CONSTRUCTION OF 200W UNINTERRUPTIBLE POWER SUPPLY

CONSTRUCTION OF 200W UNINTERRUPTIBLE POWER SUPPLY

CHAPTER ONE

1.0     INTRODUCTION

The concept of a UPS (Uninterruptible Power Supply) is self-explanatory; in addition to filtering, enhancing, or modifying the unity power, special circuits and batteries are used to prevent electrical machines from losing power during a disruption (blackout or voltage sag brownout). The units have different names depending on the design, but they all fall into the general category of backup power.

Before delving into the specifics of how an uninterruptible power supply works, let’s review the fundamentals of the type of equipment. An electrical device that is plugged into the wall or a surge suppressor has only one power source. When there is a blackout, the electricity goes out and the device immediately turns off. A

UPS alters this equation by providing its equipment with two power sources.

UPSs are designed with one power source that is normally used as the primary power source and another that kicks in if the primary is disrupted as the secondary power source. One of those sources is always power from the wall, and the other is the battery contained within the UPS. Each of these powers and the equipment at any given time are controlled by a switch. When the switch detects that the primary has failed, it switches to the secondary. It returns the primary power source after switching back from the secondary power source.

Contrary to popular belief, the wall A.C power is

The primary source is not always the battery, and the battery is not always the secondary source. The type of UPS determines which sources are primary and which are secondary. As a result, a circuit is included with this UPS to convert AC power to DC in order to change the battery. An inverter is also provided to convert the battery’s DC electricity to AC power to power your equipment.

Furthermore, those components of the UPS and others are discussed in detail in the section covering the various parts of the UPS. The size of the UPS is primarily determined by the amount of time your equipment can run on battery power before switching off; larger units not only can power equipment for longer periods of time, but they can also handle higher loads a large total demand for power.

1.1     BACKGROUND

In this section, we’ll take a quick look at the various components that make up a typical UPS. The emphasis is on small units, which are more commonly used at home and in small businesses.

ALL UPS include a cone circuit that manipulates electricity, converting it from AC power generated by your utility company to DC power stored in the battery and back again for use by your equipment. The inverter section uses an oscillator to convert a DC voltage to an AC voltage. This section also includes two stages of switching circuits, each of which includes a power transistor connected in the common emitter configuration.

Because the oscillator has two outputs, each switching circuit is coupled. to the oscillator’s two outputs, respectively. The two outputs are explained in detail in the following chapter. The exact type, network size, and quality of the circuit are determined by the type of UPS and, more specifically, the model selected. As with all things, the better the unit, the higher the quality of the components, and as with all things, quality is often but not always corrected to price.