Analysis of the main difference between UPS and EPS power supply

UPS is the abbreviation of UninterruptiblePowerSupply, which is what we often call UPS uninterruptible power supply. The common UPS power sources on the market mainly include online interactive pure online and backup.

EPS Emergency Power System is the abbreviation of Emergency Power Supply, which is an emergency power supply that meets the special requirements of the fire protection industry.

1. The backup UPS supplies power directly to the load from the mains when the mains supply is normal. When the mains exceeds its working range or power failure, it is converted to battery inverter power supply through the transfer switch. Its characteristics are: simple structure, small size, low cost, but the input voltage range is narrow, the output voltage is stable and accurate, there is switching time, and the output waveform is generally square wave

Second, the online interactive UPS is in the city. When the power is normal, the mains supply power directly to the load. When the mains is low or high, the output is regulated by the internal voltage regulation line of the UPS. When the mains is abnormal or the power is cut off, the inverter is turned into the battery inverter through the conversion switch. Its characteristics are: wide input voltage range, low noise, small size, etc., but there is also switching time.

Third, pure online UPS when the mains is normal, the mains is rectified to provide DC voltage to the inverter, the inverter provides AC power to the load, when the mains is abnormal, the inverter Power is supplied from the battery and the inverter is always in operation, ensuring uninterrupted output. Its characteristic is that it has an extremely wide input voltage range, basically no switching time and high output voltage stability, especially suitable for occasions with high power requirements, but the cost is high.

UPS has the functions of voltage regulation and filtering at the same time. Some UPS can be powered by the mains bypass when the fault or overload occurs.

The backup voltage output has large fluctuations. Between 170V and 260V, the high-speed relay is used to realize the conversion between the mains and the battery, and the conversion time is less than 10 milliseconds. The online type always uses the inverter circuit to work, its voltage stability is high, basically in the range of 220V±5%, there is basically no conversion time for the battery; with the mains bypass conversion using static switch, the conversion time can reach microseconds level.

EPS is somewhat similar to a backup UPS. Usually, the inverter does not work, and the battery is put into operation when the utility power is cut off. Generally, the power supply is not subjected to constant current and constant voltage processing. Contactor switching is usually used, and the switching time is 0.1 to 0.25S. The utility model has the advantages of simple structure, low cost, low energy consumption and no noise, and can be adapted to inductive, capacitive and comprehensive loads, and can realize variable frequency soft start when needed.