Design And Construction Of A 2.5KVA DC To AC Inverter

CHAPTER ONE

1.0     INTRODUCTION

1.1     BACKGROUND OF STUDY

It is a well known fact today that electrical power supply is not reliable. All over the world, there is a significant electrical power supply interruption. Because of these electrical power supply interruption, many electrical equipment have either developed problems or even stopped working entirely. Hence this has crippled much business thereby affecting even the economy of many countries as Nigeria. Also there is increase in occurrence of power supply disturbance, which can be viewed as a form of power pollution. High voltage spikes and momentary voltage drops are therefore common. These power disturbance may affect the performance of sensitive equipment in private and corporate organization causing loss of data ad even damage to equipment.

In Nigeria today, it is not an over-statement to talk about the epileptic supply of electrical power. This has become the order of the day such that many Nigeria now view these power outages as “Normal” and part of their daily life. A wide range of factors have been identified for this problem. They include natural disasters, vandalism, maintainability and sustainability and lack of local content. The problem of poor quality power supply cannot be properly addressed without a review of other factors such as lack of political will to invest adequately in power sector, absence of replacement policy resulting in obsolete equipment, unsustainable human capacity building and inadequate reward and remuneration system to motivate human resources team to perform well.

According to the recommendation made by the Institute of Electrical Electronics Engineering (IEEE), the supplies that should be available for use should be continuous, uninterrupted with constant frequency and within the load determine in terms of voltage and current. These requirements have become even more relevant in view of the high sensitivity and sophistication of modern technological equipment in use today.

The progress made in developing alternate source of energy over the last decades has shown that independent power systems are not only possible but also very practical. In fact a wide variety of generating equipment is now available to allow individuals take advantage of just any renewable source of energy, for number of reasons, however, most of these system produce only direct current (DC) and often do so only at low voltages. Nonetheless, it is generally agreed that the greatest and most useful form of current is the Alternating current (AC), since these exist in the vast majority of homes.

Therefore, there arises the need to able to convert Direct Current (DC) to Alternating Current (AC) that will be of a constant frequency and also be used to power electrical circuits either in homes or in industries. Such electrical device is called an INVERTER.

An inverter is a power electronics device or apparatus which converts direct current to alternating current, allowing the direct current power from these generators to be used with ordinary a.c appliances and or mixed with the existing electrical grid.

An inverter is an electrical device that converts direct current (DC) to alternating current (A.C); the converted A.C can at any required voltage and frequencies, with the use of appropriate transformer, switching and control circuit. Inverters are commonly used to supply A.C power from D.C sources such as panels or batteries.

This inverter is designed to provide uninterrupted 220volts a.c supply to the loads connected at its outputs socket. It provide a constant a.c supply to the output socket even when the a.c mains supply is no longer available. When the a.c main supply is available, it goes to the a.c mains sensor, relay and battery charging section of the inverter. This a.c mains sensor informs the relay about the availability of a.c mains supply. When this relay receives a.c mains signals from the main supply, it directly passes the a.c main signals to the inverter output socket.

This project is also written in five chapters. Chapter one contains of the Introduction, Background of the study, the problems statements and the Scope of study . The chapter two contains Literature review discussion. While Chapter three talks about the designing of the inverter and necessary derivation on the design circuit, and calculations. Chapter four contain the information on the result obtain, and the principle of operation of the inverter. Finally, Chapter five is the Conclusion and Recommendation.

1.2 AIM AND OBJECTIVE

 AIM

The main aim of this work is to build a 2.5KVA inverter which can be powered from a 24V battery which incorporated a battery charger.

OBJECTIVE

The objectives of the study are:

1. To build the prototype model of an inverter.
2. to change direct current (24VDC) to alternating current (220VAC) which can be used to power appliances both in Houses and industries.

• To provide a means of solving power generation problem in our country.

1. To provide a noiseless source of electricity power generation.

To provide a source of electricity power with low maintenance cost and

zero fuel cost.

1.3   STATEMENT OF PROBLEM

If there is one factor that has perpetually maintained the status of Nigeria as a less developed country, it is its electricity sector. Till date, many households and industrial businesses cannot be guaranteed of 24 hours supply of electricity from the National grid. At this stage of Nigeria’s social and economic development, the country cannot deliver sufficient energy to the citizens despite huge financial resources that have been expended in the sector.

Rather, Nigerians have continued to rely on electricity generators for their power supply, fuel marketers are taking significant portion of households’ institutions of learning and businesses’ incomes to supply power, noise pollution from regular humming generators have become integral part of living for many Nigerians with imaginable consequences on their health. Our institution  is not immune to the aforementioned problems of Nigeria’s power sector, which has led to increase in day to day running cost of the university. Because of these problems, there is a need to design and construct an inverter for the department of electrical and electronics, federal university of technology to complement or augment the electricity supply from the National grid, reduce cost of energy consumed and eliminate noise/environmental pollution that is associated with running of generator.

1.4 SCOPE OF STUDY

This project covers the design and construction of 2.5KVA inverter with the following stages – Power Supply unit, Inverting unit, Power transformer unit, triggering unit. The scope of this project is primarily to show how the low voltage D.C power supplied is used to energize the circuit. It will also show how the inverter units convert the low voltage D.C into a low voltage A.C in form of square wave. The triggering unit provides the trigging pulse needed by MOSFET to operate.