UPS
Stands
for "Uninterruptible Power Supply." In the technology world, UPS is
more than just a brown shipping company. It is also a type of power supply that
uses battery backup to maintain power during unexpected power outages.
A typical consumer UPS is a surge protector that contains a high-capacity rechargeable battery. Smaller UPS devices look like bulky power strips, while larger ones may stand upright and look almost like small computers. Many businesses use uninterruptible power supplies to keep their equipment running in case of a power failure. While a UPS may only keep a computer running for 15 minutes after the power is lost, it is usually sufficient time to save all necessary documents and properly shut down the computer. That extra time can be invaluable to someone who is working on an important document or project that has not been recently saved.
The
working principle of uninterruptible power supply (UPS)
The working principle of UPS power supply is very simple. It is rectified by the mains, then charge the battery, and then supply power to the inverter through the battery, so as to achieve the purpose of automatically supplying power to the load after the mains is cut off.
AC-DC
Conversion: The alternating current from the grid is reduced by an
auto transformer, full-wave rectification, and filtering into a direct current
voltage, which is then supplied to the inverter circuit. The AC-DC input has a
soft start circuit, which can avoid the impact on the power grid when starting.
DC-AC Inverter Circuit: adopts high-power IGBT module full-bridge inverter circuit, which has a large power margin, and the output impedance is particularly small in the output dynamic range, and it has a fast response characteristic. Due to the use of high-frequency modulation current-limiting technology and fast short-circuit protection technology, the inverter can work safely and reliably whether it is a transient supply voltage, a load impact or a short circuit.
Control
Drive: Control drive is the core to complete the function control of the whole
machine. In addition to providing detection, protection, synchronization and
various switch and display drive signals, it also completes the control of SPWM
sinusoidal pulse width modulation, due to the use of static and dynamic dual
voltage feedback . Greatly improve the dynamic characteristics and stability of
the inverter.
UPS
power supply is divided into Backup Type and Online Type according to the
working principle
- The Backup UPS Power Supply has the most basic and important functions of UPS such as automatic voltage stabilization and power failure protection. Although there is generally a conversion time of about 10ms, the AC output of the inverter is square wave instead of sine. Wave, but due to its simple structure, low price and high reliability, it is widely used in microcomputers, peripherals, POS machines and other fields;
The working principle of backup UPS, when the power supply of the power grid is normal, one mains power supply will charge the battery through the rectifier, while the other mains power supply is initially stabilized by the automatic voltage stabilizer and absorbs part of the grid interference, and then the bypass transfer switch directly supplies Load power supply. At this time, the battery is in a state of charge until the battery is fully charged and transferred to a floating state. UPS is equivalent to a voltage stabilizer with poor voltage stabilization performance, but it only improves the fluctuation of the mains voltage range, and does not make any adjustments to "electrical pollution" such as frequency instability and waveform distortion on the grid.
When the grid voltage or grid frequency exceeds the input range of the UPS, that is, under abnormal conditions, the AC input has been cut off, the charger stops working, the battery discharges, and the inverter starts to work under the control of the control circuit. The inverter generates 220V, 50Hz alternating current. At this time, the UPS power supply system is converted to continue to supply power to the load by the inverter. The inverter of the backup UPS is always in the state of backup power supply.
- The Online UPS Power Supply structure is more complex, but its performance is perfect, and it can solve all power problems. Its distinctive feature is that it can continuously output pure sine wave AC power with zero interruption, and can solve all power problems such as spikes, surges, and frequency drift. Larger investments are usually used in critical equipment and network centers and other environments with demanding power requirements.
The working principle of online UPS, when the online UPS is normally powered by the grid, the input voltage of the grid passes through the noise filter to remove high-frequency interference from the grid, and pure AC power can be obtained, which enters the rectifier for rectification and filtering, and converts the AC power into After smoothing the DC power, it is divided into two channels, one enters the charger to charge the battery, and the other is supplied to the inverter. However, the inverter converts the DC power into 220V, 50Hz AC power for the load.
When the mains power is interrupted, the AC input has been cut off and the rectifier no longer works. At this time, the battery discharges and delivers energy to the inverter, and the inverter converts the DC power to AC power for use by the load. Therefore, for the load, although the mains power no longer exists, the load is not stopped due to the interruption of the mains and can still operate normally.
The working principle of online interleaved UPS, when the mains power is normal, the mains supply power to the load directly, when the mains power is low or high, the output is stabilized through the internal voltage stabilizing circuit of the UPS, and when the mains power is abnormal or power failure, it is passed The transfer switch is converted to battery inverter power supply. Its characteristics are: a wide input voltage range, low noise, small size, etc., but there is also a switching time, but compared with the general backup UPS, this model has a stronger protection function, and the inverter output voltage waveform is relatively large. Well, it is generally a sine wave.
