Thesis Abstract

Abstract
This project focuses on the construction of a 200W uninterruptible power supply (UPS) system. The UPS system is designed to provide backup power to critical electrical devices in case of mains power failure. The system consists of a battery, a charger, an inverter, and control circuitry to ensure seamless switchover between mains power and battery power. The UPS system is designed to be compact and efficient, with a total power output of 200W. The battery used in the system is a lead-acid battery with a capacity of 12V and 7.2Ah, providing sufficient energy storage for backup power. The charger circuit is responsible for charging the battery when mains power is available and ensuring that the battery remains fully charged and ready for use. The inverter circuit is responsible for converting the DC power stored in the battery into AC power that can be used to power electrical devices. The inverter is designed to provide a clean and stable power output to ensure the safe operation of connected devices. The control circuitry monitors the status of the mains power supply and automatically switches to battery power in case of a power outage. It also includes protection features to safeguard the UPS system and connected devices from overvoltage, overcurrent, and short circuits. The construction of the UPS system involves assembling the various components, including the battery, charger, inverter, and control circuitry, into a compact and sturdy enclosure. The system is designed to be user-friendly, with clear indicators to show the status of the mains power supply and battery power. The system also includes audible alarms to alert users in case of a power outage or system fault. Overall, the construction of the 200W uninterruptible power supply system provides a reliable and efficient backup power solution for critical electrical devices. The system is designed to be easy to use and maintain, making it suitable for both residential and small commercial applications. By ensuring continuous power supply during mains power outages, the UPS system helps prevent data loss, equipment damage, and disruptions to daily operations.

Thesis Overview

1.0 INTRODUCTION

The idea behind a UPS (Uninterruptible Power Supply) is pretty obvious from the name, in addition to filtering, enhancing or modifying the unity power, special circuit and batteries are used to prevent electrical machines from losing power during a disruption (blackout or voltage sag brownout). The units are all called different names depending on the next design, but all fit into general category of backup power.
Before delving into details of how an uninterruptible power supply works, let’s take a quick look of the basic of the type of equipment. An electrical device plugged into the wall or into a surge suppressor has only one source of power. If there is a blackout, the electricity is out an the device obviously goes off immediately. A UPS changes this equation by providing its equipment two source of power.
UPS are designed so that there is one source of power normally used called the primary power source and another source that kicks in if the primary is disrupted called the secondary power source. The power from the wall is always one of those sources and the battery contains within the UPS is the other. A switch is used to control each of these powers and the equipment of any given time. The switch changes from the primary of the secondary when it detects the primary has gone out. It switches back from the secondary power the primary power, source has returned.
Contrary to what you might think, the wall A.C power is not always the primary power source and the battery the secondary source. Which source is primary and which is secondary depends on the type of UPS. Therefore, circuit is provided with this UPS to convert AC power to DC to change the battery. A device called an invert is also provided to change the battery stone DC electricity to AC to run your equipment.
Furthermore, those components of the uninterruptible power supply and other one discussed in details in the section covering the various parts of the UPS. The size of the UPS is primary dictated by the size of the time your equipment can run on battery power switching down, higher units not only can power equipment for more time they can also handle a large total demand for power.
1.1 BACKGROUND
In this section we will take a brief look of the various parts that are made up of typical UPS. Focus is on small units more commonly used for home and smaller business.
INVERTER PART: That is inversion circuit, all UPS include cone circuit that manipulates electricity converting it from AC power produced by your utility company to DC power stored in the battery and back again for use by your equipment. The inverter section converts a DC voltage into an AC voltage with the help of an oscillator. This section also consists of two stages of switching circuits which comprises of a power transistor connected i in the common emitter configuration.
Since the oscillator has two outputs each of the switching circuits is coupled to the two outputs of the oscillator respectively. The two outputs one explained in detail in subsequent chapter. The exact type, netune size and quality of the circuit depend on the type of UPS and more specifically the model you have chosen. As with all things the better the unit, the high the quality of the components and as with all thins quality is often corrected to price but not always.