Description
CHAPTER ONE
- INTRODUCTION
1.1 BACKGROUND OF STUDY
All modern engineering system include certain aspects of control systems at some point in their broadcast sense, control engineering and the associated theory are concerned with the means by which systems may be made to behave an a desired way.
The system on this thesis is a DC – AC converter, which is an apparatus which is used for conversion of Direct Current to Alternating Current or signal.
In our country, this equipment is not all that in used not because it is not important but because people never give it a thought as per the construction and design.
It is meant, use with a 12v lead acid battery. If it’s in a car for example a suitable output voltage of 230v AC is obtainable [2].
This output voltage of 230v AC can be used for powering small electrical appliances such as light, electric fans, radio, soldering iron etc.
However, it is worthwhile that AC operated with this appliance is nothing comparable to the AC generated by big generators. This is so because the voltage and power are less in terms of AC generation duration. This appliance is therefore suitable for short time replacement for the real AC generation especially in the remote areas and install where electrical appliances are sold and the need might arise for it to be tested and certified good.
Another main area where this equipment can be of great utility is in communication system, in a situation where there is constant AC power supply failure e.g in offices, DC – AC converter is need and in such cases can be used as a light sources.
Most industries in the country do not make use of DC – AC converter because they are thought to be costly with respect to the task they perform. However, putting into consideration the task this appliance can be used for, it can be concluded that it is cheaper. The construction is simple, cheaper easy to operate and portable. The usefulness of this device and the function cannot to be over emphasizing now in our economic situation and also when our power generating authority (NEPA) has been dubbed NEVER EXPECT POWER ALWAYS.
In these times when control and monitor a complex field engineering operations have gone computer based, a failure of AC power supply to communication equipment means work stoppage and to some small scale industries a lot of economic and material losses avoidable. To this end, the equipment (DC-AC Converter) is incorporated to an impulse sealer machine which has about 3 sections where the,
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 pursuit of technological development [2].
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. Then, this project is to provide a back-up and reliable power supply to power some selected home appliances such as computers, television set, lighting systems.
1.3 AIM / OBJECTIVE OF THE PROJECT
The aim of this project is to design and construct a circuit that will take a 12v dc input from battery and provide a 220v ac and 3000w output that will be able to supply electricity to a home with charging system that charges the battery through mains supply. At the end of this work the student involved shall able:-
- To build the system prototype.
- To provide a noiseless source of electricity generation.
- To have a source of generating electricity that has no negative effect on the environment (i.e. no greenhouse effect).
- To provide a source of electricity power with low maintenance cost and zero fuel cost.
1.4 PURPOSE OF THE PROJECT
The purpose of this work is to provide a means of having a backup power supply by building an electronic device or circuitry that changes direct current (DC) to alternating current (AC) with charging circuit.
1.5 PROJECT MOTIVATION
Inverters are the best when it comes to back-up since they can come up very fast and they generate little or no noise unlike generator. Even in an area with constant power supply, power outage due to natural cause and faults are usually unannounced. It is therefore very important to prevent causalities and loss of goodwill by having a reliable back-up power installed.
1.5 SIGNIFICANCE OF THE SYUDY
In the recent years, power inverter has become a major power source due to its environmental and economic benefits and proven reliability.
Power inverter is produced by connecting the device on the 12VDC battery as the input to produce 220VAC as the required output. It can also be connected to solar panel [1].
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 [1][2].
1.6 SCOPE OF THE PROJECT
A power inverter is a power conversion device. It converts fixed direct current (DC) voltage to frequency sinusoidal alternating current (AC) voltage output.
Power 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 traditional generators
- There are no large capacity inverter in the markets
- The inverter can power a few appliances for a short period
- The input is limited to 12VDC, output to 220VAC and the frequency to 50Hz
1.7 APPLICATION OF THE PROJECT
the applications and uses of a power inverter which are as follows:
DC power source utilization
Inverter designed to provide 240 VAC from the 12VDC 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
An 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
Modified Sine wave 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.
VFDs that operate directly from an AC source without first converting it to DC are called cyclo-converters. They are now commonly used on large ships to drive the propulsion motors.
Electric vehicle drives
Adjustable speed motor control inverters are currently 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 to control the speed of the motor and thus the compressor.
Electroshock weapons
Electroshock weapons and tasters have a DC/AC inverter to generate several tens of thousands of V AC out of a small 12V DC battery. First the 24VDC is converted to 400–2000V AC with a compact high frequency transformer, which is then rectified and temporarily stored in a high voltage capacitor until a pre-set threshold voltage is reached.
1.8 BENEFITS OF THE PROJECT
- Extended Power Backup: Get several hours of backup to meet your power need over most of the day. For the right load, your inverter over 10 hours of supply.
- Zero Running costs: They require no consumables like diesel, petrol or oil, saving you lots of money on spent on power generators. Also no frequent breakdowns as you’re likely to get with your overworked power generator.
- Noise-Free: inverter is noiseless. Now you can spare yourself all that generator noise you’ve been enduring as a necessary evil
- No Oil Mess too: inverter uses no oil, causes no oil spill or dirt and is a clean appliance like other gadgets in your room.
- No Fumes: the inverter also produces any fumes or smoke, saving your environment all the air pollution your power generator punishes you with.
- Auto-run: All the stress of starting, stopping, changing over, topping oil, pouring diesel, cleaning oil mess and all the other tedious chores of managing a generator are eliminated for you. Inverters run in automated mode, requiring no manual intervention.
Conserve, Optimize: The inverter is an economy device, helping you optimize. Switch on only your TV and that’s the power you use, all else stays stored. For a generator, it must run at full capacity, burning fuel at full requirement, even if it’s just a bulb you want to light.
