Internet Data Centres (IDC): For power system performance
The latest technology offers the ideal solution to the perennial request for great availability and reliability of the power supply. The UPS (Uninterruptible Power Supply) is the device that can guarantee the required continuity and quality of supply, not only by protecting from mains failures but also from variations beyond tolerance.
A double conversion UPS configuration guarantees, stable voltage and frequency. Double AC/DC conversion provides more guarantees than any other UPS
architectures: the AC mains at the input is converted to DC by a total controlled rectifier; an inverter at the output rebuilds the sine wave. This stage can also provide frequency conversion. In normal operation mode the double conversion UPS always powers the load always through the inverter, thus completely decoupling the load from the electrical distribution, and protecting it from any disturbance that could cause a system malfunction.
Source : http://chloridepower.com