There is probably not a single person who has not encountered unstable operation of domestic power grids. The voltage either drops or rises, or even the electricity disappears altogether. And if this does not mean a death sentence for household appliances, then such sensitive electronics as a computer can be completely damaged by such power surges. To avoid trouble, you need to install computer UPS(uninterruptable power source).
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The need to use a UPS for a computer
The uninterruptible power supply is equipped with a special rechargeable battery, thanks to which household electrical equipment can continue to operate for some time after voltage surges or during a power outage. There are devices for different types equipment – PC, electrical equipment sensitive to voltage surges. But in this review we will only consider uninterruptible power supplies for computers. A UPS (UPS) makes it possible to correctly shut down programs and turn off the PC during a power outage, as well as protect all components of an electronic device from the negative effects of sudden power surges.
In this article we will consider the most important parameters of an uninterruptible power supply for the home in order to make right choice and buy exactly the device you need.
Main types of uninterruptible power supplies for computers
Manufacturers offer a wide variety of UPS types for the home, differing in a variety of characteristics:
- according to the principle of operation - backup (Back-UPS), line-interactive (Smart-UPS), double conversion UPS (On-Line);
- type of automatic voltage regulation;
- quality of filtering network interference;
- battery capacity;
- device response time when the voltage is turned off;
- possibility of connecting additional batteries for UPS;
- various additional functions.
Backup (Back-UPS)
A backup or offline uninterruptible power supply has the most simple design and the following operating principle:
- when there is voltage in the network, electricity is supplied through the UPS directly to the device, simultaneously recharging the battery. Electricity is not regulated, and interference is filtered at the simplest level;
- When there is a power outage, the uninterruptible power supply switches the PC to battery power. The inverter, which converts direct current into alternating current, installed in devices of this type is the simplest, and therefore the signal shape does not correspond to the correct sine wave;
- The uninterruptible power supply also comes into operation when the voltage thresholds set by manufacturers depending on the device model change;
- The turn-on time of the UPS is 5÷20 ms, which is quite a lot since in some models such a delay can negatively affect the functioning of the device.
The advantages of offline models include low cost, quiet operation and a fairly high level of efficiency. Among the shortcomings are the duration of the transition to offline mode, a non-sinusoidal output signal, insufficient filtering of noise and pulses, as well as the lack of voltage and frequency adjustment when operating from the mains.
Reasons to buy a line-interactive UPS for your computer
This type of UPS is the most popular among users due to the optimal combination of price and functionality. In his schematic diagram There is automatic input voltage regulation - AVR. At a normal voltage value when operating from the mains, the uninterruptible power supply passes the incoming signal through passive filters, and at the same time the batteries are charged.
When the permissible voltage values increase or decrease, the UPS switches the computer to battery operation. When the UPS battery is 70% charged and the voltage is 160 V, the device will go into offline mode, and at 30% charge and the voltage is 150 V, adjustment will be made via the AVR.
Some linear-interactive models of uninterruptible power supply systems are practically no different in output signal from offline-type devices with a stepped sinusoidal shape. Devices such as Smart-UPS switch the computer to battery power much faster than standby UPSs.
The advantages of linear-interactive uninterruptible power supply systems are:
- affordable price;
- quiet operation of the device;
- automatic voltage regulation;
- quickly switching devices from the network to the battery - on average the time is 2÷8 ms.
The disadvantages include the lack of frequency regulation, still insufficient filtering of various interferences and non-smooth voltage regulation, low efficiency in comparison with offline UPSs.
Double conversion uninterruptible power supply (On-Line)
This type of UPS is a professional, most reliable and expensive device, which is perfect for ultra-sensitive equipment. Models of this type operate on the principle of double conversion of input electricity - first into direct current, and then into alternating current. As a result, the efficiency of the device increases to 95%, and noise and interference completely disappear due to double conversion.
Since the On-Line uninterruptible power supply device for a private home works almost constantly, it can, if necessary, instantly switch the operation of the computer from the mains to batteries, since the power is supplied through a rectifier, a battery (during charging) and an inverter. The double conversion UPS can also operate in bypass mode. This is a spare line running directly from the input to the output of the uninterruptible power supply, bypassing the rectifier, batteries and inverter. Such a system makes it possible in an emergency (for the device) situation to supply voltage to the PC directly.
The advantages of an uninterruptible power supply with double conversion are as follows:
- continuous ;
- effective filtering of all kinds of interference;
- pure sine wave output and instant transition to battery operation.
The disadvantages include:
- high price;
- the lowest efficiency among all types of UPS, however, there are exceptions and therefore, when purchasing, you should carefully study the instructions;
- Due to constant operation, the UPS generates a lot of heat, which requires effective cooling, which means that the device does not operate very quietly, unlike other types of uninterruptible power supplies.
How to choose a UPS for a computer based on its main characteristics
In order to choose a good uninterruptible power supply for computers, you need to know the basic characteristics of the device. Among the most important parameters are:
- power;
- battery life;
- software;
- controls;
- types and number of connectors.
Before choosing an effective uninterruptible power supply for your equipment, you need to carefully study all the technical characteristics of the device in order to purchase the necessary model.
How to choose a UPS for a computer based on device power
To ensure uninterrupted power supply for your home, you need to take into account one of the most important parameters - the maximum power of the equipment that can be connected to the UPS. If the maximum value of the connected equipment is higher than the maximum power of the uninterruptible power supply, the device will simply fail. To choose an uninterruptible power supply that is ideal for your equipment, you need to calculate its power in advance, which can be done using the formula below.
WUPS = WPC(or the sum of the power of all equipment)/0.6 × 1.4 , Where
- 0,6 – coefficient of load conversion from W to VA (Volt-ampere);
- 1,4 – power safety factor for UPS.
Battery life
This characteristic directly depends on the capacity of the battery with which the UPS is equipped. Most models of uninterruptible power supplies can operate in autonomous mode for 4÷8 minutes. This time is enough for the system to be able to correctly close all programs, save edited documents and turn off the computer.
Some UPS models are able to work after a power outage for about 15–20 minutes. However similar devices Naturally, they are much more expensive than their other counterparts due to the high-capacity battery. Such uninterruptible power supplies are especially good if several types of household appliances are connected to them.
Software
Since some UPS systems must not only connect to the power grid and PC, but also be able to “communicate” with the computer OS in order to issue commands, receive the necessary data and monitor the operation of the device. For this purpose, manufacturers equip all UPS models with special software.
Before you buy a UPS for your home, you need to make sure that it is compatible with your computer’s operating system, and that it can be connected via the Internet, USB or COM ports. If the network voltage is lost in the absence of a user, then thanks to a special software Uninterruptible power supply will allow you to correctly close running programs and turn off your PC.
Controls
In addition to the audible alarm, which informs the user that the UPS has switched to autonomous operation mode during a power outage and LED indicators some advanced models are equipped with LCD displays by the manufacturer. These small screens reflect almost all information about the operation and status of the uninterruptible power supply. Through the display, the user has the opportunity to set a specific operating mode for his equipment.
Types and number of connectors
As a rule, UPSs for PCs are equipped with sockets that are protected from both power outages and power surges. When choosing an uninterruptible power supply, you should take into account the number of both types of connectors, since most likely you will need at least two protected from power outages in the electrical network.
Budget UPSs are equipped with 1-2 connectors for connecting external devices - a system unit and a monitor. In more expensive models, manufacturers install more, as well as USB or RJ-45 connectors.
How not to make a mistake when choosing a UPS for your computer
We have already briefly reviewed the main characteristics of an uninterruptible power supply. Let's look at some more device parameters that you need to pay attention to when choosing an uninterruptible power supply for your home in case of a power outage.
Selection by power
As already mentioned, the most important parameter of a UPS is its power. However, in order to buy a device that will save your household appliances from troubles associated with power outages and voltage surges, you also need to know the power of the connected equipment, in our case, the system unit and monitor.
Determining the power of a monitor is not difficult, since it is usually indicated on the device body. The situation is worse with the system unit, since determining the load value without special devices pretty hard. Typically, the power of the system unit is 2-3 times less than the value indicated on the case pulse block nutrition. Therefore, when assembling a PC, as a rule, they are guided by the maximum power consumption.
Advice! When purchasing a UPS, it is advisable to choose a device with a power reserve of approximately 20% greater than the total power of the connected equipment.
By connection type
Uninterruptible power supplies also differ in their input and output connections.
Input Connection Types
A UPS intended for use at home, in the office and in server rooms, with low and medium power up to 2 KVA, is characterized by the presence of an IEC-320 C13 connector, the same as on PC power supplies. Some consumer computer models have a built-in power cable. Uninterruptible power supply units with a power of 2÷5 kVA are equipped with an IEC-320 C19 connector, which differs from the previous one in the presence of contacts rated for 16A and in shape. UPS with a power of 5 kVA or more uses rigid mounting and ground connection.
Output Connection Types
In low-power uninterruptible power supplies for home use, Schuko CEE 7 type F output connectors for a Euro plug are usually used. In office devices, sockets of the IEC-320 C13 type are often used, and in UPSs for server rooms, IEC-320 C13 and IEC-320 C19 are installed simultaneously. Single and multi-rack systems are equipped with three-phase connectors for hard wiring.
By input voltage range
Before you go to the store to buy a UPS for your computer, you need to assess the quality of the household electrical network - interference, voltage surges, frequency of complete power outages, etc. Based on these data, the range of operating input voltage and the operating time of the equipment in offline mode are determined.
The input voltage range determines the acceptable values within which the uninterruptible power supply can supply stable voltage to the connected equipment without using the battery. Standby UPSs have a small range - approximately 190÷260 V, while inverter and interactive ones have a much wider range. Some uninterruptible power supply models provide the ability to manually adjust the input voltage limits.
Leading manufacturers of UPS for computers
After you have considered the main characteristics that you will focus on when choosing an uninterruptible power supply, it is worth familiarizing yourself with the leaders in the production of these devices.
APC
Over the four decades of its existence, this American company has become an industry benchmark in the field of highly reliable IT infrastructure and power supplies. The innovative solutions created by the company throughout its existence have brought it popularity all over the world. They are currently used in infrastructure solutions and for data management and protection around the world.
In 2007, the company merged with the European transnational corporation Schneider Electric, which is known for its solutions in the field of automation and energy management. This move led to the creation of critical power and cooling systems that this moment are produced under the APC and MGE UPS Systems brands.
Powercom
The company was founded in 1987 and has production in the USA, Germany, China and Taiwan. Powercom specializes in the development of power protection systems for residential and corporate use. For quite short term the company has become one of the industry leaders and introduced a wide range of uninterruptible power supplies to the market.
All the company's products are of high quality and have almost American and European certificates of quality and safety.
IPPON
The brand is one of the most popular in Russia. The company was founded in 2001 in Hong Kong and the purpose of its creation was high-quality protection personal computers. The brand's product line includes 25 UPS models of various types.
When creating their models, the company's developers focus on the use of inexpensive but durable materials. The brand's products meet all quality and safety requirements and meet the needs of consumers. In addition, IPPON's product range includes accessories and additional batteries for uninterruptible power supplies, surge protectors, chargers and adapters for laptop PCs and much more.
INELT
A Russian company that was founded in 2002 and produces reliable uninterruptible power supplies for PCs, boilers and various household appliances. Container power plants, diesel generator sets, energy complexes and UPSs are produced under this brand.
The products of this domestic manufacturer are very popular among consumers, thanks to high quality offered equipment and optimal price-quality ratio.
Rating of the best UPS models for a computer
Uninterruptible power supplies are a necessary device for PCs and household appliances, especially if your place of residence experiences frequent power outages or power surges. When choosing a UPS you should focus on:
- stability of work;
- durability and ease of use;
- power;
- noiselessness;
- dimensions and weight of equipment;
- value for money;
- manufacturer.
Based on these parameters, a rating of uninterruptible power supplies for personal computers has been compiled, which will help when choosing this equipment.
Powercom IMD-1025AP
Interactive uninterruptible power supply with an output power of 615 W, which is enough to shut down the computer and peripherals within 4 minutes in the event of a power outage. The model is equipped with a built-in LCD display that optimizes the operation of the device and facilitates its setup. The UPS has an optimal price/quality ratio.
- output power;
- LCD display;
- USB port;
- a sufficient number of connectors;
- easy setup.
Flaws:
- dimensions;
- loud signals;
- output sockets are computer only.
Review effects710 Ukraine, Nikopol: Uninterruptible power supply Powercom IMD-1025AP LCD - came to the rescue more than once
Advantages: long operating time without electricity
Disadvantages: insufficient equipment
I'll start, as always, with the good. Since I live in the private sector, a UPS is simply a necessity, since we often have power outages and fluctuations. After purchasing the IMD-1025AP, the voltage dropped several times and the computer continued to work. For me, this is a big plus since I spend almost all my free time right at the computer. On the back there are 6 outputs 4 with protection against overload, undervoltage and lack of voltage 2 with overload protection and 1 input is also for phone and USB and I don’t know why but there is also a coaxial one.
More details on Otzovik: http://otzovik.com/review_718409.html
APC Back-UPS 1100VA
Just like the previous model, this device is quite reliable and durable. Despite the higher cost than its predecessor in this rating, the APC Back-UPS 1100VA is not equipped with an LCD display, making it more difficult to control the operation of the equipment.
However, the presence of 4 connectors supplying battery power to the PC and peripherals distinguishes this model from its competitors. The power of the device is 660 W, which classifies it as an interactive type model and makes equipment protection from power surges more reliable.
It will take about 8 hours to fully charge the batteries, which, you must admit, is not very fast and does not satisfy some users.
The advantages include:
- price;
- output power;
- USB port;
- number of Euro output connectors.
- long battery charging;
- no display.
Ippon Back Basic 1050 IEC
Although this model does not have a large number of connectors, this is compensated by a power of 600 W, which allows you to correctly shut down the computer and turn off the computer in the event of a power outage or power surges. The Ippon Back Basic 1050 IEC also does not have a display, and information about the operation of the device is displayed via.
The time to fully charge the batteries is 6 hours, which is not bad at all, especially considering that this model is still in an affordable price segment. The appearance of the device does not stand out in any way, and its weight is just over 5 kilograms, which is caused by the presence of capacitive batteries that can be replaced if necessary.
This model of uninterruptible power supply has an audio alarm, an interference filter and a standard set of protective mechanisms against unpleasant surprises in the domestic power grid. According to user reviews, Ippon Back Basic 1050 IEC is characterized as a worthy uninterruptible power supply.
APC Back-UPS 650VA
The model is an interactive device, but its output power is only 390 W, and there are 3 output connectors. However, these sockets are of the EURO type, which allows you to connect not only a computer to the UPS, but also other household appliances that are sensitive to voltage surges.
A full eight-hour battery charge and the absence of an LCD display complicates the user's work with the device. The cost of an uninterruptible power supply does not correspond to such low characteristics, which is also a disadvantage. However, all the disadvantages are compensated by the high reliability of the model, which provided the APC Back-UPS 650VA with a fairly long service life.
Equipment advantages:
- compactness;
- reliability;
- USB port and EURO output connectors;
- noiselessness.
The disadvantages include:
- low power output;
- insufficient number of outlets;
- lack of LCD display;
- price;
- charging duration.
Cyber Power UT650EI
Interactive UPS model with 4 computer output connectors that supply battery power to connected equipment. The output power is 360 W, which gives a battery life of about 3.5 minutes. This uninterruptible power supply is not equipped with a USB port, which eliminates the possibility of connecting a PC to monitor the equipment status. The cost of the equipment corresponds to its functionality.
- affordable price;
- device reliability;
- sufficient battery life;
- number of output connectors.
- low power output;
- computer output connectors only;
- lack of display and USB connector.
Review by dagonmama Russia, Barnaul: Uninterruptible power supply CyberPower Value 800EI - A necessary thing
Pros: Good battery
Disadvantages: loud
In general, “uninterruptible power supply” is very useful thing, and even more so if where you live or work there are often problems with electricity! In my area where I live, you simply can’t do without such a thing, because there are often problems with electricity, and sometimes you’re working on the computer and everything suddenly goes out, it’s a shame! Therefore, I purchased for myself a CyberPower Value 800EI uninterruptible power supply.
More details on Otzovik: http://otzovik.com/review_2458194.html
How and where to buy a UPS?
Exists a large number of electronics stores where you can buy uninterruptible power supplies. However, in our age of technology, more and more users prefer to make purchases in online stores, where the price of UPS for computers is usually lower than in traditional retail outlets. The table shows the already listed models and their average cost, as well as the main online catalogs where they can be purchased.
| Photo | Manufacturer/Model | Average price (as of December 2017), rub | Where can I buy |
 | Powercom/ IMD-1025AP | 10 500 | http://www.e-katalog.ru/list/178/ |
 | APC/Back-UPS 1100VA | 12 500 | https://www.citilink.ru/catalog/computers_and_notebooks/powersafe/ups/ |
 | Ippon/ Back Basic 1050 IEC | 3 600 | https://tiu.ru/Ibp-dlya-kompyuterov.html |
 | Cyber/ Power UT650EI | 3 000 | http://www.propartner.ru/offers/ibp-dlya-kompyutera |
 | APC/Back-UPS 650VA | 6 600 | https://www.xcom-shop.ru/catalog/periferiya_i_ orgtehnika/sistemy_zaschity_pitaniya/ istochniki_bespereboynogo_pitaniya/ |
This video will help you better navigate uninterruptible power supplies and make the right choice:
Afterword
So, we looked at what a UPS for a computer is, how to choose it, what it is for, and even where to buy it. Although a UPS is not such a necessary device, it will protect your computer and household appliances from power outages and voltage surges. In principle, the decision whether or not to buy an uninterruptible power supply for your home is yours. Good luck with your choice, and may your equipment arrive safe and sound!
At the moment, it is almost impossible to imagine your life without the existence of such a brainchild of technological progress as a computer. Personal computers have changed a lot over the past twenty years, becoming much more productive and powerful. Old computers have given way to powerful new machines that can handle more work than ever before.
But no matter how powerful a personal computer is, it will still remain dependent on electricity. Since there are a number of factors that can interfere with the operation of a computer, and at the same time lead to the loss of important user data, there is a need to create uninterruptible power supplies.
If a user is working at his personal computer, and several applications are open on the desktop at once, performing a huge amount of work, then during the activity dozens of important files can be created, which will subsequently be of great importance to the user. But in the midst of work, the unexpected may happen - some kind of power failure, and the computer will turn off. Of course, many files that have a self-saving function will remain on the system and will be used by the user, but most of the data will be irretrievably destroyed.
Electrical networks cannot be called ideal. At any moment, a power failure can occur in any house, in any apartment, which will entail certain consequences. It is impossible to predict and prevent the occurrence of another failure that may cause problems with personal data user.
Uninterruptible power supply (UPS, UPS, uninterruptible power supply for computer) - very interesting device, which can prolong the operation of the computer, prevent possible breakdowns and perform “filtering” of voltage (in some cases).
Possible power problems
In order to decide for yourself whether an uninterruptible power supply is needed at all or not, you should think carefully about what power problems may occur when working on a computer:
All currently existing UPS systems for computers are divided into three groups. Uninterruptible power supply systems from different groups differ from each other in some properties, the presence or absence of certain functions, etc.
How to choose a UPS for your computer
After the user has learned about the existence of such devices and got to know them better, he may want to purchase a power supply for himself. But in order to buy, you must first carefully weigh the pros and cons" and decide whether the user really needs this device. After a positive answer, you should understand UPS better so as not to get into an unpleasant situation or waste more money than originally expected.
To choose the right model of uninterruptible power supply, you should know the main characteristics by which UPSs are distinguished. When choosing a UPS, the PC user must take into account the following characteristics:
- output power
- stated battery life
- price
- device dimensions
Most common cause The reason why users purchase uninterruptible power supplies for their personal computers is the occurrence of problems in the electrical network. In this case, most often such problems are associated with the disappearance of voltage. Also, many personal computer users purchase uninterruptible power supplies to ensure that all operations carried out while working on their PC will be completed to completion. Everyone knows that power problems can lead to damage to data stored on the computer, and in some cases, damage to the operating system. Here the problems may become more serious.
Present on the market UPS from various manufacturers. This may create difficulties, but they can be easily avoided. The fact is that this factor of great importance does not have. Almost all UPS systems for a computer with similar characteristics will cost approximately the same, even if they are made by different manufacturers. So it’s better not to create unnecessary difficulties for yourself and not pay attention to the brand of UPS. It is better to study the characteristics to find a device that will fully meet all user requirements.
The UPS should be purchased from those stores where the specified warranty will be at least one year. Also, do not forget that the cost of an uninterruptible power supply includes the price of batteries and is approximately half of the total cost. In most cases, batteries last an average of half a year, or a year at most.
Home personal computers supplied with Off-Line UPS structures, A local networks office or home scale - line-interactive UPS.
In order to select an uninterruptible power supply for your computer, you should use a special ratio: the rated load should be multiplied by 1.2.
The buyer should also pay attention to the presence of several useful parameters, which not all models have. These parameters are: “cold start” function - a function with which the uninterruptible power supply can be turned on when the mains voltage is turned off; opportunity self-replacement batteries or adding additional ones; the presence of power filters that suppress pulse surges in the electrical network.
Another important factor that a buyer should pay attention to when choosing an uninterruptible power supply is its switching time to the battery and back. It should be remembered that the lower this value, the better, since a long switching (15 ms) can cause a malfunction of the personal computer.
An example of selecting a UPS for a computer
For example, you need to protect the device, the total whose power is 440 W(implies the power of the power supply and LCD monitor). The minimum UPS power value can be taken as 630 VA.
How can we now convert active power (W) into total power (VA)?
The power of the uninterruptible power supply (VA) must be equal to the connected load(BT) and the resulting value is divided by 0.7.
It is very important to note that sellers may confuse VA and W, which may cause a discrepancy in the buyer's calculations and the seller's recommendations. If we assume that the buyer follows the lead of the seller who made such a common mistake, then he will have to be content with an uninterruptible power supply, the power of which will be significantly less than expected by about 1.4 times, which can subsequently cause problems, not to mention a spoiled mood.
conclusions
Uninterruptible power supplies are devices that can help users in their work on personal computers. In addition to the power maintenance function, some uninterruptible power supply models carry out control function monitoring voltage and preventing breakdowns. It can be stated that uninterruptible power supplies can prolong the operation of a personal computer and protect it from the adverse effects of power supply problems.
No one is immune from the unpleasant consequences of various power failures. This can happen to any user of personal computers. But problems can be eliminated by having an uninterruptible power supply, which will perform a protection function and get rid of troubles.
Choosing an uninterruptible power supply is not so difficult, but this process cannot be called definitely easy. The fact is that all the characteristics of uninterruptible power supplies are not so easy to fit in your head, and not everyone can figure it out. But in principle, if you remember the main important functions of uninterruptible power supplies, you will be able to choose a device that is suitable specifically for a specific personal computer.
Purchasing an uninterruptible power supply for your personal computer will allow the user to avoid problems that are most often associated with failures in power supply networks. If a problem occurs, the uninterruptible power supply will be able to switch to battery power, which will prolong the operation of the computer. This will allow the user avoid potential problems with data corruption or loss.
There are enough manufacturers of uninterruptible power supplies for computers, but you shouldn’t rack your brains and choose a device from a specific manufacturer from the entire expanse of the presented assortment. This does not justify the effort and nerve expended. There is no need to conduct deep comparative analysis, since essentially all UPS models that have similar characteristics cost the same and work approximately the same.
Uninterruptible power supply - irreplaceable helpers users who perform a huge amount of work and whose activities are inextricably linked with the computer. You can rely on the illusory quality of power supply networks and their uninterrupted operation, but it is better to be practical and once again play it safe.
Currently, few of us are completely satisfied with the quality of electricity in our home - probably everyone is familiar with the situation when the light in an apartment (house) suddenly disappears completely or “flashes”. As a result of such “flashing” or due to a network voltage drop, unsaved data in the computer system unit very often disappears, or even the office equipment itself breaks down, circulation pumps stop, which leads to a stop in the operation of heating boilers, etc.
No one will doubt that an uninterruptible power supply (UPS) in such situations is simply necessary, however, the correct choice of a UPS is very important, since an “uninterruptible power supply” incorrectly selected for its operating characteristics can only worsen the situation and simply lead to your household appliances are out of order.
There are three main types of UPS, therefore, when choosing one, first of all you should decide for which devices you are purchasing the UPS and from what you want to protect it. Here are the main and most common power problems:
Main types of UPS:
Off-Line UPS (aka backup, stand-by or in-line): this backup UPS is a passive uninterruptible power supply and operates according to the following scheme:
In normal mode, the power supply from such a UPS to the device is supplied from the external network through its filter; in the case when this external voltage disappears completely or the values of its parameters exceed the permissible limits, the power supply switches to autonomous mode. The supply voltage to the load in this case comes from the storage device (DC battery) through an inverter, which converts it to AC.
Due to the simplicity of the design and design, the main advantage of this type of UPS is, of course, its relatively low cost. Among the shortcomings, it is worth noting the length of time it takes to switch to power from the drive (~4 ms) and the lack of voltage and frequency stabilization in normal mode.
It is worth using a UPS of this type for backup power supply of office equipment with a relatively good external network ~ 220 V. Such “uninterruptible power supplies” help mainly against short-term power outages in the network.
UPS of the Line-Interactive type (line-interactive) - has a similar operating principle to a backup UPS, but unlike the latter, its circuit is supplemented with an external voltage stabilizer (autotransformer with switchable windings) - a booster that ensures normal power supply to the load during small voltage surges in network without switching the UPS to offline mode and a microprocessor that controls the switching of taps of this autotransformer.
This can be attributed to the advantages of the UPS, which significantly extends the service life of its batteries. To the advantages of these devices, it is also worth adding greater power compared to Off-Line UPSs - many models of this type are capable of “holding” a load of 10 kW.
However, like Off-Line UPSs, these “uninterruptible power supplies” have similar disadvantages in many respects (response time when switching to off-line mode, lack of frequency stabilization in normal mode, penetration of radio frequency and electromagnetic interference from the external network).
The use of such UPSs is advisable for protecting computer networks with unstable voltage from the consequences of frequent power outages.
On-Line UPS (on-line, double-conversion, uninterruptible power supply with double conversion of electricity) is the most “advanced” and reliable type of UPS among the listed ones, providing a high level of quality power supply to the load.
The peculiarity of its operation is the double conversion of the input voltage. The input voltage of the network is converted into DC by a rectifier and then, using an inverter, again into AC.
Electric storage energy (battery), constantly connected between the rectifier and the inverter, powering it in autonomous mode. That is, it turns out that even with significant deviations in the mains voltage parameters, such a UPS will supply the load device with pure sinusoidal stabilized voltage.
The advantages of this type of UPS are, first of all, the high reliability of their operation and good quality load power supply voltage and switching time to backup power from batteries, or rather its complete absence.
Disadvantages are the complexity of the circuit (due to the use of double voltage conversion in it) and design and, as a consequence, a slight decrease in overall efficiency. It is clear that these UPSs have a much higher cost compared to the UPS types listed above.
The use of these UPSs must be justified: most often they are used for backup power and protection of file servers, telecommunications equipment, and computer networks that have high power consumption (the power range of some models of such UPS exceeds 100 kW).
The article discusses the types of UPS, the principles of operation of the UPS, and also provides real oscillograms of the output voltages.
To begin with, some general terminology. Uninterruptible power supplies (abbreviated as UPS) are also called UPS, from the English abbreviation Uninterruptable Power Supply (uninterruptible power supply). Therefore, they say both UPS and UPS, whichever is more convenient for you. In the article I will call it this way and that way.
Why do you need a UPS (UPS)
The principle of operation of a UPS is revealed in the name - it is a source whose output there is always tension. But we are technical realists gathered here, and we understand that nothing is eternal, so below we will understand the principle of operation.
UPSs are mainly used where a power failure can cause negative consequences. For example, power supply for computers and servers, power supply for communication and signal distribution devices (routers), power supply for devices whose automatic reboot (restart) is impossible without human intervention.
How my reader modified the UPS for a strategically important system (2 servers, etc.). In addition, I improved the circuit and added the ability to use a regular car battery.
For household items, these are primarily computers and heating systems.
It should be understood that UPSs are selected for a load operating time of 10-15 minutes, rarely up to half an hour. It is assumed that during this time the power will appear, or the person (operator) will take the necessary actions (save the data, call the enterprise’s energy service, complete the technological process).
The UPS should not be considered as a backup power source. It is only an emergency source, and at best is used very rarely, for a total of no more than 10 minutes per year (several times, for a period of no more than a minute). If this time is longer, then you should think about improving the quality of the power supply.
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A backup power source can be considered those sources that can completely replace the main power supply for a long time, from several hours to several days. This may be another line (see article about), wind generator. Theoretically, a UPS can serve for these purposes, but this requires batteries of huge capacity, which will significantly affect the price of such a system.
Types of uninterruptible power supplies
Types (types) of UPS have many names, but there are still exactly three of them. Let's figure it out.
So, there are three main types of UPS:
Back UPS
Other equivalent names are Off-line UPS, Standby UPS, standby UPS. The most common UPS are used for most types of household and computer equipment.
Back simply switches the load to battery power when the input voltage goes out of range. Lower limit different models– about 180V, upper – about 250V. Transitions to the battery and back are with hysteresis. That is, for example, when decreasing, the transition to the battery will take place at 180 V or less, and back at 185 V or more. The same principle applies to all types of UPS.
Reminds me something of which disables load, but Back UPS does not disconnect, but switches on the battery, which allows it to work for some time.
Smart UPS
Other names: Line-Interactive, interactive type UPS. The principle of operation is not far removed from Back.
Smart UPS operate smarter, as the name suggests. They also additionally switch the internal autotransformer, in a sense stabilizing the input voltage. And only as a last resort do they switch to a battery.
Thus, the output voltage norm is maintained even with larger deviations at the input (150...300V). The autotransformer has several switching stages, so the Smart UPS switches the autotransformer terminals until the last moment, turning on the battery only at the last moment. This allows you to save the battery by turning it on only when there is a complete power failure.
This device resembles the stepwise switching of the windings of an autotransformer. The only difference is that when it goes beyond the operating limits, the stabilizer will be powerless, and our “clever girl” will put the battery into operation, and the power will not be lost.
Online UPS
Other names: online, double conversion uninterruptible power supply, inverter. A completely different principle of operation, for lovers of pure sine. The energy from the input is converted into direct voltage and supplied to the inverter, which generates pure sine wave. And at the same time, it maintains the battery at 100% readiness. If necessary, the inverter continues to operate in the same way, only it receives power from the battery.
Used for emergency power supply of equipment sensitive to the shape of the output voltage - for example, gas boilers, servers, professional audio-video equipment and other strategically important equipment.
There are two disadvantages of online UPS - price and efficiency. The efficiency is low, because such a UPS is constantly on, as the name suggests. Unlike the other two types.
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There are varieties of online UPS that use the so-called “end-to-end zero” to proper operation gas electric boilers. This is due to the fact that such boilers are sensitive to the presence of real zero for proper ignition.
Examining a UPS using an oscilloscope
And now - the most interesting part.
Output voltage Back UPS
I conducted a study using a Fluke 124 oscilloscope. I present and comment on the oscillograms (the shape of pulses and oscillations at the ups output) below.
What can you see from this timing diagram? Period 20ms, frequency 50Hz, amplitude 315V. It is worth noting that the phase of the sine and the generated pulses coincides, which is good. When the mains voltage fails, the UPS hesitates for 5-7 ms, and then there are pulses called “quasi-sine”. Here they are:
Back UPS. Output voltage when powered by batteries.
The oscilloscope measured the RMS voltage (root mean square), it corresponds to the norm. However, when I measured the same voltage with a multimeter, I got a value of 155 V. Why is the UPS output low voltage?
The fact is that the multimeter only measures the first harmonic with a frequency of 50 Hz. For sinus everything is smooth. But if you measure the voltage of such pulses, it is necessary to measure RMS, root mean square, otherwise the following harmonics will not be taken into account - 100, 150, 200 Hz. And they make up a significant part of the energy, up to 30%. UPS manufacturers know this feature, and in order not to bother (and not to increase the price of their products), they issue such pulses with an amplitude of about 370V to our devices.
Learn more about measuring root mean square non-sinusoidal voltage in the video:
Here is an enlarged graph, where you can see that the voltage after switching first increases for half a second to 400V, and then stabilizes:
Back UPS. Exit, duration 2 seconds
And here’s how the voltage shape changes at the Back-UPS output when switching from battery to mains power:
Back UPS, – Voltage at the UPS output when switching from battery to mains. Ups output pulse shape
The phase also does not change, everything is fine. I connected a UPS to the output, switched power modes back and forth - the starter was pulled in reliably, no problems.
The test subject was an APC Back-500-RS UPS, parameters in the photo below:
Back UPS parameters - rear panel
Smart UPS output voltage
Now, for the sake of completeness, I will give an oscillogram of the voltage at the output of the Smart UPS. The UPS Ippon Smart Power Pro 1000 was tested.
Smart UPS_Network-battery
The switching time is also insignificant for all modern equipment - less than 7 ms.
I did not smoothly change the input voltage, since there was no such goal. I believe that in this case the Smart UPS behaves exactly the same as a relay voltage stabilizer.
These studies were carried out as part of a project on an industrial refrigerator.
Domestic electricity supply is characterized by low reliability and unsatisfactory This is due to outdated electrical networks, wear and tear of equipment, low performance of energy converters, transient processes at sources and users of electricity, natural and climatic factors. In such conditions, uninterruptible power supply systems are extremely necessary to ensure the operation of consumers of both the first and other categories.
For apartment and house owners, stable operation of the electrical network is also important. Termination of work household appliances- this is not the biggest of troubles. Much more important is the trouble-free functioning of life support systems, in particular the heating system, if it directly depends on the power supply. Uninterruptible power supply UPS (UPS) comes to the rescue - a device that protects electrical receivers from shutdowns by storing electricity in rechargeable batteries (AB) and guarantees required quality energy (CE) in autonomous and network operating modes.
Before outlining an approach to creating power supply to loads without failures, you should find out what failures can be expected from domestic power grids.
Power failures in electrical networks
Low voltage is a common occurrence in the power supply. But it is not particularly dominant over the elevated one, which is also common. At night, the voltage is stable, during the day it decreases, and in the evening, when most of the loads are turned off, it increases.
Unstable frequency is also a failure, although quite rare. When the network is heavily loaded, it can drop to 45 Hz, which leads to significant signal distortion that negatively affects the operation of the UPS. Some devices perceive a decrease in frequency as an emergency, and the battery can quickly drain.
A complete power outage is not such a rare occurrence. Electricians are not very careful with the operation of electronics and can unexpectedly cut off power to a building. A momentary power outage is enough to cause loss of information on a computer. When networks are overloaded, power outages can occur. Therefore, it is important how reliably the UPS system supplies uninterruptible power.
UPS classification
They are divided into three groups:
- Low-power UPS for connection through electrical outlets. The design can be tabletop or floor-standing, and the power ranges from 0.25 to 3 kW.
- Medium power devices - from 3 to 30 kW - contain a block of sockets built inside, or are also connected through groups of sockets in the consumer power supply network from the control panel. The devices are manufactured for placement both in offices and in separate equipped rooms.
- High power UPS - from 10 to 800 kW. Located in electrical machine rooms. They are collected in groups and create energy systems high power- up to several thousand kW.
UPS types
There are currently 4 types of UPS (UPS). The properties common to all are:
- filtering from impulses and noise;
- elimination of signal shape distortions;
- voltage stabilization (not available for all models);
- keeping the battery charged;
- When the UPS battery is low, it will first signal and then shut down the consumer.
Off-line UPS
The principle of operation of devices of this modification is to power the consumer from the existing network and instantly switch to an autonomous backup power supply when emergency situations(4-12 ms). They are simpler and cheaper than other types.
The UPS usually switches to operation from the built-in battery.
When operating from the network, the device suppresses noise with pulses and maintains the voltage at a given level. Part of the energy is spent on recharging the battery. If the network operates in a non-standard mode, the consumer switches to battery operation. Each UPS model determines in its own way the need to switch to this mode. The operating time of the battery depends on its characteristics and the power consumed by the load. If the backup power supply is discharged, a command is given to turn off the consumer. If the mains voltage reaches normal level, the UPS switches to normal mains operation mode and battery charging begins.
Linear interactive
Line interactive ups models are equipped with stabilizers that operate continuously and ensure that batteries are rarely connected.
The device interacts with the network, controlling the amplitude and shape of the network voltage.
When the voltage decreases or increases, the unit adjusts its value by switching the taps of the autotransformer. In this way its nominal value is maintained. If the parameter exceeds the permissible limits and the switching range is no longer sufficient, the UPS switches to battery backup power. The unit can be disconnected from the main power when a distorted signal is received. There are models that adjust the voltage waveform without switching to battery operation.
Ferroresonant UPS
The device contains a ferroresonant transformer, which works as a voltage stabilizer. Its advantage is the accumulation of energy in the magnetic field, which is released during switching within 8-16 ms. This period of time is enough for the UPS to enter a new operating mode.
The transformer performs additional function noise filter. Input voltage distortion does not affect the output waveform, which remains sinusoidal.
Double Conversion UPS
The double energy conversion device works on the principle of rectifying the mains voltage, and then again converting it into stabilized alternating voltage. Here a more powerful rectifier is used, which not only recharges the battery, but also supplies the inverter with a stabilized constant voltage.
From the output of the device, a stabilized alternating voltage is supplied to the load.
When double conversion is not enough to adjust the grid voltage, additional charge is supplied from the battery to the inverter. There are no switches, but the mode is already different.
If the inverter fails, it switches to operation from the mains via a bypass. Choosing a double conversion UPS for private use is irrational due to high energy losses. This type protection is used by organizations where high equipment reliability is required.
Types of systems
Uninterruptible power supply systems can be centralized or distributed. In the first case, one UPS operates for the entire building or a separate floor, which copes with all loads.
Uninterruptible power supplies include several protection devices, each of which operates on a single computer or other piece of equipment. They are quite effective.
The advantages of a distributed system are as follows:
- The UPS is selected specifically for an individual device that is the most critical or operates in harsh conditions.
- The system can be gradually expanded, starting with server protection and moving to workstations.
- Failed UPSs can be replaced with others with less important elements systems.
- The low-power UPS does not require installation and maintenance by special personnel.
- Possibility of connecting to a regular power supply via sockets.
- UPSs are used independently of each other.
Centralized uninterruptible power systems include UPS high level, which better protect equipment. Despite their high cost, overall cost savings are achieved since one device is cheaper than several. But for simple computers the system will cost more because it requires personnel to maintain it highly qualified or the services of specialized companies that install uninterruptible power supply systems and service them.
It is necessary in the following cases:
- computers are the main load on the network;
- some organizations need very reliable systems, such as banks;
- consumers vary significantly in power: computer system, communications, security system.
What to look for when choosing a UPS?
When choosing an uninterruptible power supply system, there are several important factors to consider. Let's list the main ones.
What is the equipment protected from?
First of all, it is necessary to measure the voltage in the electrical network. The minimum cycle duration will be a day. It best reflects the operation of the electrical network. If you have to work on weekends, you need to get information on a weekly cycle, during the day and night.
It is important to determine the maximum and minimum voltage, as well as the power and frequency of pulses in the network. The device can be a recorder.
The simplest way for the user is to measure the voltage, during which, in his opinion, the voltage reaches a maximum and minimum. Don't ignore weekends.
If the apartment owner has powerful equipment, it is necessary to measure the voltage in the home network when it is turned on and off. You should find out how often the power supply at home is cut off and for what reasons. It is important to have a grounding wire in the apartment. In this case, you should find out how reliably it is connected to the floor panel bus.
Type of protected equipment
A list of equipment that requires the use of a UPS is compiled. In this case, you need to know what is consumed by each. It is enough to determine its nominal value, which is in technical specifications. Some equipment sometimes consumes maximum energy that is several times its rated value. A power reserve should be set for it.
Battery life
Here it is important to determine for what period it is possible to safely save data or complete the necessary technological operations (transferring information, saving files, receiving messages).
Required Personnel
Depending on the complexity of the system, a certain staff of specialists is required to operate it. This must be clarified in order to correctly calculate all costs. The price of the protection system should not exceed 10% of the cost of the main equipment.
UPS for home
For an average cottage, a UPS (UPS) uninterruptible power supply system with a power of about 15 kW is convenient. To ensure autonomous operation for 2-3 hours, you need 4 batteries with a total capacity of 2000 Ah. They allow you to accumulate electricity of about 7 kWh.
In the house, the most important ones are the heating system and household appliances with a computer. The cost of a UPS depends on the power, number of batteries and manufacturer. For a boiler, you can purchase a source with a power of 360 W at a price of 7 thousand. For the whole house you will need a UPS power of up to 15 kW, the price of which is more than 70 thousand rubles.
In addition to the converters, batteries are needed, which need to be changed periodically. A UPS for a home costs a lot of money. Battery uninterruptible power supply systems are especially expensive.
Despite this, you can save on repairing other equipment. In addition, there is alternative options using generators. Sometimes you can get by with installing voltage stabilizers, which cope with many tasks, including correctly turning off equipment.
Modern UPSs are equipped with a clear interface. Using the display, you can monitor the operation of the system, where the main parameters are input and output voltage, power consumption, operating circuit, battery charge.
Which UPS to choose depends on the user's needs. A home computer may have enough power for the duration of its shutdown. For uninterrupted operation of the boiler for 8-9 hours, you will need a 1 kW protective device with three 65 A/h batteries.
Conclusion
The systems are designed to ensure autonomous operation of electrical appliances and electronic equipment for a short time. The main indicator is the power of the UPS and the capacity of the battery. It is advisable to choose equipment that contains a voltage stabilizer.
The operating time of the battery depends on its characteristics and the power consumed by the load. If the backup power supply is discharged, a command is given to turn off the consumer. If the mains voltage reaches a normal level, the UPS switches to normal mains operation mode and battery charging begins.