Design And Construction Of A 500VA Photo Voltaic System

This work is on design and construction of a 500VA photo voltaic system. Photovoltaic is also called solar inverter. Solar inverter converts the variable direct current (DC) output of a photovoltaic (PV) solar panel into a utility frequency alternating current (AC) that can be fed into a commercial electrical grid or used by a local, off-grid electrical network. It is a critical component in a photovoltaic system, allowing the use of ordinary AC-powered equipment.

In photo voltaic system, Solar panels produce direct electricity with the help of electrons that are moving from negative to positive direction. Most of the appliances that we use at home work on alternative current. This AC is created by the constant back and forth of the electrons from negative to positive. In AC electricity the voltage can be adjusted according to the use of the appliance.  As solar panels only produce Direct current the solar inverter is used to convert the DC to AC.

TABLE OF CONTENTS

TITLE PAGE

APPROVAL PAGE

DEDICATION

ACKNOWLEDGEMENT

ABSTRACT

TABLE OF CONTENT

CHAPTER ONE

1.0      INTRODUCTION

1.1      BACKGROUND OF THE PROJECT

1.2      OBJECTIVE OF THE PROJECT

1.3      SCOPE OF THE PROJECT

1.4      PURPOSE OF THE PROJECT

1.5     SIGNIFICANCE OF THE PROJECT

1.6      PROBLEM OF THE PROJECT

1.7      LIMITATION OF THE PROJECT

1.8      COMPONENTS OF PV SYSTEM AND THEIR FUNCTIONS

1.9      SOLAR PV INSTALLATION BLOCK AND DESCRIPTION

1.10   PROJECT ORGANISATION

CHAPTER TWO

2.0     LITERATURE REVIEW

2.1      HISTORITICAL BACKGROUND OF PHOTOVOTAIC CELL

2.2     THEORETICAL REVIEW OF SOLAR CELL

2.3      REVIEW OF SOLAR CELL EFFICIENCY

2.4      REVIEW OF SOLAR CELL MATERIALS

2.5      REVIEW OF EARLY INVERTERS

CHAPTER THREE

3.0     CONSTRUCTION

3.1      BASIC DESIGNS OF A SOLAR INVERTER

3.2     BLOCK DIAGRAM OF THE SYSTEM

3.3     DESCRIPTION OF SOLAR INVERTER UNITS

3.4     SYSTEM CIRCUIT DIAGRAM

3.5      CIRCUIT OPERATION

3.6     DESCRIPTION OF COMPONENTS USED

3.7      HOW TO CHOOSE THE BEST INVERTER BATTERY

CHAPTER FOUR

RESULT ANALYSIS

4.0      CONSTRUCTION PROCEDURE AND TESTING

4.1      CASING AND PACKAGING

4.2      ASSEMBLING OF SECTIONS

4.3      TESTING OF SYSTEM OPERATION

4.4     COST ANALYSIS

CHAPTER FIVE

5.0      CONCLUSION

5.1      RECOMMENDATION

5.2      REFERENCES

CHAPTER ONE

1.0                                                        INTRODUCTION

Photo voltaic system converts direct current (DC) output of a photovoltaic (PV) solar panel into a utility frequency alternating current (AC) that can be fed into a commercial electrical grid or used by a local, off-grid electrical network. It is a critical balance of system (BOS)–component in a photovoltaic system, allowing the use of ordinary AC-powered equipment. Photo voltaic system have special functions adapted for use with photovoltaic arrays, including maximum power point tracking and anti-islanding protection [1].

The photo voltaic panel used in solar inverter produces direct electricity with the help of electrons that are moving from negative to positive direction. Most of the appliances that we use at home work on alternative current. This AC is created by the constant back and forth of the electrons from negative to positive. In AC electricity the voltage can be adjusted according to the use of the appliance.  As solar panels only produce Direct current the solar inverter is used to convert the DC to AC[2] [3].

An inverter produces square waves or a sine wave which can be used for running lights, televisions, lights, motors etc. However these inverters also produce harmonic distortion [2].

1.1                                         BACKGROUND OF THE PROJECT

Solar technology isn’t new. Its history spans from the 7th Century B.C. to today. We started out concentrating the sun’s heat with glass and mirrors to light fires. Today, we have everything from solar-powered buildings to solar-powered vehicles. Here you can learn more about the milestones in the historical development of solar technology, century by century, and year by year. You can also glimpse the future. From the 3rd Century BC when Archimedes fought off Roman ships by concentrating the suns rays at them with brass shields (they burst into flame), through work by some of the best known figures in the history of science, harnessing the power of the sun has long been a goal of human innovation. Let’s look at some of the highlights:

In 1767 Swiss physicist, alpine explorer, and aristocrat Horace de Saussure is credited with inventing the first working solar oven, amongst other discoveries. Constructed from 5 layers of glass and measuring around 12 inches across, the oven worked by allowing light to pass through the glass before being absorbed by the black lining and turned into heat. The heat is then reflected by the glass, therefore heating the space inside the box up to 87.5 degrees Celsius [4][5].

Also in 1839 Edmond Bequerel, born in Paris in 1820, discovered that when two electrodes were placed in an electrolyte (electricity-conducting solution), a voltage developed when light fell upon the electrolyte. The basic principles of solar power had been uncovered [4].

Many people using solar power these days which prove that its necessity has been increased in the current years. A Solar inverter is similar to a normal electric inverter but uses the energy of the Sun, that is, Solar energy. A solar inverter helps in converting the direct current into alternate current with the help of solar power. Direct power is that power which runs in one direction inside the circuit and helps in supplying current when there is no electricity. Direct currents are used for small appliance like mobile e phones, MP3 players, IPod etc. where there is power stored in the form of battery. In case of alternative current it is the power that runs back and forth inside the circuit [4] [5]. The alternate power is generally used for house hold appliances. A solar inverter helps devices that run on DC power to run in AC power so that the user makes use of the AC power. If you are thinking why to use solar inverter instead of the normal electric one then it is because the solar one makes use of the solar energy which is available in abundant from the Sun and is clean and pollution free.

Solar inverters are also called as photovoltaic solar inverters. These devices can help you save lot of money.  The small-scale grid  one have just two components i.e. the panels and inverter while  the off grid systems are complicated and consists of batteries which allows users to use appliances during the night when there is no Sunlight available.  The solar panel and the batteries that are placed on rooftops attract Sun rays and then convert the Sunlight into electricity. The batteries too grab the extra electricity so that it can then be used to run appliances at night [4].

1.2                                             OBJECTIVE OF THE PROJECT

The main objective of this project is to design and construct a solar power generating device that can collect an input dc voltage (12vdc) from the solar panel and convert it to 220vac output which can be use to power ac appliances which is rated 1kw.

1.3                                                 SCOPE OF THE PROJECT

The main function of solar inverter is to convert battery’s Direct Current (DC) into pure sine wave Alternative Current (AC) to feed home compliances.

Solar power inverter system is consisted of solar panels, charger controllers, inverters and rechargeable batteries, while solar DC power system is not included inverters. The inverter is a power conversion device, which can be divided into self-excited oscillation inverter and external excited oscillation inverter.

1.4                                              PURPOSE OF THE PROJECT

The purpose of this work is to have a steady power supply that is independent on the mains grid system [9].

1.5                                         SIGNIFICANCE OF THE PROJECT

Solar inverter is useful in making appliances work at residential and industrial levels, such as:

• A Solar Inverter is better optimised for solar power than the regular one. For example, it will prioritise power supply from the solar panels. This means that when the energy from the Sun is adequate like during afternoons, the inverter will draw power entirely from the solar panels to power your home or office even if public power supply is available. This can lead to huge savings on power bills [7].
• Similarly, a Solar hybrid inverter will prioritise charging from solar panels, enabling your batteries to charge via the PV panels even when public power supply is on, leading also to savings on your power bills.
• Solar inverter has always helped in reducing global warming and green house effect.
• Also use of solar inverter helps in saving money that would have used for buying fuel for conventional generator
• Some solar inverters will allow you prioritise charging to solar panels or power grid depending on the battery level. Some solar inverters are even intelligent enough just to take just as much deficit current from the grid as is required [7].
• A solar inverter helps in converting the Direct current in batteries into alternative current. This helps people who use limited amount of electricity.
• There is this synchronous solar inverter that helps small homeowners and power companies as they are large in size.
• Then there is this multifunction solar inverter which is the best among all and works efficiently. It converts the DC power to AC very carefully which is perfect for commercial establishments.
• Solar inverters are the best way and they are better than the normal electric ones. Also their maintenance does not cost much money.
• Solar Inverters can work when there is no Sunlight but provided their battery is charged fully with the help of Sunlight [7].

1.6                                              PROBLEM OF THE PROJECT

• Initially you need to shell out a lot of money for buying a solar inverter
• It will work effectively and produce direct current only when the Sunlight is strong.
• The solar panels that are used to attract Sunlight requires lots of space
• The device can work efficiently only if the presence of the Sun is strong.
• Maintenance and replacement may require more effort. In the event of a problem, a technician will need to access the roof to make repairs. Depending on your maintenance plan and warranty, this may cost you money [8].

1.7                                           LIMITATION OF THE PROJECT

• This device is rated 500w that means any load more than 500w should for no reason applied to this device.
• The intensity of the Sun varies throughout the day. This creates an over-charging problem if the panels are connected to the battery directly, and It should also be able to tell you when you connect the panels wrongly (i.e. positive to negative, etc) and also provide protection against short-circuit. For this reason a charge controller must be used to offer protection from high voltage and current from the panels [5].
• The inverter frequency is rated at 50hz
• Iron casing and good heat sink is been used for heat absorption

1.8      COMPONENTS OF PV SYSTEM AND THEIR FUNCTIONS

Components used for the photovoltaic system installation and their functions are listed in the table.1 below:

Table 1: Components of PV system and their functions

1.9             SOLAR PV INSTALLATION BLOCK AND DESCRIPTION

The stand-alone photovoltaic system is a collection of interconnected electrical components, which can generate electricity from sunlight and satisfy our daily energy requirement without worrying about any interval when the sunlight may not be available. The components (see Figure 2) of such a system are:

1. Solar PV array: This is commonly refers to as solar panel. It is responsible for trapping of the solar energy as it is placed outside under the sun. They are arranged in series and parallel to meet desired output.
2. B) Charge Controller: The charge controller is use in controlling the charge (from the word charge control) in the batteries, either to prevent overcharging or discharging.
3. Inverter: This is used in converting DC to AC as power from solar PV arrays is in DC form.
4. Battery: These are used to store power for usage during the non-sunshine hour. The recommended batteries that should be used in stand-alone photovoltaic power system are deep-cycle lead-acid batteries because of their high performance (Abu-Jasser, 2010).

Balance of System Components: Components such as protective devices, blocking & bypass diodes, lightning-protection system and cable wiring constitute what is known as balance of system components (Abu- Jasser, 2010). Such components are necessary to keep the PV power system safe and reliable. In particular, selecting the correct size and type of cable will enhance the performance of the system while selecting inadequate cable size will cause voltage drop from the source to the load. In low voltage systems, such voltage drops will lead to inefficiencies.

Figure 2. Pictorial representation of Solar PV system

1.10                                     ORGANISATION OF THE PROJECT

This work is organized in such a way that every reader of this work will understand how solar power inverter is been made. Starting from the chapter one to chapter five focused fully on the topic at hand.

Chapter one of this work is on the introduction to solar power inverter. In this chapter, the background, significance, objective limitation and problem of solar power inverter were discussed.

Chapter two is on literature review of solar power inverter. In this chapter, all the literature pertaining to this work was reviewed.

Chapter three is on design methodology. In this chapter all the method involved during the design and construction were discussed.

Chapter four is on testing analysis. All testing that result accurate functionality was analyzed.

Chapter five is on conclusion, recommendation and references.