rectification and detection of

radio frequency signals very effectively, as long as

their amplitude is above the forward conduction

threshold of silicon (around 0.7V) or the diode is

biased.

PHOTOVOLTAIC CELLS

Photovoltaic (PV) cells are made of special materials called

semiconductors such as silicon, which is currently the most commonly

used. Basically, when light strikes the cell, a certain portion of it is

absorbed within the semiconductor material. PV cells also all have one or more electric fields that act to force

electrons freed by light absorption to flow in a certain direction. This flow of electrons is a current, and by placing metal contacts on

the top and bottom of the PV cell, we can draw that current off to use

externally.

SOLAR PANEL

Expose the cell to light, and the energy

from each photon (light particle) hitting

the silicon, will liberate an electron and a

corresponding hole. If this happens within range of the

electric field’s influence, the electrons will

be sent to the N side and the holes to the P

one, resulting in yet further disruption of

electrical neutralityThis flow of electrons is a current; the

electrical field in the cell causes a voltage

and the product of these two is power

The term duty cycle describes the proportion of on time to the regular

interval or period of time; a low duty cycle corresponds to low power,

because the power is off for most of the time.

Duty cycle is expressed in percent, 100% being fully on.

The main advantage of PWM is that power loss in the switching devices

is very low. When a switch is off there is practically no current, and when

it is on, there is almost no voltage drop across the switch.

PWM works also well with digital controls, which, because of their on/off

nature, can easily set the needed duty cycle.

The longer the switch is on compared to the off periods, the higher the

power supplied to the load is.

WORKING OF PROJECT

Solar panel being a current source is used to change battery B1 via D10. While

the battery is fully charged the voltage at cathode point of D10 goes up. This

results in the set point voltage at pin 3 of U1:A to go up above the reference

voltage because the potential divider formed out of R12, 5K variable

resistor,R13 goes up. This results in pin no 1 of U1:A to go high to switch ‘ON’ the transistor Q1

that places drive voltage to the Mosfet IRF640 .such that the current from solar

panel is bypassed via D11 and the Mosfet drain and sourceSimultaneously pin 7 of U1:B also goes high to drive a led D1 indicating battery

is being fully chargedWhenever the solar charge is low the circuit utilizes the power from battery, if

the battery goes into deep discharge ,then it utilizes power from solar power then

the Led’s flashes light

THANKYOU