Maximum solar absorption using dual axis solar panel report

Maximum Solar Absorption using Dual Axis Solar Panel

CONTENTS

PAGE NO:

CHAPTER 1: PREAMBLE

1.1: INTRODUCTION 4

1.2: LIST OF FIGURES 7 1.3: BASIC BLOCK DIAGRAM 8

1.4: BLOCK DIAGRAM FOR 9 THE READY PROJECT

CHAPTER 2: LITERATURE SURVEY 11

CHAPTER 3: SENSORS

3.1: PHOTOSENSORS 14 3.2: CURRENT SENSORS 15

CHAPTER 4: MODULES

4.1: SOLAR TRACKER ASSEMBLY 19 4.2: MOTOR CONTROL 20 4.3: GEAR CONTROL 224.4: CHARGE CONTROLLER 244.5: BATTERY 25

CHAPTER 5: MECHANICS

5.1: PLUMMER BLOCK 295.2: BALL BEARING 305.3: SCHEMATIC ASSEMBLY 31

CHAPTER 6: SOFTWARE

6.1: ARDUINO (SOFTWARE) 34 6.2: ARDUINO BREAKOUT BOARD 36 6.3: FLOW CHARTS 38

CHAPTER 7: TESTING 41

CHAPTER 8: APPLICATIONS

Dept. of ECE, PESIT-BSC 1


8.1: ALTERNATE ENERGY SOURCE 448.2: PANEL MEASURING APPARATUS 49

CHAPTER 9: CONCLUSION

9.1: CONCLUSION 51 9.2: FUTURE ENHANCEMENTS 52

BIBLIOGRAPHY 53 APPENDIX 1

A1.1 MILESTONES AND TARGETS 55A1.2 ACTIVITIES AND GANNT CHART 57



CHAPTER 1

PREAMBLE



CHAPTER 1

PREAMBLE

1.1 INTRODUCTION

One of the most promising renewable energy sources characterized by a huge potential of

conversion into electrical power is the solar energy. The conversion of solar radiation into

electrical energy by Photo-Voltaic (PV) effect is a very promising technology, being clean, silent

and reliable, with very small maintenance costs and small ecological impact. The continuous

evolution of the technology determined a sustained increase of the conversion efficiency of PV

panels, but nonetheless the most part of the commercial panels have efficiencies no more than

20%. A constant research preoccupation of the technical community involved in the solar energy

harnessing technology refers to various solutions to increase the PV panel’s conversion

efficiency.

The continuous modification of the sun-earth relative position determines a continuously

changing of incident radiation on a fixed PV panel. The point of maximum received energy is

reached when the direction of solar radiation is perpendicular on the panel surface. Thus an

increase of the output energy of a given PV panel can be obtained by mounting the panel on a

solar tracking device that follows the sun trajectory. PVs offer added advantages over other

renewable energy sources in that they give off no noise and require practically no maintenance.

A tracking system must be able to follow the sun with a certain degree of accuracy, return the

collector to its original position at the end of the day and also track during periods of cloud over.

The major components of this system are as follows.

Light dependent resistor

Microcontroller

Output mechanical transducer (stepper motor)

The main aim of our project is to track the maximum solar energy without radiation loss for the

efficient use of solar energy. The problem with the existing system is stationary solar panels

cannot track maximum radiations hence most of energy is wasted.



In order to overcome this, our project aims at implementing rotatory solar panel using

microcontrollers which will rotate by sensing the intensity of the radiation for the efficient

utilization of tracked solar energy and avoid unnecessary usage of power when not in use.

BACKGROUND: By using solar arrays, a series of solar cells electrically connected, a DC

voltage is generated which can be physically used on a load. Solar arrays or panels are being

used increasingly as efficiencies reach higher levels, and are especially popular in remote areas

where placement of electricity lines is not economically viable. This alternative power source is

continuously achieving greater popularity especially since the realization of fossil fuels

shortcomings. Renewable energy in the form of electricity has been in use to some degree as

long as 75 or 100 years ago. Sources such as Solar, Wind, Hydro and Geothermal have all been

utilized with varying levels of success. The most widely used are hydro and wind power, with

solar power being moderately used worldwide.

A Solar Tracker is a device onto which solar panels are fitted which tracks the motion of the sun

across the sky ensuring that the maximum amount of sunlight strikes the panels throughout the

day. The Solar Tracker will attempt to navigate to the best angle of exposure of light from the

sun.

Technology of Solar Panel:

Solar panels are devices that convert light into electricity. They are called solar after the sun

because the sun is the most powerful source of the light available for use. They are sometimes

called photovoltaic which means "light-electricity". Solar cells or PV cells rely on the

photovoltaic effect to absorb the energy of the sun and cause current to flow between two

oppositely charge layers. A solar panel is a collection of solar cells. Although each solar cell

provides a relatively small amount of power, many solar cells spread over a large area can

provide enough power to be useful. To get the most power, solar panels have to be pointed

directly at the Sun. The development of solar cell technology begins with 1839 research of

French physicist Antoine-Cesar Becquerel. He observed the photovoltaic effect while

experimenting with a solid electrode in an electrolyte solution. After that he saw a voltage

developed when light fell upon the electrode.



Evolution of Solar Tracker:

Since the sun moves across the sky throughout the day, in order to receive the best angle of

exposure to sunlight for collection energy. A tracking mechanism is often incorporated into the

solar arrays to keep the array pointed towards the sun. A solar tracker is a device onto which

solar panels are fitted which tracks the motion of the sun across the sky ensuring that the

maximum amount of sunlight strikes the panels throughout the day. When compare to the price

of the PV solar panels, the cost of a solar tracker is relatively low. Most photovoltaic solar panels

are fitted in a fixed location- for example on the sloping roof of a house, or on framework fixed

to the ground. Since the sun moves across the sky though the day, this is far from an ideal

solution. Solar panels are usually set up to be in full direct sunshine at the middle of the day

facing South in the Northern Hemisphere, or North in the Southern Hemisphere. Therefore

morning and evening sunlight hits the panels at an acute angle reducing the total amount of

electricity which can be generated each day.

Fig1. Sun’s apparent motion

During the day the sun appears to move across the sky from left to right and up and down above

the horizon from sunrise to noon to sunset. Figure shows the schematic above of the Sun's

apparent motion as seen from the Northern Hemisphere.



1.3 LIST OF FIGURES:

1. Sun’s apparent position 6

2. Basic block diagram 8

3. Final block diagram of prepared project 9

4. Working flowchart for block diagram 9

5. Light dependent resistor 14

6. Current sensor ACS712 15

7. Current sensor pin out 15

8. Voltage divider circuit 17

9. Types of trackers 19

10. Stepper motor 20

11. Unipolar and bipolar motors 21

12. Gear box 23

13. Gear box cross section 23

14. Charge controller 25

15. Plummer block 30

16. Ball bearing 31

17. Schematic assembly of tracker 31

18. Snapshot of the assembly 32

19. Arduino Uno snapshot 34

20. ARDUINO pin out 34

21. ARDUINO MEGA 2560 board 36

22. ARDUINO breakout board 36

23. Constant solar panel current and voltage vs time graph 47

24. Rotating solar panel current and voltage vs time graph 48

25. Snapshot of voltage & current readings 49

26. Milestones 55

27. Gantt chart 57



1.3 BASIC BLOCK DIAGRAM

Fig.2

The solar panel is designed in such a way that maximum efficiency is obtained. The solar energy

from sun is converted into electrical energy by the use of photovoltaic cells. This power from

solar panels cannot be used directly to charge the battery directly so we use a charge controller.

To facilitate this charge controller is developed. We use a dc to dc converter which is given to

load regulator which monitors the load. A pressure sensor is used to monitor the incoming or

outgoing person so, the lights are on or off.

TOOLS:

Hardware: Solar panel, Geared Motor, Load, Sensors, Microcontroller unit.



1.3 BLOCK DIAGRAM FOR READY PROJECT

Fig.3

Fig.4



CHAPTER 2

LITERATURE SURVEY



LITERATURE REVIEW

Sun-synchronous navigation is related to moving the solar powered rover (robot) in such a way

that its solar panel always points toward the sun and which results into maximum battery

charging and hence the rover can work for long hours. The unique feature of this solar tracking

system is that instead of taking the earth as its reference, it takes the sun as a guiding source. Its

active sensors constantly monitor the sunlight and rotate the panel towards the direction where

the intensity of sunlight is maximum. The light dependent resistor’s do the job of sensing the

change in the position of the Sun. The control circuit does the job of fetching the input from the

sensor and gives command to the motor to run in order to tackle the change in the position of the

sun. By using this system the additional energy generated is around 25% to 30% with very less

consumption by the system itself. The project describes the use of a microcontroller based design

methodology of an automatic solar tracker. Light dependent resistors are used as the sensors of

the solar tracker. The tracking system maximizes solar cell output by positioning a solar panel at

the point of maximum light intensity. This paper describe the use of DC motors, special motors

like stepper motors, servo motors, real time actuators, to operate moving parts of the solar

tracker. The system was designed as the normal line of solar cell always move parallel to the rays

of the sun.

The Aim of one of the referred project publications is to develop and implement a prototype of

two-axis solar tracking system based on a microcontroller. The parabolic reflector or parabolic

dish is constructed around two feed diameter to capture the sun’s energy. The focus of the

parabolic reflector is pointed to a small area to get extremely high temperature. The temperature

at the focus of the parabolic reflector is measured with temperature probes. This auto-tracking

system is controlled with two 12V, 6W DC gear box motors. The five light sensors (LDR) are

used to track the sun and to start the operation (Day/Night operation). The paper adopts the

PWM DC motor controller. It is capable of archiving the timeliness, reliability and stability of

motor speed control, which is difficult to implement in traditional analog controller. The project

concentrates on the design and control of dual axis orientation system for the photovoltaic solar

panels. The orientation system calculations are based on astronomical data and the system is

assumed to be valid for any region with small modifications. The system is designed to control

the Altitude angle in the vertical plane as well as the Azimuth angle in the horizontal plane of the

photovoltaic panel workspace. And this system is expected to save more than 40% of the total



energy of the panels by keeping the panel’s face perpendicular to the sun. In the previous

solutions, each tracking direction is controlled by using a Sun sensor made by a pair of

phototransistors.

Sensor control is that sunray is detected by photoelectric detector and then the changed signal is

transmitted to control step motor to adjust the attitude of the solar. The paper discusses the

technology options, their current status and opportunities and challenges in developing solar

thermal power plants in the context of India. The National Solar Mission is a major initiative of

the Government of India and State Governments to promote ecologically sustainable growth

while addressing India’s energy security challenge. It will also constitute a major contribution by

India to the global effort to meet the challenges of climate change.



CHAPTER 3

SENSORS



SENSORS

3.1 PHOTOSENSORS

Light Dependent Resistor

Light Dependent Resistor is made of a high-resistance semiconductor. It can also be referred to

as a photoconductor. If light falling on the device is of the high enough frequency, photons

absorbed by the semiconductor give bound electrons enough energy to jump into the conduction

band. The resulting free electron conducts electricity, thereby lowering resistance. Hence, Light

Dependent Resistors is very useful in light sensor circuits. LDR is very high-resistance,

sometimes as high as 10MΩ, when they are illuminated with light resistance drops dramatically.

A photo resistor is a passive component and does not have a PN-junction. The photo resistivity

of any photo resistor may vary widely depending on ambient temperature, making them

unsuitable for applications requiring precise measurement of or sensitivity to light.

We are using two LDR’s at opposite ends of the solar panel to increase the light detection

efficiency of the solar tracker, with a 10K POT for control.

A Light Dependent Resistor is a resistor that changes in value according to the light falling on it.

A commonly used device, the ORP-12, has a high resistance in the dark, and a low resistance in

the light. Connecting the LDR to the microcontroller is very straight forward, but some software

‘calibrating’ is required.

Fig.5



3.2 CURRENT SENSORS

Fig.6

A current sensor is a device that detects electric current (AC or DC) in a wire, and generates a

signal proportional to it. The generated signal could be analog voltage or current or even digital

output. It can be then utilized to display the measured current in an ammeter or can be stored for

further analysis in a data acquisition system or can be utilized for control purpose.

ACS712 provides economical and precise solutions for AC or DC current sensing in industrial,

commercial, and communications systems.

Fig.7



The ACS712 Low Current Sensor Breakout outputs an analog voltage that varies linearly with

sensed current. To calibrate, first set the output offset to the desired level (with zero current on

the sense lines, read output with a DVM). Then with a known current input (a 100mA limited

supply works well for this), set the output deflection with the gain pot. Sensitivity is then

calculated as (Vref - Vdeflect)/ (current input).

Features and Benefits

Low-noise analog signal path

5 μs output rise time in response to step input current

Total output error 1.5% at TA = 25°C

1.2 mΩ internal conductor resistance

2.1 kVRMS minimum isolation voltage from pins 1-4 to pins 5-8

5.0 V, single supply operation

66 to 185 mV/A output sensitivity

Output voltage proportional to AC or DC currents

Factory-trimmed for accuracy

Extremely stable output offset voltage

Nearly zero magnetic hysteresis

Ratiometric output from supply voltage



MATHEMATICS INVOLVED IN ADC CONVERSION:

ACS712: 5amps current sensor has sensitivity of 0.185 V/Amp

For Vcc = 5V and ADC Vref=Vcc

Relationship between input voltage and ADC count is

Count = (1024/Vcc) x Vin

But Vin =(Vcc/2)+0.185(I)

Count =(1024/Vcc)x (Vcc/2)+0.185(I)

I =0.0264 x (count -512)

Voltage Sensing Circuit

Fig.8

Voltage divider circuit is used as a voltage sensor. The maximum voltage extracted from the

solar panel is 20 V. But the arduino microcontroller board is devised for working on atmost 5 V

therefore we are using a voltage divider circuit as shown above with values designed as:

Vo= (Vin x R2)/(R1+R2)

Given Vinmax = 20 Volts

Vomax= 5 Volts

Assume R2=1.5KΩ

Therefore R1= 4.55KΩ



CHAPTER 4

MODULES



4.1 SOLAR TRACKER ASSEMBLY

DRIVE TYPES:

Active tracker

Active trackers use motors and gear trains to direct the tracker as commanded by a controller

responding to the solar direction. As each mirror in a large field will have an individual

orientation these are controlled programmatically through a central computer system, which also

allows the system to be shut down when necessary.

Passive tracker

Passive trackers use a low boiling point compressed gas fluid that is driven to one side or the

other (by solar heat creating gas pressure) to cause the tracker to move in response to an

imbalance. As this is a non-precision orientation it is unsuitable for certain types of concentrating

photovoltaic collectors but works fine for common PV panel types. These will have viscous

dampers to prevent excessive motion in response to wind gusts. Shader/reflectors are used to

reflect early morning sunlight to "wake up" the panel and tilt it toward the sun, which can take

nearly an hour.

Fig.9


Single Axis Trackers:A single axis tracker can pivot in only one plane – horizontal or vertical. The horizontal type is used in tropical regions where the sun gets very high at noon, but the days are short. The vertical type is used in high latitudes (such as in UK) where the sun does not get very high, but summer days can be very long.Although the construction is less complicated it is also less effective in harnessing the total solar energy.

Dual Axis Trackers:Dual axis solar tracker has two degrees of freedom that act as axes of rotation. These axes are typically normal to one another.It can rotate simultaneously in horizontal and vertical directions and are able to point at the sun at all times. Dual axis trackers track the sun both East to West and North to South for added power output (approx. 40% gain) and convenience.


4.2 MOTOR CONTROL

Motor is use to drive the Solar Tracker to the best angle of exposure of light. For this section, we

are using stepper motor.

Stepper Motor

Features

Linear speed control of stepper motor

Control of acceleration, deceleration, max speed and number of steps to move

Driven by one timer interrupt

Full - or half-stepping driving mode

Supports all AVR devices with 16bit timer

Introduction

The stepper motor is an electromagnetic device that converts digital pulses into mechanical shaft

rotation. Many advantages are achieved using this kind of motors, such as higher simplicity,

since no brushes or contacts are present, low cost, high reliability, high torque at low speeds, and

high accuracy of motion.

Fig.10

Bipolar vs. Unipolar stepper motors



The two common types of stepper motors are the bipolar motor and the Unipolar motor. The

bipolar and unipolar motors are similar, except that the Unipolar has a centre tap on each

winding.

Fig.11

Unipolar stepper motor

Stepper motors are very accurate motors that are commonly used in computer disk drives,

printers and clocks. Unlike dc motors, which spin round freely when power is applied, stepper

motors require that their power supply be continuously pulsed in specific patterns. For each pulse

the stepper motor moves around one step often 15 degrees giving 24 steps in a full revolution.

There are two main types of stepper motors - Unipolar and Bipolar. Unipolar motors usually

have four coils which are switched on and off in a particular sequence. Bipolar motors have two

coils in which the current flow is reversed in a similar sequence. Each of the four coils in a

Unipolar stepper motor must be switched on and off in a certain order to make the motor turn.

Many microprocessor systems use four output lines to control the stepper motor, each output line



controlling the power to one of the coils. As the stepper motor operates at 5V, the standard

transistor circuit is required to switch each coil. As the coils create a back emf when switched

off, a suppression diode on each coil is also required. The table below show the four different

steps required to make the motor turn.

Bipolar Stepper motor

The bipolar stepper motor has two coils that must be controlled so that the current flows in

different directions through the coils in a certain order. The changing magnetic fields that these

coils create cause the rotor of the motor to move around in steps.

The bipolar motor needs current to be driven in both directions through the windings, and a full

bridge driver is needed as shown in Figure. The center tap on the Unipolar motor allows a

simpler driving circuit shown in Figure, limiting the current flow to one direction. The main

drawback with the Unipolar motor is the limited capability to energize all windings at any time,

resulting in a lower torque compared to the bipolar motor. The Unipolar stepper motor can be

used as a bipolar motor by disconnecting the center tap.

DESCRIPTION RATING

Drive Voltage 12 to 24 volts

Current setting 2.5amps per phase

Type Bipolar/micro- stepping

Maximum input frequency 50KHz

Outermost size 42 x 42 x 30mm

4.3 GEAR CONTROL

A gearbox is defined as the metal casing within which a train of gears is sealed. There are several

important characteristics of motors that provide information about a motor and its capabilities.

They are the motor’s output torque, its current draw, its output speed, its power, and its

efficiency, each of which I will discuss in turn. These characteristics are interdependent and can



all be derived from four values: the motor’s stall torque, stall current, free current, and free

speed.

The gear ratio of a gear train, also known as its speed ratio, is the ratio of the angular velocity of

the input gear to the angular velocity of the output gear. The gear ratio can be calculated directly

from the numbers of teeth on the gears in the gear train.

Fig.12

The gear ratio used in this application is 1:14.33 means that for every one revolution of the

pinion, the gear has made 1/14.33, revolutions. In practical terms, the gear turns more slowly.

Fig.13



Here is a basic explanation of how the gearbox works. The engine drives the input shaft. The

gears transfer the torque to the output shaft. This shaft has a pinion on it which drives the ring

gear around the diff assembly. These two parts determine the final drive ratio of the vehicle, and

as it is before the diff they can be changed independent of any other ratio.

The ring gear is around the center diff. This diff splits the torque between front and rear axle.

Think of it purely as a normal diff, with two output shafts for now. One of these shafts goes to

the front diff, which acts in the normal matter to split torque between the front two wheels. The

other goes to the rear diff, just like a rwd car.

4.4 CHARGE CONTROLLER

A solar charge controller or regulator is a small box consisting of solid state circuits pcb which

is placed between a solar panel and a battery. Its function is to regulate the amount of charge

coming from the panel that flows into the battery bank in order to avoid the batteries being

overcharged.

A charge controller limits the rate at which electric current is added to or drawn from electric

batteries. It prevents overcharging and may prevent against overvoltage, which can reduce

battery performance or lifespan, and may pose a safety risk. It may also prevent completely

draining ("deep discharging") a battery, or perform controlled discharges, depending on the

battery technology, to protect battery life.

A solar charge controller is needed in virtually all solar power systems that utilize batteries. The

job of the solar charge controller is to regulate the power going from the solar panels to the

batteries. Overcharging batteries will at the least significantly reduce battery life and at worst

damage the batteries to the point that they are unusable.

Most solar power systems use 12 volt batteries, like you find in cars. (Some use other voltages

and the same advantages apply to these systems as well.) Solar panels can deliver far more

voltage than is required to charge the batteries. By, in essence, converting the excess voltage into



amps, the charge voltage can be kept at an optimal level while the time required to fully charge

the batteries is reduced. This allows the solar power system to operate optimally at all times.

Fig.14

4.5 BATTERY

Batteries are device which are used for storing chemical energy in form of electrical energy. It

consists of one or more electrochemical cells. Although there are different types of battery but

for PV systems lead acid batteries are preferred.

When buying a battery, there are several factors that should be taken into account to determine

the total cost of ownership over the life of the battery.

• The Most Important Consideration – Cycle Life: While the factors above are important, the

most critical consideration is cycle life, which measures the number of discharge/charge cycles

the battery can provide before capacity drops to a specified percentage of its rated capacity.

• Capacity: A battery’s capacity is very important since it is the measurement of the amount of

energy stored in the battery.

• Voltage: The battery bank voltage must be considered to ensure it matches the system

requirements. By the voltage of the loads in a DC system.



Although there are different types of battery but for PV systems lead acid batteries are preferred.

This kind of battery needs charging when 60% of its capacity is used and is superior to all other

batteries in terms of price to power ratio.

Advantages of Lead Acid Batteries:

It is robust and reliable and cheap.

Has slight tolerance towards overcharging.

Has low internal impedance

Ability to deliver high current.

Comes in variety of charge and storage capacities.

Disadvantages of Lead Acid Batteries:

Must be stored in charged state to avoid crystallization of cells.

Charge efficiency is 55 to 60%.

Cycle life of 300 to 500 cycles.

Cannot be charged very fast.

Lead Acid Batter Discharge Cycle:

A fully charged battery is connected to a load (light bulb) and the chemical reaction between

sulfuric acid and the lead plates produces the electricity to light the bulb. This chemical reaction

also begins to coat both positive and negative plates with a substance called lead sulfate also

known as sulfation (shown as a yellow build-up on plates). This build-up of lead sulfate is

normal during a discharge cycle. As the battery continues to discharge, lead sulfate coats more

and more of the plates and battery voltage begins to decrease from fully charged state of 12.6-

volts. The battery is now fully discharged, the plates are almost completely covered with lead

sulfate (sulfation) and voltage has dropped to 10.5-volts.

Lead sulfate (sulfation) now coats most of the battery plates. Lead sulfate is a soft material,

which can is reconverted back into lead and sulfuric acid, provided the discharged battery is



immediately connected to a battery charger. If a lead acid battery is not immediately recharged,

the lead sulfate will begin to form hard crystals, which cannot be reconverted by a standard fixed

voltage (13.6 volts) battery converter/charger.

Lead Acid Battery Recharge Cycle

The discharged battery is connected to a converter/charger with its output voltage set at 13.6-

volts. In order to recharge a 12-volt lead acid battery with a fully charged terminal voltage of

12.6-volts, the charger voltage must be set at a higher voltage. Most converter/chargers on the

market are set at approximately 13.6-volts. During the battery recharge cycle lead sulfate

(sulfation) begins to reconvert to lead and sulfuric acid. During the recharging process as

electricity flows through the water portion of the electrolyte and water, (H2O) is converted into

its original elements, hydrogen and oxygen. These gasses are very flammable and the reason

your RV or Marine batteries must be vented outside. Gassing causes water loss and therefore

lead acid batteries need to have water added periodically. Sealed lead acid batteries contain most

of these gasses allowing them to recombine into the electrolyte. If the battery is overcharged

pressure from these gasses will cause relief caps to open and vent, resulting in some water loss.

Most sealed batteries have extra electrolyte added during the manufacturing process to

compensate for some water loss.

DESCRIPTION RATING

Nominal Voltage 12 volts

Nominal Capacity 40Amp hr

Max Charging current 12 A



CHAPTER 5

MECHANICS



5.1 PLUMMER BLOCK

A pillow block, also known as a plummer block or bearing housing, is a pedestal used to provide

support for a rotating shaft with the help of compatible bearings & various accessories. Housing

material for a pillow block is typically made of cast iron or cast steel.

Pillow blocks are usually referred to the housings which have a bearing fitted into them and thus

the user need not purchase the bearings separately. Pillow blocks are usually mounted in cleaner

environments and generally are meant for lesser loads of general industry. These differ from

"plummer blocks" which are bearing housings supplied without any bearings and are usually

meant for higher load ratings and corrosive industrial environments. However the terms pillow

block and plummer block are used interchangeably in certain parts of the world.

The fundamental application of both types is the same which is to mount bearings safely

enabling their outer ring to be stationary while allowing rotation of the inner ring. The housing is

bolted to a foundation through the holes in the base. Bearing housings are either split type or

unsplit type. Split type housings are usually two piece housings where the cap and base can be

detached, while certain series are one single piece housings. Various seals are provided to

prevent dust and other contaminants from entering the housing. Thus the housing provides a

clean environment for the expensive bearings to freely rotate, hence increasing their performance

and duty cycle.

Bearing housings are usually made of grey cast iron. However various grades of metals can be

used to manufacture the same.

ISO 113 specifies internationally accepted dimensions for plummer blocks.



Fig.15

5.2 BALL BEARING

A ball bearing is a type of rolling-element bearing that uses balls to maintain the separation

between the bearing races.

The purpose of a ball bearing is to reduce rotational friction and support radial and axial loads. It

achieves this by using at least two races to contain the balls and transmit the loads through the

balls. In most applications, one race is stationary and the other is attached to the rotating

assembly (e.g., a hub or shaft). As one of the bearing races rotates it causes the balls to rotate as

well. Because the balls are rolling they have a much lower coefficient of friction than if two flat

surfaces were sliding against each other. Ball bearings tend to have lower load capacity for their

size than other kinds of rolling-element bearings due to the smaller contact area between the

balls and races. However, they can tolerate some misalignment of the inner and outer races. For a

bearing to operate properly, it needs to be lubricated. In most cases the lubricant is based

on elastohydrodynamic effect (by oil or grease) but working at extreme temperatures dry

lubricated bearings are also available.

For a bearing to have its nominal lifespan at its nominal maximum load, it must be lubricated

with a lubricant (oil or grease) that has at least the minimum dynamic viscosity (usually denoted

with the Greek letter ) recommended for that bearing. The recommended dynamic viscosity is

inversely proportional to diameter of bearing.



Fig.16

5.3 SYSTEM SCHEMATIC

Fig.17

Mounting System

The mounting system refers to the structure which holds the solar panels, the structure

consist of movable and fixed parts based on a set of criteria.

The structure must be able to support the weight of the solar panel which is mounted on

it.

Fabrication

The base part of mounting system is shown above.



The plumber blocks are used to provide support for a rotating shaft with the help of

compatible bearings.

At the one end of the metal shaft stepper motor is mounted with gear box. Gear box with

stepper motor controls the east to west rotation of solar panel.

The below structure is mounted on shaft for north to south rotation. The solar panel frame is

mounted on the top.

Fig.18



CHAPTER 6

SOFTWARE



6.1 ARDUINO

The Arduino integrated development environment (IDE) is a cross-platform application written

in Java, and derives from the IDE for the Processing programming language and

the Wiring projects. It is designed to introduce programming to artists and other newcomers

unfamiliar with software development. It includes a code editor with features such as syntax

highlighting, brace matching, and automatic indentation, and is also capable of compiling and

uploading programs to the board with a single click. A program or code written for Arduino is

called a "sketch". These systems provide sets of digital and analog I/O pins that can be interfaced

to various extension boards and other circuits. The boards feature serial communications

interfaces, including USB on some models, for loading programs from personal computers. For

programming the microcontrollers, the Arduino platform provides an integrated development

environment (IDE) based on the Processing project, which includes support for C and C+

+ programming languages.

Arduino programs are written in C or C++. The Arduino IDE comes with a software

library called "Wiring" from the original Wiring project, which makes many common

input/output operations much easier.

Fig.19 Fig.20



ARDUINO MEGA 2560:

The Arduino Mega 2560 is a microcontroller board based on the ATmega2560. It has 54 digital

input/output pins (of which 15 can be used as PWM outputs), 16 analog inputs,

4 UARTs (hardware serial ports), a 16 MHz crystal oscillator, a USB connection, a power jack,

an ICSP header, and a reset button. It contains everything needed to support the microcontroller;

simply connect it to a computer with a USB cable or power it with a AC-to-DC adapter or

battery to get started.

The power pins are as follows:

VIN. The input voltage to the Arduino board when it's using an external power source (as

opposed to 5 volts from the USB connection or other regulated power source). You can supply

voltage through this pin, or, if supplying voltage via the power jack, access it through this pin.

5V. This pin outputs a regulated 5V from the regulator on the board. The board can be supplied

with power either from the DC power jack (7 - 12V), the USB connector (5V), or the VIN pin of

the board (7-12V). Supplying voltage via the 5V or 3.3V pins bypasses the regulator, and can

damage your board.

3V3. A 3.3 volt supply generated by the on-board regulator. Maximum current draw is 50 mA.

GND. Ground pins.

IOREF. This pin on the Arduino board provides the voltage reference with which the

microcontroller operates. A properly configured shield can read the IOREF pin voltage and

select the appropriate power source or enable voltage translators on the outputs for working with

the 5V or 3.3V. In addition, some pins have specialized functions.

The Arduino Mega2560 has a resettable polyfuse that protects your computer's USB ports from

shorts and overcurrent. Although most computers provide their own internal protection, the fuse

provides an extra layer of protection. If more than 500 mA is applied to the USB port, the fuse

will automatically break the connection until the short or overload is removed.



Fig.21

6.2 ARDUINO BREAKOUT BOARD

Fig.22

If you have a project with any audio, video, graphics, data logging, etc in it, you'll find that

having a removable storage option is essential. Most microcontrollers have extremely limited

built-in storage. For example, even the Arduino Mega chip (the Atmega2560) has a mere

4Kbytes of EEPROM storage. There's more flash (256K) but you can't write to it as easily and

you have to be careful if you want to store information in flash that you don't overwrite the

program itself! To get that kind of storage we're going to use the same type that's in every digital

camera and mp3 player: flash cards! Often called SD or microSD cards, they can pack gigabytes

into a space smaller than a coin. They're also available in every electronics shop so you can

easily get more and best of all, many computers have SD or microSD card readers built in so you

can move data back and forth between say your Arduino GPS data logger and your computer

graphing software.



There are a few things to watch for when interacting with SD cards: One is that they are strictly

3.3V devices and the power draw when writing to the card can be fairly high, up to 100mA (or

more)! That means that you must have a fairly good 3.3V power supply for the card. Secondly

you must also have 3.3V logic to interface to the pins. We've found that SD cards are fairly

sensitive about the interface pins - the newest cards are edge triggered and require very 'square'

transitions - things like resistor dividers and long wires will have a deleterious effect on the

transition speed, so keep wires short, and avoid using resistor dividers for the 3.3V logic lines.

SD cards require a lot of data transfer, they will give the best performance when connected up to

the hardware SPI pins on a microcontroller. Arduino mega uses digital pins as 50 (MISO), 51

(MOSI), 52 (SCK), and for the CS line, the most common pin is 53 (SS).

Connect the 5V pin to the 5V pin on the Arduino

Connect the GND pin to the GND pin on the Arduino

Connect CLK to pin 13 or 52



FLOWCHART FOR STEPPER MOTOR ROTATION:


Start

Initialize the digital 8 & 9 pins as a output pins(LDR o/p)

a=digitalRead(8)

b=digitalRead(9)

c=a-b

?

c=0 or c>0 or

Clockwise rotation

Anticlockwise rotation No rotation

End

C=0 C<0

c>0

? sd.begin(53)


FLOWCHART FOR SD CARD DATA LOGGING:


Start

Set pin 53 (chip/ slave select) as a output pin

Initialization done

Initialization failed

Create and open text file in sd card

Read or write data to sd card file

Close the file

End

No

Yes


CHAPTER 7

TESTING

SOLAR PANEL

A solar panel is an assembly of photovoltaic cells. Solar Panel is responsible for

harnessing the solar energy and converting it into electrical energy in order to be stored in



the battery for providing power to the stepper motor rotation and supply electricity for

commercial and residential applications.

The solar panel of 60Watt is used in the project because stepper motor requires 48Watt to

rotate which is less than panel output.

Solar panel has been tested for a day being still and then the rotating panel has been

tested for voltage and current readings.

The specifications of solar panel is given below

DESCRIPTION RATING

Open Circuit Voltage 20 volts

DC Output 17 volts

Current 3.2 Amperes

Power 60Watts

Weight 1.5 kg

STEPPER MOTOR

The stepper motor is an electromagnetic device that converts digital pulses into

mechanical shaft rotation.

Our design includes stepper motor in order to provide stepwise rotation of solar panel.

The upper setup includes solar panel, panel base, supporting structure panel base which

will result into the total weight of around 18Kgs.

In order to withstand the weight of upper rotating part and to effective rotation a motor of

20Kgcm is used in the design.

GEAR BOX



The gear box used in the design to hold the panel in the proper position when there is no

power otherwise panel will fall into either of the end. Which also reduces power

consumption by the motor.

The gear ratio of 1:14.33 is used in the design, slow movement as the sun doesn’t move

so fast within an hour.

VOLTAGE DIVIDER CIRCUIT

Voltage divider circuit is used as a voltage sensor. The maximum voltage extracted from

the solar panel is 20 V. But the arduino microcontroller board is devised for working on

atmost 5 V therefore we are using a voltage divider circuit.

CURRENT SENSOR

A current sensor is a device that detects electric current (AC or DC) in a wire, and

generates a signal proportional to it. The generated signal could be analog voltage or

current or even digital output.

Arduino controller only senses the voltage not current , so we need a current sensor.

ACS712 current sensor used in the design has 185 mV/A output sensitivity.

ACS712 current sensor output is voltage proportional to the corresponding input voltage.



CHAPTER 8

APPLICATIONS

8.1 ALTERNATE ENERGY SOURCE

The Earth receives an incredible supply of solar energy. The sun, an average star, is a fusion

reactor that has been burning over 4 billion years. It provides enough energy in one minute to

supply the world's energy needs for one year. In one day, it provides more energy than our



current population would consume in 27 years. In fact, "The amount of solar radiation striking

the earth over a three-day period is equivalent to the energy stored in all fossil energy sources."

Solar energy is a free, inexhaustible resource, yet harnessing it is a relatively new idea. The

ability to use solar power for heat was the first discovery. Producing electricity from solar

energy was the second discovery. In 1839 a French physicist named Edmund Becquerel realized

that the sun's energy could produce a "photovoltaic effect" (photo = light, voltaic = electrical

potential). In the 1880s, selenium photovoltaic (PV) cells were developed that could convert

light into electricity with 1-2% efficiency ("the efficiency of a solar cell is the percentage of

available sunlight converted by the photovoltaic cell into electricity"), but how the conversion

happened was not understood. Photovoltaic power therefore "remained a curiosity for many

years, since it was very inefficient at turning sunlight into electricity.""Only in the last few

decades when growing energy demands, increasing environmental problems and declining fossil

fuel resources made us look to alternative energy options have we focused our attention on truly

exploiting this tremendous resource."

We will enumerate the results of our solar tracker project for both still solar panel and a rotating

solar panel so to show that the voltage and current we get by a tracker assembly is much

favourable than the still one.

For constant solar panel

TIME VOLTAGE(volts) CURRENT(amps)



7.15 am 12.71 0.42 7.30 am 13.03 0.72 7.45 am 13.15 1.09 8.00 am 13.28 1.43 8.15 am 13.59 1.80 8.30 am 13.63 1.80 9.00 am 14.65 1.83 9.20 am 15.5 2.03 9.40 am 17.6 2.1 10.00 am 18 2.15 10.15 am 18.5 2.19 10.45 am 18.7 2.3 11.15 am 18.9 2.49 11.50 am 19.0 2.51 12.30 pm 19.0 2.53 1.00 pm 19.0 2.5 1.30 pm 19.0 2.47 2.00 pm 18.9 2.16 2.30 pm 18.6 2.12 3.00 pm 18.3 2.05 3.30 pm 18.15 1.98 4.00 pm 18.03 1.95 4.30 pm 18.0 1.80

For rotating solar panel east -xº +xº west



Angle TIME VOLTAGE(volts) CURRENT(amps) -30 6.00 am 6.3 0.21 -30 6.30 am 10.2 0.36 -25 7.15 am 12.71 0.42 -25 7.30 am 13.03 0.72 -25 7.45 am 13.15 1.09 -20 8.00 am 13.28 1.43 -20 8.15 am 13.59 1.80 -20 8.30 am 13.63 1.80 -15 9.00 am 14.65 1.83 -15 9.20 am 15.5 2.03 -15 9.40 am 17.6 2.1 -10 10.00 am 18 2.15 -10 10.15 am 18.5 2.19 -10 10.45 am 18.7 2.3 -5 11.15 am 18.9 2.49 0 12.0 am 19.0 2.51 0 12.30 pm 19.0 2.53 5 1.00 pm 19.0 2.5 5 1.30 pm 19.0 2.47 10 2.00 pm 18.9 2.16 10 2.30 pm 18.6 2.12 15 3.00 pm 18.3 2.05 15 3.30 pm 18.15 1.98 20 4.00 pm 18.03 1.95 20 4.30 pm 18.0 1.80





Fig.23



Fig.24



8.2 PANEL MEASURING APPARATUS

We have also expanded the scope of our project by using it as a measuring instrument for any

sized solar panel. What we expect in this kind of application is that before a user buys any solar

panel and is expecting it to work at the given rated voltage or current, he or she can check the

validity of that rating on the apparatus used for solar tracking by our project.

To achieve this we are using ARDUINO breakout board to store the values of voltage and

current outputted by the solar panel over an hour throughout a day so that we can concur the

power efficiency through the readings. After the readings are stored for a day the user can relate

to the outputs and as per his/her requirements it can choose to buy or not to buy the same solar

panel. A snapshot of the same can be shown as

Fig.25



CHAPTER 9

CONCLUSION



9.1 CONCLUSION:

With Global Warming constantly affecting the world in numerous ways, it is essential we begin

taking care of nature in whatever way possible. Present day technologies stress on being clean

and green.

Being environmentally friendly, solar power generators and panels are reasonably easy, safe and

convenient to install. Hence enhancing the solar powered systems with intelligent trackers proves

to be the optimal solution for utilizing the available solar energy.

In recent years, the generation of electricity using solar technology has seen a tremendous

growth, in particular because of the economic considerations and smooth operation of the solar

panels. Even though the initial costs are high, but operation costs and maintenance costs are low.

Solar tracking system today offer an innovative method to track the solar insolation and provide

economic compatibility of the generation of electric power where grid connections are difficult

to setup and costly.

The solar tracker can be still enhanced additional features like rain protection and wind

protection which can be done as future work. From the design of experimental set up with Micro

Controller Based Solar Tracking System Using Stepper Motor If we compare Tracking by the

use of LDR with Fixed Solar Panel System we found that the efficiency of Micro Controller

Based Solar Tracking System is improved by 30-45% and it was found that all the parts of the

experimental setup are giving good results.

Solar Energy Advantages

1. Saves you money

After the initial investment has been recovered, the energy from the sun is practically FREE. The

recovery/ payback period for this investment can be very short depending on how much

electricity your household uses.



2. Environmentally friendly

Solar Energy is clean, renewable (unlike gas, oil and coal) and sustainable, helping to protect our

environment. It does not pollute our air by releasing carbon dioxide, nitrogen oxide, sulphur

dioxide or mercury into the atmosphere like many traditional forms of electrical generations

does. Therefore Solar Energy does not contribute to global warming, acid rain or smog.

Solar Energy Disadvantages

The initial cost is the main disadvantage of installing a solar energy system, largely because of

the high cost of the semi-conducting materials used in building one. The cost of solar energy is

also high compared to non-renewable utility-supplied electricity. As energy shortages are

becoming more common, solar energy is becoming more price-competitive. Solar panels require

quite a large area for installation to achieve a good level of efficiency. The efficiency of the

system also relies on the location of the sun, although this problem can be overcome with the

installation of certain components.

9.2 FUTURE SCOPE

Fabrication of Microcontroller using ASIC concepts: The number of wires can be greatly

reduced by directly if a customized PCB is made upon which all the resistors can be

directly soldered. This also eliminates the use of a Breadboard which was used to make

all the external connections.

Mounting of the Panels: In our design, the panels are mounted on a horizontal shaft

supported strongly at both ends. We can mount the panels directly onto a motor placed at

the center of the Panel-Base in order to provide East-West movement. This reduces the

weight and effective cost of the project.



BIBLIOGRAPHY:

[1] Rizk J. and Chaiko Y. “Solar Tracking System: More Efficient Use of Solar Panels”, World

Academy of Science, Engineering and Technology 41 2008.

[2] Filfil Ahmed Nasir, Mohussen Deia Halboot, Dr. Zidan Khamis A. “Microcontroller-Based

Sun Path Tracking System”, Eng. & Tech. Journal, Vol. 29, No.7, 2011.

[3] P.J. Hession and W.J Bonwick , 1984 “Experience with a sun tracker system” Solar Energy,

Volume 32, Issue 1, pp 3-11.

[4] SOLAR PANEL/TRACKER on Wikipedia.com

[5] Gear box ratio and gear box dependent solar tracker on howstuffworks.com



APPENDIX 1



A1.1 MILESTONES:

Fig.26

JANUARY 2015:

For the solar tracker components design as the solar panel, battery and charge controller

were decided for having a prototype design of the project.

Programming was done using PIC BASIC for the rotation of solar panel based on LDR

inputs and the motor rotation was checked in with the program.

The mechanical design of the tracker was verified and given for the making.

FEBRUARY 2015:

The first model of the tracker was ready for testing but the problem of bearing its own

weight and the weight of the solar panel on one shaft was intolerable.

A new design strategy had to be devised for the better implementation of the project.

Also the solar panel chosen was not outputting enough power to compensate for the loss

through the motors.

Charge controller of suitable current and voltage compatible to the battery being used and

the application to be presented with was decided.



MARCH 2015:

Unlike the first model design the second design was agreed upon the principles of

distributed weight over two assemblies instead of one.

As the first model had to use two motors for dual rotation, so now we had prepared a

design that has only one motor and thus reducing the power loss.

Also the motor had to be powered in throughout to keep the solar panel in the same

position thus we had decided to use a gear box to hold the weight of the panel after it

rotates to a certain angle.

APRIL 2015:

The gearbox was completed within the starting of the month and checked for the weight

tolerance and rotation of the solar panel.

As the whole system was heavy enough to withhold the panel assembly the base had to

be made larger and heavier to provide it with the perfect balance from the ground.

The hardware was assembled completely by the end of the month and was presented in

the project exhibition.

The feedbacks of all the students and faculties were duly noted and the possible

improvements were decided to be made.

Also to expand the scope of application of our project there was a suggestion to make our

project an experimental apparatus for any solar panel to check its practical voltage and

current for a day before deciding on buying the product. This improvement gave a new

direction to our viewpoint.

For this to be done we had to have a data logging part with the rest of the software

assembly which couldn’t be done using PIC thus we switched over to ARDUINO UNO

and used its breakout board sd-card interface to make this improvisation. The current and

voltage were sensed by a current sensor and then they were logged in a text file.

MAY 2015:

The whole system was presented before the project review panel for final remarks and

testing.

Final report was documented as a draft for thorough analysis by the project guide.



A1.2 ACTIVITIES & GANNT CHART:

Fig.27
