Design And Construction Of A 1KVA Microcontroller Based Power Inverter System
The aim of this project is to design and implement a single phase inverter which can convert DC voltage to AC voltage at high efficiency and low cost. Solar and wind powered electricity generation are being favored nowadays as the world increasingly focuses on environmental concerns. Power inverters, which convert solar-cell DC into domestic-use AC, are one of the key technologies for delivering efficient AC power. A low voltage DC source is inverted into a high voltage AC source in a two-step process. First the DC voltage is stepped up using a boost converter to a much higher voltage. This high voltage DC source is then transformed into an AC signal using pulse width modulation. Another method involves first transforming the DC source to AC at low voltage levels and then stepping up the AC signal using a transformer. A transformer however is less efficient and adds to the overall size and cost of a system. Therefore the former method is the one used to implement this project.
To deliver such performance, the power inverters is driven by high-performance PIC 16F877A microcontroller units (MCUs) that can achieve high-level inverter control, and therefore this microcontroller is the heart of the system and controls entire system. The microcontroller is programmed using embedded c compiler and in specific mikroC pro to generate sine pulse width modulated (SPWM) pulses which are used to drive H-bridge. By alternate switching switches of two legs of H-bridge alternating 12V DC voltage is converted into 240V Ac voltage.
The design is essentially focused upon low power electronic appliances such as personal computers, chargers, television sets. To build the design it is first mathematically modeled then is simulated in Proteus and finally the results are practically verified
INTRODUCTION
Electronic devices run on AC power, however, batteries and some forms of power generation produce a DC voltage so it is necessary to convert the voltage into a source that devices can use. Hence a need for power rating inverter to smoothly operate electrical and electronic appliances. Most of the commercially available inverters are actually square wave or quasi square wave inverters. Electronic devices run by this inverter will damage due to harmonic contents. Available sine wave inverters are expensive and their output is not so good. For getting pure sine wave we’ve to apply sinusoidal pulse width modulation (SPWM) technique. This technique has been the main choice in power electronics because of its simplicity and it is the mostly used method in inverter application. To generate this signal, triangular wave is used as a carrier signal is compared with sinusoidal wave at desired frequency.
Advances in microcontroller technology have made it possible to perform functions that were previously done by analog electronic components. With multitasking capability, microcontrollers today are able to perform functions like comparator, analog to digital conversion (ADC), setting input/output (I/O), counters/timer, among others replacing dedicated analog components for each specified tasks, greatly reducing number of component in circuit and thus, lowering component production cost. Flexibility in the design has also been introduced by using microcontroller with capability of flash programming/reprogramming of tasks.
The proposed approach is to replace the conventional method with the use of microcontroller. In this project PIC16F877A microcontroller was used. It has low cost and reduces the complexity of the circuit for the single phase full bridge inverter. The focus of this report is on the design and prototype testing of a DC to AC inverter which efficiently transforms a DC voltage source to a high voltage AC source similar to the power delivered through an electrical outlet (240Vrms, 50Hz) with a power rating of approximately 1000W.
The method in which the low voltage DC power is inverted is completed in two steps. The first being the conversion of the low voltage DC power to a high voltage DC source, and the second step being the conversion of the high DC source to an AC waveform using pulse width modulation. Another method to complete the desired outcome would be to first convert the low voltage DC power to AC, and then use a transformer to boost the voltage to 240 volts
This paper focused on the first method described and specifically the transformation of a high voltage DC source into an AC output.
This project builds upon the work of another project which mandated to build the DC to DC boost. In this report, it is detailed how the inverter’s controls are implemented with a digital approach using a microprocessor for the control system and how effective and efficient a 3- level PWM inverter can be. The inverter device will be able to run more sensitive devices that a modified sine wave may cause damage to such as: laser printers, laptop computers, power tools, digital clocks and medical equipment. This form of AC power also reduces audible noise in devices such as fluorescent lights and runs inductive loads, like motors, faster and quieter due to the low harmonic distortion
…chapter one continues
2.0 INTRODUCTION:
This chapter provides the background and context of the research problems, reviews the existing literature on the Design And Construction Of A 1KVA Microcontroller Based Power Inverter System, and acknowledges the contributions of scholars who have previously conducted similar research [REV2679] …
TITLE PAGE
APPROVAL PAGE
DEDICATION
ACKNOWLEDGEMENT
ABSTRACT
TABLE OF CONTENT
CHAPTER ONE
1.0 INTRODUCTION
1.1 OBJECTIVE OF THE PROJECT
1.2 PURPOSE OF THE PROJECT
1.3 SIGNIFICANCE OF THE PROJECT
1.4 LIMITATION OF THE PROJECT
1.5 PROBLEM STATEMENT
1.6 APPLICATION OF THE PROJECT
1.7 INVERTER RATING
1.8 IMPORTANT CONSIDERATION OF INVERTER
1.9 DIFFERENCE BETWEEN CONVENTIONAL GENERATOR AND INVERTER
1.10 PROJECT ORGANISATION
CHAPTER TWO
2.0 LITERATURE REVIEW
2.1 HISTORITICAL BACKGROUND OF AN INVERTER
2.2 TYPES OF INVERTER
2.3 SATETY OF INVERTER
2.4 INVERTER CAPACITY
2.5 REVIEW OF EARLY INVERTERS
2.6 HOW TO CHOOSE AN INVERTER
CHAPTER THREE
3.0 CONSTRUCTION
3.1 BASIC DESIGNS OF A PURE SINE WAVE
3.2 BLOCK DIAGRAM OF THE SYSTEM
3.3 DESCRIPTION OF PURE SINE WAVE INVERTER UNITS
3.4 SYSTEM CIRCUIT DIAGRAM
3.5 CIRCUIT OPERATION
3.6 DESCRIPTION OF COMPONENTS USED
3.7 HOW TO CHOOSE THE BEST INVERTER BATTERY
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
4.4 COST ANALYSIS
CHAPTER FIVE
5.0 CONCLUSION
5.1 RECOMMENDATION
5.2 REFERENCES