What is the difference between backup, online, and online interactive UPS?

According to the working principle of UPS uninterruptible power supply , there are backup UPS , online UPS and online interactive UPS.

Back-up UPS uninterruptible power supply. The English is Back UPS or Off-line UPS. The UPS battery is in the main machine, which is also called standard machine / standard machine. Because the battery is in the UPS main unit, the backup UPS uninterruptible power supply has a shorter load time, usually a few minutes. When the mains power fails, it usually takes a few milliseconds to switch to UPS battery power, so it is not recommended to choose a backup UPS for precision equipment.

On-line UPS: On-line UPS. The UPS battery must be configured according to the power supply time.

The main circuit architectures are: surge absorption filter circuit, AC power conversion DC power circuit (AC / DC), DC power conversion AC circuit (DC / AC), microprocessor control circuit, bypass and other five types.

How it works:

When the city power is normal, the city power passes the surge absorption filter circuit → AC power conversion to DC power circuit → DC power conversion to AC power circuit → and converts the AC power output to supply the load, and simultaneously charges the battery;

Once the microprocessor control circuit detects the interruption of the mains power, it is immediately discharged by the battery → the DC power is converted to the AC power circuit → and the AC power output is converted to the load.

If the microprocessor control circuit detects a UPS failure, then the UPS will jump to the bypass (BYPASS) by the relay (RELAY), the mains supply the load power, and it will sound an alarm to the user.

Online interactive UPS: Line-Interactive UPS. In the circuit architecture, the more special is the bi-directional converter (BI-LATERAL CONVERTER) and the automatic voltage regulation adjustment circuit (AVR: AUTO VOLTAGE REGULATION)

Its function is: two-way converter has charger (CHARGER) and converter (DC / AC) two functions, of which the charger is similar to a fast charger, which can reduce the charging time from 7-8 hours to 2 ~ The battery can be fully charged in 4 hours, so it is more efficient than a normal charger.

In the AVR part, it is a transformer with automatic boost (BOOST) and buck (BUCK) functions. When the microprocessor detects that the voltage is low, the AVR uses the relay to automatically switch to the boost coil, and vice versa. Reach a more stable output voltage.

In principle, the main difference between a backup UPS and an online UPS is that the backup UPS only stabilizes the mains when there is mains power, the inverter does not work and is in a waiting state. When the mains is abnormal, the backup type The UPS will quickly switch to the inverter state, inverting the battery power into AC power to continue to supply power to the load, so the backup UPS will have a conversion time when it is reversed from the mains, usually less than 10ms;

The inverter is always working after the online UPS is turned on, so there is no interruption time when the mains power is abnormally transferred to the battery, that is, 0 interruption. On-line interactive UPS means that when the input mains power is normal, the UPS's inverter works in reverse to charge the battery, and when the mains power is abnormal, the inverter immediately switches to the inverter to convert the battery pack voltage to AC output. So the online interactive UPS also has conversion time.