Design And Construction Of A 3.5KVA Pure Sine Wave Inverter

ABSTRACT

This project is titled the design and construction of a 3.5Kva pure sine wave inverter system with battery feed indicator. Pure sine wave inverters produce a pure sine wave output.  This means the power output from a pure sine wave inverter is the same as the mains supply.

A pure sine wave is not only critical for the correct functioning of high end electronic equipment, it will also ensure that appliances run more smoothly, producing less heat and noise.  A sine wave inverter circuit developed to run AC appliances at a low cost which high efficiency

Pure sine wave inverter take up 12v DC from battery and inverts it to an output of 220v, 50H2 AC. It makes no noise during operation and no hazardous carbon monoxide is generated in the surrounding.   In a pure wave inverter a low pass filter was used to filter out the high frequencies and thus isolate the harmonics so a 50 Hz fundamental frequency was retained. The main aim of this device is to build a 3.5kva pure sine wave inverter.

TABLE OF CONTENTS

TITLE PAGE

APPROVAL PAGE

DEDICATION

ACKNOWLEDGEMENT

ABSTRACT

TABLE OF CONTENT

CHAPTER ONE

1.0     INTRODUCTION

1.1     BACKGROUND OF THE STUDY

1.2     PROBLEM STATEMENT

1.3     AIM AND OBJECTIVE OF THE PROJECT

1.4     PURPOSE OF THE STUDY

1.5     SIGNIFICANCE OF THE PROJECT

1.6    APPLICATION OF THE PROJECT

1.7     LIMITATION OF THE PROJECT

1.8     SCOPE OF THE PROJECT

1.9     RESEARCH METHODOLOGY

1.10      PROJECT ORGANISATION

CHAPTER TWO

2.0     LITERATURE REVIEW

2.1     REVIEW OF THE RELATED STUDY

2.2     REVIEW OF HISTORY OF AN INVERTER

2.3     REVIEW OF HOW TO CHOOSING THE RIGHT INVERTER

2.4      REVIEW OF THE DIFFERENCE BETWEEN SINE WAVE AND MODIFIED SINE WAVE   INVERTER.

2.5     REVIEW OF INVERTER CAPACITY

2.6     SAFETY OF INVERTER

2.7     TYPES OF INVERTER

CHAPTER THREE

3.0     CONSTRUCTION

3.1     BASIC DESIGNS OF AN INVERTER

3.2      BLOCK DIAGRAM OF THE SYSTEM

3.3     SYSTEM OPERATION

3.4     CIRCUIT DIAGRAM

3.5     CIRCUIT DESCRIPTION

3.6     DESCRIPTION OF COMPONENTS USED

3.7      HOW TO CHOOSE A RIGHT INVERTER AND BATTERY

3.8      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

1.1                                        BACKGROUND OF THE STUDY

A power inverter converts DC power (12VDC) to standard AC power (220 VAC). It is designed to meet up with the power demand in the offices and in homes in the absence of power supply from the power holding company of Nigeria, PHCN. In order words the device / item serves as a substitute for PHCN which almost monopolises electricity to people.

Electricity is one of the greatest inventions man has ever made, due to its very important role in socio-economic and technological development (Owen and Edward, 1996) [7]. Electricity can be transmitted in two different ways namely: alternating currents (AC) or Direct current (DC). Alternating current is the form obtained from power outlets in homes and offices. It consists of a sinusoidal voltage source in which a continuous change in the direction of flow of voltage (and current) can be used to employ magnetic components (Cooks et al., 2001) [1]. Direct current is electricity flowing in a constant direction, and/or possessing a voltage with constant polarity and is appropriate for short-range transmission. Direct current is the form stored up in batteries. It uses is limited and it depends on AC power (Owen and Edward, 1996) [7].

A common difference between AC and DC involves the amount of energy that each can carry. Direct current has a voltage level and cannot travel very far until it losses energy. Ac is safer to transmit over long distance (Nergaard et al., 2001) [5]. DC is preferred over AC because of its portability hence the introduction of the inverter that are mobile AC source from a portable DC battery. An inverter is an electrical device that converts DC to AC; the converted AC can be at any required voltage frequency with the use of appropriate transformers, switching and control circuits. There are three types of DC-AC inverters, the square wave, the modified sine wave and pure sine wave.

Pure sine wave inverters are the most affluent in terms of efficiency and accurate timing output. They use batteries to generate power and it’s important to have a means of recharging (Cunningham, 1999) [3]. Various methods can be adopted such as solar panels, wind turbine etc. Pure sine wave inversion is obtained by taking a DC voltage source and switching it across a load using an H-bridge. If this voltage needs to be boosted from the DC source in the inverter, it can be accomplished either before the AC stage by using a DC-DC boost converter, or after AC stage by using a Boost transformer (Crowley and Leung, 2001) [2]. The inverted signal is composed of a pulse width-modulated signal which encodes a sine wave. The duty cycle of the output is changed such that power transmitted is exactly that of a sine wave. This output can be used as it is or, alternatively, can be filtered easily into a pure sine wave (Nuzhat et al., 2010) [6]. The aim of this proposed study is to build a pure sine wave inverter which is an electronic device or circuitry that changes direct current (DC) to alternating current (AC). The input voltage, frequency and output voltage and overall power handling depend on the design of the specific device or circuitry. It allows to have a reliable source of electricity for various appliances even if they are off the power grid. Mode of operation of an inverter is divided in three stages: oscillator, amplifier, and output transformer stage.

1.2                                 PROBLEM STATEMENT

Recently it was discovered that Square wave inverter and modified sine wave inverter has high harmonic distortion and as result of that it does not have clean electricity. Inductive loads do not run faster or cooler, it produces noise and causes crash of appliances such as computer. To overcome these problems, pure sine wave was invented. A sine wave is a continuous wave that describes a smooth repetitive oscillation. It is the ideal waveform for the transfer of AC power with very low harmonic distortion. Pure sine wave inverters produce power which equals or better than the power in home. It use sophisticated technology to protect even the most sensitive electronics. It can be used for digital microwaves ,televisions, fridges, laptops and other electronic equipments. Pure Sine inverters can power just about any AC appliance without risk of damage.

1.3                          OBJECTIVE OF THE PROJECT

The main aim of this device is to build a 3.5kva pure sine wave inverter. The objectives of this project are:

1. To build a pure sine wave inverter that can be used to power appliances both in house and industries.
2. To safely operate any electronic devices (such as micro wave, drills, clock, speed motor) that require sensitive calibration.

• To back-up the erratic power supply by PHCN.

1. To ensure the protection of the back-up source consumer equipment and supply.

1.4                                           PURPOSE OF THE PROJECT

The purpose of this work is to produce power which equals or better than the power in home. It uses sophisticated technology to protect even the most sensitive electronics.

1.5                                       SIGNIFICANCE OF THE PROJECT

The output voltage of a sine-wave inverter has a sine wave-form like the sine wave-form of the mains / utility voltage. In a sine wave, the voltage rises and falls smoothly with a smoothly changing phase angle and also changes its polarity instantly when it crosses 0 Volts.

1.6                                              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. This unit of the system is responsible for powering the entire system. The input voltage of the system is 12V, and the output voltage is 230VAC. The microcontroller is used to generate the required frequency ranging from 20 KHZ-500 KHz. The battery feed indicator indicates when the battery is connected to system.

1.7                                         LIMITATION OF THE PROJECT

• Expensive when compared to traditional generators
• The inverter can power a few appliances for a short period
• The input is limited to 12VDC, output to 220VAC and the frequency to 50Hz
• The power rating of the work is 3.5kva

1.8                                       APPLICATION OF THE PROJECT

various applications of the inverter are Wind/solar electrical systems, Back-up for power cells, Generator support systems, Remote homes, Telecommunications, Computers, Tools, Security applications, Mobile power, Boats and yachts, Airplane, Monitoring equipment, Emergency power and lighting etc.

1.9                                             RESEARCH METHODOLOGY

In the course of carrying this study, numerous sources were used which most of them are by visiting libraries, consulting journal and news papers and online research which Google was the major source that was used.

1.10                                     PROJECT ORGANISATION

The work is organized as follows: chapter one discuses the introductory part of the work,   chapter two presents the literature review of the study,  chapter three describes the methods applied, chapter four discusses the results of the work, chapter five summarizes the research outcomes and the recommendations.