Normal operation methods
According to the power supply principle of UPS, when the electric power is normal, the machine will transform the AC of the electric power into DC, and then charge the battery for use during electricity interruption. Here, it should be noted that the UPS moves not just during blackout. When the voltage is too low or too high, or there is instant surge which will influence the equipment’s electricity quality of normal operation, the UPS will move, providing equipment with steady and clean electric power.

From the perspective of professionalism, the most objective and reliable method to judge whether the UPS is good or not is to measure with the test indexes.
Take the input power factor which might influence the power supply quality of the power grid for example. The rated power factor of the traditional double-transfer UPS is generally around 0.8. As a result, around 30% of the harmonic current will influence the power grid. Finally, the transformer, cable, fuse and  switch on the power grid will be heated and become fatigues. To change the situation should add the harmonic filter or change the six-pulse rectification into the 12-pulse rectification. This will cause two side effects. First, increase the cost, volume and weight of the power protection equipment, including the UPS. On the other hand, the consumption of the UPS will be increased, thus impairing its reliability.

The UPS is made up of four parts, including rectification, energy storage, inverter, and switch control. The voltage stabilization of the UPS is usually accomplished by the rectifier. The rectifier can be the silicon controlled rectifier or the high-frequency-switch rectifier. The rectifier itself can control the output range according to changes of the external power. When the external power is changed (the change meets the system requirements), the output range has a basically unchanged rectification voltage.

The UPS power test includes the static test and the dynamic test. The static test is conducted under the empty load, 50% of the rated load and 100% of the rated load to test the different phase voltage, wire voltage, empty load consumption, power factor, efficiency, output voltage waveform, distortion and output voltage frequency of the input and output terminal. The dynamic test is to test changes of the UPS output voltage waveform under sudden changes of the load to test the UPS’s dynamic characteristics and energy-feedback channel.

UPS is short for “uninterruptible power supply;” while EPS is short for “Emergency Power Supply,” which can satisfy special needs of the fire-fighting industry.
When the electric power supply is normal, the reserve UPS is directly provided by the electric power supply to the load. However, when the electric power supply exceeds its working range or there is a blackout, UPS will be replaced by battery inversion power supply via switch conversion. Characteristics of the reserve UPS include a simple structure, a small volume and a low cost, but a narrow input voltage scope, poor stability and precision of the output voltage, existence of switching period, and the output waveform as the square wave.

UPS is a widely used equipment to ensure power supply, and it plays an increasingly important role in IT industry.
With the protection of UPS, data security of computer system has been greatly improved, so UPS has been well received since it’s invented. The earliest UPS was a generator with a large flywheel, which had the disadvantage of low conversion efficiency. Later, it was replaced by diesel engine generator. At present, such a rotary power generator UPS is still used in some special fields, its capacity can be as high as 1000KVA.

Power-off protection: when the power supply provided by power grid is powered off, UPS immediately converts the DC power stored in its battery into AC power to supply the load, so as to avoid inconvenience and loss caused by power failure.
Voltage stabilization: Voltage of commercial power supply is easily affected by distance and quality of power transmission lines. User voltage near the substation is higher while the user voltage far from the substation is lower. Excessive or low voltage will affect the service quality and service life of user’s instruments and equipment, seriously, it will even damage the device and cause serious losses to user. Application of UPS system can provide stable voltage power supply for user equipment, so as to ensure the normal operation of equipment and prolong service life.

The UPS, that is, the uninterruptible power supply, is an uninterruptible power supply with a constant voltage constant frequency including an energy storage device and an inverter as a main component. Its primary role is to provide uninterrupted power to a single computer, computer network system, or other power electronics. When the mains input is normal, the UPS uninterruptible power supply will supply the load after the mains voltage is regulated. At this time, the UPS uninterruptible power supply is equivalent to an AC mains voltage regulator, and it also charges the internal battery; When the mains supply is interrupted, the UPS will immediately supply the 220V AC power to the load through the inverter conversion method, so that the load can maintain normal operation and protect the load from soft and hardware.

Distributed UPS
Distributed UPS is not installed directly on the server rack, or is installed next to the server rack, resulting in all servers connected to the UPS hardware, leaving little or no space between the hardware and the server.
1. Reliability: proximity strength
For an enterprise's IT network and power supply system, the greater the distance between the server and its associated UPS, the higher the risk to the power, such as noise interference, grounding, and/or loose wiring. Since the distributed UPS is mounted directly on or near the servo rack, the distance between them is shortened, and the probability of wiring failure along the power line link can be greatly reduced.

When choosing UPS, you need your own business needs, but also understand your own budget, set the investment capital and operating costs of the UPS system. You also need to understand the availability of UPS, then the UPS system you choose should not be those that can only tolerate a few hours of downtime. Your UPS configuration should be chosen to match your availability needs and your budget should be set based on the potential loss of data center downtime.

Does the UPS power supply have a voltage regulation function?
1. The high-grade UPS power supply will be supplied to the load after the mains voltage is regulated, which is equivalent to an AC mains voltage stabilizer. When the mains is interrupted, the UPS immediately converts the battery's power into a stable 220V through the inverter to continue to supply power to the load. Therefore, it has a voltage regulation function.

Intelligent
Through the analysis and synthesis of various types of information, the intelligent system should complete the real-time monitoring of the running UPS in addition to the normal operation of the corresponding part of the UPS, and analyze and process the important data in the circuit. If some UPS fails, it can analyze according to the test result, diagnose the fault location, and give the treatment method; take necessary emergency protection control action according to the site needs in time to prevent malfunction The expansion of the influence surface; the completion of the necessary self-maintenance, the exchange of information functions, the ability to input data to or from the networked machine at any time.