Construction Of Short Circuit Detector On Motherboard

ABSTRACT

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 solar inverter, 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.

Alternating power supply from a solar inverter supplies an alternative means of electrification to the user. This paper shows the assembling and maintenance of a 6kw inverter with solar energy.

TABLE OF CONTENT

COVER PAGE

APPROVAL PAGE

DEDICATION

ACKNOWLEDGEMENT

TABLE OF CONTENT

• INTRODUCTION
• SYSTEM DESCRIPTION
• PROBLEM STATEMENT
• AIM AND OBJECTIVES
• SIGNIFICANT STUDY
• ADVANTAGES OF SOLAR INVERTER
• DISADVANTAGES OF SOLAR INVERTER
• LIMITATION OF THE STUDY
• RESEARCH QUESTION/HYPOTHESIS
• DEFINITION OF TERMS 

CHAPTER TWO

2.0   LITERATURE REVIEW

2.1   PHOTOVOLTAIC SOLAR SYSTEM

2.2   DIFFERENT TYPES OF SOLAR CELLS

2.3   PHOTOVOLTAIC SOLAR GENERATOR

2.4   REVIEW OF SOLAR CELL MATERIALS

2.6      REVIEW OF EARLY INVERTERS

CHAPTER THREE

METHODOLOGY

3.0   PHOTOVOLTAIC SYSTEM SIZING

3.1   SYSTEM BLOCK

3.2   COMPONENTS OF A SOLAR INVERTER

3.3   SYSTEM DESCRIPTION

3.4   CONFIGURATION

3.5   PHOTOVOLTAIC SYSTEM SIZING

3.6   FACTORS AFFECTING PHOTOVOLTAIC SYSTEM SIZING

3.7   SIZING OF THE SOLAR ENERGY

3.8   SIZING OF THE BATTERY

3.9   SIZING OF THE VOLTAGE REGULATOR

3.10 SIZING OF THE INVERTER

3.11   SOLAR PANEL INSTALLATION PROCESS

3.12   SOLAR CONNECTION DIAGRAM

CHAPTER FOUR

4.1   TESTING OF SOLAR PANELS

4.2   OFFICE APPLIANCES

4.3   SIZING THE SOLAR ENERGY

4.4   SIZING OF THE BATTERY BANK

4.5   DISCHARGE DURATION

4.6   SIZING OF THE SYSTEM WIRING

4.7   PRECAUTION

4.8   MAINTANANCE

4.9   CARE AND MAINTENANCE TIPS FOR INVERTERS

4.10  BILL OF ENGINEERING MEASUREMENTS AND EVALUATION

CHAPTER FIVE

5.1    CONCLUSION

5.2    RECOMMENDATION

REFERENCES

CHAPTER ONE

1.0    INTRODUCTION

1.1     Background of the study

The sun provides the energy to sustain life in our solar system. In one year, the earth receives enough energy from the sun to meet its energy needs for nearly a year. Photovoltaic is the direct conversion of sunlight to electricity, it is a beautiful alternative source of energy to conventional sources of electricity for many reasons it is safe, silent, non – polluting, renewable, highly modular in that their capacity can be increased incrementally to match with gradual load growth, it is reliable with minimal failure rates and projected service lifetimes of about 20 to 30 years. It requires no special training to operate, it contains no moving parts, it is extremely reliable and it’s virtually maintenance free, and can be installed almost anywhere.

A photovoltaic system is a complete set of interconnected components for converting sunlight into electricity by photovoltaic process including array, balance of system and load. The intensity of sunlight that reaches the earth varies with time of the day, season, location and the weather condition, the total energy on a daily or annual basis is called Irradiation and indicates the straight of sunshine. Irradiation is expressed in Whm ^{– 2} per day or KWh.m^-2 per day. Different geographical regions experience different weather patterns, so the site we live is a major factor that affects the photovoltaic system design, the orientation of the panels, finding the number of days of autonomy where the sun does not shine in the sky and choosing the best tilt angle of the solar panels.

Photovoltaic panels collect more energy, if they are installed on a tracker that follows the movement of the sun although it is an expensive process; for this process they are usually fixed in a particular position with an angle called the tilt angle B. This angle varies according to seasonal variation, for instance, in summer the solar panel must be more horizontal while in the winter, it is placed at a steeper angle.

In this project, the various components of a 6kw solar inverter are assembled and maintained.

1.2    PROBLEM STATEMENT

This study was carried out to overcome the difficulty in assembling of solar inverter seen among electrical students of Nigeria and poor maintenance skills observe among users of solar inverters.

1.3    AIM AND OBJECTIVES

1.3.1 AIM

The main aim of this project is to assemble and maintain a 6k solar inverter

1.3.2           Objectives

1. To generate electricity from solar energy in which the source is free in nature and abundant.
2. To find solution to irregularity in power supply by PHCN
3. To carry out the system sizing in solar power inverter.
4. To study the performance of each component constituting the solar power inverter.
5. To assemble and maintain a solar inverter

1.4    Significant Study

In respect to failure of power supply and perpetual increase in fuel price to run power and most times fuel scarcity, there is need to introduce the use of solar energy power system towards a stable power supply for developing and developed nations of the world.

1.6    Advantages of Solar Inverter

1. The use solar inverter can result significant power bill savings.
2. Similarly, a solar inverter prioritizes charging from solar panels, allowing your batteries to be charged via PV panels even while the grid is on, saving you money on your power bills.

• The use of an inverter with solar energy has always aided in the reduction of global warming and greenhouse gas emissions.

1. Using an inverter with solar energy also saves money that would otherwise be spent on fuel for a convectional generator.
2. Depending on the battery level, some solar inverter aids will allow you to prioritize charging to solar panels or the power grid. Some solar converters are smart enough to draw exactly as much shortfall current from the grid as is needed.
3. Solar inverters are the finest option and are superior to traditional electric inverters. In addition, they are inexpensive to maintain.

• Solar inverters can work even when there is no sunlight, as long as their batteries are fully charged by sunlight.
• inverter with solar energy can operate even when there is no sunlight, as long as their batteries have been fully charged by sunlight.

1.7                            Disadvantages of Solar Inverter

1. Space: Photovoltaic cells take up a lot of space, which we may anticipate being addressed with correct design.
2. High Cost: The cost of a solar system is now prohibitively expensive for the typical Nigerian person.

iii. Low energy efficiency: At the moment, the commercially available units have a 45 percent efficiency.

1. Because the device is rated at 6000W, any load more than that should not be applied to it.
2. The battery will need to be charged and recharged from time to time.
3. Designing a pure sine wave inverter circuit is relatively costly; this leaves space for improvement.

1.8                                    Limitation of the study

There are different types of inverter used for solar energy with different sizes, but in this work a 6000w modified sine wave inverter was used for the assembling.

1.9                             Research question/hypothesis

Research question

At the end of this work answers to the following question shall be made known:

1. What are the advantages of assembling an inverter with solar energy?
2. What are the components used in assembling an inverter with solar energy?

• Does it cost much money to assemble an inverter with solar energy?

Research hypothesis

There is a significant relationship between inverter and solar energy.

1.10 Definition of Terms

SUN – Source of energy

SOLAR PANEL – It’s device that converts light energy to electrical energy

SOLAR REGULATOR – It’s a device that regulates from 40VDC to 28VDC

BATTERY – It’s a device that serves as reservoirs/storage device

INVERTER – It’s a device that converts D.C (12v) [Battery/Solar] 28VDC to   AC 220AC.

LOAD – AC output using devices (laptop, Bulb, Ceiling fan, Handset Charger)

POWER – Voltage × Current

WATTAGE – Power factor [0.8] × Power i.e. power (VA)

SOLAR CELLS – Is the smallest semiconductor (silicon) device that converts solar energy (sunlight) to electrical energy (DC)

ARRAY – Is the combination of panel in series or parallel

PANEL/MODULES – Is the combination of cell in series or parallel.

SHORT CIRCUIT – It has low resistance or no resistance and potential differences of zero.

CLOSED CIRCUIT – The current is generated across the load.

OPEN CIRCUIT – It has no current to generate across the with high resistances

 CHAPTER TWO

2.0    LITERATURE REVIEW

2.1    PHOTOVOLTAIC SOLAR SYSTEM

Photovoltaic cell is a semiconductor device consisting large area of P – N junction diode, which in the presence of sunlight is capable of generating usable electrical energy. In 1883, the first solar cell was built by Charles Fritts, who coated the semi – conductor Selenium with an extremely thin layer of gold to form the junction. However the device was only one percent (1%) efficient, it is made from thin slices of crystalline Silicon, Gallium Arsenide and other semi – conductor materials which when irradiated  with light excites electrons to move from one energy level to another through semi – conducting Silicon material which then convert Solar radiation directly to electricity. Cells with conversion efficiencies above 30 percent are now available by connecting large number of these cells into modules. The simplest solar cell provide small power for electricity to houses and electric grid, usually solar cells provides low power to remote unattended devices such as buoys, weather and communication satellites, equipment aboard space craft, solar cells and energy payback.

2.2    Different types of Solar cells

Photovoltaic materials may fall into one of the listed classes;

1. Crystalline: Mono – crystalline silicon and poly – crystalline Silicon
2. Thin Film Material
3. Amorphous
4. Multi – Junction
5. Organic or Photochemical

Mono-crystalline Silicon: cell have dominated the market in the past but now overtaken by poly- crystalline Silicon. The interest of mono – crystalline Silicon by many people was due to the good stability and desirable electronic, physical and chemical properties of Silicon. More over, Silicon was already successful in micro – electronic and enormous industry created to be of advantage for the smaller photovoltaic industry with regards to economic scale.

Polycrystalline silicon: cell is currently the most dominant material and has surpassed the demand of the mono – crystalline silicon because it is cheaper. The manufacturing process of poly – crystalline Silicon reduces the cost of solar cells by avoiding pulling in the manufacturing process which results in a block with large crystal grain structure. This actually result in cheaper cells with lower efficiency. The assembly of multi–crystalline wafers and therefore offsets (counteract by having an equal and opposite effect) the low efficiency.

Thin film – material: This photovoltaic device are made using very thin semi – conductor film deposited on some type of low – cost structural substrate such as glass, metal or plastic because thin layer of photovoltaic material have high absorptivity, the deposited layer of photovoltaic material is extremely thin. This result, in the reduction of the dominating material cost, although thin film photovoltaic cells suffers from poor cell conversion efficiency.

Amorphous Silicon: This material has a significant advantage of higher absorptivity of about 40 times that of crystalline Silicon. It can be deposited on a low cost substrate and the manufacturing process requires low temperature and less energy. It has lower material and manufacturing costs. Amorphous hydrogenated silicon (a.Si:H) has been used majorly by the Japanese to power small consumer goods such as watches and calculators.

2.3 Photovoltaic Solar Generator

The solar panel consist of solar cells made of semi conductor device consisting of large P – N junction diode which when exposed to sunlight produces usable electrical energy. Other components include the storage bank or battery that accumulates and store the excess energy during the day. This stored energy is then consume during the hours of low irradiation at night or autonomy days. The controller automatically manages the operation of the total system and their interconnections and supports. A typical Silicon photovoltaic cell is composed of a thin layer consisting of an ultra – thin layer of Phosphorus doped (N – type) Silicon. An electrical field near the top – surfaces of the cell where those two materials are in contact called P-N junction.

2.4                                     REVIEW OF SOLAR CELL MATERIALS

The Shockley-Queisser limit for the theoretical maximum efficiency of a solar cell. Semiconductors with band gap between 1 and 1.5eV, or near-infrared light, have the greatest potential to form an efficient single-junction cell. (The efficiency “limit” shown here can be exceeded by multijunction solar cells.)

Solar cell materials must have characteristics that match the spectrum of available light. Some cells are designed to handle sunlight that reaches the Earth surface. Others are optimized for use in space. Light-absorbing materials can often be used in multiple physical configurations to take advantage of various absorption and charge separation mechanisms.

Industrial cells are made of monocrystalline silicon, polycrystalline silicon, amorphous silicon, cadmium telluride, copper indium selenide/sulfide or GaAs-based multijunction.

As of 2014 typical solar cells are made from semiconductors wafers between 180 to 240 micrometers thick.

2.5                                  REVIEW OF EARLY INVERTERS

From the late nineteenth century through the middle of the twentieth century, DC-to-AC power conversion was accomplished using rotary converters or motor-generator sets (M-G sets). In the early twentieth century, vacuum tubes and gas filled tubes began to be used as switches in inverter circuits. The most widely used type of tube was the thyratron.

The origins of electromechanical inverters explain the source of the term inverter. Early AC-to-DC converters used an induction or synchronous AC motor direct-connected to a generator (dynamo) so that the generator’s commutator reversed its connections at exactly the right moments to produce DC. A later development is the synchronous converter, in which the motor and generator windings are combined into one armature, with slip rings at one end and a commutator at the other and only one field frame. The result with either is AC-in, DC-out. With an M-G set, the DC can be considered to be separately generated from the AC; with a synchronous converter, in a certain sense it can be considered to be “mechanically rectified AC”. Given the right auxiliary and control equipment, an M-G set or rotary converter can be “run backwards”, converting DC to AC. Hence an inverter is an inverted converter.

Controlled rectifier inverters

Since early transistors were not available with sufficient voltage and current ratings for most inverter applications, it was the 1957 introduction of the thyristor or silicon-controlled rectifier (SCR) that initiated the transition to solid state inverter circuits.

The commutation requirements of SCRs are a key consideration in SCR circuit designs. SCRs do not turn off or commutate automatically when the gate control signal is shut off. They only turn off when the forward current is reduced to below the minimum holding current, which varies with each kind of SCR, through some external process. For SCRs connected to an AC power source, commutation occurs naturally every time the polarity of the source voltage reverses. SCRs connected to a DC power source usually require a means of forced commutation that forces the current to zero when commutation is required. The least complicated SCR circuits employ natural commutation rather than forced commutation. With the addition of forced commutation circuits, SCRs have been used in the types of inverter circuits described above.

In applications where inverters transfer power from a DC power source to an AC power source, it is possible to use AC-to-DC controlled rectifier circuits operating in the inversion mode. In the inversion mode, a controlled rectifier circuit operates as a line commutated inverter. This type of operation can be used in HVDC power transmission systems and in regenerative braking operation of motor control systems.

Another type of SCR inverter circuit is the current source input (CSI) inverter. A CSI inverter is the dual of a six-step voltage source inverter. With a current source inverter, the DC power supply is configured as a current source rather than a voltage source. The inverter SCRs are switched in a six-step sequence to direct the current to a three-phase AC load as a stepped current waveform. CSI inverter commutation methods include load commutation and parallel capacitor commutation. With both methods, the input current regulation assists the commutation. With load commutation, the load is a synchronous motor operated at a leading power factor.

As they have become available in higher voltage and current ratings, semiconductors such as transistors or IGBTs that can be turned off by means of control signals have become the preferred switching components for use in inverter circuits.

Rectifier and inverter pulse numbers

Rectifier circuits are often classified by the number of current pulses that flow to the DC side of the rectifier per cycle of AC input voltage. A single-phase half-wave rectifier is a one-pulse circuit and a single-phase full-wave rectifier is a two-pulse circuit. A three-phase half-wave rectifier is a three-pulse circuit and a three-phase full-wave rectifier is a six-pulse circuit.

With three-phase rectifiers, two or more rectifiers are sometimes connected in series or parallel to obtain higher voltage or current ratings. The rectifier inputs are supplied from special transformers that provide phase shifted outputs. This has the effect of phase multiplication. Six phases are obtained from two transformers, twelve phases from three transformers and so on. The associated rectifier circuits are 12-pulse rectifiers, 18-pulse rectifiers and so on…

When controlled rectifier circuits are operated in the inversion mode, they would be classified by pulse number also. Rectifier circuits that have a higher pulse number have reduced harmonic content in the AC input current and reduced ripple in the DC output voltage. In the inversion mode, circuits that have a higher pulse number have lower harmonic content in the AC output voltage waveform.