Uninterruptible power supply (UPS) is a system equipment that connects the battery (mostly lead-acid maintenance free battery) with the host computer, and converts the DC power into the municipal power through the module circuit such as the host inverter.It is mainly used to provide stable and uninterrupted power supply for single computer, computer network system or other power electronic equipment such as solenoid valve and pressure transmitter.
UPS is widely used in mine, aerospace, industry, communication, national defense, hospital, computer business terminal, network server, network equipment, data storage equipment, emergency lighting system, railway, shipping, transportation, power plant, substation, nuclear power station, fire safety alarm system, wireless communication system, program-controlled exchange, mobile communication, solar energy storage energyConversion equipment, control equipment and its emergency protection system, personal computer and other fields.
With the development of power system, such as power supply, frequency stabilization and so on, it has been paid more and more attention.Especially in the power grid line and power supply quality is not too high, anti-interference technology is backward, and the computer system on the power supply requirements are relatively high, the role of UPS is more obvious.
The protection function of UPS is to stabilize the power supply. The input voltage range of UPS is relatively wide, generally from 170V to 250V, while the quality of output power is quite high. The output voltage of backup UPS is 5% ~ 8%, and the output frequency is stable at 1Hz. As shown in Figure 1, the output voltage of online UPS is stable within 3%, and the output frequency is stable at 0.5Hz.When the power supply is normal, the UPS power supply is equivalent to the AC mains voltage regulator; at the same time, the utility charges the battery, which is also equivalent to the charger.In the case of sudden power failure, UPS automatically switches to the battery power supply, so that the computer can maintain normal operation and protect the software and hardware from damage.