Solar Tracking System

A Solar Energy System by Effective Sun Tracking System

SANTHIRAM ENGINEERING COLLEGE

NANDYAL_518501

KURNOOL (DT)

Presented by

T.GURUBHASKAR

[email protected]

3/4.E.E.E

Ph. no: 9491417285

M.Jithendra

[email protected]

3/4 E.E.E

Ph.no:9700717030

ABSTRACT

Electric power is the major aspect for a human

being. Without electric power there is no world.

Electric power can be generated by many ways like

coal, water, nuclear etc. Generation of power from

non-conventional energy sources improves the

system efficiency, reliability and reduces pollution.

One of such non-conventional energy source is

SOLAR ENERGY which is a complete pollution

free. A solar panel is a device that converts the

energy of sunlight directly into electricity by the

photovoltaic effect. In our project we are

generating power from sun by effective sun

tracking system means we utilize the maximum

radiation from sun by following the sun’s elevation

throughout the day using solar plates. A battery is

connected to the solar plant to store the generated

electric power. This power is utilized for the

domestic applications. Solar panel is connected to

Microcontroller through AT89S52 for controlling

panel such that it follows sun direction.

I. INTRODUCTION

Most of the electricity in India comes from

fossil-fuels like coal, oil and natural gas. Today the

demand of electricity in India is increasing and is

already more than the production of

electricity where as the reserves of the fossil-fuel

are depleting every day. We can feel this fact from

the electricity-cuts during summer. Luckily Sun

throws so much energy over India, that if we can

trap few minutes of solar energy falling over India

we can provide India with electricity for whole

year. Most parts of India get 7 KWH/ sq.-meter of

energy per day averaged over a year.

The main aim of this project is to generate

the maximum power from solar panel by

continuously tracking the sun rays.

The purpose of the project is to implement a system

to continuously track the sun rays with the help of

the solar panel and grasping the maximum power

from the sun by rotating the solar panel according

to the sun rays direction with respect to time.

In present situation everyone is facing the

problem with power cuts which is creating very

much trouble to the people. So, to solve this

problem we have a solution that is sun. Yes by

using sun radiation we can get power i.e., the solar

energy using which we generate the power. All we

are know that there are so many renewable energy

sources like solar, wind, geothermal etc. but solar

energy system is very simple and easy to

implement. But the main drawback of the solar

system is it is very poor efficient system. By using

this project we are going to improve the efficiency

of solar system.

In which solar panel will turn according to

the sun rotation with predefined angle. So by using

DC motor we are going to turn the panel according

to the time. Whenever the radiation of the sun falls

on the solar panel it grasps the radiation and stores

in it and it will send the message to the controller

about its power which is stored in it.

Microcontroller will receive this information and

display on LCD. As the time passes the panel

rotates with the help of motor. Here RTC (Real

Time Clock) is used to give the exact time intervals

to the controller.

Solar Panels are a form of active solar

power, a term that describes how solar panels make

use of the sun's energy: solar panels harvest

sunlight and actively convert it to electricity. Solar

Cells, or photovoltaic cells, are arranged in a grid-

like pattern on the surface of the solar panel. Solar

panels are typically constructed with crystalline

silicon, which is used in other industries (such as

the microprocessor industry), and the more

expensive gallium arsenide, which is produced

exclusively for use in photovoltaic (solar) cells.

Solar panels collect solar radiation from

the sun and actively convert that energy to

electricity. Solar panels are comprised of several

individual solar cells. These solar cells function

similarly to large semiconductors and utilize a

large-area p-n junction diode. When the solar cells

are exposed to sunlight, the p-n junction diodes

convert the energy from sunlight into usable

electrical energy. The energy generated from

photons striking the surface of the solar panel

allows electrons to be knocked out of their orbits

and released, and electric fields in the solar cells

pull these free electrons in a directional current,

from which metal contacts in the solar cell can

generate electricity. The more solar cells in a solar

panel and the higher the quality of the solar cells,

the more total electrical output the solar panel can

produce. The conversion of sunlight to usable

electrical energy has been dubbed the Photovoltaic

Effect.

BLOCK DIAGRAM

Fig2.1: Block diagram

2.1 BLOCK DIAGRAM EXPLANATION

MICROCONTROLLER:

The microcontroller is the heart of the

proposed embedded system. The controller used is

a low power, cost efficient chip manufactured by

ATMEL having 8K bytes of on-chip flash memory.

Microcontroller will receive this information and

display on LCD.

POWER SUPPLY:

A device or system that supplies electrical

or other types of energy to an output load or group

of loads is called a power supply unit or PSU. The

term is most commonly applied to electrical energy

supplies, less often to mechanical ones, and rarely

to others. Here we giving 5v to the micro

controller.

LCD:

Used as real time display, to know the status of the

speed of the DC motor.

H-BRIDGE:

As the time passes the panel rotates with

the help of motor. It is a driver circuit to operate the

motor.

RTC (REAL TIME CLOCK):

Here RTC (Real Time Clock) is used to

give the exact time intervals to the controller.

SOLAR PANELS:

Solar panels collect solar radiation from the sun

and actively convert that energy to electricity.

DC MOTOR:

By using DC motor we are going to turn the panel

according to the time. Whenever the radiation of

the sun falls on the solar panel it grasps the

radiation and stores in it and it will send the

message to the controller about its power which is

stored in it.

II. HARDWARE COMPONENTS

3.1POWER SUPPLY:

Fig3.1: Block diagram of power supply

Power supply is a reference to a source of electrical

power. A device or system that supplies electrical

or other types of energy to an output load or group

of loads is called a power supply unit or PSU. The

term is most commonly applied to electrical energy

supplies, less often to mechanical ones, and rarely

to others.

This power supply section is required to convert

AC signal to DC signal and also to reduce the

amplitude of the signal. The available voltage

signal from the mains is 230V/50Hz which is an

AC voltage, but the required is DC voltage (no

frequency) with the amplitude of +5V and +12V

for various applications.

In this section we have Transformer, Bridge

rectifier, are connected serially and voltage

regulators for +5V and +12V (7805 and 7812) via a

capacitor (1000µF) in parallel are connected

parallel as shown in the circuit diagram below.

Each voltage regulator output is again is connected

to the capacitors of values (100µF, 10µF, 1 µF, 0.1

µF) are connected parallel through which the

corresponding output (+5V or +12V) are taken into

consideration.

Fig3.2: Power supply diagram

Circuit Explanation

A) Transformer

A transformer is a device that transfers

electrical energy from one circuit to another

through inductively coupled electrical conductors.

A changing current in the first circuit (the primary)

creates a changing magnetic field; in turn, this

magnetic field induces a changing voltage in the

second circuit (the secondary). By adding a load to

Re

Filter

Bridge

Step

the secondary circuit, one can make current flow in

the transformer, thus transferring energy from one

circuit to the other.

The secondary induced voltage VS, of an

ideal transformer, is scaled from the primary VP by

a factor equal to the ratio of the number of turns of

wire in their respective windings:

B) Bridge Rectifier

A diode bridge or bridge rectifier is an arrangement

of four diodes in a bridge configuration that

provides the same polarity of output voltage for any

polarity of input voltage. When used in its most

common application, for conversion of alternating

current (AC) input into direct current (DC) output,

it is known as a bridge rectifier. A bridge rectifier

provides full-wave rectification from a two-wire

AC input, resulting in lower cost and weight as

compared to a center-tapped transformer design,

but has two diode drops rather than one, thus

exhibiting reduced efficiency over a center-tapped

design for the same output vol tage.

Basic Operation

When the input connected at the left

corner of the diamond is positive with respect to

the one connected at the right hand corner, current

flows to the right along the upper colored path to

theoutput, and returns to the input supply via the

lowerone.

Fig3.3: Bridge rectifier (+ve cycle)

When the right hand corner is positive relative to

the left hand corner, current flows along the upper

colored path and returns to the supply via the lower

colored path.

Fig 3.4: Bridge rectifier (-ve cycle)

In each case, the upper right output remains

positive with respect to the lower right one. Since

this is true whether the input is AC or DC, this

circuit not only produces DC power when supplied

with AC power: it also can provide what is

sometimes called "reverse polarity protection".

That is, it permits normal functioning when

batteries are installed backwards or DC input-

power supply wiring "has its wires crossed" (and

protects the circuitry it powers against damage that

might occur without this circuit in place).

Fig 3.5: Wave forms of rectifier

C) Output smoothing (Using Capacitor)

For many applications, especially with

single phase AC where the full-wave bridge serves

to convert an AC input into a DC output, the

addition of a capacitor may be important because

the bridge alone supplies an output voltage of fixed

polarity but pulsating magnitude (see diagram

above).

Fig 3.6: Smoothing capacitor

The function of this capacitor, known as a

reservoir capacitor (aka smoothing capacitor) is to

lessen the variation in (or 'smooth') the rectified AC

output voltage waveform from the bridge. One

explanation of 'smoothing' is that the capacitor

provides a low impedance path to the AC

component of the output, reducing the AC voltage

across, and AC current through, the resistive load.

In less technical terms, any drop in the output

voltage and current of the bridge tends to be

cancelled by loss of charge in the capacitor.

This charge flows out as additional current

through the load. Thus the change of load current

and voltage is reduced relative to what would occur

without the capacitor. Increases of voltage

correspondingly store excess charge in the

capacitor, thus moderating the change in output

voltage / current

Output can also be smoothed using a choke and

second capacitor. The choke tends to keep the

current (rather than the voltage) more constant. Due

to the relatively high cost of an effective choke

compared to a resistor and capacitor this is not

employed in modern equipment.

D) Voltage Regulator

A voltage regulator is an electrical regulator

designed to automatically maintain a constant

voltage level.

The 78xx (also sometimes known as LM78xx)

series of devices is a family of self-contained fixed

linear voltage regulator integrated circuits. The

78xx family is a very popular choice for many

electronic circuits which require a regulated power

supply, due to their ease of use and relative

cheapness.

When specifying individual ICs within this family,

the xx is replaced with a two-digit number, which

indicates the output voltage the particular device is

designed to provide (for example, the 7805 has a 5

volt output, while the 7812 produces 12 volts). The

78xx line is positive voltage regulators, meaning

that they are designed to produce a voltage that is

positive relative to a common ground. There is a

related line of 79xx devices which are

complementary negative voltage regulators. 78xx

and 79xx ICs can be used in combination to

provide both positive and negative supply voltages

in the same circuit, if necessary.

78xx ICs have three terminals and are most

commonly found in the TO220 form factor,

although smaller surface-mount and larger TrO3

packages are also available from some

manufacturers.

These devices typically support an input

voltage which can be anywhere from a couple of

volts over the intended output voltage, up to a

maximum of 35 or 40 volts, and can typically

provide up to around 1 or 1.5 amps of current

(though smaller or larger packages may have a

lower or higher current rating).

Fig3.7: Internal block diagram of voltage regulator

3.2 MICROCONTROLLERS:

MICROPROCESSORS VS

MICROCONTROLLERS:

• Microprocessors are single-chip CPUs used in

microcomputers.

• Microcontrollers and microprocessors are

different in three main aspects: Hardware

architecture, applications, and instruction set

features.

• Hardware architecture: A microprocessor is a

single chip CPU while a microcontroller is a single

IC contains a CPU and much of remaining circuitry

of a complete computer (e.g., RAM, ROM, serial

interface, parallel interface, timer, and interrupt

handling circuit).

• Applications: Microprocessors are commonly

used as a CPU in computers while microcontrollers

are found in small, minimum component designs

performing control oriented activities.

• Microprocessor instruction sets are processing

Intensive.

• They have instructions to set and clear individual

bits and perform bit operations.

• Processing power of a microcontroller is much

less than a microprocessor.

AT89S52:

Features:

• Compatible with MCS-51 Products

• 8K Bytes of In-System Programmable (ISP) Flash

Memory

– Endurance: 1000 Write/Erase Cycles

• 4.0V to 5.5V Operating Range

• Fully Static Operation: 0 Hz to 33 MHz

• Three-level Program Memory Lock

• 256K Internal RAM

• 32 Programmable I/O Lines

• 3 16-bit Timer/Counters

• Eight Interrupt Sources

• Full Duplex UART Serial Channel

• Low-power Idle and Power-down Modes

• Interrupt Recovery from Power-down Mode

• Watchdog Timer

The AT89S52 provides the following standard

features: 8K bytes of Flash, 256 bytes of RAM, 32

I/O lines, Watchdog timer, two data pointers, three

16-bit timer/counters, full duplex serial port, on-

chip oscillator, and clock circuitry. In addition, the

AT89S52 is designed with static logic for operation

down to zero frequency and supports two software

selectable power saving modes. The Idle Mode

stops the CPU while allowing the RAM

timer/counters, serial port, and interrupt system to

continue functioning. The Power-down mode saves

the RAM contents but freezes the oscillator,

disabling all other chip functions until the next

interrupt or hardware reset.

PIN DESCRIPTION OF

MICROCONTROLLER 89S52

VCC

Supply voltage.

GND

Ground.

Port 0

Port 0 is an 8-bit open drain bi-directional I/O port.

As an output port, each pin can sink eight TTL

inputs. When 1sare written to port 0 pins, the pins

can be used as high impedance inputs. Port 0 can

also be configured to be the multiplexed low order

address/data bus during accesses to external

program and data memory. In this mode, P0 has

internal pull-ups.Port 0 also receives the code bytes

during Flash Programming and outputs the code

bytes during program verification. External pull-

ups are required during program verification

Port 1

Port 1 is an 8-bit bi-directional I/O port with

internal pull-ups. The Port 1 Output buffers can

sink/source four TTL inputs. When 1s are written

to Port 1 pins, they are pulled high by the internal

pull-ups and can be used as inputs

Port 2

Port 2 is an 8-bit bi-directional I/O port

with internal pull-ups. The Port 2 output buffers

can sink/source four TTL inputs. When 1s are

written to Port 2 pins, they are pulled high by the

internal pull-ups and can be used as inputs. Port 2

emits the high-order address byte during fetches

from external program memory and during

accesses to external data memory that uses 16-bit

addresses (MOVX @DPTR). In this application,

Port 2 uses strong internal pull-ups when emitting

1s. During accesses to external data memory that

use 8-bit addresses (MOVX @ RI), Port 2emits the

contents of the P2 Special

Function Register. Port 2 also receives the

high-order address bits and some control signals

during Flash programming and verification

Port 3

Port 3 is an 8-bit bi-directional I/O port

with internal pull-ups. The Port 3 output buffers

can sink/source four TTL inputs. When 1s are writ

1s are written to Port 3 pins, they are pulled high by

the internal pull-ups and can be used as inputs. Port

3 also serves the functions of various special

features of the AT89S52, as shown in the following

table.

Port 3 also receives some control signals for Flash

programming

And verification.

RST

Reset input. A high on this pin for two machine

cycles while the oscillator is running resets the

device.

ALE/PROG

Address Latch Enable (ALE) is an output

pulse for latching the low byte of the address

during accesses to external memory. This pin is

also the program pulse input (PROG) during Flash

programming. In normal operation, ALE is emitted

at a constant rate of1/6 the oscillator frequency and

may be used for external timing or clocking

purposes. Note, however, that one ALE pulse is

skipped during each access to external data

Memory. If desired, ALE operation can be disabled

by setting bit 0 of SFR location 8EH. With the bit

set, ALE is active only during a MOVX or MOVC

instruction. Otherwise, the pin is weakly pulled

high. Setting the ALE-disable bit has no effect if

the micro controller is in external execution mode.

PSEN

Program Store Enable (PSEN) is the read strobe to

external program memory. When the AT89S52 is

executing code from external program memory,

PSEN is activated twice each machine cycle,

except that two PSEN activations are skipped

during each access to external data memory.

EA/VPP

External Access Enable. EA must be strapped to

GND in order to enable the device to fetch code

from external program memory locations starting at

0000H up to FFFFH.Note, however, that if lock bit

1 is programmed, EA will be internally latched on

reset. A should be strapped to VCC for internal

program executions. This pin also receives the 12-

voltProgramming enables voltage (VPP) during

Flash programming.

XTAL1

Input to the inverting oscillator amplifier and input

to the internal clock operating circuit.

XTAL2

Output from the inverting oscillator amplifier.

Oscillator Characteristics

XTAL1 and XTAL2 are the input and

output, respectively, of an inverting amplifier that

can be configured for use as an on-chip oscillator,

as shown in Figure 1. Either a quartz crystal or

ceramic resonator may be used. To drive the device

from an External clock source, XTAL2 should be

left unconnected while XTAL1 is driven, as shown

in Figure

Figure 3.8: Oscillator Connections

Special Function Register (SFR) Memory:

Special Function Registers (SFR s) are areas of

memory that control specific functionality of the

8051 processor. For example, four SFRs permit

access to the 8051’s 32 input/output lines.

Another SFR allows the user to set the

serial baud rate, control and access timers, and

configure the 8051’s interrupt system.

Accumulator:

The Accumulator, as its name suggests is

used as a general register to accumulate the results

of a large number of instructions. It can hold 8-bit

(1-byte) value and is the most versatile register.

“R” registers:

The “R” registers are a set of eight

registers that are named R0, R1. Etc up to R7.

These registers are used as auxiliary registers in

many operations.

The “B” registers: The “B” register is very similar

to the accumulator in the sense that it may hold an

8-bit (1-byte) value. Two only uses the “B” register

8051 instructions: MUL AB and DIV AB.The Data

Pointer: The Data pointer (DPTR) is the 8051’s

only user accessible 16-bit (2Bytes) register. The

accumulator, “R” registers are all 1-Byte values.

DPTR, as the name suggests, is used to point to

data. It is used by a number of commands, which

allow the 8051 to access external memory.

3.3 LCD (LIQUID CRISTAL DISPLAY)

1. The declining prices of LCDs make its use cost-

effective.

2. The ability to display numbers, characters and

graphics. This is contrast to LEDs, which has

limited to numbers and few characters.

Incorporation of a refreshing controller into LCD,

thereby relieving the CPU of the task of refreshing

the LCD. In contrast, the LED must be refreshed by

the CPU to keep displaying data.

3. Ease of programming for characters and

Fig 3.9: LCD pin description

LCD PIN DESCRIPTION

The LCD which we have used in our

project is a 16×2 alpha numeric LCD. It has 16

pins. Figure shows the position of various pins.

1. VCC, VSS, and VEE

While VCC and VSS provide +5V and

ground, respectively, VEE is used for controlling

LCD contrast.

2. RS (Register Select)

There are two very important registers

inside the LCD. The RS pin is used for their

selection as follows. If RS=0, the instruction

command code register is selected, allowing the

user to send a command such as clear display,

cursor at home, etc. If RS=1, the data register is

selected, allowing the user to send data to be

displayed on LCD.

3. R/W (Read/Write)

R/W input allows the user to write

information to LCD or read information from it.

R/W=1 when reading; R/W=0 when writing.

4. E (Enable)

The enable pin is used by the LCD to latch

information presented to its data pins. When data is

supplied to data pins, a high-to-low pulse must be

applied to this pin in order for the LCD to latch in

the data present the data pins. This pulse must be a

minimum of 450 ns wide.

5. D0-D7 (8-bit Data bus)

The 8-bit data pins, D0-D7, are used to

send information to the LCD or read the contents of

the LCD’s internal registers. To display letters and

numbers, we send ASCII codes for the letters A-Z,

a-z, and numbers 0-9 to these pins while making

6. RS=1

There are also instruction command codes

that can be sent to LCD to clear the cursor to the

home position or blink the cursor. Table lists some

of the instruction command codes.

Code Command to LCD Instruction Register (Hex)

1 Clear Display screen

2 Return home

4 Shift cursor left

6 Shift cursor right

5 Shift Display right

7 Shift Display left

8 Display off, cursor off

A Display off, cursor on

C Display on, cursor off

E Display on, cursor blinking

F Display on, cursor blinking

80 Force cursor to beginning of 1st line

C0 Force cursor to beginning of 2nd line

3.4 DC MOTOR:

A DC motor is designed to run on DC

electric power. Two examples of pure DC designs

are Michael Faraday's homopolar motor (which is

uncommon), and the ball bearing motor, which is

(so far) a novelty. By far the most common DC

motor types are the brushed and brushless types,

which use internal and external commutation

respectively to create an oscillating AC current

from the DC source -- so they are not purely DC

machines in a strict sense.

Fig3.10: DC Motor

Types of dc motors:

1. Brushed DC Motors

2. Brushless DC motors

3. Coreless DC motors

4. Brushed DC motors:

The classic DC motor design generates an

oscillating current in a wound rotor with a split

ring commutator, and either a wound or

permanent magnet stator. A rotor consists of a

coil wound around a rotor which is then

powered by any type of battery.Many of the

limitations of the classic commutator DC

motor are due to the need for brushes to press

against the commutator. This creates friction.

At higher speeds, brushes have increasing

difficulty in maintaining contact. Brushes may

bounce off the irregularities in the commutator

surface, creating sparks. This limits the

maximum speed of the machine. The current

density per unit area of the brushes limits the

output of the motor. The imperfect electric

contact also causes electrical noise. Brushes

eventually wear out and require replacement,

and the commutator itself is subject to wear

and maintenance.

Brushless DC motors:

Some of the problems of the brushed DC

motor are eliminated in the brushless design. In this

motor, the mechanical "rotating switch" or

commutator/brush gear assembly is replaced by an

external electronic switch synchronized to the

rotor's position. Brushless motors are typically 85-

90% efficient, whereas DC motors with brush gear

are typically 75-80% efficient.

Midway between ordinary DC motors and stepper

motors lies the realm of the brushless DC motor.

Built in a fashion very similar to stepper motors,

these often use a permanent magnet external rotor,

three phases of driving coils, one or more Hal

effect sensors to sense the position of the rotor, and

the associated drive electronics. The coils are

activated, one phase after the other, by the drive

electronics as cued by the signals from the Hall

effect sensors. In effect, they act as three-phase

synchronous motors containing their own variable-

frequency drive electronics.

Brushless DC motors are commonly used where

precise speed control is necessary, as in computer

disk drives or in video cassette recorders, the

spindles within CD, CD-ROM (etc.) drives, and

mechanisms within office products such as fans,

laser printers and photocopiers. They have several

advantages over conventional motors:

Compared to AC fans using shaded-pole

motors, they are very efficient, running much

cooler than the equivalent AC motors. This

cool operation leads to much-improved life of

the fan's bearings.

Without a commutator to wear out, the life of a

DC brushless motor can be significantly longer

compared to a DC motor using brushes and a

commutator. Commutation also tends to cause

a great deal of electrical and RF noise; without

a commutator or brushes, a brushless motor

may be used in electrically sensitive devices

like audio equipment or computers.

The motor can be easily synchronized to an

internal or external clock, leading to precise

speed control.

Coreless DC motors:

Nothing in the design of any of the motors

described above requires that the iron (steel)

portions of the rotor actually rotate; torque is

exerted only on the windings of the electromagnets.

Taking advantage of this fact is the coreless DC

motor, a specialized form of a brush or brushless

DC motor.

Optimized for rapid acceleration, these

motors have a rotor that is constructed without any

iron core. The rotor can take the form of a winding-

filled cylinder inside the stator magnets, a basket

surrounding the stator magnets, or a flat pancake

(possibly formed on a printed wiring board)

running between upper and lower stator magnets.

These motors were commonly used to

drive the capstan(s) of magnetic tape drives and are

still widely used in high-performance servo-

controlled systems, like radio-controlled

vehicles/aircraft, humanoid robotic systems,

industrial automation, medical devices, etc.

3.5 H-BRIDGE (MOTOR DRIVER)

Fig3.11: Structure of an H-bridge (highlighted in

red)

An H-bridge is an electronic circuit which

enables a voltage to be applied across a load in

either direction. These circuits are often used in

robotics and other applications to allow DC motors

to run forwards and backwards. H-bridges are

available as integrated circuits The term "H-

bridge" is derived from the typical graphical

representation of such a circuit. An H-bridge is

built with four switches . When the switches S1 and

S4 (according to the first figure) are closed (and S2

and S3 are open) a positive voltage will be applied

across the motor. By opening S1 and S4 switches

and closing S2 and S3 switches, this voltage is

reversed, allowing reverse operation of the motor.

Operation:

Fig3.12: The two basic states of an H-bridge

The H-Bridge arrangement is generally used to

reverse the polarity of the motor, but can also be

used to 'brake' the motor, where the motor comes to

a sudden stop, as the motor's terminals are shorted,

or to let the motor 'free run' to a stop, as the motor

is effectively disconnected from the circuit. The

following table summarizes operation.

S1 S2 S3 S4 Result

1 0 0 1 Motor moves right

0 1 1 0 Motor moves left

0 0 0 0 Motor free runs

0 1 0 1 Motor brakes

1 0 1 0 Motor brakes

Construction

Fig3.13: Typical solid state H-bridge

A solid-state H-bridge is typically constructed

using reverse polarity devices (i.e., PNP BJTs or P-

channel MOSFETs connected to the high voltage

bus and NPN BJTs or N-channel MOSFETs

connected to the low voltage bus).

The most efficient MOSFET designs use N-channel

MOSFETs on both the high side and low side

because they typically have a third of the ON

resistance of P-channel MOSFETs. This requires a

more complex design since the gates of the high

side MOSFETs must be driven positive with

respect to the DC supply rail. However, many

integrated circuit MOSFET drivers include a

charge pump within the device to achieve this.

Alternatively, a switch-mode DC-DC converter can

be used to provide isolated ('floating') supplies to

the gate drive circuitry. A multiple-output fly back

converter is well-suited to this application.

A "double pole double throw" relay can generally

achieve the same electrical functionality as an H-

bridge (considering the usual function of the

device). An H-bridge would be preferable to the

relay where a smaller physical size, high speed

switching, or low driving voltage is needed, or

where the wearing out of mechanical parts is

undesirable.

3.6 REAL-TIME CLOCK

Dallas semiconductor real-time clock from

an older PC. This version also contains a battery

backed SRAM.

A real-time clock (RTC) is a computer clock

(most often in the form of an integrated circuit) that

keeps track of the current time. Although the term

often refers to the devices in personal computers,

servers and embedded systems, RTCs are present in

almost any electronic device which needs to keep

accurate time.

Terminology

The term is used to avoid confusion with

ordinary hardware clocks which are only signals

that govern digital electronics, and do not count

time in human units. RTC should not be confused

with real-time computing, which shares its three-

letter acronym, but does not directly relate to time

of day.

Purpose

Although keeping time can be done without an

RTC, using one has benefits:

Low power consumption (important when

running from alternate power)

Frees the main system for time-critical tasks

Sometimes more accurate than other methods

A GPS receiver can shorten its startup

time by comparing the current time, according to

its RTC, with the time at which it last had a valid

signal. If it has been less than a few hours then the

previous ephemeris is still usable.

Power source

RTCs often have an alternate source of

power, so they can continue to keep time while the

primary source of power is off or unavailable. This

alternate source of power is normally a lithium

battery in older systems, but some newer systems

use a supercapacitor, because they are rechargeable

and can be soldered. The alternate power source

can also supply power to battery backed RAM.

Timing

Most RTCs use a crystal oscillator, but some use

the power line frequency. In many cases the

oscillator's frequency is 32.768 kHz. This is the

same frequency used in quartz clocks and watches,

and for the same reasons, namely that the

frequency is exactly 215 cycles per second, which is

a convenient rate to use with simple binary counter

circuits.

System time

In computer science and computer

programming, system time represents a computer

system's notion of the passing of time. In this sense,

time also includes the passing of days on the

calendar.

System time is measured by a system

clock, which is typically implemented as a simple

count of the number of ticks that have transpired

since some arbitrary starting date, called the epoch.

For example, Unix and POSIX-compliant systems

encode system time as the number of seconds

elapsed since the start of the epoch at 1 January

1970 00:00:00 UT. Windows NT counts the

number of 100-nanosecond ticks since 1 January

1601 00:00:00 UT as reckoned in the proleptic

Gregorian calendar, but returns the current time to

the nearest millisecond.

UNIX date command

System time can be converted into

calendar time, which is a form more suitable for

human comprehension. For example, the Unix

system time that is 1,000,000,000 seconds since the

beginning of the epoch translates into the calendar

time 9 September 2001 01:46:40 UT. Library

subroutines that handle such conversions may also

deal with adjustments for time zones, Daylight

Saving Time (DST), leap seconds, and the user's

locale settings. Library routines are also generally

provided that convert calendar times into system

times.

Closely related to system time is process

time, which is a count of the total CPU time

consumed by an executing process. It may be split

into user and system CPU time, representing the

time spent executing user code and system kernel

code, respectively. Process times are a tally of CPU

instructions or clock cycles and generally have no

direct correlation to wall time.

File systems keep track of the times that

files are created, modified, and/or accessed by

storing timestamps in the file control block (or

inode) of each file and directory.

It should be noted that most first-generation PCs did

not keep track of dates and times. Retrieving

system time.

3.7 SOLAR PANEL

Solar panel specifications:

Solar panels use sunlight to re-charge RV

batteries. The process is called PHOTOVOLTAICS

(PV). We stock panels that have a life expectancy

of over 30 years and have a manufacturer's

warranty on output of 25 years long. We prefer the

brands that use "solid crystal silicon" cells for the

highest efficiency as they work well under adverse

conditions -- even on rainy days.

The strong aluminum frame is glazed with

special clear and toughened tempered glass that

may withstand hailstones and other hazards. We

expect these long-life panels made by SHELL, BP

SOLAR, KYOCERA/SHARP/ and others will

work for 30 years or more.

Photovoltaic module:

"Solar panel" redirects here. For the heat collectors,

see Solar thermal collector.

Fig3.14: Photovoltaic module

A photovoltaic module is composed of

individual PV cells. This crystalline-silicon module

has an aluminium frame and glass on the front.

A PV module on the ISS.

A photovoltaic module or photovoltaic

panel is a packaged interconnected assembly of

photovoltaic cells, also known as solar cells. The

photovoltaic module, known more commonly as

the solar panel, is then used as a component in a

larger photovoltaic system to offer electricity for

commercial and residential applications.

Because a single photovoltaic module can

only produce a limited amount of power, many

installations contain several modules or panels and

this is known as a photovoltaic array. A

photovoltaic installation typically includes an array

of photovoltaic modules or panels, an inverter,

batteries and interconnection wiring.

Photovoltaic systems are used for either on- or off-

grid applications, and for solar panels on

spacecraft.

Working of SOLAR panel:

Solar panels collect solar radiation from

the sun and actively convert that energy to

electricity. Solar panels are comprised of several

individual solar cells. These solar cells function

similarly to large semiconductors and utilize a

large-area p-n junction diode. When

the solar cells are exposed to sunlight, the p-n

junction diodes convert the energy from sunlight

into usable electrical energy. The energy generated

from photons striking the surface of the solar panel

allows electrons to be knocked out of their orbits

and released, and electric fields in the solar cells

pull these free electrons in a directional current,

from which metal contacts in the solar cell can

generate electricity.

The more solar cells in a solar panel and

the higher the quality of the solar cells, the more

total electrical output the solar panel can produce.

The conversion of sunlight to usable electrical

energy has been dubbed the Photovoltaic Effect.

Solar Insolation and Solar Panel Efficiency:

Solar Insolation is a measure of how much

solar radiation a given solar panel or surface

receives. The greater the insolation, the more solar

energy can be converted to electricity by the solar

panel. Click to learn more about solar insolation.

Other factors that affect the output of solar

panels are weather conditions, shade caused by

obstructions to direct sunlight, and the angle and

position at which the solar panel is installed. Solar

panels function the best when placed in direct

sunlight, away from obstructions that might cast

shade, and in areas with high regional solar

insolation ratings.

Solar panel efficiency can be optimized by

using dynamic mounts that follow the position of

the sun in the sky and rotate the solar panel to get

the maximum amount of direct exposure during the

day as possible.

Current research on materials and devices:

Developing new technologies based on

new solar cell architectural designs; and developing

new materials to serve as light absorbers and

charge carriers.

Crystalline silicon modules:

Most solar module are currently

produced from silicon PV cells. These are typically

categorized into either mono crystalline or multi

crystalline modules.

Thin-film modules:

Third generation solar cells are advanced

thin-film cells. They produce high-efficiency

conversion at low cost.

Rigid thin-film modules:

In rigid thin film modules, the cell and the

module are manufactured in the same production

line.

The cell is created directly on a glass

substrate or superstrate, and the electrical

connections are created in situ, a so called

"monolithic integration". The substrate or

superstrate is laminated with an encapsulant to a

front or back sheet, usually another sheet of glass.

The main cell technologies in this

category are CdTe, or a-Si, or a-Si+uc-Si tandem,

or CIGS (or variant). Amorphous silicon has a

sunlight conversion rate of 6-12%.

Flexible thin-film modules:

Flexible thin film cells and modules are

created on the same production line by depositing

the photoactive layer and other necessary layers on

a flexible substrate.

If the substrate is an insulator (e.g.

polyester or polyimide film) then monolithic

integration can be used.

If it is a conductor then another technique for

electrical connection must be used.

Module performance and lifetime:

Module performance is generally rated

under Standard Test Conditions (STC) : irradiance

of 1,000 W/m², solar spectrum of AM 1.5 and

module temperature at 25°C.Electrical

characteristics include nominal power (PMAX,

measured in W), open circuit voltage (VOC), short

circuit current (ISC, measured in amperes),

maximum power voltage (VMPP), maximum power

current (IMPP) and module efficiency (%).Solar

panels must withstand heat, cold, rain and hail for

many years. Many Crystalline silicon module

manufacturers offer warranties that guarantee

electrical production for 10 years at 90% of rated

power output and 25 years at 80% .

Solar cell:

A solar cell is a device that converts the

energy of sunlight directly into electricity by the

photovoltaic effect. Sometimes the term solar cell

is reserved for devices intended specifically to

capture energy from sunlight such as solar panels

and solar cells, while the term photovoltaic cell is

used when the light source is unspecified.

Assemblies of cells are used to make solar panels,

solar modules, or photovoltaic arrays.

Photovoltaics is the field of technology and

research related to the application of solar cells in

producing electricity for practical use. The energy

generated this way is an example of solar energy

(also known as solar power).

Fig3.15: Solar cell

History of solar cells:

The term "photovoltaic" comes from the

Greek φῶς (phōs) meaning "light", and "voltaic",

meaning electric, from the name of the Italian

physicist Volta, after whom a unit of electro-motive

force, the volt, is named. The term "photo-voltaic"

has been in use in English since 1849.

The photovoltaic effect was first

recognized in 1839 by French physicist A. E.

Becquerel. However, it was not until 1883 that the

first solar cell was built, by Charles Fritts, who

coated the semiconductor selenium with an

extremely thin layer of gold to form the junctions.

The device was only around 1% efficient.

Subsequently Russian physicist Aleksandr Stoletov

built the first solar cell based on the outer

photoelectric effect (discovered by Heinrich Hertz

earlier in 1887). Albert Einstein explained the

photoelectric effect in 1905 for which he received

the Nobel Prize in Physics in 1921. Russell Ohl

patented the modern junction semiconductor solar

cell in 1946, which was discovered while working

on the series of advances that would lead to the

transistor.

Simple explanation for working of solar panel:

1. Photons in sunlight hit the solar panel and are

absorbed by semiconducting materials, such as

silicon.

2. Electrons (negatively charged) are knocked

loose from their atoms, allowing them to flow

through the material to produce electricity. Due

to the special composition of solar cells, the

electrons are only allowed to move in a single

direction.

3. An array of solar cells converts solar energy

into a usable amount of direct current (DC)

electricity.

Photo generation of charge carriers:

When a photon hits a piece of silicon, one of three

things can happen:

1. The photon can pass straight through the silicon

— this (generally) happens for lower energy

photons.

2. The photon can reflect off the surface.

3. The photon can be absorbed by the silicon, if

the photon energy is higher than the silicon

band gap value. This generates an electron-hole

pair and sometimes heat, depending on the band

structure.

Charge carrier separation:

There are two main modes for charge carrier

separation in a solar cell:

1. Drift of carriers, driven by an electrostatic field

established across the device

2. Diffusion of carriers from zones of high carrier

concentration to zones of low carrier

concentration (following a gradient of

electrochemical potential).

In the widely used p-n junction solar cells,

the dominant mode of charge carrier separation is

by drift. However, in non-p-n-junction solar cells

(typical of the third generation solar cell research

such as dye and polymer solar cells), a general

electrostatic field has been confirmed to be absent,

and the dominant mode of separation is via charge

carrier diffusion.

The p-n junction:

The most commonly known solar cell is

configured as a large-area p-n junction made from

silicon. As a simplification, one can imagine

bringing a layer of n-type silicon into direct contact

with a layer of p-type silicon. In practice, p-n

junctions of silicon solar cells are not made in this

way, but rather by diffusing an n-type dopant into

one side of a p-type wafer (or vice versa).

If a piece of p-type silicon is placed in

intimate contact with a piece of n-type silicon, then

a diffusion of electrons occurs from the region of

high electron concentration (the n-type side of the

junction) into the region of low electron

concentration (p-type side of the junction). When

the electrons diffuse across the p-n junction, they

recombine with holes on the p-type side. The

diffusion of carriers does not happen indefinitely,

however, because charges build up on either side of

the junction and create an electric field. The

electric field creates a diode that promotes charge

flow, known as drift current, that opposes and

eventually balances out the diffusion of electron

and holes. This region where electrons and holes

have diffused across the junction is called the

depletion region because it no longer contains any

mobile charge carriers. It is also known as the

space charge region.

Connection to an external load:

Ohmic metal-semiconductor contacts are

made to both the n-type and p-type sides of the

solar cell, and the electrodes connected to an

external load. Electrons that are created on the n-

type side, or have been "collected" by the junction

and swept onto the n-type side, may travel through

the wire, power the load, and continue through the

wire until they reach the p-type semiconductor-

metal contact. Here, they recombine with a hole

that was either created as an electron-hole pair on

the p-type side of the solar cell, or a hole that was

swept across the junction from the n-type side after

being created there. The voltage measured is equal

to the difference in the quasi Fermi levels of the

minority carriers, i.e. electrons in the p-type portion

and holes in the n-type portion.

SOLAR CELL EFFICIENCY FACTORS:

Energy conversion efficiency:

A solar cell's energy conversion efficiency

(η, "eta"), is the percentage of power converted

(from absorbed light to electrical energy) and

collected, when a solar cell is connected to an

electrical circuit. This term is calculated using the

ratio of the maximum power point, Pm, divided by

the input light irradiance (E, in W/m2) under

standard test conditions (STC) and the surface area

of the solar cell (Ac in m2).

STC specifies a temperature of 25 °C and

an irradiance of 1000 W/m2 with an air mass 1.5

(AM1.5) spectrum. These correspond to the

irradiance and spectrum of sunlight incident on a

clear day upon a sun-facing 37°-tilted surface with

the sun at an angle of 41.81° above the horizon.

This condition approximately represents solar noon

near the spring and autumn equinoxes in the

continental United States with surface of the cell

aimed directly at the sun. Thus, under these

conditions a solar cell of 12% efficiency with a

100 cm2 (0.01 m2) surface area can be expected to

produce approximately 1.2 watts of power.

The efficiency of a solar cell may be

broken down into reflectance efficiency,

thermodynamic efficiency, charge carrier

separation efficiency and conductive efficiency.

The overall efficiency is the product of each of

these individual efficiencies.

Due to the difficulty in measuring these

parameters directly, other parameters are measured

instead: thermodynamic efficiency, quantum

efficiency, VOC ratio, and fill factor. Reflectance

losses are a portion of the quantum efficiency under

"external quantum efficiency". Recombination

losses make up a portion of the quantum efficiency,

VOC ratio, and fill factor. Resistive losses are

predominantly categorized under fill factor, but

also make up minor portions of the quantum

efficiency, VOC ratio.

Bulk technology:

These bulk technologies are often referred

to as wafer-based manufacturing. In other words, in

each of these approaches, self-supporting wafers

between 180 to 240 micrometers thick are

processed and then soldered together to form a

solar cell module.

Crystalline silicon:

Fig3.16: Basic structure of a silicon based solar cell

and its working mechanism

By far, the most prevalent bulk material

for solar cells is crystalline silicon (abbreviated as a

group as c-Si), also known as "solar grade silicon".

Bulk silicon is separated into multiple categories

according to crystallinity and crystal size in the

resulting ingot, ribbon, or wafer.

1. Mono crystalline silicon (c-Si): often made using

the Czochralski process. Single-crystal wafer cells

tend to be expensive, and because they are cut from

cylindrical ingots, do not completely cover a square

solar cell module without a substantial waste of

refined silicon. Hence most c-Si panels have

uncovered gaps at the four corners of the cells.

2. Poly or multi crystalline silicon (poly-Si or mc-Si):

made from cast square ingots — large blocks of

molten silicon carefully cooled and solidified.

Poly-Si cells are less expensive to produce than

single crystal silicon cells, but are less efficient. US

DOE data shows that there were a higher number

of multi crystalline sales than mono crystalline

silicon sales.

Ribbon silicon is a type of multi

crystalline silicon: it is formed by drawing flat thin

films from molten silicon and results in a multi

crystalline structure. These cells have lower

efficiencies than poly-Si, but save on production

costs due to a great reduction in silicon waste, as

this approach does not require sawing from ingots.

Lifespan:

Most commercially available solar cells

are capable of producing electricity for at least

twenty years without a significant decrease in

efficiency. The typical warranty given by panel

manufacturers is for a period of 25 - 30 years,

wherein the output shall not fall below 85% of the

rated capacity.

Costs:

Cost is established in cost-per-watt and in

cost-per-watt in 24 hours for infrared capable

photovoltaic cells.

SOFTWARE COMPONENTS

4.1 EMBEDDED ’C’

Software’s used are:

*Keil software for c programming

*Express PCB for lay out design

*Express SCH for schematic design

4.2 KEIL SOFTWARE

Installing the Keil software on a Windows PC

Insert the CD-ROM in your computer’s CD

drive.

On most computers, the CD will “auto run”,

and you will see the Keil installation menu. If

the menu does not appear, manually double

click on the Setup icon, in the root directory:

you will then see the Keil menu.

On the Keil menu, please select “Install

Evaluation Software”. (You will not require a

license number to install this software).

Follow the installation instructions as they

appear.

Loading the Projects

The example projects for this book are NOT loaded

automatically when you install the Keil compiler.

These files are stored on the CD in a directory

“/Pont”. The files are arranged by chapter: for

example, the project discussed in Chapter 3 is in

the directory “/Pont/Ch03_00-Hello”.

Rather than using the projects on the CD (where

changes cannot be saved), please copy the files

from CD onto an appropriate directory on your

hard disk.

Note: you will need to change the file properties

after copying: file transferred from the CD will be

‘read only’.

III. RESULT ANALYSIS

Case (i):

Fig 5.1: Panel inclination at initial

condition

At the initial condition, the panel is perpendicular

to the sunlight with ZERO inclination.

Case (ii):

Fig 5.2: Panel inclination after one hour

After one Hour duration, the sun is elevated.

According to sun direction the panel is also

elevated with inclination of 15o.

Case (iii):

Fig 5.3: Panel inclination at noon period

At the noon period, the sun’s radiation is

perpendicular to the earth surface. At this time, the

panel is parallel to earth surface i.e., perpendicular

to sun’s radiation as usual.

FUTURE ASPECTS

By using special sensors we can get exact sun

tracking instead of time based tracking system.

By preparing infrared solar panels we may generate

power even in night times and also in cloudy days.

Infrared solar panels are differing from traditional

solar panels in the glass cover of collector only.

To turn a photovoltaic solar cell into an infrared

solar energy panel the glass has to be treated during

the production phase. It is turned into low ironed

tempered glass as opposed to normal ironed

tempered glass.

By producing low ironed tempered glass, it means

that the system can absorb high wavelength

sunlight. The high wave length range is from 800 to

1200nm and this is the infrared range. A lower

wave length from 400 to 800nm is the normal

visible sunlight.

APPENDIX

Code:

#include<reg51.h>

#include<string.h>

#include “lcddisplsy.h”

#include “eeprom.h”

Sbit in1 = p2^2;

Sbit in1 = p2^3;

Sbit in1 = p2^4;

Sbit in1 = p2^5;

Sbit sw = p3^1;

Unsigned char B1 , B2 , B3 , Z ;

Unsigned char l , s , n , a , b , I , count , b2temp ,

rcount ;

Unsigned int x ;

Bit BK=0 ;

Void main()

{

b2temp=rcount=0 ;

lcd_init();

display(100);

lcd_init();

display(100);

lcdcmd(0×84);

msgdisplay(“WELCOME”);

display(1000);

lcdcmd(0×01);

msgdisplay(“SOLAR TRACKER”);

lcdcmd(0×01);

/*****start rtc chip*****

/Write_eeprom(0,0)

Display(500);

Write_eeprom(1,0);

Display(500);

Write_eeprom(1,0);

Display(500);

Msgdisplay(“ TIME:”);

While(1)

{

Xx:lcdcmd(0×c1);

For(i=3;i>0;i- -)

{

Z=read_eeprom(i-1);

B1=z&0×0f;

B2=(z&0×f0)>>4;

Lcddata(B2+0×30);

Lcddata(B1+0×30);

If(I !=1)

Lcddata( ‘ : ‘);

If(i==2)

{

If(b2temp!=z)

{

En1=1;

If(rcount<10) //rotate in clockwise

direction

{

In1=1;

In2=0;

}

Else // rotate in anticlockwise direction

{

In1=0;

In2=1;

}

rcount=rcount+1;

if(rcount==20)

rcount=0;

b2temp=z;

delay(200);

en1=0;

in1=in2=0;

}

}

For(x=0;x<1000;x++) //check for switch

{

if(sw==0) //if switch is pressed then

rotate the base

{

delay(1000);

while(sw==0);

en2=1;

in3=1;

in4=0;

delay(1000);

while(sw==1);

en2=0;

in3=0;

in4=0;

while(sw==0);

goto xx;

}

}

}

}}

CONCLUSION

By using solar energy for power generation we are

saving the conventional energy sources for future

generation to maintain balanced power generation.

In our project, we are going to replace the

traditional solar energy collection which is a costly

and very low efficiency process by using solar

tracking system connecting to the solar panel such

that the panel is always perpendicular to the sun

elevation.

It is convenient for the higher power generation.

But it also has a drawback of highly economic.

BIBLIOGRAPHY

Reference Books:

1. The 8051 Micro controller and Embedded

Systems by Muhammad Ali Mazidi,

Janice Gillispie Mazidi

2. Fundamentals of Micro processors and Micro

computers by B. Ram

3. Micro processor Architecture, Programming &

Applications by Ramesh S.

Gaonkar

4. Electrical Machines By P.S.Bimbra

5. .Non-Conventional Energy Sources by G.D.

Rai

References on the Web:

1. www.national.com

2. www.atmel.com

3. www.microsoftsearch.com

4. www.geocities.com