·UPS Operation Modes

1. the normal operation mode

Uninterruptible power system theory is that when electricity supply is normal, the machine will convert AC electricity to DC, then charge the battery to prepare for the use in case of power failure; What emphasized is that an uninterruptible power supply system is not operated only when the power outage, but when the voltage is too low or too high or transient surges, etc., if it can affect the normal operation of power quality equipment, the uninterrupted power supply system will take action to provide stable and clean power to the equipment.

When the electricity supply is normal, and the power go through by the filter circuit, the same action will be took in two loops, one is through the charging circuit on the battery charge, the other is by the rectifier circuit as the inverter input, and then the conversion inverter will provide power for the load to use; Thus, on-line UPS output was completely supplied by inverter, hence no matter how is the quality of the power, stability of its output will not be affected.

2. battery operation mode

Once an exception occurs in power supply, DC stored in the battery will be converted into AC, and then the input of inverter will be changed to the supply from the battery. Inverter will continue to provide power, and the supply resistance continues to use to provide uninterrupted power supply. The source of power comes from battery, while the battery capacity is limited, hence the UPS does not like the general unlimited supply of electricity, hence no matter how large capacity uninterruptible power supply system can be, only if it’s under fully loaded state , it must have a limited time of supply. To extend the discharge time requires purchasing a long-term uninterruptible power supply system.

3. bypass operation mode

When online UPS overloads, bypass commands (manual or automatic), inverter overheats or machine fails, UPS will generally convert to bypass output from inverter output, namely directly depends on electricity supply. UPS phase of the output frequency needs is same with power frequency phase at the bypass time, so that the phase-locked synchronization technology to ensure the UPS output and electricity simultaneously. Bidirectional thyristor bypass switch in parallel work to resolve the bypass switching time, truly achieves continuous switching, control circuit complexity, the general application in the high-power UPS.

4. bypass maintenance mode

When the UPS is under maintenance, manual bypass will be done to ensure the normal supply of the load equipment, when the maintenance operation is completed, and restart the UPS to normal operation. Maintenance rate is very low, MTTR is 15 million hours which greatly increase the availability of UPS.