ABSTRACT

An inverter is an electronic device that converts direct current (DC­) to alternating current (AC) the converted Ac can be at any required voltage and frequency with the use of appropriate transformers, switching and control circuit. It’s simple put, is an electronic box that makes household electricity for everyday items.  It converts power from eg car batteries, windmills, solar panels or fuel cells, then turns it into normal household power.  That is, supply AC power from DC source.       Solid state inverters have no moving parts and are used in a wide range of applications, from small switching power supplies in computers, to large electric utility high voltage direct current applications that transport bulk power.  The Inverter performs the opposite function at a rectifier.  There is one more thing you need to be very careful about that is, do you want clean or dirty electricity? What I mean here is that there are two types of electricity that inverters can produce.  Pure sine wave Inverters and Modified sine wave Inverters. The difference is that pure sine wave matches the power to that of which you get from you electricity supplier, its clean and you can run any appliances safely even sensitive equipment. Modified sine wave is dirty power, you can use this to power a lot of things that don’t have sensitive electronics.  Kettle for example fridges, cookers, hot plates etc. You cannot run led lighting on these Inverters as they over head and die within a couple of hours. You have to be careful with some Tvs PCs as they do n like it either, but I have heard that lot of people use them for this with no problems, but I like to be safe, rather than sorry.

3.1    Description Of Components          

3.2    Capacitors                         

3.2.1 Types of Capacitor              

3.3    Semi-Conductor Diode         

3.4    Transistors                                

3.4.1   Bipolar Transistor                     

3.5      Field Effect Transistor (FET)        

CHAPTER FOUR         

Operation and Design Consideration

4.1            Features of the Device                      

4.1.1      Supply Unit              

4.1.2      Inverter Unit                    

4.1.3      Stepup Transformer Unit   

4.1.4      Triggering or Switching Unit               

4.2            Design                                            

4.2.1      Required Specification       

4.2.2      Triggering or Switching Circuit

4.2.3      Buffer Stage                            

4.2.4      Transformer Turns Ratio            

5.1        Casing and Packaging         

6.1        Testing of System Operation        

CHAPTER SEVEN:       INSTALLATION OF COMPLETED DESIGN                       

List, Quantity And Prizes Of Components Used

Conclusion                                         

INTRODUCTION

        All modern engineering system includes certain aspects of control system at some point in their broadcast scenes, control engineering and the associated theory are concerned with the means of making system to behave in a desired may.

        The system on this thesis is a DC – AC inverter which is an apparatus used in the conversion of direct current (DC) to alternating current (AC).

        In our country today, this equipment is not all that in use not because it is not important but because people never give it a thought as per the construction and design.

        It is meant for use with a 12volts lead acid battery of it’s in a car for example a suitable output voltage of 240volts AC obtainable.

        This output voltage of 240volts AC can be used for powering small electrical appliances such as lights, electrical tools radio, soldering iron, fan etc. However, it is with mentioning that the DC generated with this appliance is nothing comparable to the AC generated by big generation duration. This appliance is therefore suitable for short time replacement for the real AC generation especially in the remote areas and it is 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 a constant AC power supply failure example in offices DC – AC inverter is needed and such cases, inverter can be used as a source of light.

        Most industries in the country do not make use of DC – AC inverter because there are through to be costly with respect to the task they perform. However, putting into consideration the task, this appliance can perform. 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 be over emphasized especially now that our country is passing through a very sensitive era in our power generating Authority (NEPA) has been dubbed NEVER EXPECT POWER ALWAYS. In these times when control and monitor of complex field operations have based in computer, a failure of AC, power supply to communication equipment means work stoppage and to some small scale industries a lot of economic and materials losses is avoidable.

        Inverters come in different types. Examples

Modified sine wave, pure sine wave and grid tie inverter are:

Modified Sine Wave: The output of a modified sine wave inverter is similar to square wave output except that the output goes to zero Volts for a time before switching positive or negative. It is simple and low cost, also it’s compatible with most electronic devices, except for sensitive or specialized equipment for example certain laser printers, fluorescent lighting, audio equipment.  Most AC motors will run off this power source about at a reduction inefficiency of approximately 20%.

        A pure sine wave inverter produces a nearly perfect sine wave output (<3% total harmonic distortion) that is essentially the same as utility –supplied grid power.  Thus it is compatible with all AC electronic devices.  This is the type used in grid tie inverts. Its design is more complex, and costs more per unit power.  The electrical inverter is a high power electronic oscillator.  It is so named because early mechanical AC to PC converters were made to work in reserve and thus were “inverted” to convert DC to AC.

        A grid tie inverter is a sine wave inverter designed to inject electricity into the electric power distribution system.  Such inverter must synchronise with the frequency of the grid.  They usually contain one or more maximum power point tracking features to extract the maximum amount of power, and also include safety features.

APPLICATIONS

DC Power Source Utilization

Inverter designed to provide 115 VAC from the 12 VDC source provided in an automobile.  The unit shown provides up to 1.2 amperes of alternating current, or enough to power two sixty watt light bulbs.

Micro –inverter convert direct current from individual solar panels into alternating current for the electric grid.  They are grid tie designs by default.

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 rectified supplies DC power to recharge the batteries.

        Induction heating inverters convert low frequency main AC power to higher frequency for use in induction heating.  To do this, AC power is first rectified to proved DC power.  The inverter then charges the DC power to high frequency AC power.

This material content is developed to serve as a GUIDE for students to conduct academic research