Analysis of EPS power supply and UPS power supply

1 Introduction

EPS power supply and UPS power supply are increasingly used as backup power supply in society. There are many similarities between them, which can easily cause misunderstandings. Let's talk about EPS power supply and UPS power supply.

2 Basic concepts of EPS power supply and UPS power supply

EPS (Emergency Power Supply) is an emergency power supply. When the mains fails, it can continue to supply power to the load to ensure that there is no power outage to protect the safety of people's lives and property. EPS power supply can be divided into three categories according to its use: emergency lighting, power and power frequency conversion. UPS (uninterruptible power system) is an uninterruptible power supply. When the mains power is abnormal and suddenly interrupted, it can continue to supply power to the equipment for a certain period of time, giving users ample time to deal with the work. UPS can be divided into three categories according to its working principle: backup type, online type and online interactive type.

3 Uses of EPS power supply and UPS power supply

EPS power supply is widely used in the field of building electrical and emergency lighting, fire protection and other occasions that require emergency power supply. It is called an important part of the "city lifeline system". From the perspective of the use of government agencies, enterprises, institutions and civil buildings, it is far from enough to rely solely on the public power grid for power supply. An emergency power supply system EPS is required. Its importance is to ensure the provision of the required emergency power in the event of an accident, so as to effectively reduce the losses caused by power outages and provide protection for people's production and life safety. UPS is widely used in the IT industry and special precision equipment, covering all aspects from information collection, transmission, processing, storage and application. Its importance continues to increase with the increasing importance of information application.

4 Power supply mode of EPS power supply and UPS power supply

When the mains power is normal, various EPS power supplies directly provide the load with mains power through bypass. The backup UPS and online interactive UPS in the UPS power supply provide the load with adjusted and purified mains power through bypass, and the online UPS in the UPS power supply always provides the load with pure inverter AC power with the same frequency, same phase and small error as the mains power.

When the mains power is interrupted, both EPS power supply and UPS power supply provide inverter AC power to the load. In order to better protect information and equipment, the UPS power supply automatically switches to inverter power supply when the mains power is abnormal, including power surges, high voltage spikes, switching transients, power sags, electrical line noise, frequency variation, and continuous low voltage (brownout).

5 EPS power supply and UPS power supply technology

Most of the EPS power supplies for emergency lighting use the old UPS power supply technology, but when the mains power is normal, they are switched to direct bypass power supply; when the mains power is abnormal, when the UPS battery protection is activated, they can still force discharge and inverter work. Most of the power and power frequency conversion EPS directly use finished inverters as the inverter part of the EPS (connect the battery to the DC bus of the inverter). The backup, small online and online interactive UPS in the UPS power supply are constantly developing and improving in high frequency, intelligence, lightness, thinness, shortness and smallness; large UPS are constantly developing and improving in terms of higher power, N+1 redundancy and direct parallel output on the basis of high frequency and intelligence.

6 Battery Charging and Management Technology

Most EPS power supplies use the floating charging technology of the old UPS power supply, and some use chargers with fast charging time. However, due to the poor working environment of EPS power supply, it has strict requirements on battery management and is equipped with battery management and single battery testing system. UPS power supply has made great progress in charging technology. In order to further improve the battery life, advanced UPS adopts a three-stage intelligent charging technology of ABM (Advanced Battery Management), that is, charging is divided into three stages: initialization charging, floating charging and rest: the first stage is constant current equalization charging, charging the battery capacity to 90%; the second stage is floating charging, charging the battery capacity to 100%, and then stopping charging; the third stage is natural discharge, in which the battery uses its own leakage current to discharge until the specified voltage lower limit, and then repeats the above three stages. This method changes the previous method of keeping the battery in a floating charging state for 24 hours a day after being fully charged, thus extending the battery life.

7 Conclusion

With the development of society and technology, it is hoped that EPS power supply and UPS power supply can learn from each other and develop together on the basis of their own development and improvement.