Tunisia small UPS uninterruptible power supply design

An uninterruptible power supply is a device that has the ability to convert and control direct current (DC) energy to alternating current (AC) energy . UPS is a battery backup for PC, when the power goes off the UPS kicks in and continues to supply power for some period of time to the particular system.

The human desire to have a steady power supply for domestic and industrial purposes gave rise to an uninterrupted Power supply (UPS). Globally, the need and demand for computers, electronics, and other electrical devices are on the rise. These types of equipment required quality, high stability, and uninterrupted power supply.

UPS differs from an auxiliary emergency power system or standby generator that provides instantaneous or near-instantaneous protection from interrupted input power interruptions, utilizing one or more attached batteries and associated electronic circuitry for low power users. Or using diesel generators and flywheels for high power users.

For larger power units, Dynamic uninterruptible power supply (DUPS) are sometimes used, a synchronous motor/alternator is connected on the mains via a choke. Energy is stored in a flywheel, when the mains supply fails; an eddy-current regulation maintains the power on the load as long as the flywheels energy is not exhausted.

In this work, we made use of solid state components, with the aid of background knowledge in the field of electronics, to locally manufacture a UPS which could be used for back-up power for critical and essential loads. For the design, a battery is used to provide direct voltage and current, which is inverted by the inverter.

UPS unit comes in different sizes. For instance, there are small units designed to protect a single computer without a video monitor (around 200VA rating, and also large units designed to power entire data centers, buildings, or an entire city.