CHAPTER ONE
1.0 INTRODUCTION
Electricity power system is one of the economic infrastructural facilities that are indispensable to a nation’s economic development. The efficiency of the supply of electricity will not only influence returns on investment on existing enterprises, it also plays a major role in the creation of an economic environment which influences decisions on potential investment.
The electricity which is the main source of power for our domestic consumption, industrial development, centre of learning and medical centres should really be rehabilitated into enhancement of productivity.
However power failure has resulted in people buying generators for their own daily activity. Other businesses are also not functioning due to absence of constant power supply. These are the reasons that necessitate the designing and construction of inverter and other standby system that can deliver maximum output power to the load. As society grows from simple to complex, mankind began to spread all over the earth and so it becomes necessary to enjoy power using an inverter.
Statistics have shown that the number of business that have been closed simply because of power problem cannot be over emphasized, so mankind need inverter seriously in other to restore technology development, businesses, communications, learning centre and medical centres. However, the background of the study lies within the reason why the construction of inverter should be forwarded and factor that enhance inverter marketability.
Recent large prices increase of fossil fuels in addition to the fact that their reserves are of finite existence such that mankind reliance on them is only for a few more decades has led to the research on alternative energy source which would replace fossil fuel (which currently is the bedrock of power generation). Which brings us to the importance of generating power on the sides to compliment the power supply
Finally, the success of this study will be beneficial to the society at large. Mass production of inverters will lead to improve standard of living of the populace and the nation will move forward in its pursuit of technological development. Power inverters are used to convert direct current (DC), such as that from a battery, to alternating current (AC), such as what can be drawn from a standard wall outlet. These devices are used in a large number of applications, including conditioning energy derived from solar cells into usable power and supplying electricity to household appliances during power outages.
1.2 Statement of problems
As a result of continuous power failure and fluctuation in power supply by the power distribution company, sensitive appliances and system are affected by interrupted power supply and also considering the relationship between the standard of living and the energy usage, the situation is worse year by year. And again the processes to convert the fossil fuels are expensive and deeply hazardous for the environment.
Due to the important nature of energy and the need for individuals to produce and use power outside that from the grid. This project will be timely as it provides a back-up and reliable power supply of 2.5kva to power sensitive equipments.
1.3 AIM AND OBJECTIVES
The main aim of this project is to design and construct a pure sine wave single phase 2.5kva inverter capable of achieving the following objectives:
An inverter that will produce an output up to 2.5kva with input from a 24V battery and can be used to power AC loads Generation of a pure sine wave output Use a microcontroller as the main circuit control component hence reducing system complexity. To ensure that provision is made for backup supply to consumer equipment.
1.3.1 OBJECTIVES
Inverters allow the user to provide AC power in areas where only batteries can be made available, allowing portability and freeing the user of long power cords.
1.4 SCOPE OF STUDY
This project is designed for power supply up to 2.5kva, with a battery input of 24V DC. Although the project design is limited only to a single phase, with output of 230(±30V). With implementation of both overload and low battery protections.
1.5 DEFINITION OF TERMS
The operational terms used in this project are defined as follows:
• RECTIFIER: a rectifier or converter is a circuit that converts AC voltage in pulsating DC voltage.
• OSCILLATOR WAVEFORM: this is the heart of the construction, in generating AC voltage at a frequency of a 5toHZ using a pulse width modulated IC (SG3526)
• BATTERY: a battery is an aggregate of two or more cells, assembled together in series formation to produce DC.
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• DIODE: this is a semi-conductor device with a p-n junction, which conducts only in forward bias direction,
• TRANSISTOR: this is the most important device in electronics. It can be used as an amplifier to increase power, voltage or current or as a switch.
• RELAY: is an electromechanical or static device which makes or open to control flow of electrical signal at its voltage free contacts.
• COMPARATOR: the function of the comparator is to compare two voltages this gives an output that specifies their equality or inequity. It employs an operational amplifier which brings about a high gain, provided by the differential amplifier input and one output.