UPS power supply is a relatively common emergency power supply system. It works differently in the case of normal utility power and abnormal utility power. This paper mainly introduces four working modes of UPS power supply: normal operation, battery operation, and bypass operation. And bypass maintenance.
1.Normal operation mode
The power supply principle of the UPS power system is that when the utility power is normal, the machine converts the AC power of the mains into DC power, and then charges the battery to prepare for power interruption.
It should be emphasized that the uninterruptible power system will not work when the power is off.
If the voltage is too low or too high, an instantaneous surge, etc., which is enough to affect the power quality of the normal operation of the equipment, the UPS system is in working condition to provide stable and clean power for the load equipment.
2.Bypass operation mode
When the online UPS power supply overload, bypass command (manual or automatic), inverter overheating or machine failure, the UPS power supply generally turns the inverter output into a bypass output, that is, direct power supply from the mains.
In bypass operation, the UPS output frequency phase needs to be the same as the mains frequency phase. Therefore, the phase-locked synchronization technology is used to ensure that the UPS power output is synchronized with the mains. Bypass switch bidirectional thyristor(TRIAC) parallel working mode solves the problem of bypass switching time, truly zero time switching, and the control circuit is complex, generally applied to medium and large power UPS power supply.
If the UPS is overloaded, the load must be artificially reduced, otherwise the bypass breaker will automatically cut off the output.
3.Battery operation mode
In case of abnormal mains electricity, the direct current stored in the battery will be converted into alternating current. At this time, the input of the inverter will be supplied by the battery pack. The inverter will continue to provide power and the load will continue to use to achieve the continuous power supply function.
The power source of the UPS power system is the battery, and the battery capacity is limited.
Therefore, the UPS system will not continuously supply power like the municipal electric power. Therefore, no matter what the capacity of the uninterruptible power system, its power supply time must be limited when it is fully loaded. In order to extend the discharge time, it is necessary to buy a long-delay UPS power supply.
4.Bypass maintenance mode
When the UPS power supply is being repaired, the normal power supply of the load device is ensured by manually setting to bypass mode.
When the maintenance operation is completed, restart the UPS power supply, and the UPS power supply at this time is turned to normal operation.