DESIGN AND CONSTRUCTION OF A 5KVA INVERTER

CHAPTER ONE

INTRODUCTION

1.0 BACKGROUND OF THE STUDY

According to cseafrica.org, Presently, seventy-six million Nigerians or 40.7% of

the Nigerian population (more than twice the population of Canada) are not

connected to the national power grid. For those connected, power supply is a

serious problem as about approximately 90% of total power demanded is not

supplied.

The erratic and intermittent nature of power supply is a thing of major concern

to all Nigerians. The cost of acquiring a generator set and the need to

supplement the irregular voltage supply by the Electricity Distribution

Companies of Nigeria make it essential for the construction of the

DC/AC power inverter. It is not an exaggeration to say that Nigeria's electrical

power supply is epileptic today. This has become the norm, and many

Nigerians now consider power outages to be "normal" and part of everyday life.

This condition has been linked to a number of causes. Natural disasters,

vandalism, maintainability and sustainability, and a lack of local content are

only a few of them. Without examining other factors such as a lack of political

will to invest adequately in the power sector, a lack of replacement policy

resulting in obsolete equipment, unsustainable human capacity building, and

an inadequate reward and remuneration system to motivate human resources

to perform well, the problem of poor-quality power supply cannot be properly

addressed. The Institute of Electrical Electronics Engineering (IEEE)

recommends that the supplies available for usage be continuous,

uninterrupted, with constant frequency, and within the load determined in

terms of voltage and current. Given the increased sensitivity and sophistication

of today's technological technology, these needs have become even more

important. Over the last few decades, research in generating alternative energy

sources has demonstrated that independent power systems are not only viable,

but also quite practical. In fact, a large range of generating equipment is now

available to allow users to take advantage of virtually any renewable energy

source; however, for a variety of reasons, most of these systems only produce

direct current (DC), and sometimes only at low voltage. Nonetheless, because

alternating current (AC) is found in the vast majority of households, it is often

accepted as the best and most useful form of current.

DESIGN AND CONSTRUCTION OF A 5KVA INVERTER

1.1 PROBLEM STATEMENT

Sensitive appliances and systems are affected by power interruptions caused

by Power Holding Company of Nigeria (PHCN)'s power outages [or as Niger state call it Abuja Electricity Distribution Company (AEDC)] and volatility in power

supply. After that, this project will provide a 5kVA backup and stable power

source to power at least a typical four-bedroom flat.

DESIGN AND CONSTRUCTION OF A 5KVA INVERTER

1.2 AIMS AND OBJECTIVES OF THE PROJECT

The aim of this project is to design and construct a circuit that will take a 24v

dc input from battery and provide a 5000VA output that will be able to supply a

standard four bedroom flat.

The objectives are;

➢ To design a circuit that will convert Dc to Ac power for various appliances

used in domestic home.

➢ To provide a noiseless source of electricity generation.

➢ To provide a source of AC power with low maintenance cost and zero fuel

cost.

➢ To improve our understanding on simple electrical designs, building of

electrical circuits and basic principle of operation of inverter.

DESIGN AND CONSTRUCTION OF A 5KVA INVERTER

1.3 SCOPE OF WORK

The project undertaken i.e. 5KVA to 220 – 240volt inverter has four stages or

units. These units include;

i. Supply unit

ii. Inverter unit

iii. Step-up transformer unit

iv. Triggering unit.

The scope of this project is primarily to show how the low voltage DC power

supplied is used to energize the circuit. It will also show how the inverter unit

convert the low voltage DC into a low voltage AC in form of square wave. The

triggering unit provides the trigging pulse needed by MOSFET to operate.

DESIGN AND CONSTRUCTION OF A 5KVA INVERTER
1.4 LIMITATION

Despite the fact that an inverter is built on a noiseless and pollution-free

foundation, unlike other alternative sources of generating power, the battery

must be charged and recharged from time to time.

Also, instead of using a copper transformer, which is lighter and smaller in size

but more expensive, a massive transformer is used. One limitation of this

inverter is that it can only be used for loads within the load rating and cannot

be used for large loads and industrial machines. Another limitation is the

inability of the circuit to provide a pure sine wave output wave form. This is

because it is quite expensive to design a pure sine wave inverter circuit.

DESIGN AND CONSTRUCTION OF A 5KVA INVERTER

DESCRIPTION OF COMPONENTS

One of the goals of this chapter is to showcase the many components utilized

in the circuits that make up the project, as well as to outline any calculations

that may be required.

Relays, resistors, capacitors, transistors, voltage regulators, MOSFETs, and

other ICs are among the inverter's components.

DESIGN AND CONSTRUCTION OF A 5KVA INVERTER

1.1.1 RESISTOR

The resistor is the most common circuit component. In an electric circuit, it

provides opposition or causes resistance to the flow of charges (electrons) or

current. They're used to control current flow and voltage drop in electrical and

electronic circuits. They are used in power circuits to lower voltage by

dissipating power. A resistor is made out of a conducting material (carbon, a

thin metal, a carbon film, or a low-conductivity wire) with a wire coming out of

each end. It is distinguished by its tenacity: V/I = R

Where V is the voltage across the resistor in volts.

The current flowing through the conductor, measured in amperes, is denoted

by I.

The resistance to current flow, measured in ohms, is R.

Resistors are also classified by the amount of power they can safely dissipate,

as well as tolerance, noise, temperature co-efficient, voltage co-efficient, time

stability, and inductance.