Description
ABSTRACT
This seminar is on a DC to AC inverter system. It is designed to meet up with the power demand in the offices and in homes in the absence of power supply from the national supply authority, PHCN. In order words the device / item serves as a substitute for PHCN which almost monopolises the power supply to people.
It is designed in such a way that it will take up 12v DC from battery and inverts it to an output of 230v, 50Hz AC. It makes no noise during operation and no hazardous carbon monoxide is generated in the surrounding.
This is a feature that makes it safe to use anywhere when compared to generator. Also, the circuit is capable of charging the battery (i.e 12v source) when the power from the supply authority is on. This greatly reduces the cost of operation of the system.
This work is aimed at discussing on a 3kva modified sine wave inverter that can be used to power appliances both in homes and industries.
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 OBJECTIVES OF THE STUDY
1.4 SIGNIFICANCE OF THE PROJECT
1.5 APPLICATION OF THE PROJECT
1.6 SCOPE OF THE PROJECT
CHAPTER TWO
2.0 LITERATURE REVIEW
2.1 REVIEW OF AN INVERTER
2.2 HOW TO CHOOSING THE RIGHT INVERTER
2.3 DIFFERENCE BETWEEN SINE WAVE AND MODIFIED SINE WAVE INVERTER.
2.4 TYPES OF INVERTER
2.5 DIFFERENCE BETWEEN CONVENTIONAL GENERATOR AND INVERTER
CHAPTER THREE
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 CONCLUSION
3.7 RECOMMENDATION
REFERENCES
CHAPTER ONE
1.0 INTRODUCTION
1.1 BACKGROUND OF THE STUDY
A power inverter converts DC power (also known as direct current), to standard AC power (alternating current). Inverters are used to operate electrical equipment from the power produced by a car or boat battery or renewable energy sources, like solar panels or wind turbines. DC power is what batteries store, while AC power is what most electrical appliances need to run so an inverter is necessary to convert the power into a usable form. For example, when a cell phone is plugged into a car cigarette lighter to recharge, it supplies DC power; this must be converted to the required AC power by a power inverter to charge the phone [1].
In modified sine wave, The waveform in commercially available modified-sine-wave inverters is a square wave with a pause before the polarity transition, which only needs to cycle through a three-position switch that outputs forward, off, and reverse output at the pre-determined frequency. The peak voltage to RMS voltage does not maintain the same relationship as for a sine wave. The DC bus voltage may be actively regulated or the “on” and “off” times can be modified to maintain the same RMS value output up to the DC bus voltage to compensate for DC bus voltage variation.
The ratio of on to off time can be adjusted to vary the RMS voltage while maintaining a constant frequency with a technique called PWM. Harmonic spectrum in the output depends on the width of the pulses and the modulation frequency. When operating induction motors, voltage harmonics is not of great concern, however harmonic distortion in the current waveform introduces additional heating, and can produce pulsating torques[1].
Most AC motors will run on MSW inverters with an efficiency reduction of about 20% due to the harmonic content.
1.2 PROBLEM STATEMENT
As a result of continuous power failure and fluctuation in power supply by Power Holding Company of Nigeria (PHCN), sensitive appliances and system are affected by interruption power supply and also the blackout also affect human generally in that it takes away our happiness. Then, this project is to provide a back-up and reliable power supply of 3000VA from a renewable energy source (solar panel) to power some selected home appliances such as computers, television set, lighting systems.
1.3 AIM AND OBJECTIVES OF THE STUDY
The main aim of this seminar is to carry out a study on a 3kva modified sine wave inverter which is a device that can be powered from the source of 12V battery to produce an output of 230vac. The objectives are:
- To discuss the working principle of an inverter
- To study the application of an inverter
- To study the circuit description of an inverter
1.4 SCOPE OF THE STUDY
The scope of this seminar is to study device that changes direct current (DC) to alternating current (AC). The input voltage (12vdc), output voltage (230vac) and frequency (50hz).
A typical power inverter device or circuit requires a relatively stable DC power source capable of supplying enough current for the intended power demands of the system. The input voltage depends on the design and purpose of the inverter. The waveform of this work is modified sine wave. The modified sine wave output of such an inverter is the sum of two square waves one of which is phase shifted 90 degrees relative to the other. The result is three level waveform with equal intervals of zero volts; peak positive volts; zero volts; peak negative volts and then zero volts. This sequence is repeated. The resultant wave very roughly resembles the shape of a sine wave [7, 8].
1.5 SIGNIFICANCE OF THE STUDY
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 12VDC battery as the input to produce 230VAC as the required output. It can also be connected to battery or 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 [4].
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