As the economy continues to develop, computers are widely used, and some important places such as finance, information, communications, and public equipment control have high requirements for power supply reliability and stability. Industries such as VLSI manufacturing also have high requirements for power supplies. Degradation of power quality such as voltage deviation, voltage waveform distortion, and continuous power failure will cause serious economic losses and social impact. Most of the key equipment in the above-mentioned places uses LIPS power supply.

1. Types of online UPS

Usually, the equipment chooses online UPS as economically as possible according to the requirements of power supply reliability, functional requirements, and ease of use. Choose different types of online UPS according to different load characteristics. Starting from practicability and convenient choice, online UPS power supplies can be divided into three categories:
Single operation, backup operation;
With bypass conversion, no bypass conversion;
Usually the inverter runs. Usually the mains is running.

2. Features of online UPS power supply

Single-operation online UPS, used for general important loads; used for loads with input, different output frequencies, or with little impact on the mains, and high frequency accuracy requirements.
Backup operation online UPS, using multiple non-power-off devices, with backup function, when part of the failure occurs, other normal parts to supply power to the load, used for particularly important loads.
There is a bypass conversion on-line UPS, and the load can be supplied by mains and inverters, which improves the reliability of power supply. Most online UPSs are bypassed.
On-line UPS without bypass conversion, used for loads with different input and output frequencies, or with extremely high requirements for mains frequency and voltage accuracy.
Normally the inverter is running, and the load has high requirements on the quality of the power supply, and it is not affected by the mains, power supply voltage and frequency.
Usually the mains operation, the load does not require high power quality, high reliability requirements, high efficiency without conversion. The three operating modes are combined and applied according to the nature of the load.