ABSTRACT
Uninterruptible power supply (UPS) systems provide uninterrupted, reliable, and high-quality power for vital loads. UPS systems also suppress line transients and harmonic disturbances. Applications of UPS systems include medical facilities, life-support systems, data storage and computer systems, emergency equipment, telecommunications, industrial processing, and on-line management systems. Generally, an ideal UPS should be able to deliver uninterrupted power while simultaneously providing the necessary power conditioning for the particular power application. UPS systems are classified into three general types: static, rotary, and hybrid static/rotary. In contrast with the on-line UPS, which drives the load in the normal operating mode, off-line UPS provides power for the load in case of power outage, overvoltage, and undervoltage situations in the AC line. However, most of the line-interactive UPS systems operate on-line in order to either improve the power factor of the load or regulate the output voltage for the load.
