UPS refers to an uninterruptible power supply. It is a device that contains energy storage devices. It can provide continuous voltage stabilization and stable frequency AC output for electrical equipment even in the event of a power outage. It is mainly used to provide uninterrupted power supply to some devices that require high power stability. When the mains input is normal, the UPS supplies the mains with stabilized voltage to the load. At this time, the UPS is an AC-type electric voltage stabilizer, and it also charges the battery in the machine; when the mains is interrupted (accidental power failure) At that time, the UPS immediately supplies the DC power of the battery to the load through the inverter switching method to continue to supply 220V AC power to the load to maintain normal work and protect the loaded software and hardware from damage. UPS equipment usually provides protection against too high or too low voltage. According to the way of work, it is divided into three categories: online interactive ups, offline ups and online ups.
(Line interactive UPS-A series for personal computer)
The protection function of UPS is first of all to stabilize the mains power supply. The input voltage range of the UPS is relatively wide, generally from 170V to 250V, and the quality of the output power supply is quite high. The output voltage of the backup UPS is 5% ~8%, the output frequency is stable at 1Hz; online UPS output voltage is stable within 3%, the output frequency is stable at 0.5Hz. When the mains power supply is normal, the UPS power supply is equivalent to an AC mains voltage stabilizer; at the same time, the mains power charging the battery is also equivalent to a charger. In the case of a sudden power failure, the UPS automatically switches to the battery power supply to keep the computer working normally and protect the hardware and software from damage. In the case of externally disconnecting the power supply system, power is immediately supplied to the computer and other machinery and equipment to prevent the interruption of communication interruption, the loss of key data information, and the destruction of the hardware configuration.
Online interactive UPS: also known as interactive UPS, with basic filtering function, strong anti-mains interference ability, the conversion time is less than 4ms, the inverter output is an analog sine wave, the price is much less than online; The power is supplied to the load. When the mains power is low or high, it is output after being stabilized by the internal voltage stabilizing line of the UPS. When the mains power is abnormal or blackouts, it is transferred to the battery inverter power supply through the transfer switch. It has a wide input voltage range, low noise, and small size, but it also has a switching time.
Online interactive UPS is a UPS device between the working mode of backup UPS and online UPS. It combines the advantages of the high efficiency of backup UPS and high power supply quality of online UPS. The circuit of online interactive UPS is simple, low cost, high reliability, efficiency can be as high as 95% or more, the overload capacity is strong, when the city power supply, the overload capacity can reach 200%.
Online UPS: When the mains power supply is normal, the mains power supplies rectifiers to provide DC voltage to the inverter, and the inverter supplies AC power to the load. When the mains power supply is abnormal, the inverter supplies energy from the battery. It is always in a working state to ensure uninterrupted output. It is characterized by an extremely wide input voltage range, no switching time, and high output voltage stability and accuracy. It is particularly suitable for occasions with higher power requirements, but the cost is higher. At present, almost all UPS with a power greater than 3KVA are online UPS.
With an inductive load, the loading rate cannot exceed 0.5 (weak inductance), and cannot exceed 0.35 for a strongly inductive load. The structure is complicated, the use performance is sound, it can continuously output pure sine wave AC power, and can handle all power problems such as spikes, surges, frequency drift, etc.; the price is high, and it is generally used in important electronic computers and network equipment. In a strict indoor environment. Reduce the number of its on and off times, and add a purification power supply at the front end. In addition to the purification function, it can also greatly buffer the impact of large current when the UPS starts, reducing the failure rate. For thyristor loads or half-wave rectification equipment, the UPS cannot be equipped with bands in principle. However, when other resistive loads are mixed and the total load factor is less than 0.5, it can be banded. In addition, if the thyristor load or half-wave rectifier equipment is connected to the front end of the UPS, it is easy to cause a large increase in the input wave distortion of the UPS and cause large noise interference (the power frequency machine has more noise, and the high-frequency machine will cause the internal relay to frequently pull in and Disconnected and prone to failure).
Offline UPS (backup UPS): When the mains power is normal, the mains power is directly supplied to the load. When the mains power exceeds its working range or power failure, it is transferred to the battery inverter power supply through the transfer switch. The structure is simple, the volume is small, and the cost is low, but the input voltage range is narrow, the output voltage stability is poor, the switching time is long, and the output waveform is generally a square wave. With basic functions such as automatic voltage stabilization and power failure protection, the conversion time is about 10ms, and the load rate is 0.4-0.6 times. No-load or greater than 0.8 load UPS output third harmonic component is large, which is not conducive to the normal operation of the computer and other loads. The back-up UPS cannot be placed behind an inductive power supply (such as a purified power supply). In principle, it should not be equipped with an inductive load (such as a motor, etc.), otherwise, it will easily cause a long switching time and cause a computer crash when the mains power fails.
If the backup UPS uninterruptible power supply can automatically discharge and the duration can be set, it is recommended that the UPS uninterruptible power supply perform a self-discharge first, which can initially determine whether the battery can discharge.
The rectifier and bypass input switch of the high-power UPS power supply are designed independently. It is recommended to close the rectifier switch to prevent the UPS from going to the bypass operation mode if the battery discharge occurs.
Before discharging, it is necessary to understand the length of time that the backup UPS power supply can last. In this way, when discharging, it can avoid downtime that constitutes a load and damage to the equipment.
It is not necessary to completely discharge the capacity of the battery when discharging the backup UPS for the first time. It only needs to be placed at 70% of the rated capacity, and the discharge only has the effect of activating the battery. Can extend the service life of UPS battery.
If you can see the condition of the UPS battery, you need to visually inspect the battery for obvious deformation and leakage damage.
When man-made discharge, need to pay attention to the UPS battery voltage drop state at any time, can be easily connected to the mains input at any time.
The offline UPS power supply generally has a small power, and is mostly used in temporary power supply, where the frequency and voltage of household personal power and personal computer host are relatively stable, and the power requirements are relatively low.
The simple way to detect whether the UPS can provide power protection to the computer is to suddenly unplug the power plug of the UPS. If the computer can continue to operate normally, the UPS is considered competent for protection. Besides, users should also pay attention to the inspection of UPS output capacity and reliability, because the performance indexes of UPS output capacity are all quantifiable reliability indexes. Under the same operating conditions, the reliability of a UPS with high efficiency, large output current peak coefficient, and strong overload capacity must be high.
UPS (online) has three basic functions: uninterrupted power supply function; voltage stabilization frequency stabilization function; city power purification function. Most people only know that UPS has an uninterruptible power supply function, but it is often overlooked that it also has a function of steady voltage regulation and mains purification. In fact, in many cases, the frequent dynamic fluctuations of voltage and frequency (especially during peak periods of electricity consumption) will cause the sensitive electronic components inside your computer or other electronic equipment to wear out more and reduce their service life. Although some electronic devices are equipped with corresponding switching power supplies, in the face of poor power grids, the actual protection effect is very limited.
In addition, many low-end electrical equipment do not have green power conditions and are still heavily used on the power grid, causing chaotic spikes, higher harmonics, and clutter noise to be fed back to the public power grid, causing secondary pollution of the power grid. The damage caused to the use of the user's computer can cause the malfunction of the internal components of the computer, cause the computer to lose data inexplicably, loss of files in disorder, and also cause the internal components of the computer to overheat and wear and accelerate aging.
Therefore, it is not to say that there is no need to configure UPS devices without frequent power outages. On the contrary, you should configure the corresponding UPS for your electronic equipment at any time.
(Super affordable line interactive UPS : Line interactive UPS S series with LCD display for personal computers & Line interactive UPS AK series for PC and peripherals)
The installation environment of the UPS power supply should avoid direct sunlight, and leave enough ventilation space to keep the temperature of the working environment not higher than 25℃. If the working environment temperature exceeds 25°C, and each temperature rise increases by 10°C, the battery life will be shortened by about half.
Strictly follow the correct startup and shutdown sequence to avoid large fluctuations in the voltage output of the UPS power supply when the load suddenly increases or decreases, thereby preventing the UPS power supply from working properly.
It is not suitable to use a high-power thyristor load, thyristor bridge rectifier, or half-wave rectifier load at the output of the UPS power supply. Such a load is easy to cause the final drive transistor of the inverter to be burned.
It is forbidden to turn off and turn on the UPS power frequently. Generally, after turning off the UPS power, wait at least 30 seconds before turning on the UPS power. Because the cause of high failure of a small and medium-sized UPS power supply is: users frequently turn on or shut down, UPS power supply with load for inverter power supply and bypass power supply switching period.
Perform regular maintenance work on the UPS power supply: observe the status of the work indicator, remove dust, measure the battery voltage, replace the unqualified battery, check the fan operation and detect and adjust the UPS system parameters.
UPS power supply is more suitable for micro-capacitive loads, but not for inductive loads, such as air conditioners, motors, electric drills, fans, etc. If the UPS power load is resistive or inductive, the load must be reduced as appropriate to avoid overload operation.
It is not possible to operate the UPS at rated power for a long time if the load rate of 60-80 is maintained. For most UPS power supplies, it is the best working method to control the load within the range of 50%~60% of rated output power.
The use of overload is prohibited. The manufacturer recommends that the maximum starting load of the UPS power supply should be controlled within 80%. If the overload is used, the inverter triode will often break down in the inverter state. Excessive light-load operation is not suitable. In this case, the battery is likely to fail due to the battery discharge current being too small.
Uninterruptible power supplies are widely used in mining, aerospace, industry, communications, national defense, hospitals, computer business terminals, network servers, network equipment, data storage equipment, emergency lighting systems, railways, shipping, transportation, power plants, substations, nuclear power plants, fire protection Security alarm system, wireless communication system, program-controlled switchboard, mobile communication, solar energy storage energy conversion equipment, control equipment, and it is emergency protection system, personal computer and other fields.