UPS (Uninterruptible Power Supply) is considered as one of the best ways to save electrical equipments from power problems. It is an electrical apparatus that provides emergency power to a load when the input power source, typically mains power fails. At home we need UPS when we use our PC. Others areas that need UPS are data centre, process backup, military operation etc. There are several varieties of UPS: online UPS, offline UPS and line interactive UPS. Online UPS is inverter supply directly to load; offline UPS is the inverter starts only when utility is not present, line interactive UPS is an offline UPS with an AVR / line conditioner. There is an inverter which converts DC current (Battery power) to AC current is called UPS inverter. IGBT rectifier technology is the latest and most effective technology in the UPS industry. It uses the high frequency to rectify the AC to DC. IGBT rectifier reduces harmonics substantially and reduces the upsize of upstream components. Hence, reduce initial cost and operation cost.