Offline UPS, also known as backup UPS, means that the inverter does not work when the mains is normal, and only starts to work when the mains is out of power and the battery is discharged. When the mains is normal, the mains is supplied to the electrical equipment through a simple voltage regulation filter output, and the battery is in a charged state. When there is a power failure, the inverter works to convert the DC power provided by the battery into a stable AC power output to the electrical equipment.
Offline UPS has the advantages of small size, high efficiency, low price and low operating cost. Since the inverter is in a non-working state under normal circumstances, the grid power is directly supplied to the load, so the power conversion efficiency of the offline UPS is very high.
1. The load is not really isolated from the on-line power supply system.
2. The long transfer time and the lack of a true static switch means that the time required to transfer the load to the inverter is relatively long.
3. Although this conversion time is acceptable in some applications (such as a separate computer, etc.), this performance cannot meet the requirements of large or complex sensitive loads (such as large computer centers, telephone exchanges, etc.).
4. The output voltage cannot be adjusted.