Synopsis

Of

Minor Project Work

ON

“SOLAR TRACKER AND CHARGING MONITOR”

Bachelor of Technology

In

Electronics and Communication Engineering

Submitted by:

NAME ROLL NO.

LOGO OF THE INSTITUTE

NAME OF THE INSTITUTE

SOLAR TRACKER AND CHARGING MONITOR

PROBLEM DEFINITION

A Solar panel (also solar module, photovoltaic module or photovoltaic panel) is a packaged,

connected assembly of photovoltaic cells. The solar panel can be used as a component of a larger

photovoltaic system to generate and supply electricity in commercial and residential applications

thereby effectively Producing renewable Energy. Each panel is rated by its DC output power

under standard test conditions, and typically ranges from 100 to 320 watts. Generally, solar

panels are stationary and do not follow the movement of the sun and hence cannot obtain

maximum sun light throughout the day. There is another major problem to check whether the

storage battery of a solar power unit is being charged or not.

OBJECTIVE

The objective of this project is to provide solution to above problems as solar energy is one of

the abundant sources of energy provide by nature and one of the most efficient form of

renewable energy. In above problems mentioned we will use a Solar Tracker System that tracks

the sun’s movement across the sky and tries to maintain the solar panel perpendicular to the

sun’s rays, ensuring that the maximum amount of sunlight is incident on the panel throughout the

day. The solar tracker starts following the sun right from dawn, throughout the day till evening,

and starts all over again from the dawn next day. Along with the Solar Tracker we will use a

simple Charging Monitor that indicates whether the storage battery of a solar power unit is

being charged or not.

DEVELOPMENT PHASE

STUDY AND ANALYSE PHASE

SOLAR TRACKER

The solar tracker comprises comparator IC LM339, H-bridge motor driver IC L293D (IC2) and a few discrete components. Light-dependent resistors LDR1 through LDR4 are used as sensors to detect the panel’s position relative to the sun. These provide the signal to motor driver IC2 to move the solar panel in the sun’s direction. LDR1 and LDR2 are fixed at the edges of the solar panel along the X axis, and connected to comparators A1 and A2, respectively. Presets VR1 and VR2 are set to get low comparator output at pins 2 and 1 of comparators A1 and A2, respectively, so as to stop motor M1 when the sun’s rays are perpendicular to the solar panel.

When LDR2 receives more light than LDR1, it offers lower resistance than LDR1, providing a high input to comparators A1 and A2 at pins 4 and 7, respectively. As a result, output pin 1 of comparator A2 goes high to rotate motor M1 in one direction (say, anti-clockwise) and turn the solar panel.

When LDR1 receives more light than LDR2, it offers lower resistance than LDR2, giving a low input to comparators A1 and A2 at pins 4 and 7, respectively. As the voltage at pin 5 of comparator A1 is now higher than the voltage at its pin 4, its output pin 2 goes high. As a result, motor M1 rotates in the opposite direction (say, clock-wise) and the solar panel turns. Similarly, LDR3 and LDR4 track the sun along Y axis. Fig(1) below shows the proposed assembly for the solar tracking system.

Fig(1)

CHARGING MONITOR

The circuit consists of two common ICs, an npn transistor, ten 5mm red LEDs and a few discrete components. It can be divided into two parts: voltmeter and display controller.

The voltmeter, built around IC LM3914 (IC1), is a low-power, expanded-scale type LED voltmeter that indicates small voltage steps over the 7-16V range for 12V solar panels. The meter saves power by operating in a low-duty-cycle 'flashing' mode where the LED indicators are on (and hence consuming power) briefly. The circuit may be switched to steady mode where the active indicator remains on at all times.

The input for IC1 (LM3914) is derived from the solar panel voltage via a potential divider network comprising preset VR1 and resistors R1 and R2. This variable input is about 3V for a DC potential of 12V.

The display range depends on the internal voltage reference and resistors R3-VR2-R4. The lowest LED (LED1) glows when the input voltage at pin 5 of IC1 is 1.8V and the top most LED (LED10) glows when the voltage exceeds 4V. as the input signal is divided by 4, the display ranges should be multiplied by this figure. So the actual display range is 7-16V, i.e., 1V per LED.The display controller is built around IC LM555 (IC2) that is wired in astable (free-running) mode with a narrow-pulse output. The duty-cycle of IC2 is controlled by the ratio of resistors R6 and R7. If you want faster blinking, use a smaller value of resistor R7. A preset may be substituted for R7 if a rate adjustment is desired. Increase the value of resistor R6 to get a longer 'on' time for LED indicators. The frequency of oscillations is determined by the combination of capacitor C4 and resistors R6 and R7.

The output of timer IC2 is fed (through current-limiting resistor R5) to transistor T1 ,which, in turn, controls the power to IC1. Capacitor C1 filters the control voltage input to IC1 and capacitor C3 provides DC filtering for the entire circuit. When you press switch S1 across capacitor C4, the output of IC2 remains high, and the display switches to steady mode from flashing mode .Switch S2 is the master power-on/off switch.

For calibration, lock preset VR1 at the centre position and then set VR2 to its maximum resistance with the help of a digital multimeter. Now close both the switches (S1 and S2) and connect the circuit to a variable-voltage DC power supply unit with its output level set to 12V (1%). Adjust VR1 until LED6 (at pin 14 of IC1) lights up. Finally, lock presets VR1 and VR2 using glue.  

IMPLEMENTATION

The primary step is towards the search of components and IC’s which will be required. For the

designing of our project we require some specific hardware and software followed by

interfacing the components to accomplish the task required by our project.

In secondary phase for Hardware section we will implement circuit on PCB. After PCB

designing, we will place all the components on PCB. A Charger Controller will also be placed

with the Charging Monitor circuit along with different IC’s and components.

HARDWARE

SOLAR TRACKER

SEMICONDUCTORS:

IC1(A1-A4) – LM339

IC2-L293D

RESISTORS:

R1 - 50-kilo-ohm

R2 - 12-kilo-ohm

R3 - 12-kilo-ohm

R4 - 50-kilo-ohm

R5 - 22-kilo-ohm

R6 - 22-kilo-ohm

R7 - 10-kilo-ohm

R8 - 10-kilo-ohm

R9 - 10-kilo-ohm

R10 - 10-kilo-ohm

LDR1,LDR2,LDR3,LDR4

PRESETS:

VR1-47-kilo-ohm

VR2-100-kilo-ohm

VR3-100-kilo-ohm

VR4-47-kilo-ohm

DIODES:

D1-D4-IN4148

MOTORS:

M1,M2-12V,3RPM Geared Motors

CHARGING MONITOR

SEMICONDUCTORS:

IC1-LM3914

IC2-LM555

RESISTORS:

R1-5.6-kilo-ohm

R2-2.7-kilo-ohm

R3-1.2-kilo-ohm

R4-1.8-kilo-ohm

R5-12-kilo-ohm

R6-100-kilo-ohm

R7-2.2-mega-ohm

PRESETS:

VR1-5K

VR2-2K

DIODES:

D1-IN4148

CAPACITORS

C1-47uf,40V

C2-220nf

C3-220uf,40V

C4-1uf,40V

C5-0.01uf

TRANSISTORS:

T1-BC548

LED’S

LED 1-10

SWITCHES:

S1,S2

BLOCK DIAGRAM

FIG.1 (Block Diagram)

CIRCUIT DIAGRAM

FIG.2 (Circuit Diagram of Solar Tracker)

FIG.3 (Circuit Diagram of Charging Monitor)

PCB LAYOUT

PCB layout of above circuits are yet to be designed.

REFERRENCE

http://ezine.efymag.com/

http://en.wikipedia.org/wiki/Solar_panel

http://en.wikipedia.org/wiki/Solar_power

Parts List