Design And Construction Of Digital Power Supply

ABSTRACT

These days, majority of electronic devices work on DC power source, so there was a requirement of a reliable and customized power supply. Generally, the requirements are not too varied, but still they require every time a new hardware designing. The idea presented here is to build a digital controlled power supply [1] that is flexible enough to meet different requirements, with minor software changes and no corresponding hardware change. The aim of this work is to build a digital power supply that has programmable output voltage and current. It is able to recognize faults and take corrective actions to prevent any permanent damage to the system. The system discussed here is capable of functioning independently by its own without any intervention from the user.

TABLE OF CONTENTS

TITLE PAGE

APPROVAL PAGE

DEDICATION

ACKNOWELDGEMENT

ABSTRCT

TABLE OF CONTENT

CHAPTER ONE

• INTRODUCTION
• AIM/OBJECTIVE OF THE PROJECT
• SIGNIFICANCE OF THE PROJECT
• ADVANTAGES OF THE PROJECT
• LIMITATION OF THE PROJECT
• APPLICATION OF THE PROJECT
• PROJECT ORGANISATION

CHAPTER TWO

LITERATURE REVIEW

2.0      LITERATURE REVIEW

2.1     REVIEW OF POWER SUPPLY

2.2     REVIEW OF POWER SUPPLY CHARACTERISTICS

2.3     REVIEW OF GENERAL APPLICATION OF POWER SUPPLY APPLICATIONS

2.4       REVIEW OF TYPES OF POWER SUPPLY

CHAPTER THREE

3.0      CONSTRUCTION METHODOLOGY

3.1      BLOCK DIAGRAM OF THE SYSTEM

3.2      BLOCK DIAGRAM DESCRIPTION

3.3      CIRCUIT DIAGRAM

3.4      CIRCUIT DESCRIPTION

3.5     SOFTWARE USED

3.6     HARDWARE USED

3.7      SYSTEM OPERATION

3.8     CIRCUIT DESCRIPTION

3.9     DESCRIPTION OF MAJOR COMPONENTS USED

CHAPTER FOUR

4.0       RESULT ANALYSIS

4.1      CONSTRUCTION PROCEDURE AND TESTING

4.2      ASSEMBLING OF SECTIONS

4.3      CONSRUCTION OF THE CASING

4.4     TESTING

4.5     INSTALLATION OF THE COMPLETED DESIGN

CHAPTER FIVE

• CONCLUSIONS
• RECOMMENDATION
• REFERENCES

CHAPTER ONE

1.1                                                        INTRODUCTION

Power supply supplies electric energy to an electrical load. The primary function of a power supply is to convert one form of electrical energy to another and, as a result, power supplies are sometimes referred to as electric power converters. Some power supplies are discrete, stand-alone devices, whereas others are built into larger devices along with their loads. Examples of the latter include power supplies found in desktop computers and consumer electronics devices.

Every power supply must obtain the energy it supplies to its load, as well as any energy it consumes while performing that task, from an energy source. Depending on its design, a power supply may obtain energy from various types of energy sources, including electrical energy transmission systems, energy storage devices such as a batteries and fuel cells, electromechanical systems such as generators and alternators, solar power converters, or another power supply.

All power supplies have a power input, which receives energy from the energy source, and a power output that delivers energy to the load. In most power supplies the power input and output consist of electrical connectors or hardwired circuit connections, though some power supplies employ wireless energy transfer in lieu of galvanic connections for the power input or output. Some power supplies have other types of inputs and outputs as well, for functions such as external monitoring and control.

To obtain a complete circuit for this work, the circuit is mainly composed of the:

• Input transformer:   The input transformer is used to transform the incoming line voltage down to the required level for the power supply. Typically the input transformer provides a step down function. It also isolates the output circuit from the line supply.
• Rectifier:   The power supply rectifier converts the incoming signal from an AC format into raw DC. Either half wave or more commonly full wave rectifiers may be used as they make use of both halves of the incoming AC signal.
• Smoothing:   The raw DC from the rectifier is far from constant falling to zero when the AC waveform crossed the zero axis, and then rising to its peak. The addition of a reservoir capacitor here fills in the troughs in the waveform, enabling the next stage of the power supply to operate. Large value capacitors are normally used within this stage.
• Regulator:   This stage of the power supply takes the smoothed voltage and uses a regulator circuit to provide a constant output virtually regardless of the output current and any minor fluctuations in the input level.

DISPLAY: this power supply is unique in that it has the ability to display the actual measured values for voltage and current and also display shows the pre-set limits for voltage and current.

1.2                                                   AIM OF THE PROJECT

The aim of this work is to build a dc power supply that displays its output voltage and current digitally.

1.3                                             OBJECTIVE OF THE PROJECT

The objective of this project is to develop a power conversion system suitable for supplying power to dc loads with a displayable output.

1.4                                          APPLICATION OF THE PROJECT

• This device is used in powering of electronics appliances such as radio, DVD.
• It is used in Solar energy system
• It is used in vehicles
• It is used in transmitters
• Electronics labs

1.5                                         SIGNIFICANCE OF THE PROJECT

• The output voltages and current can be read through the LCD without using multi-meter or voltmeter
• A good, reliable and easy to use bench power supply unit is probably the most important and most used device in every electronic lab.
• The display shows the pre-set limits for voltage and current.
• Only standard components are used (no special chips).

1.6                                           LIMITATION OF THE PROJECT

• It is mainly design for 12v power supply.
• When loaded with a load more than the output voltage can damage the device.

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 digital power supply. In this chapter, the background, significance, objective limitation and problem ac-dc power supply were discussed.

Chapter two is on literature review of a digital power supply. 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.