Application of the hottest UPS in Engineering

Application of ups in engineering

with the continuous development of economy, computers are widely used. Some important places, such as finance, information, communication, public equipment control, have high requirements for the reliability and stability of power supply. Industries such as VLSI manufacturing also have quite high requirements for power supply. Voltage offset, voltage waveform distortion, continuous power failure and other power quality degradation will cause serious economic losses and social impact. Most of the key equipment in the above places are powered by lips

1. Type of ups

usually, the equipment selects ups as economically as possible according to the requirements of power supply reliability, functional requirements, ease of use and so on. Select different types of UPS according to different load characteristics. From the perspective of practicality and easy selection, UPS can be divided into three categories:

single operation and backup operation

with bypass conversion and without bypass conversion

the inverter operates normally. Normal mains operation

2. UPS features

single operation UPS is used for general important loads; It is used for loads with different input and output frequencies, or with little impact on the mains power and high requirements for frequency accuracy

backup operation UPS uses multiple uninterruptible devices and has backup function. When some parts fail, other normal parts supply power to the load for particularly important loads

there is bypass conversion UPS, and the load can be powered by mains power and inverter to improve the reliability of power supply. Most ups are set with bypass

no bypass conversion UPS is used for loads with different input and output frequencies or with extremely high requirements for mains frequency and voltage accuracy

during normal operation of the inverter, the load has high requirements on the quality of the power supply and is not affected by the mains supply, power supply voltage and frequency

during normal mains operation, the load has low requirements for power quality, high requirements for reliability, and high efficiency of constant change operation. When in use, the three operation modes are combined and applied according to the load nature

3. Principle of selecting UPS for power supply system

3.1 importance of load

whether there is potential abnormality in the power supply. In principle, there is no need to set ups if there is no abnormal power supply. Whether the load is important depends on the damage of the load part caused by abnormal power supply. More and more suppliers choose PPS resin for automotive powertrain and sensors. Damage includes direct loss and indirect loss. Direct losses include defective products on the production line and the loss of important data for scientific and technological research and development. Indirect losses include the time required to restore power supply and social reputation. According to the damage size, measure the total investment of UPS system, in order to improve the reliability, whether to use UPS, whether to set backup and bypass for UPS, and determine the operation mode

3.2 influence of power quality on load

the influence of power quality on load includes: the allowable voltage drop range and duration of power supply voltage; Daily voltage distortion range and frequency accuracy. The load has a strong bearing on the power quality, which can simplify the system, improve the reliability and reduce the cost. For example, when adding bypass, the switching mode of instantaneous power failure is generally 0.02~0.2s. Daily voltage distortion, frequency accuracy is generally not a special load, and it is sufficient to operate under the mains power supply, so it is generally unnecessary to consider the impact of the power supply on the load. Computers that are sensitive to the instantaneous reduction of power supply voltage and power failure will have an impact even if the power supply voltage decreases by 10% for half a cycle. You need to provide high-quality power supply

3.3 UPS capacity selection

UPS capacity is selected according to the following factors, such as characteristics, calculated load, impulse current, peak current, overload capacity and load sudden change. The payload capacity is compensated by the following values

(1) about impulse current

calculated capacity of UPS capable of withstanding peak current = effective load capacity x impulse current (maximum)/ups rated current, which is generally 5~10 times the effective capacity

when the load is put into power supply, considerable impulse current is generated, especially for computers and peripheral equipment. During UPS power supply, in order to reduce UPS capacity, the load is put into operation in turn or UPS mains operation is selected; When the current returns below the rated current value, it will be switched to rectifier and inverter for power supply without power failure

(2) about peak current

ups that can withstand peak current

capacity = payload capacity x peak current (maximum)/ups rated current

the peak capacity is generally twice the effective capacity

for UPS with peak coefficient of more than 2.5, the peak current bearing capacity is above 250% pa, which generally does not exceed the rated capacity of ups. It can be directly used without compensation

(3) about overload

ups overload capacity is generally more than 1.1 times the effective load, and UPS should be protected if the load overload exceeds 1.1 times

(4) load mutation

most UPS load mutations are within 0 "100%, and the output voltage fluctuation can be controlled within u 10%l~a. therefore, the effective load capacity can not be compensated.

(5) Generator UPS cooperates with

in some places, UPS is converted to self-contained generator for power supply after mains power failure. When the self-contained generator supplies power, it shall be able to provide large impulse current during UPS startup without affecting the operation of the generator

a. select ups with low starting current of rectifier equipment. For example, 12 pulse rectifier, the capacity of self-contained generator should be twice that of rectifier

b. select several groups of ups in parallel and start them in groups with delay. It can be combined with the ramp start function to avoid excessive impulse current caused by the simultaneous start of all ups

c. select the ups with controllable input power of rectifier charger, so that the rectifier charger can input part of the power, and the insufficient power is provided by the battery

d. select the ups with the function of limiting charging current. When starting the generator, limit the charging and set the charging current value to 0 a. That is, the charging can be stopped when the generator is running, so as to reduce the power absorbed by UPS from the generator

4. UPS application example

Figure 1 is normally powered by mains power and automatically switched to battery power in case of mains power failure. It is used for different input and output frequencies, without bypass power supply

Figure 1 single operation UPS without bypass (maintenance bypass) inverter operation

Figure 2 is normally powered by rectifier and inverter module. If the main power supply fails, the load will be continuously switched to be powered by the battery. Only when the inverter fails or the battery discharge ends, the load will be switched to the side to supply more power for the acquisition actions among enterprises entering the new material industry

Figure 2 single UPS has the company's combination of small high-power engine static switch (automatic bypass) and manual bypass (maintenance bypass) inverter operation on the basis of corresponding lightweight technology. Figure 3: if the normal bypass power supply is within the allowable range, the power supply is used to improve efficiency. If the bypass power supply is out of range, the system will automatically switch to the rectifier and inverter module for power supply. If the above two power supplies are out of range, it will switch to battery power supply

Figure 3 single UPS has bypass switch (automatic bypass), manual bypass (maintenance bypass) bypass operation

Figure 4: each UPS has the same capacity and equally shares the same load, and the load power is less than or equal to the rated power of a single ups. If one UPS fails, the other can continue to supply power to all loads. Redundant parallel UPS increases the power supply reliability of the whole UPS system

Figure 4 dual redundant direct parallel UPS

Figure 5: the parallel UPS system is bypassed by the same single machine and public external manual maintenance. This parallel connection is to increase the total capacity of ups and provide redundant configuration. For example, three ups with the same capacity are connected in parallel. If one fails, the other two UPS can supply power to all loads. It can have 1/3 redundancy

Figure 5 capacity increase and parallel connection UPS

Figure 6: one UPS is used as the backup of another ups. If the main UPS fails, the static switch will transfer the load to the standby ups to provide high reliability of power supply

Figure 6 hot backup redundant ups

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