Theory- 36 :- Types of UPS

 

Types of UPS

Electrical power supply intrusions can come in different forms like surges, voltage dips, voltage spikes and harmonics. These troubles can cause serious damage to electrical gears, mostly during the production stages or critical processing of an action. 

To decrease the risk of power supply distortion, UPS systems are frequently integrated in electrical networks. Electronic power supply equipment makers can offer consistent, high-quality power flow for various electrical load gear and these devices are generally found in industrial processing applications, medical services, emergency gear, telecommunications, & computerized data systems. A UPS system can be a helpful device for ensuring accurate power supply performance.

Uninterruptible Power Supply devices are classified into three types such as

1. The Standby UPS
2. The Line Interactive UPS
3. Online UPS

The Standby UPS

The standby Uninterruptible Power Supply is also called as off line UPS, that is generally used for PCs. The block diagram of this UPS is shown below. This UPS includes a battery, an AC or DC & DC or AC inverter, a static switch and a LPF which is used to decrease the switching frequency from the o/p voltage & a surge suppressor.The standby UPS system works with the switch arrangement to select the AC i/p as a primary power source, and interchanging to the battery & inverter as backup sources in case of primary power gets disrupted. The inverter normally relies on standby, only triggering when the power fails and the transfer switch routinely switches the load to the backup units. This kind of UPS system offers a small size, high degree of efficiency, & pretty low costs, making of this UPS is easy.

The Line Interactive UPS

The block diagram of Line Interactive UPS is shown below, it is the most common UPS used for small business. The designing of line interactive UPS is alike to a standby UPS, in addition the design Line Interactive generally includes an automatic voltage regulator(AVR) or a tap-changing transformer.

This enhances the regulation of voltage by regulating transformer taps as the i/p voltage differs. Voltage regulation is a significant feature when the conditions of a low voltage exist, otherwise the UPS would transfer to battery & then finally down the load. The usage of more common battery can cause early battery failure. The features of this UPS are small size, low cost, high efficiency can make the UPS in the range of 0.5-5kVA power

Online UPS

The online UPS is also called as double conversion online uninterruptible power supply. This is the most commonly used UPS and the block diagram of this UPS is shown below. The designing of this UPS is similar to the Standby UPS, excluding that the primary power source is the inverter instead of the AC main. In this UPS design, damage of the i/p AC does not cause triggering of the transfer switch, because the i/p AC is charging the backup battery source which delivers power to the o/p inverter. So, during failure of an i/p AC power, this UPS operation result in no transfer time.

In this design, both the inverter and the battery charger change the total load power flow, resulting in reduced efficiency with its associated increased heat generation. This UPS affords nearly perfect electrical o/p performance. But the constant wear on the power components decreases reliability over further designs and the energy spent by the electrical power inefficiency is an important part of the life-cycle cost of the UPS. Also, the i/p power drawn by the large battery charger has been frequently non-linear and can interfere with the building power wiring with standby generators.