Ups technical index

What is 1? UPS？

UPS is the abbreviation of uninterruptible power supply, and it is an important external device that can provide continuous, stable and uninterrupted power supply.

In principle, UPS is a kind of power electronic equipment which integrates digital and analog circuits, automatic control inverter and maintenance-free energy storage device.

Functionally, UPS can effectively purify the commercial power when it is abnormal. You can also supply power to computers and other equipment for a certain period of time when the power supply is suddenly interrupted, so that you have enough time to deal with it;

In terms of use, with the advent of the information society, UPS is widely used in all aspects from information collection, transmission, processing, storage to application, and its importance is increasing with the increasing importance of information application.

What are the types of 2.2? UPS？

UPS can be divided into three categories according to their working principles: standby, online and online interaction:

Standby UPS is the most commonly used one, which has the most basic and important functions of UPS, such as automatic voltage stabilization and power failure protection. Although the conversion time is generally around 10ms, the alternating current output by the inverter is square wave rather than sine wave, but because of its simple structure, low price and high reliability, it is widely used in microcomputer, peripherals, POS machines and other fields.

On-line UPS has complex structure, but perfect performance, which can solve all power supply problems. Its remarkable feature is that it can continuously output pure sine wave alternating current, and can solve all power supply problems such as peak, surge and frequency drift. Because of the large investment, it is usually used in key equipment, network center and other environments with strict power requirements;

[4] Compared with traditional UPS, modular UPS has many advantages and represents one of the development directions of UPS. However, at present, its cost is still high. The actual reliability of some products is not as high as the theoretical calculation value, but the safety factor has far exceeded the traditional UPS. The research on modular UPS will help to improve the reliability of modularity, thus improving customers' awareness of modular UPS and accelerating the development of modular UPS. EAST modular UPS Each module is an independent UPS, with complete and optional power sections, high efficiency and low interference, environmental protection and energy saving, and high safety factor.

3. Why should you equip yourself with UPS?

According to IDC statistics, 45% of all computer failures are caused by power problems; In China, the average number of power outages is 0.5 times/month in big cities, 2 times/month in medium cities and 4 times/month in small cities or villages. There are at least nine problems in the power grid: power failure, lightning surge, surge, frequency oscillation, voltage mutation, voltage fluctuation, frequency drift, voltage drop and pulse interference. Therefore, from the point of view of improving the quality of power supply, it is necessary to equip the computer with a UPS.

In addition, sophisticated network equipment and communication equipment are not allowed to have uninterrupted power supply. It is self-evident that the network center with the server as the core should be equipped with UPS. Even an ordinary computer, after three months of use, the value of software such as data files has exceeded the value of hardware, so it is very necessary to equip UPS to prevent data loss.

4. What kind of UPS should be equipped?

According to the situation of equipment, power environment and the purpose of power protection, appropriate UPS can be selected. For example, for low-power equipment with built-in switching power supply, standby UPS can generally be selected, and online interactive or online UPS should be selected in places with bad electricity consumption environment, while online UPS can only choose equipment that does not need sine wave alternating current for intermittent time or time.

5. What power supply UPS should be equipped with?

First, determine the power of your equipment. Generally speaking, the power of an ordinary PC or industrial computer is about 200W, that of a Mac is about 300W, and that of a server is between 300 W and 600 W. For the power values of other devices, please refer to the instruction manual of the device.

Secondly, it should be understood that there are two ways to express the rated power of UPS: apparent power (unit VA) and actual output power (unit W). This difference is caused by the existence of reactive power, and the conversion relationship between them is: apparent power * power factor = actual output power.

The power factor of standby and online interaction is between 0.5 and 0.7, and the power factor of online interaction is generally 0.8.

When the equipment is equipped with UPS, the actual output power of UPS shall prevail. Some dealers have intentionally or unintentionally confused the difference between (VA) and (W), which should attract users' attention.

6. What is the difference between "centralized" and "decentralized" UPS equipment?

If many devices need to be equipped with UPS, you can use "centralized" or "decentralized" devices:

"Centralized" means using high-power UPS to load all devices. If the equipment is far away, it needs to be wired separately. This method is often used in large data centers and control centers. Although it is easy to manage, the cost is high.

"Decentralized" configuration mode is a popular configuration mode at present, that is, equipped with appropriate UPS according to the needs of equipment. For example, for the power protection of a local area network, the server can be equipped with online UPS, and each node is equipped with backup UPS, which has low cost and high reliability.

The advantages and disadvantages of these two power supply methods are as follows:

Centralized power supply mode: convenient management, high wiring requirements, low reliability and high cost.

Decentralized power supply mode: inconvenient management, low wiring requirements, high reliability and low cost.

UPS needs more professional knowledge, please consult professionals, and they will design a reasonable configuration scheme for you.

7. Why does UPS have to buy famous brands?

The function of UPS products is to guarantee. For users, UPS is often the last line of defense to protect equipment and data security. Compared with other products, "reliability and quality" is more important to UPS, and only famous brand products can have such strength.

At present, the UPS market in China is very prosperous, and internationally renowned brands have basically entered China, such as Meilan Rilan from Europe, Exeter from the United States, APC and so on. Foreign brands have certain advantages in technology, and the price is relatively expensive. The main market share is concentrated in the medium and high-power UPS market (above 10KVA); Since 1990s, some excellent domestic brands have emerged in UPS market. With the continuous pursuit of technology and the advantages of localized production and service, they have made remarkable achievements and become the main force in the medium and small power UPS market.

8. What determines the length of 8? UPS standby time?

This is determined by the energy storage device of UPS. At present, UPS generally uses fully sealed and maintenance-free lead-acid batteries as energy storage devices. The battery capacity is reflected by the index "Ahh", which indicates the time for discharging according to the specified current. The battery with the same voltage has large ampere-hours and large capacity; A battery with the same ampere hour has a large capacity when the voltage is high. Generally, the battery capacity is based on voltage and ampere hour * * *, such as 12V/7AH, 12V/24AH, 12V/65AH,12v/kloc-0.

Generally, standby UPS has built-in 4AH or 7AH batteries, and the standby time is fixed. Online and online interactive UPS has standard models with built-in 7AH batteries and long-term models with large-capacity batteries. Users can determine the battery capacity according to the required standby time.

Battery is an important part of UPS, which occupies a large proportion of value. Its quality is directly related to the normal use of UPS, so we should carefully choose genuine batteries with quality assurance.

9. What are the precautions when using UPS?

1) The operating environment of UPS should be well ventilated to facilitate heat dissipation and keep the environment clean.

2) Do not bring inductive loads, such as money counters, fluorescent lamps, air conditioners, etc. , to avoid damage.

3) 3) The output load of UPS should be controlled at about 60% for the highest reliability.

4) The light load of UPS (such as 1000VA UPS) may cause deep discharge of the battery and reduce the service life of the battery, which should be avoided as far as possible.

5) Proper discharge helps to activate the battery. For example, if the commercial power is not used for a long time, the commercial power will be cut off artificially every three months, and UPS will be used to discharge with load, which can prolong the service life of the battery.

6) For most small UPS, turn on UPS after work, avoid starting with load when starting, and turn off UPS after work; For the UPS in the network room, since most networks work 24 hours a day, UPS must also run all the time.

7)UPS should be charged in time after discharge to avoid battery damage due to excessive self-discharge.

Working principle of PS series

High frequency advantages of 1.PS series

Firstly, the input part of PS series UPS cancels the power frequency transformer or step-down autotransformer isolated from the mains, and adopts SPWM technology to realize high frequency rectification (AC/DC). On that one hand, the allowable variation range of the commercial voltage is improve; On the other hand, the digital signal processor (DSP) is adopted in the control technology, so that the input current is sinusoidal and in phase with the mains voltage, thus realizing the high input power factor of UPS (PF≈ 1), eliminating the harmonic pollution to the mains and achieving the purpose of environmental protection. At the same time, the reactive power loss is greatly reduced, and the operation cost is obviously reduced.

Secondly, the traditional inverter output power frequency transformer is abandoned, and the high frequency transformer is used to isolate UPS from the mains, which not only has low noise, but also has high efficiency. The inverter control circuit of UPS output stage adopts sine wave direct feedback technology, which makes its adjustment speed fast and far superior to the traditional analog feedback technology. Coupled with a small output filter and SPWM modulation above 20kHz, the dynamic response of UPS is very good, and the output sine wave is very pure and smooth.

In addition, the filter protection technology with excellent performance is adopted in the inverter protection circuit, which makes the inverter not only have strong overload function, but also have strong self-protection ability; The batteries in PS series UPS are also charged by high frequency conversion. When the mains power is cut off and UPS is converted into battery to supply power to inverter, it is also realized by high-frequency conversion and voltage reduction (DC/DC).

Second, the intelligent advantages of PS series

The intelligentization of UPS includes automatic identification and control of system running state, self-diagnosis of system fault, automatic monitoring and management of storage battery, intelligent detection and display of internal information, etc.

In the aspect of system operation state identification and control, internal sensors and state logic can identify the system operation state in time, judge whether the system operation program and operation are normal, effectively prevent the harm of system misoperation to the system itself and load, and improve the reliability of UPS.

Another aspect of UPS intelligence is realized by monitoring the software running in the PC. UPS is connected with PC serial port through RS232 interface, and the monitoring software of UPS runs on PC. The PC sends the inquiry instruction regularly, and the UPS returns the operation parameter information within the specified time. Then the PC further judges the running state and specific components of UPS, issues instructions to intervene and remind maintenance personnel when necessary, and automatically stops the operation of computer or local area network before the end of UPS power supply time.

Three. Network advantages of PS series

On the basis of introducing a large number of microprocessor monitoring technologies, Stone PS series can establish two-way communication regulation and management functions between UPS and computer network, regard UPS as an independent node of WAN, install communication adapters and assign independent IP addresses to UPS. In this way, network administrators or authorized personnel can remotely monitor UPS anywhere on the network in real time just like managing computers. Through this control function, users can monitor the operating parameters of UPS in real time on the computer network terminal (such as input and output voltage, current and frequency, charging and discharging of UPS battery pack and display of voltage value, UPS output power and related fault and alarm information). In addition, users can automatically power on and off the output of UPS at regular intervals on the computer network terminal, and orderly power-off operation will ensure the safety and reliability of user software and data.

In a word, the four-channel PS series UPS adopts MOSFET and IGBT power components, which successfully realizes high frequency, miniaturization and high efficiency, and also prolongs the service life of the battery. Network intelligence technology not only provides a completely reliable network power management, but also provides the best scheme for energy saving. It can be said that Stone PS series conforms to the latest development trend of UPS technology, and it is a highly competitive product with cost performance, which will surely shine in the enterprise UPS market in China.

12. What is the capacity of the battery?

Generally speaking, the ampere-hour (C 10) of the 20-hour discharge rate represents the rated capacity of the battery, that is, it is discharged at a constant current for 20 hours at 25℃ until the termination voltage (1.75V/ cell), and 20 times of this current is the capacity of the battery, which is generally expressed by AH number. For example, 12V/ 100AH battery means that the battery can be continuously discharged at a current of 5A(0.05C) to the termination voltage 10.5V for 20 hours. In addition, it should be noted that the discharge time of the battery is not linear with the discharge current. For example, for a battery with 100AH, the discharge of current 100A cannot last 1 hour, but only lasts for several tens of minutes; However, discharging at a current of 1A will exceed 100 hours (this discharge is not recommended).

13. Can a standard UPS be directly connected to the battery to realize lasting uninterrupted power supply?

Not suitable, because the charging current of standard UPS design is small, and it is limited by heat dissipation conditions. If it is used as UPS for a long time, on the one hand, it will not achieve the purpose of use, on the other hand, it will easily have adverse effects on the use of UPS and batteries, and even damage them.

14. how to extend the power supply time of uninterruptible power supply system?

There are two ways to extend the power supply time of uninterruptible power supply system:

1. External large-capacity battery pack: The battery pack with corresponding capacity can be externally connected according to the required power supply time. However, it should be noted that this method will lead to a relatively long charging time of the battery pack, and will also increase the floor space and maintenance cost, which needs careful evaluation.

2. Buy a large-capacity uninterruptible power supply system: This method can not only reduce the maintenance cost, but also make the large-capacity uninterruptible power supply system put into operation immediately if the load equipment is expanded.

15. What are the common power problems? What are the different solutions?

There is a common misunderstanding that the commercial power we use is continuous and stable except for occasional power outages, but it is not. As a public power grid, commercial power system is connected with thousands of loads, some of which are inductive, capacitive and switching power supplies. They not only get electricity from the power grid, but also have adverse effects on the power grid itself and worsen the power supply quality of the power grid. In addition, sudden natural and man-made accidents, such as earthquake, fire, lightning strike, short circuit of power transmission and transformation system, will endanger the normal power supply, thus affecting the normal work of the load. According to the test of electric power experts, the problems that often occur in the power grid that cause interference or damage to computers and precision instruments mainly include the following:

1, power surge: the effective value of the output voltage is higher than the rated value 1 10% for one or several cycles. Surge is mainly due to the high voltage caused by the sudden unloading of large electrical equipment connected to the power grid.

2. High voltage spike: refers to the voltage with a peak value of 6000V and a duration of one ten thousandth of a second to half a cycle (10 ms), which is mainly caused by lightning strike, arc discharge, electrostatic discharge or switching operation of large electrical equipment.

3. Switching transient: refers to the pulse voltage whose peak voltage is as high as 20000V, but its duration is between one millionth of a second and one ten thousandth of a second. The main causes and possible hazards are similar to those of high voltage surge, but the solutions are different.

4. Power sag: refers to the low voltage state where the effective value of the mains voltage is between 80% and 85% of the rated value and lasts for one to several cycles. This problem may be caused by the startup of large equipment, the startup of large motor or the connection of large power transformer.

5. Electrical line noise: refers to high-frequency interference such as radio frequency interference (RFI) and electromagnetic interference (EFI), which can be caused by motor operation, relay operation, motor controller operation, broadcast emission, microwave radiation and electrical storm.

6. Frequency change: refers to the change of the mains frequency above 3Hz, which is mainly caused by the unstable operation of the emergency generator or the unstable power supply frequency.

7. Undervoltage: refers to that the effective value of the power supply voltage is lower than the rated value and lasts for a long time. The reasons include: start-up and application of large equipment, switching of main power lines, start-up of large motors, line overload, etc.

8.power fai 1: refers to the situation that power supply is interrupted for at least two cycles to several hours. The reasons are: circuit breaker tripping, power supply interruption, power grid failure, etc.

There are several different solutions to the above power supply problem, as shown in the following table.

Three UPS Solutions to Power Supply Problems

Standby Online Interaction Pure Online Surge ××/△○ High Voltage Surge×× /△○ Transient Overvoltage××/△○ Voltage Sudden Drop××/△○ Noise Interference×/△○ Frequency Drift××/△○ Low Voltage××/△○ Power supply interruption ○.

○ Represents better protection △ Represents limited or condition-based protection × Represents no protection.

16. Correct use and maintenance of UPS batteries

In the use of uninterruptible power supply system, people often think that the battery is maintenance-free, but ignore it. However, some data show that the failure or abnormal operation rate of UPS host due to battery failure is about 1/3. It can be seen that strengthening the correct use and maintenance of UPS batteries is of increasing significance for prolonging the service life of batteries and reducing the failure rate of UPS systems. In addition to choosing a regular brand battery, you should also use and maintain the battery correctly in the following aspects:

1. Maintain proper ambient temperature: ambient temperature is an important factor affecting battery life. The optimal ambient temperature required by general battery manufacturers is between 20-25℃. Although the increase of temperature improves the discharge capacity of the battery, the life of the battery is greatly shortened at the cost. According to the test, once the ambient temperature exceeds 25℃, the battery life will be shortened by half for every increase of 10℃. At present, the batteries used by UPS are generally maintenance-free sealed lead-acid batteries with a design life of 5 years, which can only be achieved in the environment required by battery manufacturers. If the specified environmental requirements are not met, the service life will vary greatly. In addition, the increase of ambient temperature will lead to the enhancement of chemical activity inside the battery, which will generate a lot of heat energy, and then promote the increase of ambient temperature. This vicious cycle will accelerate the shortening of battery life.

2. Periodic charging and discharging: The floating charging voltage and discharging voltage in UPS power supply have been debugged to the rated value at the factory, and the discharging current increases with the increase of load. In use, we should reasonably adjust the load, such as controlling the number of electronic equipment such as microcomputers. In general, the load should not exceed 60% of the rated load of UPS. In this range, the discharge current of the battery will not be over-discharged.

Because UPS is connected to the commercial power for a long time, the battery will be in a floating state for a long time under the use environment of high power supply quality and less power failure of the commercial power, which will reduce the activity of mutual conversion between chemical energy and electric energy, accelerate aging and shorten service life. Therefore, it should be completely discharged every 2-3 months, and the discharge time can be determined according to the capacity and load of the battery. After full-load discharge, charge it for more than 8 hours as needed.

Third, the use of communication function: At present, most large and medium-sized UPS have operability such as communication with microcomputer and program control. Install the corresponding software on the microcomputer, connect UPS through serial port/parallel port, and run the program to make the microcomputer communicate with UPS. Generally, it has the functions of information inquiry, parameter setting, timing setting, automatic shutdown, alarm and so on. Through information inquiry, we can get information such as mains input voltage, UPS output voltage, load utilization rate, battery capacity utilization rate, internal temperature, mains frequency and so on. By setting the parameters, you can set the basic characteristics of UPS, battery life and battery exhaustion alarm. Through these intelligent operations, the use and management of UPS power supply and its storage battery are greatly facilitated.

Classification of uninterruptible power supply

As an important peripheral of computer, UPS has developed from a single function of providing backup time at first to a dual function of providing backup time and improving power grid quality today, which plays an important role in protecting computer data, improving power grid quality, and preventing power outages and power grid pollution from harming users. At present, there are many kinds of UPS brands in the market, but they can be classified from five aspects: circuit main structure, backup time, input and output mode, output waveform and output capacity, among which the classification from circuit main structure is the most accepted at present.

In the early standby UPS, when the commercial power is normal, the commercial power directly supplies power to the load through AC bypass and transfer switch. The AC bypass is equivalent to a conductor, and the inverter does not work. At this time, the power supply efficiency is high but the quality is poor. In recent years, standby UPS is often equipped with AC voltage stabilizing circuit and filter circuit to improve it. When the commercial power is abnormal (the commercial power voltage and frequency exceed the allowable input range of the standby UPS or the commercial power is interrupted), the standby UPS switches to the battery state through the changeover switch, and the inverter enters the working state, and the output waveform at this time is AC sine wave or square wave. The switching time of backup UPS is generally 4 milliseconds to 10 milliseconds, but it will not affect the work of general computer equipment. Because the output waveform of standby UPS is mostly square wave, the power supply quality is relatively poor, and it is only suitable for occasions with low requirements, and the power is generally small, mostly below 2000 watts. Backup UPS products have price advantages and are relatively cheap, which are suitable for small office enterprises and home users.

How to choose ups power supply?

UPS products are necessary equipment in the computer room of financial institutions and durable products with one-time investment. Many users lack a comprehensive and objective understanding of the nominal single index and adopted technology of UPS products. First, confirm what kind of UPS do you need? At present, there are three types of uninterruptible power supplies:

UPS products are necessary equipment in the computer room of financial institutions and durable products with one-time investment. Many users lack a comprehensive and objective understanding of the nominal single index and adopted technology of UPS products.

1. What kind of UPS do you need first? At present, there are several types of uninterruptible power supplies:

1. The standby UPS directly supplies power to the load from the mains when the mains is normal, and when the mains exceeds its working range or power is cut off, it is converted into a battery inverter power supply through the changeover switch. Its characteristics are simple structure, small volume and low cost, but the input voltage range is narrow, the output voltage stability accuracy is poor, there is switching time, and the output waveform is generally square wave.

2. When the commercial power is normal, the online UPS is rectified by the commercial power to provide DC voltage for the inverter to work, and the inverter provides AC power for the load. When the commercial power is abnormal, the inverter is powered by the battery, and the inverter is always in working state to ensure uninterrupted output. Its characteristics are extremely wide input voltage range, no switching time and high output voltage stability precision, which is especially suitable for occasions with high requirements for power supply but high cost. At present, almost all UPS with power greater than 3KVA are on-line UPS.

3. Online interactive UPS directly supplies power to the load from the mains when the mains is normal; When the commercial power is low or high, it is output after being stabilized by the internal voltage stabilizing circuit of UPS; When the commercial power is abnormal or power is cut off, it is converted into battery inverter power supply through the changeover switch. Its characteristics are: wide input voltage range, low noise, small size, but also switching time.

4.UPS can be divided into three categories according to output capacity: single-phase input/single-phase output, three-phase input/single-phase output and three-phase input/three-phase output. Single-phase electricity refers to the power supply system composed of live wire, neutral wire and ground wire; Three-phase power supply is a power supply system consisting of three live wires, a neutral wire and a ground wire, in which the voltage (line voltage) between the two live wires is 380V, while the voltage (phase voltage) between the live wire and the neutral wire is 220V V. For users, three-phase power supply is convenient to distribute power and load, and each phase bears a part of load current, so medium and large power UPS mostly adopts three-phase input/single-phase output or three-phase input/three-phase output power supply.

5. Intelligent UPS is a major development trend of UPS today. With the application of UPS in network system, network managers emphasize that the whole network system is the object of protection, hoping that when the power supply system fails, the whole network system can continue to work without interruption. Therefore, configuring microprocessor to make it intelligent is a new trend of UPS. The combination of hardware and software in UPS greatly improves the function of UPS, and can monitor the operation and working state of UPS, such as UP.

Output voltage frequency, grid voltage frequency, battery status and fault record, etc. The software can also be used to detect batteries, automatically discharge and charge, and remotely switch batteries. Network managers can analyze the power supply quality according to this information and take corresponding measures according to the actual situation. When UPS detects the interruption of power supply network, UPS will automatically switch to battery power supply. When the battery power supply capacity is insufficient, immediately notify the server to prepare for shutdown, and shut down before the battery runs out. The intelligent UPS communicates with the computer through the interface, so that the network administrator can monitor the UPS, so the function of its management software is extremely important.

Determine the power (VA) value of the UPS you need.

The equipment you protect will be marked with its power (W) value or current (A) value.

If the power (W) value ÷0.7=VA value.

Such as city current (A) value × 220 = VA value.

Add the VA values of all devices to get the total VA value, and add 20%~30% spare capacity to get the UPS VA value.

An important factor in choosing ups is the standby time and brand of ups.

UPS can be divided into standard type and long-term type according to standby time. Standby time of standard UPS is 5- 15 minutes, and standby time of long-term UPS is 1-8 hours. If your device is dead and you only need to save or exit, then choose standard UPS；; If your equipment needs to run for a long time in case of power failure, you must choose long-term UPS. If you determine the type, capacity and standby time of UPS; The next thing you need to decide is which brand of UPS to buy. The suggestion here is that you should consider the brand's popularity and after-sales guarantee terms, such as warranty period and maintenance response time.