UPS, Uninterruptible Power Supply

The main advantage lies in its uninterrupted power supply capability. When the utility AC input is normal, the UPS rectifies the AC into DC, and then inverts the DC into stable, unadulterated AC for the back-end loads. Once the utility AC input is abnormal, such as undervoltage, blackout or frequency abnormality, then the UPS will activate the backup energy – battery, the rectifier circuit of the UPS will be shut down, and the DC power from the battery will be reversed into stable and unadulterated AC power accordingly, which will continue to be used by the back-end loads.

The main circuit topology of UPS power supply is shown below: