Design And Construction Of A 5KVA DC To AC Power Inverter Using 24-volt DC And 8 Rechargeable Battery

This project is on design and construction of a 5KVA inverter with input battery 24V to Output 220Vac 50Hz.

A power inverter, or inverter, is an electronic device or circuitry that changes direct current (DC) to alternating current (AC). The input voltage, output voltage and frequency, and overall power handling, are dependent on the design of the specific device or circuitry.

A typical power inverter device or circuit will require a relatively stable DC power source capable of supplying enough current for the intended overall power handling of the inverter. Possible DC power sources include: rechargeable batteries, DC power supplies operating off of the power company line, and solar cells. The inverter does not produce any power, the power is provided by the DC source. The inverter translates the form of the power from direct current to an alternating current waveform.

The level of the needed input voltage depends entirely on the design and purpose of the inverter. In many smaller consumer and commercial inverters a 24V DC input is popular because of the wide availability of powerful rechargeable 24V DC power source.

The aim of this inverter is construct a 5kva inverter with a 24v input dc supply (with 8 battery) which comprises of inbuilt automatic charger- which can charge an acid lead rechargeable battery and at same time turn-turn off the charger or stop charging the battery whenever the battery charge fully.
 

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 STUDY

1.3     SIGNIFICANCE OF THE PROJECT

1.4     SCOPE OF THE PROJECT

1.5     LIMITATION OF THE PROJECT

1.6     APPLICATION OF THE PROJECT

1.7     INVERTER RATING

1.8     WHY CHOOSE A MODIFIED SINE WAVE INVERTER?

1.9     TYPES OF INVERTER

1.10     PROJECT ORGANISATION

CHAPTER TWO

2.0     LITERATURE REVIEW

2.1     REVIEW AN EARLY INVERTER

2.2   REVIEW OF BASIC DESIGNS OF AN INVERTER

2.3     DIFFERENCE BETWEEN SINE WAVE AND MODIFIED SINE WAVE   INVERTER.

2.4     REVIEW OF INVERTER CAPACITY

2.5     SAFETY OF INVERTER

CHAPTER THREE

3.0     CONSTRUCTION

3.1     BASIC DESIGNS OF AN INVERTER

3.2     BLOCK DIAGRAM OF THE SYSTEM

3.3     SYSTEM CIRCUIT DIAGRAM

3.4     DESCRIPTION OF COMPONENTS USED

3.5     PARTS LIST

3.6     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

• INTRODUCTION

1.1                          BACKGROUND OF STUDY

All modern engineering system include certain aspects of control systems at some point in their broadcast sense, control engineering and the associated theory are concerned with the means by which systems may be made to behave an a desired way.

The system on this thesis is a DC – AC converter, which is an apparatus which is used for conversion of Direct Current to Alternating Current or signal.

In our country, this equipment is not all that in used not because it is not important but because people never give it a thought as per the construction and design.

It is meant, use with a 24v lead acid battery. If it’s in a car for example a suitable output voltage of 230v AC is obtainable.

This output voltage of 230v AC can be used for powering small electrical appliances such as light, electric fans, radio, soldering iron etc.

However, it is worthwhile that AC operated with this appliance is nothing comparable to the AC generated by big generators. This is so because the voltage and power are less in terms of AC generation duration. This appliance is therefore suitable for short time replacement for the real AC generation especially in the remote areas and install where electrical appliances are sold and the need might arise for it to be tested and certified good.

Another main area where this equipment can be of great utility is in communication system, in a situation where there is constant AC power supply failure e.g in offices, DC – AC converter is need and in such cases can be used as a light sources.

Most industries in the country do not make use of DC – AC converter because they are thought to be costly with respect to the task they perform. However, putting into consideration the task this appliance can be used for, it can be concluded that it is cheaper. The construction is simple, cheaper easy to operate and portable. The usefulness of this device and the function cannot to be over emphasizing now in our economic situation and also when our power generating authority (NEPA) has been dubbed NEVER EXPECT POWER ALWAYS.

In these times when control and monitor a complex field engineering operations have gone computer based, a failure of AC power supply to communication equipment means work stoppage and to some small scale industries a lot of economic and material losses avoidable. To this end, the equipment (DC-AC Converter) is incorporated to an impulse sealer machine which has about 3 sections where the,

First stage is of the dimmer switch with regulates, the rate at which the power flow is needed. The second stage being the main switch(s) which controls the primary side, secondary side of the transformer, the stage 3 comprise of the element made of construction wire which does or finishes the work needed for the machine.

1.2                        OBJECTIVE OF THE STUDY

The objective of this project is to design and construct an inverter which is rated 5KW which can be powered from the source of 24VDC and which incorporated eight (8) rechargeable battery. This inverter is capable of operating a wide variety of loads; electronic and household items including but not limited to TV, VCR, and satellite receiver, computers, and printers.

1.3                          SIGNIFICANCE OF THE SYUDY

In the recent years, power inverter has become a major power source due to its environmental and economic benefits and proven reliability. Since the solar power system does not have moving parts, virtually it does not require any kind of maintenance once installed.

Power inverter is produced by connecting the device on the 24VDC battery as the input to produce 220VAC as the required output. It can also be connected to solar panel.

Second, the whole energy conversion process is environmentally friendly. It produces no noise, harmful emissions or polluting gases. The burning of natural resources for energy can create smoke, cause acid rain and pollute water and air. Carbon dioxide, CO2, a leading greenhouse gas, is also produced in the case of burning fuels. Power inverter uses only the power of the battery as its fuel. It creates no harmful by-product and contributes actively to the reduction of global warming.

1.3                                SCOPE OF THE PROJECT

A power inverter is a power conversion device. It converts fixed direct current (DC) voltage to frequency sinusoidal alternating current (AC) voltage output.

Power inverters are used to power and control the speed, torque, acceleration, deceleration, and direction of the motor. The use of inverter has become prevalent in wide range of industrial applications; from motion control applications to ventilation systems, waste water processing facilities to machining areas, and many others. Though power inverters offer lower operating costs and higher efficiency, they are not without their problems.

1.4                          LIMITATION OF THE PROJECT

• Expensive when compared to traditional generators
• There are no large capacity inverter in the markets
• The inverter can power a few appliances for a short period
• The input is limited to 24VDC, output to 220VAC and the frequency to 50Hz

1.5                         APPLICATION OF THE PROJECT

the applications and uses of a power inverter which are as follows:

DC power source utilization

Inverter designed to provide 240 VAC from the 24VDC source provided in an automobile. The unit shown provides more than 20 amperes of alternating current, or enough to power upto 5KW load.

An inverter converts the DC electricity from sources such as batteries, solar panels, or fuel cells to AC electricity. The electricity can be at any required voltage; in particular it can operate AC equipment designed for mains operation, or rectified to produce DC at any desired voltage.

Uninterruptible power supplies

An uninterruptible power supply (UPS) uses batteries and an inverter to supply AC power when main power is not available. When main power is restored, a rectifier supplies DC power to recharge the batteries.

Induction heating

Modified Sine wave Inverters convert low frequency main AC power to higher frequency for use in induction heating. To do this, AC power is first rectified to provide DC power. The inverter then changes the DC power to high frequency AC power.

HVDC power transmission

With HVDC power transmission, AC power is rectified and high voltage DC power is transmitted to another location. At the receiving location, an inverter in a static inverter plant converts the power back to AC. The inverter must be synchronized with grid frequency and phase and minimize harmonic generation.

Variable-frequency drives

A variable-frequency drive controls the operating speed of an AC motor by controlling the frequency and voltage of the power supplied to the motor. An inverter provides the controlled power. In most cases, the variable-frequency drive includes a rectifier so that DC power for the inverter can be provided from main AC power. Since an inverter is the key component, variable-frequency drives are sometimes called inverter drives or just inverters.

VFDs that operate directly from an AC source without first converting it to DC are called cyclo-converters. They are now commonly used on large ships to drive the propulsion motors.

Electric vehicle drives

Adjustable speed motor control inverters are currently used to power the traction motors in some electric and diesel-electric rail vehicles as well as some battery electric vehicles and hybrid electric highway vehicles.

Air conditioning

An inverter air conditioner uses a variable-frequency drive to control the speed of the motor and thus the compressor.

Electroshock weapons

Electroshock weapons and tasters have a DC/AC inverter to generate several tens of thousands of V AC out of a small 24 V DC battery. First the 24VDC is converted to 400–2000V AC with a compact high frequency transformer, which is then rectified and temporarily stored in a high voltage capacitor until a pre-set threshold voltage is reached.

1.6                               INVERTER RATINGS

The ratings that you should look at when buying an inverter (depending on the type) are:

1. Continuous Rating: This is the amount of power you could expect to use continuously without the inverter overheating and shutting down.
2. Half Hour Rating: This is handy as the continuous rating may be too low to run a high energy consumption power tool or appliance, however if the appliance was only to be used occasionally then the half hour rating may well suffice.
3. Surge Rating: A high surge is required to start some appliances and once running they may need considerably less power to keep functioning. The inverter must be able to hold its surge rating for at least 5 seconds. TVs and refrigerators are examples of items that require only relatively low power once running, but require a high surge to start.
4. IP rating – defines the ability of the inverter seals to prevent water and dust ingress. Although some inverter manufacturers claim high IP ratings suitable for outdoor installation, the quality and location of the seals and ventilation will greatly affect the ability of the inverter to outlast the many years solar installations are expected to work.
5. Peak efficiency– represents the highest efficiency that the inverter can achieve.

1.7   WHY CHOOSE A MODIFIED SINE WAVE INVERTER?

For running typical resistive loads like lights and appliances, a modified sine wave inverter is a reliable, cost-effective choice. Though modified sine wave inverters do not produce a perfect replica of AC true sine wave power, they do provide an affordable option that for many mobile power applications is perfectly adequate. Some devices, however, may not recognize the modified sine wave and may run poorly or not at all.

Some of our most popular modified sine wave inverters are from our Heavy-Duty line up. These are excellent solutions for fleet, utility trucks and vans looking for a powerful and economical alternative to a pure sine wave product.

1.8                                 TYPES OF INVERTER

There are different types of inverters for home and industries available which can suit your various electricity needs. Following are the two basic types of inverters.

1. Modified Sine Wave Inverters

This type of home inverter obtains power from a battery of 12 volts and must be recharged using a generator or a solar panel. Appliances like microwave ovens, light bulbs, etc. can be run using these types of inverter.

• They can be rightly held as the best inverters for homes as they are efficient enough to provide power to the normal home requirement.
• They are the home inverters that are most affordable
• You can run the daily used home appliances using the modified sine wave home inverters.
• The electric appliances that involve motor speed controls or timers are not to be run using these types of home inverters.

The wave form of a modified sine wave inverter is as below:

2. True sine wave inverters

This is one of the better types of inverters as they provide better power as compared to the modified sine wave inverters for homes. These types of home inverter are also run using a battery of a larger capacity.

• Technically speaking, the sine waves they produce are purer, thus the efficiency.
• They are best inverters employed for the power sensitive appliances like refrigerators, televisions, air conditioners, washing machines, etc.
• These types of inverters are extremely reliable. The only drawback is that they are a bit expensive and cannot be afforded by the common man.
• There are various models available based on the electricity requirement of the house.

The wave form of a sine wave inverter is as below:

3. Square wave inverter

This is the simplest form of output wave available in the cheapest form of inverters. They can run simple appliances without problem but much else. Square wave voltage can be easily generated using a simple oscillator. With the help of a transformer, the generated square wave voltage can be transformed into a value of 240VAC or higher.

The wave form of a square wave inverter is a below:

1.10                 PROJECT WORK ORGANISATION

The various stages involved in the development of this project have been properly put into five chapters to enhance comprehensive and concise reading. In this project thesis, the project is organized sequentially as follows:

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

Chapter two is on literature review of 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.