Design And Construction Of A Sine Pulse Width Modulation

ABSTRACT

This project is titled the design and construction of a sine pulse width modulation, using 555 timer ic and dc4017 decade counter as the heart of the circuit. 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 is the out from the device that is measured using oscilloscope that gives the sine pulse width waveform.

This work is aimed at designing a device with a sine pulse width waveform.

TABLE OF CONTENTS

TITLE PAGE

APPROVAL PAGE

DEDICATION

ACKNOWLEDGEMENT

ABSTRACT

TABLE OF CONTENT

CHAPTER ONE

1.0     INTRODUCTION

1.1     OBJECTIVE OF THE PROJECT

1.2     SIGNIFICANCE OF THE PROJECT

1.3    APPLICATION OF THE PROJECT

1.4     SCOPE OF THE PROJECT

1.5     LIMITATION OF THE PROJECT

1.6     PURPOSE OF THE PROJECT

1.7     PROJECT ORGANISATION

CHAPTER TWO

2.0     LITERATURE REVIEW

2.1      OVERVIEW OF PULSE WIDTH MODULATION (PWM)

2.2      DUTY CYCLE

2.3      HISTORICAL BACKGROUND OF THE STUDY

2.4     REVIEW OF THE RELATED STUDY

2.5      DIFFERENCE BETWEEN SINE WAVE AND MODIFIED SINE WAVE INVERTER

CHAPTER THREE

3.0     METHODOLOGY

3.1     INTRODUCTION

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

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

CHAPTER FIVE

5.0     CONCLUSION

5.1     RECOMMENDATION

5.2     REFERENCES

CHAPTER ONE

1.0                                       INTRODUCTION

The term SPWM stands for “Sinusoidal pulse width modulation” is a technique of pulse width modulation used in inverters. An inverter generates an output of AC voltage from an input of DC with the help of switching circuits to reproduce a sine wave by generating one or more square pulses of voltage per half cycle. If the size of the pulses is adjusted, the output is said to be pulse width modulated. With this modulation, some pulses are produced per half cycle. The pulses close to the ends of the half cycle are constantly narrower than the pulses close to the center of the half cycle such that the pulse widths are comparative to the equivalent amplitude of a sine wave at that part of the cycle. To change the efficient output voltage, the widths of all pulses are amplified or reduced while keeping the sinusoidal proportionality. With PWM (pulse width modulation), only the on-time of the pulses are changed during the amplitudes.

sinusoidal pulse-width modulation is One of the methods used to reduce the low frequency harmonics in the inverter waveform. In this method, a reference copy of the desired sinusoidal waveform, the modulating wave, is compared to a much higher frequency triangular waveform, called the carrier wave. The resulting drive signals cause multiple turn-on of the inverter switches in each half-cycle with variable pulse width to produce a quasi-sine wave of load voltage. The pulse width increases from a very narrow width at the start of each cycle to a maximum width in the middle of each cycle. Then the pulse width reduces again after maximum until its minimum width at the end of the half-cycle period.

1.1                                                AIM OF THE PROJECT

The objective of this work is to explore sine pulse width modulation (SPWM ). The pulse width modulator takes a relatively lower frequency analog input signal and converts it to a much higher square wave signal where the duty-cycle ( pulse width ) of the square wave varies in proportion to the analog input signal.

1.2                         OBJECTIVE OF THE PROJECT

At the end of this work the student participated shall be able to built a Sinusoidal pulse width modulation device that will achieve the following objectives;

1. 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.

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

iV        a power electronics device whose output power will display a Sinusoidal pulse width modulation waveform using oscilloscope as the measurement instrument.

1.3                                           PURPOSE OF THE PROJECT

The purpose of this work is to display the waveform of Sinusoidal pulse width modulation on oscilloscope.

1.4                                              SCOPE OF THE PROJECT

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.

Sinusoidal pulse width modulation is a method of pulse width modulation used in an inverter.

In this method the switches switch on according to the carrier frequency of the signal whenever pulses are given to the switches. Its application to systems give best control of switches since the switches switch on according to the carrier frequency.

1.5                                       ADVANTAGES OF THE PROJECT

1. It is less costly
2. It is easy to implement in circuits.
3. It gives the best control of switches in circuits.

1.6                                       SIGNIFICANCE OF THE PROJECT

A Sine pulse width modulation power inverter is a power conversion device. It converts fixed direct current (DC) voltage to frequency sinusoidal alternating current (AC) voltage output. Sine pulse width modulation inverters are used to power and control the speed, torque, acceleration, deceleration, and direction of the motor. The use of inverter has become prevalent in wide range of industrial applications; from motion control applications to ventilation systems, waste water processing facilities to machining areas, and many others. Though power inverters offer lower operating costs and higher efficiency, they are not without their problems.

1.7                                         LIMITATION OF THE PROJECT

• Expensive when compared to other waveforms
• The output of the device can power a few appliances for a short period
• The input is limited to 12VDC, output to 230VAC and the frequency to 50Hz

1.8                                       APPLICATION OF THE PROJECT

Sine pulse width modulation is used in the following appliances:

DC power source utilization: Sine pulse width modulation is used in Inverter designed to provide 230 VAC from the 12 VDC source provided in an automobile. An inverter converts the DC electricity from sources such as batteries, solar panels, or fuel cells to AC electricity. The electricity can be at any required voltage; in particular it can operate AC equipment designed for mains operation, or rectified to produce DC at any desired voltage.

Uninterruptible power supplies: Sine pulse width modulation used in uninterruptible power supply (UPS) uses batteries and an inverter to supply AC power when main power is not available. When main power is restored, a rectifier supplies DC power to recharge the batteries.

Induction heating: Sine pulse width modulation Inverters convert low frequency main AC power to higher frequency for use in induction heating. To do this, AC power is first rectified to provide DC power. The inverter then changes the DC power to high frequency AC power.

HVDC power transmission: With HVDC power transmission, AC power is rectified and high voltage DC power is transmitted to another location. At the receiving location, an inverter in a static inverter plant converts the power back to AC. The inverter must be synchronized with grid frequency and phase and minimize harmonic generation.

Variable-frequency drives: A variable-frequency drive controls the operating speed of an AC motor by controlling the frequency and voltage of the power supplied to the motor. An inverter provides the controlled power. In most cases, the variable-frequency drive includes a rectifier so that DC power for the inverter can be provided from main AC power. Since an inverter is the key component, variable-frequency drives are sometimes called inverter drives or just inverters.

Electric vehicle drives: Adjustable speed motor control inverters uses Sine pulse width modulation is used to power the traction motors in some electric and diesel-electric rail vehicles as well as some battery electric vehicles and hybrid electric highway vehicles.

Air conditioning: An inverter air conditioner uses a variable-frequency drive from Sine pulse width modulation to control the speed of the motor and thus the compressor.

Electroshock weapons: Electroshock weapons and tasters have a DC/AC inverter using Sine pulse width modulation to generate several tens of thousands of V AC out of a small 12 V DC battery.

1.7                                        PROJECT WORK ORGANISATION

The various stages involved in the development of this project have been properly put into five chapters to enhance comprehensive and concise reading. In this project thesis, the project is organized sequentially as follows:

Chapter one of this work is on the introduction to a Sine pulse width modulation. In this chapter, the background, significance, objective limitation and problem of a power inverter were discussed.

Chapter two is on literature review of a Sine pulse width modulation. In this chapter, all the literature pertaining to this work was reviewed.

Chapter three is on design methodology. In this chapter all the method involved during the design and construction were discussed.

Chapter four is on testing analysis. All testing that result accurate functionality was analyzed.

Chapter five is on conclusion, recommendation and references.