UPS power supply is an uninterruptible power supply system. Its function is to provide stable AC power to the equipment through the internal battery when the power grid is out of power or the voltage fluctuates. This power supply can ensure that the equipment continues to operate for a period of time when the power is off, so that users have time to save data and safely shut down the equipment. Therefore, UPS power supply is mainly used in the power supply guarantee of important equipment such as computers, network equipment, medical equipment, industrial production lines, etc.
In addition, UPS power supplies can also provide filtering functions to reduce harmonic interference in the power grid and improve the operating efficiency of equipment. Some high-end UPS power supplies also have intelligent management functions, which can monitor the operating status of power supply and equipment, provide energy-saving operation modes, and realize remote management and other functions.
The EPS power supply is an emergency power supply system, which is characterized by being able to automatically switch to the battery pack to provide stable DC or AC power to the equipment when the city power is cut off or abnormal. Compared with the UPS power supply, the EPS power supply is smaller in size, lighter in weight and cheaper in price, so it is widely used in some occasions that do not require long-term uninterrupted power supply.
EPS power supplies are mainly used in emergency lighting of public facilities such as lighting, signboards, billboards, automatic sprinkler systems, etc. In addition, EPS power supplies are also widely used in home decoration, providing reliable backup power for home lighting, household appliances and other equipment.
With the continuous development of science and technology, people have higher and higher requirements for power supply when using various electrical equipment. In order to meet the needs of different equipment, various types of power supplies have also emerged. Among them, UPS power supply and EPS power supply are two more common types of power supply. So, what is the difference between these two power supplies? And what are their respective application ranges? This article will introduce these issues in detail.
01 UPS Classification and Working Principle
(1) Classification of UPS
According to the working principle, it can be divided into offline and online types.
According to the power supply method, it is divided into: single-phase input and single-phase output, three-phase input and single-phase output, and three-phase input and three-phase output.
According to power, they are divided into small machines below 10kVA, medium-sized machines between 10kVA and 100kVA, and large machines above 100kVA.
According to the output waveform, it can be divided into: square wave, trapezoidal wave and sine wave.
(2) Working principle of UPS
The working principle of UPS is to use the chemical energy of the battery as backup energy. When the AC power fails, the UPS can provide power to the equipment uninterruptedly. It is generally composed of a rectifier, inverter, static switch, battery, etc.
Working principle of backup and online UPS:
1) Backup UPS (offline UPS)
When the mains power is normal, the equipment is powered directly by the mains power. When the mains power is disconnected, the equipment is powered by the battery inverter.
Its characteristics are: simple structure, small size, low cost, but narrow input voltage range, switching time, not suitable for equipment with high requirements on power quality, usually used in personal computers.
2) Online interactive UPS
When the mains is normal, the mains supplies DC power to the inverter through the rectifier, and the inverter directly provides AC power to the equipment. At the same time, the charger charges the battery to keep the battery full. The inverter is always in working state, ensuring uninterrupted output and no switching time. It is suitable for equipment with high requirements for power quality.
02 Classification and working principle of EPS
(1) Working principle of EPS
The working principle of EPS is similar to that of backup UPS, which is generally composed of charger, inverter, battery, automatic switching device and control system. It is characterized by simple structure, no noise and long life. It is suitable for inductive, capacitive and comprehensive loads.
(2) Classification of EPS
According to the load type, it can be divided into:
1) Emergency lighting type
2) Emergency lighting and power hybrid
3) Dynamics
03 The difference and application between UPS power supply and EPS power supply
(1) Differentiation between UPS and EPS by output
UPS mainly supplies power to computers and network equipment, which have a relatively low load nature. Currently, the power factor of UPS output is specified to be 0.8. EPS is mainly used for emergency power supply, and the load nature is usually inductive or capacitive. Some loads require power failure before they can be put into use, so EPS must be able to provide a large surge current, and usually require continuous power supply for more than 10 minutes at 120% load. The rated capacity of UPS is in KVA, and the rated capacity of EPS is in KW.
(2) Functional differences between UPS and EPS
EPS and UPS both have AC bypass and inverter circuits, but EPS only has continuous power supply function, and does not require high inverter switching time. Currently, most EPS also have battery cell detection function. EPS will only perform inverter output after the AC power is interrupted, and the computer utilization rate is high.
UPS generally emphasizes its three functions: frequency and voltage stabilization of the mains; power supply to equipment with extremely high switching time requirements; and purification of the mains. The dual conversion circuit power supply that focuses on rectification and inversion is not very efficient in terms of power utilization. However, UPS not only provides inversion power supply during power outages, but also provides stable power output when the mains has abnormal conditions such as large voltage deviation and surge, which is not available in EPS.
(3) Differences in application scope between UPS and EPS
EPS is mainly used for fire-fighting loads and some equipment that do not require high switching time but require continuous power supply.
UPS is mainly used for loads with high requirements on power supply quality, such as computers and digital information systems.