CHAPTER 1

INTRODUCTION

1.1 OVERVIEW OF THE PROJECT

Solar based agricultural water pumping is an efficient method that

drastically reduces the power supply cost of normal method. In this proposed

method, the total cost of the apparatus is reduced as only renewable source is used

as the source of energy.

1.2 WORK SUMMARY

A photovoltaic energy conversion system for converting solar power into

useable DC at 5V to 15V has been proposed and implemented which can be used

for charging batteries of low power devices like mobile phones. The energy

obtained from the photovoltaic module is unregulated. But for charging Lithium

ion batteries, we require approximately 11.5V steady DC supply. Therefore the

18V unregulated DC obtained from the PV module is stepped down up to 12V by

DC-DC boost converter.

For efficient usage of photovoltaic energy conversion system, it is essential

to design a maximum power point tracking (MPPT) system. The concept of MPPT

is to automatically vary a PV array's operating point so as to get maximum power.

This is necessary because the PV cell has a very low conversion efficiency and it is

necessary to reduce the cost of the overall system.

The power delivered by array increases to maximum as the current drawn

rises and after a particular value, the voltage falls suddenly making the power drop

to zero. This frequent rise and drop reduces the efficiency drastically, to avoid this

the algorithm keeps tracking the maximum power point in the photo voltaic arrays

1

there by keeping the output almost at a constant value given that the illumination

of the sun stays within a particular range. The efficiency is also is maintained at its

perfect level.

2

CHAPTER 2

LITERATURE SURVEY

2.1 EXISTING METHOD

There is a different commercial pump setup that is in existence powered up

by solar radiation. It has a disadvantage that it does not use the maximum power

point tracking algorithm. It also uses more number of power semiconductor control

circuits. It probably leads to the decrease in the efficiency of the pump. The

existing setup uses an alternating current motor which needs an additional power

semiconductor control setup, an inverter, in addition to the existing power

semiconductor control setup, a converter. This is because the energy obtained from

photovoltaic cells is direct current energy.

2.2 RENEWABLE ENERGY

In recent years, there is a substantial increase of energy consumption in

India. This fast rate of energy consumption is influenced by the population growth

and economic development in India. In the last four decades the commercial

energy consumption in India has grown by about 7 times. This has led to the per

capita consumption in India to be in region of 400 KWH per annum. Driven by the

rise in population, ever expanding economy and an ultimate quest for improved

quality of life, energy usage in India is expected to grow in an exponential rate.

Compared to the other developing countries the per capita energy

consumption in India is still very low even though there is an overall increase in

energy demand every year. Today, India is one of the potential competitors for the

effective usage of renewable energy. India is the world’s largest producer of wind

power after Denmark, Germany, Spain and the USA. India has a significant

3

potential for generation of power from renewable energy sources - Small hydro

power, wind energy, bio-mass and solar energy.

2.3 RENEWABLE ENERGY SCENARIO IN INDIA

Renewable Energy in India is a sector that is still undeveloped. India was

probably the first country in the world to set up a separate ministry of non-

conventional energy resources in early 1980s. However the results have been very

mixed and in recent years it has lagged far behind other developed nations in using

renewable energy (RE). RE contribution to energy sector is less than 1% of India's

total energy needs.

India is one of the largest and fastest growing economies in the world with

an expansive populace of above 1.1 billion people. There is a very high demand for

energy, which is currently satisfied mainly by coal, foreign oil and petroleum,

which apart from being a non-renewable, and therefore non-permanent solution to

the energy crisis, it is also detrimental to the environment.

The price of crude oil has risen sharply over the last few years, and there are

no signs of a change in this trend. Thus, it is imperative that India obtains energy

security without affecting the booming economy, which would mean that

alternative energy sources must be developed. This would mean that the country

must switch from the non-renewable energy (crude oil and coal) to renewable

energy.

The Government of India has already made several provisions, and

established many agencies that will help it achieve its goal. According to reports

Renewable Energy, excluding large hydro projects already accounts for 9% of the

total installed energy capacity, equivalent to 12,610 MW. In combination with

4

large hydro, the capacity is more than 34%, i.e. 48,643MW, in a total installed

capacity of 1,44,980 MW.

2.4 SOLAR ENERGY IN INDIA

Solar power, a clean renewable resource with zero emission, has got

tremendous potential of energy which can be harnessed using a variety of devices.

With recent developments, solar energy systems are easily available for industrial

and domestic use with the added advantage of minimum maintenance. Solar

energy could be made financially viable with government tax incentives and

rebates.

An exclusive solar generation system of capacity of 250KWh per month

would cost around Rs.5 lakhs, with present pricing and taxes (2010). Most of the

developed countries are switching over to solar energy as one of the prime

renewable energy source. The current architectural designs make provision for

photovoltaic cells and necessary circuitry while making building plans.

India is a country near the equator – which means that given its geographical

location, it is subject to a large amount of solar irradiation throughout the year.

India is also, according to area, the seventh largest country in the world.

Combining the two points together, it is not difficult to gauge that solar energy in

India is a vast and plentiful resource. Much of the country does not have access to

electrical grid; one of the first applications of solar power has been for water

pumping; to begin replacing India's four to five million diesel powered water

pumps, each consuming about 3.5 kilowatts, and off-grid lighting.

Some large projects have been proposed, and a 35,000 km² area of the Thar

Desert has been set aside for solar power projects, sufficient to generate 700 to

2,100 Giga Watts. About 7.7 lakhs solar lanterns, 5.1 lakhs solar home lighting

5

systems, 82,500 solar street lighting systems, 7,247 solar water pumping systems,

stand-alone and grid connected solar photovoltaic (SPV) power plants of about 10

MW peak aggregate capacity, about 3.12 million square meter solar water heater

collector area and 6.57 lakhs solar cookers have been distributed/installed in the

country, as on 30.11.2009, under the solar energy programs. The present cost of

electricity generation from solar thermal and solar photovoltaic energy systems is

Rs. 13.45 and Rs. 18.44 per unit, respectively as fixed by Central Electricity

Regulatory Commission.

6

CHAPTER 3

DEVELOPMENT OF SPIP

3.1 INTRODUCTION

In this chapter we get to know the specifications of the components used for

the demonstration of the solar powered irrigation. It also gives the functional

abilities of the components. The functions of the components are explained from

the functional block diagram of the project shown in figure 3.1.

The functional setup consists of the following,

1. Solar Panel

2. Boost converter

3. Battery

4. Motor pump

5. PIC microcontroller

6. MPPT

7

Solar ray

Solar panel Boost Converter Battery

PIC Controller

Display

Motor

Pump

Output

Fig: 3.1: Block Diagram

3.2OBJECTIVE OF THE PROJECT

The use of new efficient photovoltaic solar cells (PVSCs) has emerged as an

alternative measure of renewable green power, energy conservation and demand-

side management. Owing to their high initial cost, PVSCs have not yet been fully

an attractive alternative for electricity users who are able to buy cheaper electrical

power from the utility grid. However, they can be used extensively for water

pumping and air conditioning in remote and isolated areas, where utility power is

not available or is too expensive to transport. This method aims to pump water

using solar panel (Renewable energy source) only, so that the power supply cost is

reduced and reliability is increased.

8

3.3 SPECIFICATIONS

Specifications of Solar panel, Motor, Pump, Battery, Boost conversion are

given below.

3.3.1 Solar Panel

Rated Voltage:

Rated current:

Rated power:

3.3.2 Motor

Rated Voltage: 12 V

Rated current: 1 A

Rated Power: 12 W

3.3.3 Pump

Pressure:

Flow:

3.3.4 Battery

Rated Voltage: 12V

Rated Amp-Hour: 7.2Ah

3.3.5 Controller

Frequency:

9

3.3.6 Power semiconductor setup

3.4 FUNCTIONS OF THE HARDWARE COMPONENTS

3.4.1 SOLAR PANEL:

It converts the solar energy from the sun into 12V/20W electrical output

which can be fed as the input to the battery for the purpose of re-charging. In

between the solar panel and battery a charge controller device is used for

producing pulsating DC that can be fed as the input to battery. This solar energy is

used as the source of energy in the whole apparatus.

10

SOLAR PANEL (12V, 20W)

Fig 3.2: Solar energy conversion

This 12V/20W DC output is variable and that cannot be fed as the input to

the lead acid battery. If variable DC input is given to the battery, the lifetime and

reliability of the battery will be reduced. A new process that simultaneously

combines the light and heat of solar radiation to generate electricity could offer

more than double the efficiency of existing solar cell technology. The process,

called “Photon enhanced thermionic emission”, or PETE, could reduce the costs of

solar energy production enough for it to compare with oil as an energy source. In

concentrating collectors, the area intercepting the solar radiation is greater,

sometimes hundreds of time greater, than the absorber area.

11

3.4.2 BOOST CONVERTER

A boost converter, used as the voltage increase mechanism in the circuit, is

known as the 'Joule thief'. This circuit topology is used with low power battery

applications, and is aimed at the ability of a boost converter to 'steal' the remaining

energy in a battery. This energy would otherwise be wasted since the low voltage

of a nearly depleted battery makes it unusable for a normal load. The energy would

remain untapped because many applications do not allow enough current to flow

through a load when voltage decreases. This voltage decrease occurs as batteries

become depleted, and is a characteristic of the ubiquitous alkaline battery. Since (

) as well, and R tends to be stable, power available to the load goes

down significantly as voltage decreases. Here MOSFET IRF540 is used in the

boost converter circuit for amplifying the energy.

3.4.3 BATTERY

Battery is charged from the solar panel through the charge controller.

Pulsating DC input is fed as the input to the battery.

A lead-acid battery is an electrical storage device that uses a reversible

chemical reaction to store energy. It uses a combination of lead plates or grids and

an electrolyte consisting of a diluted sulphuric acid to convert electrical energy into

potential chemical energy and back again. BLDC Motor shaft is connected to the

pump. The pump has two inputs, one DC input from the lead-acid battery consists

of a negative electrode made of spongy or porous lead. The lead is porous to

facilitate the information and dissolution of lead.

The positive electrode consists of lead oxide. Both electrodes are immersed

in a electrolytic solution of sulfuric acid and water. In case the electrodes come

12

into contact with each other through physical movement of the battery or through

changes in thickness of the electrodes, an electrically insulating, but chemically

permeable membrane separates the two electrodes. This membrane also prevents

electrical shorting through the electrolyte.

3.4.4 MOTOR PUMP

The brushless DC motor is connected to the battery. Output from the battery

is given as input to the Brushless DC motor. The motor is connected to a

centrifugal pump. The pump helps to pump out the water for irrigation.

Fig 3.3: Pump

The fluid enters the pump impeller along or near to the rotating axis and is

accelerated by the impeller, flowing radially outward into a diffuser

or volute chamber (casing), from where it exits. The transfer of energy from the

13

mechanical rotation of the impeller to the motion and pressure of the fluid is

usually described in terms of centrifugal force.

3.4.5 PIC MICROCONTROLLER

The PIC microcontroller is the controlling device for this project setup. The

reason for choosing PIC16F877A is because of its special features which we got to

know in the previous chapter. The solar panel absorbs the radiation and gives it to

the boost converter which boosts up the energy and provides it to the battery. The

battery runs the motor pump.

This work is overlooked and controlled by the PIC microcontroller. It gives

the current boosting limit to the boost converter, for boosting the energy as per the

necessities. It calculates the pulse signal based on the current and voltage sensed

on the output end. The pulse signal is the duty cycle signal to the MOSFET present

in the boost converter.

The PIC microcontroller also carries out the maximum power point tracking

on the solar panel based on the embedded algorithm in it. The algorithm program is

embedded on it from an external source.

The below given figure gives the complete architectural and functional

design of PIC microcontroller. The next section deals abt architrcture and func .

14

3.4.5.1 Architecture

Fig 3.4: PIC 16F877A architecture

15

3.4.6 Maximum power point tracking(MPPT)

Operating point of PVA Photovoltaic modules have a very low conversion

efficiency of around 15% for the manufactured ones. Besides, due to the

temperature, radiation and load variations, this efficiency can be highly reduced. In

fact, the efficiency of any semiconductor device drops steeply with the

temperature. In order to ensure that the photovoltaic modules always act supplying

the maximum power as possible and dictated by ambient operating conditions, a

specific circuit known as Maximum Power Point Tracker (MPPT) is employed. In

most common applications, the MPPT is a DC-DC converter controlled through a

strategy that allows imposing the photovoltaic module operation point on the

Maximum Power Point (MPP) or close to it.

3.4.6.1 I-V curve

Photovoltaic cells have a complex relationship between their operating

environment and the maximum power they can produce. The fill factor,

abbreviated FF, is a parameter which characterizes the non-linear electrical

behavior of the solar cell. Fill factor is defined as the ratio of the maximum power

from the solar cell to the product of Open Circuit Voltage Voc and Short-Circuit

Current Isc. In tabulated data it is often used to estimate the maximum power that a

cell can provide with an optimal load under given conditions, P=FF*Voc*Isc. For

most purposes, FF, Voc, and Isc are enough information to give a useful approximate

model of the electrical behavior of a photovoltaic cell under typical conditions.

16

Fig 3.5: I-V characteristics of MPPT

3.4.6.2 Perturb and observe

In one method, the controller adjusts the voltage by a small amount from the

array and measures power; if the power increases, further adjustments in that

direction are tried until power no longer increases. This is called the perturb and

observe method and is most common, although this method can result in

oscillations of power output. It is referred to as a hill climbing method, because it

17

depends on the rise of the curve of power against voltage below the maximum

power point, and the fall above that point. Perturb and observe is the most

commonly used MPPT method due to its ease of implementation. Perturb and

observe method may result in top-level efficiency, provided that a proper

predictive and adaptive hill climbing strategy is adopted.

This PO strategy MPPT is mixed along with the Fuzzy Logic Control (FLC)

and used here in this project setup. This combining will eliminate the small flaws

in PO method there by giving the best result in maximum power point tracking.

18

3.5 CIRCUIT DIAGRAM

The overall circuit diagram of the solar powered irrigation pump setup is

given.

Fig 3.6: Circuit diagram

3.6 PCB DESIGN

The Printed Circuit Board designed specifically for the controller and the

converter setup of the SPIP setup is below.

19

3.6.1 Front side

Fig 3.7: PCB front side design

3.6.2 Back side

20

Fig 3.8: PCB back side design

CHAPTER 4

HARDWARE DESCRIPTION

4.1 INTRODUCTION

In this chapter, description and specifications of the hardware components

used in this proposed method of solar based water irrigation are discussed. It gives

the specifications of the components used for the demonstration setup created and

also gives the overview of the functional abilities of the components.

4.2 PHOTOVOLTAIC CELL PANEL

A Solar photovoltaic panel is a packaged and connected assembly of

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

photovoltaic system to generate and supply electricity in commercial and

residential applications. Each panel is rated by its DC output power under standard

test conditions and typically ranges from 100 to 320 watts.

The efficiency of a panel determines the area of a panel given the same rated

output – an 8% efficient 230 watt panel will have twice the area of a 16% efficient

230 watt panel. Because a single solar panel can produce only a limited amount of

power, most installations contain multiple panels.

4.2.1 Four types of PV cells

• Selective – Emitter Cell (SEC)

• Emitter wrap- through cells (EWC)

21

• Thin Film Photovoltaic

• Single Crystal Silicon Cells

4.2.2 Single-Crystal Silicon Cell Construction

• The majority of PV cells in use are the single-crystal silicon type.

• Silica (SiO2) is the compound used to make the cells. It is first refined and purified, then melted down and re-solidified so that it can be arranged in perfect wafers for electric conduction. These wafers are very thin.

• The wafers then have either Phosphorous or Boron added to make each wafer either a negative type layer or a positive type layer respectively. Used together these two types treated of crystalline silicon form the p-n junction which is the heart of the solar– electrical reaction.

• Many of these types of cells are joined together to make arrays, the size of each array is dependent upon the amount of sunlight in a given area.

4.2.3 The Photoelectric Effect

The photoelectric effect relies on the principle that whenever light strikes the surface of certain metals electrons are released.

In the p-n junction the n-type wafer treated with phosphorus has extra electrons which flow into the holes in the p-type layer that has been treated with boron.

Connected by an external circuit electrons flow from the n-side to create electricity and end up in the p-side.

Sunlight is the catalyst of the reaction.

The output current of this reaction is DC (direct) and the amount of energy produced is directly proportional to the amount of sunlight put in.

Cells only have an average efficiency of 30%

22

Fig 4.1 photovoltaic array characteristics

4.2.4 Pros and Cons of Solar Electricity

• Expensive to produce because of the high cost of semi- conducting materials, which could be avoided by reducing manufacturing costs.

• The PV Manufacturing Research and Development Project focuses on increasing manufacturing capacity so that the cost of manufacturing will decrease. They aim to achieve break even costs.

• However, solar energy contributes positively to the nation’s energy security because it is produced domestically, reducing reliance on energy imports.

• The industry is still relatively new and extremely hi tech allowing for the creation of more jobs in the American market.

• The government has many incentives program which vary from state to state, but they exist to encourage investment in forms of alternative energy.

• Does not require the transportation of hazardous materials across country.

• Sunlight is a free abundant source

• PV can be designed for a variety of applications

23

• No noise or air pollution

Fig 4.2 solar panel

• Require minimal maintenance and have long service life times.

• Power can be either centralized in individual homes or distributed by electrical companies.

Solar panels use light energy (photons) from the sun to generate electricity

through the photovoltaic effect. The majority of modules use wafer-based

crystalline silicon cells or thin-film cells based on cadmium telluride or silicon.

The structural member of a module can either be the top layer or the black layer.

Cells must also be protected from mechanical damage and moisture.

Most solar panels are rigid, but semi-flexible ones are available, based on

thin-film cells. Electrical connections are made in series to achieve a desired output

voltage and/or in parallel to provide a desired current capability. The conducting

wires that take the current off the panels may contain silver, copper or other non-

magnetic conductive transition metals. The cells must be connected electrically to

24

one another and to rest of the system. Externally popular agricultural usage

photovoltaic panels use connectors to facilitate easy weatherproof connections to

the rest of the system.

4.3BRUSHLESS DC MOTOR

The motor used in the project is Brushless DC motor. Brushless DC Electric

motor (BLDC motors, BL motors) also known as electrically commutated motors

(ECMs, EC motors) are synchronous motors which are powered by a DC electric

source via an integrated inverter/switching power supply, which produces an AC

electric signal to drive the motor (Alternating current, does not imply a sinusoidal

waveform but rather a bi-directional current with no restriction on waveform).

Additional sensors and electronics control the inverter output amplitude and

waveform (and therefore percent

of DC bus usage/efficiency)

and frequency.

Fig 4.3 motor

25

The motor part of a brushless motor is often a Brushless DC motor, but can

also be a switched reluctance motor, or induction motor. Brushless motors may be

described as stepper motors.

4.3.1 Principle of brushless dc motor

The brushless DC motor is the combination of a permanent excited

synchronous motor and a frequency inverter. The inverter has to replace the

commutator of a conventional DC motor. A brushless DC motor can be derived

from a mechanically commutated DC motor with three armature slots. Its armature

winding corresponds to a three phase winding in delta connection. The commutator

acts like a three phase frequency converter.

The commutation of a brushless DC motor depends on the position of the

rotor. The angle between the magneto-motive forces of stator and rotor is fixed to

90 degree, so the motor produces maximum torque and needs low reactive current

that is useful to advance commutation by few degrees to compensate the effects of

the stray inductance and minimize reactive current.

Brushless motors may be described as stepper motors. However, the term

steppers motor tends to be used for motors that are designed specifically to be

operated in a

mode where

they

frequently stopped

with the rotor in

a defined angular

position.

26

Brushless DC motor may be described as stepper motors. They develop a

maximum torque when stationary, linearly decreasing as velocity increases. Some

limitations of brushed motors can be overcome by brushless motors as they include

higher efficiency and a lower susceptibility of the commutator assembly to

mechanical wear. These benefits come at the cost of potentially less rugged, more

complex, and more expensive control electronics.

A typical brushless motor has permanent magnets which rotate and a fixed

armature, eliminating problems associated with connecting current to the moving

armature. An electronic controller replaces the brush and commutator assembly of

the brushed DC motor turning. The controller performs similar timed power

distribution by using a solid-state circuit rather than the brush system.

The enhanced efficiency is greatest in the no-load and low-load region of the

motor’s performance curve. Under high mechanical loads, brushless motors and

high-quality brushed motors are comparable in efficiency. Environments and

requirements in which manufacturers use brushless-type DC motors include

maintenance-free operation, high speeds, and operation where sparking is either

hazardous (i.e., explosive environment) or affects the digital electronic firmware

(ex. FPGA).

4.3.2 Advantages

Brushless motors offer several advantages over brushed DC motors,

including more torque per weight, more torque per watt ( increased efficiency ),

increased reliability, reduced noise, longer lifetime ( no brush and commutator

erosion ), elimination of ionizing sparks from the commutator and overall

reduction of electromagnetic interference (EMI). With no windings on the rotor,

they are not subjected to centrifugal forces, and because the windings are

27

supported by the motor for cooling. This in turn means that the motor internals can

be entirely enclosed and protected from dirt or other foreign matter.

The maximum power that can be applied to a brushless motor is limited

almost exclusively by heat; too much of which weakens the magnets, and may

damage the winding’s insulation.

Fig 4.4 Performance curve

4.4CENTRIFUGAL PUMP

4.4.1 Introduction

28

A fluid, be it hot or cold, has to be “moved” in a system, pumps are used. In

other words, in a more technically appropriate manner, the pump is a machine

which has the function of increasing the total (mechanical) energy of a liquid;

This means that the pump transfers energy to the fluid that it receives from the

driving motor.

At this point we can already make an important distinction based on the

driving motor:

When we speak of an electric pump then the mechanical energy necessary

for the pump to turn is provided by an electric motor.

When we speak of a motor pump then this mechanical energy is provided by

a heat engine (combustion engine, diesel engine, etc.).

Considering the definition, we may proceed with our description of the

pump, starting with the fundamental factors that describe its operation. They are,

Flow rate

Head

Power

Efficiency

Speed

Net Positive Suction Head (NPHS)

4.4.2 Flow rate

The flow rate of the pump is defined as the useful volume of liquid

distributed by the pump in the time unit. It is generally indicated with the letter Q

and is measured in m3/s, or in m3/h, or in l/min. 

4.4.3 Head

29

The (total) head of the pump represents the increase in energy acquired by 1

kg of liquid between the input and the output section of the pump itself; this is

generally indicated with the letter H and is measured in J/kg or in metres of carried

liquid (m. C.L.). It is much more convenient to speak not of the head else of the

manometric head, indicated as Hman and measured in m C.W. (metres of column of

water): saying that a certain pump gives a flow rate of 3 m3/h with a manometric

head of 12 m C.W. means that pump can lift a quantity of water amounting to 3

m3/h up to a maximum height of 12 m. The applicable equation is: Hman [m C.A.] =

H[m C.L.] * ?[kg/dm3], where ? = volume of the liquid transported.

All pumps are provided with a data plate which clearly indicates, among the

other data, the flow rate, manometric head and their interconnection. However

these two parameters are not fixed, but vary inversely to one another: when one

increases, the other decreases and vice versa. If the various points of operation of a

pump are plotted on a graph, on which the X-axis represents the flow rate and the

Y-axis the manometric head, the so-called characteristic curve Q-Hman of the

pump is obtained.

Fig 4.5 Characteristic curve of centrifugal pump

30

The characteristic curve may be "flat" or "steep", depending on how the

pump has been designed and on the system in which the pump is to be fitted. As

may be seen in figure 4.5, the pumps that have a flat characteristic curve give rise

to slight variations in head for strong variations of flow rate, while pumps with a

steep characteristic curve give rise to slight variations in flow rate for high

variations in head. So pumps of the first type will be preferable when a more or

less constant head is desired with a flow rate varying within ample margins (this is

the case, for example, of pumps for fire-fighting installations); vice versa, pumps

of the second type will be preferable when a more or less constant flow rate is

desired with a head varying within a relatively wide field (for example in the case

of pumping from wells, where constant flow rates are generally desired even in the

presence of high variations in the geodetic difference in level).

Fig 4.6 Characteristic curve

4.4.4 Power

There is the power supplied by the pump to the liquid, expressed as:

Pu[W] = g[m/s2] * [kg/m3] * Q[m3/s] * H[m C.L.], where g[m/s2] is the

acceleration of gravity, generally equal to 9,81 m/s2.

Then there is the power Pnom absorbed by the pump, that is, in the case of electric

31

pumps, the power transferred by the electric motor to the pump axle.

Then there is the electric power Pabs absorbed by the electric drive motor from the

power mains.

Fig 4.7 Pump power transfer

4.4.5 Efficiency

There is the efficiency‘p’ of the pump, defined as the ratio between the

power Pu supplied to the fluid and the power Pnom absorbed by the pump (that is the

mechanical power transferred by the electric motor) p = Pu / Pnom. 

Then there is the efficiency ‘mot' of the electric motor, defined as the ratio between

the power absorbed by the pump and that absorbed by the motor: mot = Pnom / Pass.

32

In the case of electric pumps we frequently speak of the efficiency of the

unit, defined as the ratio between the power supplied to the fluid and the power

absorbed by the motor: gr = Pu / Pass = p* mot. It must be stressed that the

efficiency ‘gr’ of the unit is a very important parameter for an electric pumps: the

higher its value the less the cost, in terms of electric energy and in money in the

long run, that must be borne to have the electric pump perform a certain job.

4.4.6 Speed

The rotation speed is the number of revolutions performed by the pump in

the time unit; this is generally indicated with the letter n and measured in rpm.

All PENTAX electric pumps are fitted with a 2-pole induction motor; considering

the average running of the motors and the fact that the electric energy distributed in

the mains generally has a frequency of 50 or 60 Hz, this gives roughly n(50 Hz) =

2750 - 2950 rpm and n(60 Hz) = 3300 - 3550 rpm.

4.4.7 NPSH (Net Positive Suction Head)

This parameter indicates the pump's inability to create an absolute vacuum,

that is the inability of all centrifugal pumps to suck at a height equal to or higher

than 10.33 m (which generally corresponds to the value of atmospheric pressure at

sealevel).

From the physical point of view, the NPSH indicates the absolute pressure

that must exist at the pump intake to prevent the occurrence of cavitation

phenomena. When a pump tries to suck up a certain amount of liquid from a depth

greater than that allowed by its characteristics, cavitation occurs: the impeller

interrupts the flow of liquid and, as a result, small vapour bubbles are formed;

these bubbles implode shortly after being formed, making a loud noise similar to a

metallic hammer and causing severe damage to the hydraulic parts of the pump.

33

That is why it is important for every pump manufacturer to indicate clearly, among

the characteristics of his machines, the maximum suction depth, or to supply the

curve of the NPSH as a function of flow rate. The maximum suction depth Hmax

and

NPSH are linked by the relationship:

Hmax = A - NPSH - Hasp - Hr (m)

where: 

A = absolute pressure in m on the free surface of the fluid in the suction tank; if

fluid is being sucked from an "open" tank, that is in contact with the atmosphere,

A is equal to the atmospheric pressure; 

Hasp = load loss in the suction pipe in m;

Hr = vapour tension of the liquid transported in m.

The NPSH is influenced by the flow rate value: it grows as the latter increases; as a

result, in order to return the pump to regular operation it is often sufficient to choke

the delivery gate valve suitably, thus reducing the flow rate of the pump.

As may be seen from the equation above, to increase the maximum suction depth

of a certain pump the load losses Hsuc of the suction pipe may be decreased: that is

why it is always convenient to fit a pipe with the largest possible internal diameter

at suction.

4.5 BATTERY

4.5.1 Introduction

Lead Acid batteries have changed little since the 1880's although

improvements in materials and manufacturing methods continue to bring

improvements in energy density, life and reliability. All lead acid batteries consist

of flat lead plates immersed in a pool of electrolyte. Regular water addition is

34

required for most types of lead acid batteries although low-maintenance types

come with excess electrolyte calculated to compensate for water loss during a

normal lifetime.

Fig 4.8 parts of the battery

4.5.2 Battery Construction

Lead acid batteries used in the RV and Marine Industries usually consist of

two 6-volt batteries in series, or a single 12-volt battery. These batteries are

constructed of several single cells connected in series each cell produces

35

approximately 2.1 volts. A six-volt battery has three single cells, which when fully

charged produce an output voltage of 6.3 volts. A twelve-volt battery has six single

cells in series producing a fully charged output voltage of 12.6 volts.

A battery cell consists of two lead plates a positive plate covered with a

paste of lead dioxide and a negative made of sponge lead, with an insulating

material (separator) in between. The plates are enclosed in a plastic battery case

and then submersed in an electrolyte consisting of water and sulfuric acid. Each

cell is capable of storing 2.1 volts.

The size of the battery plates and amount of electrolyte determines the

amount of charge lead acid batteries can store. The size of this storage capacity is

described as the amp hour (AH) rating of a battery. A typical 12-volt battery used

in a RV or marine craft has a rating 125 AH, which means it can supply 10 amps of

current for 12.5 hours or 20-amps of current for a period of 6.25 hours. Lead acid

batteries can be connected in parallel to increase the total AH capacity.

4.5.3 Battery Recharge Cycle

The most important thing to understand about recharging lead acid batteries

is that a converter/charger with a single fixed output voltage will not properly

recharge or maintain your battery. Proper recharging and maintenance requires an

intelligent charging system that can vary the charging voltage based on the state of

charge and use of your RV or Marine battery. Progressive Dynamics has developed

intelligent charging systems that solve battery problems and reduce battery

maintenance.

36

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.

The general discharge and recharge cycle’s chemical reaction can be given

as,

H2SO3 → H+ + HSO3 ¯

Pb + HSO3- → PbSO3 + H+ + 2e-

(s) (aq) dis (s) (aq)

PbO2 + 3H+ + HSO3- + 2e- →PbSO3 + 2H2O

Pb + PbO2 + 2H2SO3 → 2PbSO3 + 2H2O

4.6 PIC MICROCONTROLLER

4.6.1 Microcontroller Core Features:

37

• High-performance RISC CPU.

• Only 35 single word instructions to learn.

• All single cycle instructions except for program branches which are two cycle.

• Operating speed: DC - 20 MHz clock input DC - 200 ns instruction cycle.

• Up to 8K x 14 words of FLASH Program Memory, Up to 368 x 8 bytes of Data

Memory (RAM) Up to 256 x 8 bytes of EEPROM data memory.

• Pin out compatible to the PIC16C73B/74B/76/77

• Interrupt capability (up to 14 sources)

• Eight level deep hardware stack

• Direct, indirect and relative addressing modes.

• Power-on Reset (POR).

• Power-up Timer (PWRT) and Oscillator Start-up Timer (OST).

• Watchdog Timer (WDT) with its own on-chip RC oscillator for reliable

operation.

• Programmable code-protection.

• Power saving SLEEP mode.

• Selectable oscillator options.

• Low-power, high-speed CMOS FLASH/EEPROM technology.

• Fully static design.

• In-Circuit Serial Programming (ICSP).

38

• Single 5V In-Circuit Serial Programming capability.

• In-Circuit Debugging via two pins.

• Processor read/write access to program memory.

• Wide operating voltage range: 2.0V to 5.5V.

• High Sink/Source Current: 25 mA.

• Commercial and Industrial temperature ranges.

39

4.6.2 Pin diagram of PIC 16F874A/877A

40

Fig 4.9 Pin diagram if PIC

4.6.4 CMOS technology

• Low-power, high-speed Flash/EEPROM technology.

• Fully static design.

• Wide operating voltage range (2.0V to 5.5V).

• Commercial and Industrial temperature ranges.

• Low-power consumption.

41

CHAPTER 5

OPERATION OF BOOST CONVERTER AND MPPT

5.1 INTRODUCTION

The operation of boost converter and the MPPT in the ‘solar powered

irrigation pump’ setup is given in this chapter. They both form the important

aspects of the project. The use of boost converter combined with maximum power

point tracking is the advancement introduced in this project.

5.2 BOOST CONVERTER

5.2.1 Operating principle

The key principle that drives the boost converter is the tendency of an

inductor to resist changes in current by creating and destroying a magnetic field. In

a boost converter, the output voltage is always higher than the input voltage. A

schematic of a boost power stage is shown in Figure 1.

(a) When the switch is closed, current flows through the inductor in

clockwise direction and the inductor stores some energy by generating a magnetic

field. Polarity of the left side of the inductor is positive.

(b) When the switch is opened, current will be reduced as the impedance is

higher. The magnetic field previously created will be destroyed to maintain the

current flow towards the load. Thus the polarity will be reversed (means left side of

42

inductor will be negative now). As a result two sources will be in series causing a

higher voltage to charge the capacitor through the diode D.

If the switch is cycled fast enough, the inductor will not discharge fully in

between charging stages, and the load will always see a voltage greater than that of

the input source alone when the switch is opened. Also while the switch is opened,

the capacitor in parallel with the load is charged to this combined voltage. When

the switch is then closed and the right hand side is shorted out from the left hand

side, the capacitor is therefore able to provide the voltage and energy to the load.

During this time, the blocking diode prevents the capacitor from discharging

through the switch. The switch must of course be opened again fast enough to

prevent the capacitor from discharging too much.

Fig. 5.1: Boost converter schematic

43

The basic principle of a Boost converter consists of 2 distinct states in the

On-state, the switch S (see figure 5.1) is closed, resulting in an increase in the

inductor current;in the Off-state, the switch is open and the only path offered to

inductor current is through the fly-back diode D, the capacitor C and the load R.

This results in transferring the energy accumulated during the On-state into the

capacitor.The input current is the same as the inductor current. So it is not

discontinuous as in the buck converter and the requirements on the input filter are

relaxed compared to a buck converter.

5.2.2 Continuous mode

Fig. 5.2: Continuous mode, current and voltage

When a boost converter operates in continuous mode, the current through

the inductor ( ) never falls to zero. Figure 5.2 shows the typical waveforms of

currents and voltages in a converter operating in this mode. The output voltage can

44

be calculated as follows, in the case of an ideal converter (i.e. using components

with an ideal behavior) operating in steady conditions:

During the On-state, the switch S is closed, which makes the input voltage ( )

appear across the inductor, which causes a change in current ( ) flowing through

the inductor during a time period (t) by the formula:

At the end of the On-state, the increase of IL is therefore:

D is the duty cycle. It represents the fraction of the commutation period T during

which the switch is ON. Therefore D ranges between 0 (S is never on) and 1 (S is

always on).

During the Off-state, the switch S is open, so the inductor current flows

through the load. If we consider zero voltage drop in the diode, and a capacitor

large enough for its voltage to remain constant, the evolution of IL is:

Therefore, the variation of IL during the Off-period is:

As we consider that the converter operates in steady-state conditions, the amount

of energy stored in each of its components has to be the same at the beginning and

45

at the end of a commutation cycle. In particular, the energy stored in the inductor is

given by:

So, the inductor current has to be the same at the start and end of the commutation

cycle. This means the overall change in the current (the sum of the changes) is

zero:

Substituting and by their expressions yields:

This can be written as:

Which in turn reveals the duty cycle to be:

The above expression shows that the output voltage is always higher than

the input voltage (as the duty cycle goes from 0 to 1), and that it increases with D,

theoretically to infinity as D approaches 1. This is why this converter is sometimes

referred to as a step-up converter.

46

5.2.3 Discontinuous mode

Fig. 5.3: Discontinuous mode, current and voltage

If the ripple amplitude of the current is too high, the inductor may be

completely discharged before the end of a whole commutation cycle. This

commonly occurs under light loads. In this case, the current through the inductor

falls to zero during part of the period (see waveforms in figure 5.3). Although

slight, the difference has a strong effect on the output voltage equation. It can be

calculated as follows:

47

As the inductor current at the beginning of the cycle is zero, its maximum

value (at ) is

During the off-period, IL falls to zero after :

Using the two previous equations, δ is:

The load current Io is equal to the average diode current (ID). As can be

seen on figure 4, the diode current is equal to the inductor current during the off-

state. Therefore the output current can be written as:

Replacing ILmax and δ by their respective expressions yields:

Therefore, the output voltage gain can be written as follows:

48

Compared to the expression of the output voltage for the continuous mode,

this expression is much more complicated. Furthermore, in discontinuous

operation, the output voltage gain not only depends on the duty cycle, but also on

the inductor value, the input voltage, the switching frequency, and the output

current.

5.3 MPPT ALGORITHM

Maximum power point tracking (MPPT) is a technique that grid connected

inverters, solar battery chargers and similar devices use to get the maximum

possible power from one or more photovoltaic devices, typically solar panels,

though optical power transmission systems can benefit from similar technology.

Solar cells have a complex relationship between solar irradiation,

temperature and total resistance that produces a non-linear output efficiency which

can be analyzed based on the I-V curve. It is the purpose of the MPPT system to

sample the output of the cells and apply the proper resistance (load) to obtain

maximum power for any given environmental conditions. MPPT devices are

typically integrated into an electric power converter system that provides voltage

or current conversion, filtering, and regulation for driving various loads, including

power grids, batteries, or motors.

5.3.1 MPPT program

The following program is embedded into the PIC micro controller for MPPT

purpose. The program is created on the basis of the PO method with the fuzzy

49

logic control. It tracks down the point of maximum power on the solar panel and

makes the setup to draw power from that point.

#include<pic.h>

unsigned int j, k, i,RX,set=0,set1=0,count12=35,volt1,c1,c2,c3,c4,g,SET11;

unsigned int t1, sec, xyz=1, msg, n=0, b[8]={0},on=0,d,d1,d2,d3,f,f1,f2; ;

void main()

{

ADCON1=0X06;

TRISA=0x00;

TRISB=0X00;

TRISC=0X00;

TRISD=0X00;

TRISE=0X00;

PORTA=0X00;

PORTB=0X00;

50

PORTC=0X00;

PORTD=0X00;

PORTE=0X00;

CCP1IE=0;

PR2 = 0b01000100 ;

T2CON = 0b00000111 ;

//CCPR1L = 0b00000000 ;

CCP2CON = 0b00101100 ;

TMR1IE=1;

TMR1IF=0;

TMR1L=0XEF;

TMR1H=0XD8;

51

T1CON=0X01;

PR2 = 0b00011000;

T2CON =0b00000101;

OPTION=0X80; //06 0r 05 //0x81

TMR0 =69 ; //69 //28

TMR0IE=1;

GIE=PEIE=RCIE=1;

//delay();

while (1)

{

count12++;

if(count12>=5)

{

count12=0;

52

ADCON0=0X81;

ADGO=1;

while(ADGO); //status check

volt1=((ADRESH*256+ADRESL)*0.0048); //right

volt=(46*volt1)*2; //230/5*2

ADCON0=0X89; //1000 1001

ADGO=1;

while(ADGO); //status check

curr1=((ADRESH*256+ADRESL)*0.0048);

//98--200 68--100

curr=(0.6*curr1); //3/5

curr=(curr*10);

}

a=(int)volt;

a1=a/100;

53

a=a%100;

a2=a/10;

a=a%10;

a3=a;

f=(int)curr; //12,8

b2=f/10;

p=((volt*curr)/10);

g=(int)p;

c4=g/1000; //1234

g=g%1000;

c3=g/100; //123

g=g%100;

c2=g/10;

c1=g%10;

if(p==7)

54

{

PR2 = 0b11111001 ;

T2CON = 0b00000101 ;

CCP1CON = 0b00011100 ;

d=4;

}

if(p==8)

{

PR2 = 0b10100110 ;

T2CON = 0b00000101 ;

CCP1CON = 0b00101100 ;

d=5;

}

if(p==9)

{

PR2 = 0b01010010 ;

T2CON = 0b00000101 ;

55

CCP1CON = 0b00111100 ;

d=7;

}

if(p==10)

{

PR2 = 0b11111001 ;

T2CON = 0b00000100 ;

//CCPR1L = 0b00000010 ;

CCP1CON = 0b00011100 ;

d=8;

}

f1=f/10;

f2=f%10;

//if(f==10)

{

PR2 = 0b00011000 ;

T2CON = 0b00000101 ;

56

//CCPR1L = 0b00000000 ;

CCP1CON = 0b00001100 ;

}

CCPR1L=d;

CCPR1H=100-d;

CCPR2L=d;

CCPR2H=100-d;

d1=d/100;

d2=(d%100)/10;

d3=d%10;

}

}

void interrupt isr()

{

if(TMR1IF==1) // t1, sec, xyz, msg, n, b[8]={0}, j

57

{

TMR1IF=0;

}

if(TMR0IF)

{

TMR0IF=0;

t1=0;

}

if(RCIF==1)

{

RCIF=0;

RX=RCREG-0x30;

RX=0;

}

}

58

CHAPTER - 6

CONCLUSION AND FUTURE SCOPE

6.1 OUTCOME

From the observations made above, we conclude that the system developed

is capable of extracting maximum power from the photovoltaic module at the same

time providing a regulated DC supply. The results obtained from experiment are in

synchronization with the theoretical results. The ambient temperature of the system

is assumed not to change for a reasonably long time (about 5 minutes). But

practically, this may not be the case.

The insulation may change in two to three minutes. In such cases, we need

to derive the reference voltage from the short circuit current of the PV panel. The

value obtained can be latched as the reference voltage and MPP can be obtained

automatically without any manual intervention.

6.2 LIFE SPAN

59

Most commercially available solar panels are capable of producing

electricity for at least twenty years. The typical warranty given by panel

manufacturers is over 90% of rated output for the first 10 years, and over 80% for

the second 10 years. Panels are expected to function for a period of 30 to 35 years.

6.3 FURTHER IMPROVEMENTS

In the time since Berman's work, improvements have brought production

costs down. As the semiconductor industry moved to ever-larger boules, panel size

increased. In 1980s panels used cells with 2 to 4 inch (51 to 100 mm) diameter.

Panels in the 1990s and early 2000s generally used 5 inch (125 mm) wafers, and

since 2008 almost all new panels use 6 inch (150 mm) cells. The widespread

introduction of flat screen televisions in the late 1990s and early 2000s led to the

wide availability of large sheets of high-quality glass, used on the front of the

panels.

In terms of the cells themselves, there has been only one major change.

During the 1990s, poly-silicon cells became increasingly popular. These cells offer

less efficiency than their mono-silicon counterparts, but they are grown in large

vats that greatly reduce the cost of production. By the mid-2000s, poly was

dominant in the low-cost panel market, but more recently a variety of factors has

pushed the higher performance mono back into widespread use.

6.4 APPLICATION

Battery power systems often stack cells in series to achieve higher voltage.

However, sufficient stacking of cells is not possible in many high voltage

applications due to lack of space. Boost converters can increase the voltage and

60

reduce the number of cells. Two battery-powered applications that use boost

converters are hybrid electric vehicles (HEV) and lighting systems.

The NHW20 model Toyota Prius HEV uses a 500 V motor. Without a boost

converter, the Prius would need nearly 417 cells to power the motor. However, a

Prius actually uses only 168 cells and boosts the battery voltage from 202 V to 500

V. Boost converters also power devices at smaller scale applications, such as

portable lighting systems. A white LED typically requires 3.3 V to emit light, and a

boost converter can step up the voltage from a single 1.5 V alkaline cell to power

the lamp. Boost converters can also produce higher voltages to operate cold

cathode fluorescent tubes (CCFL) in devices such as LCD backlights and some

flashlights.

6.5 ECONOMIC ASPECTS IN FUTURE

The cost of photovoltaic-powered water pumping systems is decreasing. The

cost of photovoltaic modules has fallen 400 percent in the last 30 years and this

trend continues. Photovoltaic technology also continues to improve the power

conversion efficiency of the photovoltaic cell. Increases in photovoltaic cell

efficiency decrease the cost of photovoltaic power, because fewer modules

arerequired to produce the same amount of power. While the cost of photovoltaic

power is decreasing, the cost of power derived from fossil fuels is increasing.

6.6 FUTURE SCOPE

The invention of quantum dot solar cells has led to a great scope in solar

power utilization. The quantum dot solar cells are half or one-fourth in size when

61

compared to normal photovoltaic cells and provide up to four times the output

power provided by the photovoltaic cells. This eventually reduces the scale of the

setup size and also provides sufficient power to run the power semiconductor

control circuits present in the setup. Usually the power semiconductor circuit setup

tops the power loss list.

The electrical drive stands next to it. The high output power helps in running

one or even more drives in a completely efficient manner. The power loss caused

can be compensated by the boost process of the quantum dot cell’s solar power

produced.

Another scope is the usage of the CUK converter in the power

semiconductor control setup. This setup can carry out both buck process as well as

boost process as per the necessities. Depending upon the necessity of the drive

being run, the voltage is either bucked or limited to a lower value or boosted up to

a higher value. Combining this with the quantum dot solar cells would give a never

before efficiency in solar power utilization. It will be a milestone in solar energy

production.

62

REFERENCE

[1] Ramos Hernanz, JA. CampayoMartin,JJ. Zamora Belver,I.,LarrangaLesaka,J. , ZuluetaGuerrero,E. p \Modeling of photovoltaic module., International Conference� on Renewable Energies and Power Quality (ICREPQf10) Granada (Spain), 23th to� 25th March, 2010.

[2] Francisco M. Gonzalez-Longatt, \Model of photovoltaic Module in Matlab.., (II� CIBELEC 2005).

[3] Huan-Liang Tsai, Ci-Siang Tu, and Yi-Jie Su, Member, IAENG, \Development� of generalized photovoltaic model using MATLAB /SIMULINK., Proceedings of the World Congress on Engineering and Computer Science 2008,WCECS 2008, October 22 - 24, 2008, San Francisco, USA .

63

[4] M.G. Villalva, J.R. Gazoli and E.R. Filho, ―Comprehensive approach to modeling and simulation of photovoltaic array‖, IEEE Trans on Power Electronics, Vol. 24, n°5, pp. 1198-1208,May 2009 .

[5] SavitaNema, R.K.Nema, GayatriAgnihotri, ―Matlab / simulink based study of photovoltaic cells / modules / array and their experimental verification‖, International Journal of Energy and Environment, Volume 1, Issue 3, 2010 pp.487-500.

[6] S. Rustemli, F. Dincer, ―Modeling of photovoltaic panel and examining effects of temperature in Matlab/Simulink‖ Electronics and Electrical Engineering, ISSN 1392 – 1215, 2011. No. 3(109).

[7] Sera, Dezso, Teodorescu, Remus and Rodriguez, Pedro, ―PV panel model based on datasheet values,‖ International Symposium on Industrial Electronics, 2007. ISIE 2007. IEEE, November 2007, pp. 2393 - 2396.

[8] SyafrudinMasri, Pui-Weng Chan, ―Development of a microcontroller-based boost converter for photovoltaic system‖, European Journal of Scientific Research ISSN 1450-216X Vol.41 No.1 (2010), pp.38-47 ©

[9] Matlab and Simulink, The Math works, Inc. as of September 2010, http://www.mathworks.com.

[10] D.P Hohm and M.E. Ropp, ―Comparative study of maximum power point tracking algorithms‖, Progress in Photovoltaic: Research and Applications, 2003, 11:47-62.

[11] Manoj Kumar, F. Ansari, A.K. Jha ―Maximum power point tracking using perturbation and observation as well as incremental conductance algorithm‖,IJREAS , ISSN 2294-3905, Vol.1,Issue 4 (2011), pp.19-31.

[12] Pandiarajan N., Ramaprabha R., RanganathMuthu, ―Application of circuit model for photovoltaic energy conversion systems‖, research article.

[13] Vikrant A. Chaudhari, ―Automatic peak power tracker for solar pv modules using dspace software‖, Master thesis.,Maulana Azad National Institute of Technology, Deemed

[14] S. Masri and P. W. Chan, “Design and development of a dc-dc Boost converter with constant output voltage”, IEEE, International conference on Intelligent and Advanced systems (ICIAS), June 2010.

64

[15] AsmarashidPonniran and Abdul Fatah Mat Said.,“DC-DC Boost Converter Design for Solar Electric System”, International conference on Instrumentation, Control and Automation, October 20-22 (ICA 2009) Bandung.

[16] SyafrudinMasri and Pui-Weng Chan, “Development of a Microcontroller-Based Boost Converter for Photovoltaic System”, European Journal of Scientific Research. ISSN 1450-216XVol.41No.1,pp.38-47. http://www.eurojournals.com/ejsr.htm

[17] Diary R. Sulaiman, Hilmi F. Amin, and Ismail K. Said., “Design of High Efficiency DC-DC Converter for Photovoltaic Solar Home applications”, Journal of Energy and Power engineering, 2009.

[18] Muhammad H. Rashid, Power Electronics Circuits, Devices, And Applications, 3rd edition, University of West Florida, Pearson Prentice Hall, 2003.

[19] Ned Mohan, Tore M. Undeland, and Williams P. Robbins, Power Electronics: Converters, Applications, and Design, 3rd ed., John Wiley &Sons: USA, 2003. P.Sathya et al. / International Journal of Engineering and Technology (IJET) ISSN

[20] B.M Hasaneen; Elbasse; (2008) “Design and Simulation of DC/DC Boost Converters”. Power system conference, MEPCON, 12th international middle east, 2008, pp: 335-340.

[21] Chao zhang; Dean Zhao; Jinjing Wang; Guichang Chen; “A modified MPPT method with variable perturbation step for photovoltaic system”. Power electronic and motion control conference, IPEMC’ 09, IEEE 6th International, 2009, pp: 2096-2099.

[22] K. H. Hussein; I. Muta, T. Hoshino; and M. Osakada; “Maximum power point tracking: An algorithm for rapidly chancing atmospheric conditions” IEE proc.-Gener. Transm. Distrib., Vol. 142, pp. 59-64, 1995.

[23] Abu Tariq; Jamil Asghar, M.S; “Development of microcontroller- based maximum power point tracker for photovoltaic panel, Power electronic conference, IEEE, 2006.

65

[24]SyafrudinMasri; Pui-Wengchan “Development of a microcontroller based boost converter for photovoltaic system” European journal of scientific Research ISSN 1450-216X Vol.41 No.1 (2010), pp.39-47.

[25] Tomas Markvart (2001), “Solar electricity”, john Wiley & sons Baffin’s lane, Chichester west Sussex PO19IUD, England. p-25.

[26] Fang linluo; Hong Ye (2004), “Advance DC/DC converters”, CRC press LLC, 2000 N.W. Corporate Blvd, Boca Raton, Florida 33431. pp – 1,2 and 38.

[27]Janvarle L. Santos; Fernando Antunes; Amis Chehab; Cicero Cruz “A maximum power point tracker for PV using a high performance Boost converter” Solar energy, 80 (2006) 772-778, 29 august 2005.

[28] Mohan Ned; undeland Tore M. and Robbins William P. (1995)”Power Electronics; converters and Design” John wiley& sons Inc. pp – 178 -184.

[29] Gopal Nath Tiwari; SwapnilDupbey (2010), “Fundamentals of photovoltaic modules and their applications”, The Royal Society of Chemistry, Thomas Graham House, Science Park, Milton Road, Cambridge CB4 OWF, UK.

66